"use strict"

// TODO: retreat withdraw co-exist with disrupted enemy - no hexside limits or control
// TODO: force withdrawal of mandatory combat during pass turn (only show end turn if not possible)

// TODO: rout during probe combat?
// TODO: allow one-hex regroup moves? (failed forced march abuse)
// TODO: rewrite regroup to group if only one hex moved (failed forced march abuse)

const max = Math.max
const min = Math.min
const abs = Math.abs

const TIMEOUT = 250

var timeout = 0

function check_timeout() {
	if (Date.now() > timeout)
		throw "TIMEOUT"
}

var states = {}
var game = null
var view = null

const {
	all_hexes, hex_exists, hex_road, side_road, side_limit, hex_name, regions,
	unit_name, unit_appearance, unit_elite, unit_class, unit_speed, unit_max_steps,
} = require("./data.js")

var after_rout_table = {
	end_battle: end_battle,
	end_refuse_battle_move_2: end_refuse_battle_move_2,
	end_retreat_2: end_retreat_2,
	goto_combat_phase: goto_combat_phase,
	goto_final_supply_check_rout: goto_final_supply_check_rout,
	goto_forced_marches_rout: goto_forced_marches_rout,
	goto_initial_supply_check_rout: goto_initial_supply_check_rout,
}

function debug_hexes3(n, list) {
	console.log("--", n, "--")
	list = list.map((x,i) => hex_exists[i] ? x : "")
	for (let y = 0; y < hexh; ++y)
		console.log("".padStart(y*2," ") + list.slice(y*hexw, (y+1)*hexw).map(x=>String(x).padStart(3, ' ')).join(" "))
}

function debug_hexes(n, list) {
	console.log("--", n, "--")
	list = list.map((x,i) => hex_exists[i] ? x : "")
	for (let y = 0; y < hexh; ++y)
		console.log("".padStart(y," ") + list.slice(y*hexw, (y+1)*hexw).map(x=>String(x).padStart(2, ' ')).join(""))
}

// === CRC32 CHECKSUM ===

const CRC32C_TABLE = new Int32Array([
	0x00000000, 0xf26b8303, 0xe13b70f7, 0x1350f3f4, 0xc79a971f, 0x35f1141c, 0x26a1e7e8, 0xd4ca64eb,
	0x8ad958cf, 0x78b2dbcc, 0x6be22838, 0x9989ab3b, 0x4d43cfd0, 0xbf284cd3, 0xac78bf27, 0x5e133c24,
	0x105ec76f, 0xe235446c, 0xf165b798, 0x030e349b, 0xd7c45070, 0x25afd373, 0x36ff2087, 0xc494a384,
	0x9a879fa0, 0x68ec1ca3, 0x7bbcef57, 0x89d76c54, 0x5d1d08bf, 0xaf768bbc, 0xbc267848, 0x4e4dfb4b,
	0x20bd8ede, 0xd2d60ddd, 0xc186fe29, 0x33ed7d2a, 0xe72719c1, 0x154c9ac2, 0x061c6936, 0xf477ea35,
	0xaa64d611, 0x580f5512, 0x4b5fa6e6, 0xb93425e5, 0x6dfe410e, 0x9f95c20d, 0x8cc531f9, 0x7eaeb2fa,
	0x30e349b1, 0xc288cab2, 0xd1d83946, 0x23b3ba45, 0xf779deae, 0x05125dad, 0x1642ae59, 0xe4292d5a,
	0xba3a117e, 0x4851927d, 0x5b016189, 0xa96ae28a, 0x7da08661, 0x8fcb0562, 0x9c9bf696, 0x6ef07595,
	0x417b1dbc, 0xb3109ebf, 0xa0406d4b, 0x522bee48, 0x86e18aa3, 0x748a09a0, 0x67dafa54, 0x95b17957,
	0xcba24573, 0x39c9c670, 0x2a993584, 0xd8f2b687, 0x0c38d26c, 0xfe53516f, 0xed03a29b, 0x1f682198,
	0x5125dad3, 0xa34e59d0, 0xb01eaa24, 0x42752927, 0x96bf4dcc, 0x64d4cecf, 0x77843d3b, 0x85efbe38,
	0xdbfc821c, 0x2997011f, 0x3ac7f2eb, 0xc8ac71e8, 0x1c661503, 0xee0d9600, 0xfd5d65f4, 0x0f36e6f7,
	0x61c69362, 0x93ad1061, 0x80fde395, 0x72966096, 0xa65c047d, 0x5437877e, 0x4767748a, 0xb50cf789,
	0xeb1fcbad, 0x197448ae, 0x0a24bb5a, 0xf84f3859, 0x2c855cb2, 0xdeeedfb1, 0xcdbe2c45, 0x3fd5af46,
	0x7198540d, 0x83f3d70e, 0x90a324fa, 0x62c8a7f9, 0xb602c312, 0x44694011, 0x5739b3e5, 0xa55230e6,
	0xfb410cc2, 0x092a8fc1, 0x1a7a7c35, 0xe811ff36, 0x3cdb9bdd, 0xceb018de, 0xdde0eb2a, 0x2f8b6829,
	0x82f63b78, 0x709db87b, 0x63cd4b8f, 0x91a6c88c, 0x456cac67, 0xb7072f64, 0xa457dc90, 0x563c5f93,
	0x082f63b7, 0xfa44e0b4, 0xe9141340, 0x1b7f9043, 0xcfb5f4a8, 0x3dde77ab, 0x2e8e845f, 0xdce5075c,
	0x92a8fc17, 0x60c37f14, 0x73938ce0, 0x81f80fe3, 0x55326b08, 0xa759e80b, 0xb4091bff, 0x466298fc,
	0x1871a4d8, 0xea1a27db, 0xf94ad42f, 0x0b21572c, 0xdfeb33c7, 0x2d80b0c4, 0x3ed04330, 0xccbbc033,
	0xa24bb5a6, 0x502036a5, 0x4370c551, 0xb11b4652, 0x65d122b9, 0x97baa1ba, 0x84ea524e, 0x7681d14d,
	0x2892ed69, 0xdaf96e6a, 0xc9a99d9e, 0x3bc21e9d, 0xef087a76, 0x1d63f975, 0x0e330a81, 0xfc588982,
	0xb21572c9, 0x407ef1ca, 0x532e023e, 0xa145813d, 0x758fe5d6, 0x87e466d5, 0x94b49521, 0x66df1622,
	0x38cc2a06, 0xcaa7a905, 0xd9f75af1, 0x2b9cd9f2, 0xff56bd19, 0x0d3d3e1a, 0x1e6dcdee, 0xec064eed,
	0xc38d26c4, 0x31e6a5c7, 0x22b65633, 0xd0ddd530, 0x0417b1db, 0xf67c32d8, 0xe52cc12c, 0x1747422f,
	0x49547e0b, 0xbb3ffd08, 0xa86f0efc, 0x5a048dff, 0x8ecee914, 0x7ca56a17, 0x6ff599e3, 0x9d9e1ae0,
	0xd3d3e1ab, 0x21b862a8, 0x32e8915c, 0xc083125f, 0x144976b4, 0xe622f5b7, 0xf5720643, 0x07198540,
	0x590ab964, 0xab613a67, 0xb831c993, 0x4a5a4a90, 0x9e902e7b, 0x6cfbad78, 0x7fab5e8c, 0x8dc0dd8f,
	0xe330a81a, 0x115b2b19, 0x020bd8ed, 0xf0605bee, 0x24aa3f05, 0xd6c1bc06, 0xc5914ff2, 0x37faccf1,
	0x69e9f0d5, 0x9b8273d6, 0x88d28022, 0x7ab90321, 0xae7367ca, 0x5c18e4c9, 0x4f48173d, 0xbd23943e,
	0xf36e6f75, 0x0105ec76, 0x12551f82, 0xe03e9c81, 0x34f4f86a, 0xc69f7b69, 0xd5cf889d, 0x27a40b9e,
	0x79b737ba, 0x8bdcb4b9, 0x988c474d, 0x6ae7c44e, 0xbe2da0a5, 0x4c4623a6, 0x5f16d052, 0xad7d5351
])

// fast with unlikely collisions
function supply_memo_idx_crc32c(data, tail1, tail2) {
	var x = 0
	for (var i = 0, n = data.length; i < n; ++i)
		x = CRC32C_TABLE[(x ^ data[i]) & 0xff] ^ (x >>> 8)
	x = CRC32C_TABLE[(x ^ tail1) & 0xff] ^ (x >>> 8)
	x = CRC32C_TABLE[(x ^ tail2) & 0xff] ^ (x >>> 8)
	return x
}

// slow but guaranteed no collisions
function supply_memo_idx_slow(data, tail1, tail2) {
	var x = 0n
	for (var i = 0, n = data.length; i < n; ++i)
		x = (x << 8n) | BigInt(data[i])
	x = (x << 8n) | BigInt(tail1)
	x = (x << 8n) | BigInt(tail2)
	return x
}

// === CONSTS ===

const AXIS = 'Axis'
const ALLIED = 'Allied'

const REAL = 0
const DUMMY = 1

const hexw = 25
const hexh = 9
const first_hex = 7
const last_hex = 215
const hexdeploy = hexw * hexh
const hexnext = [ 1, hexw, hexw-1, -1, -hexw, -(hexw-1) ]
const hexcount = last_hex + 1
const sidecount = hexcount * 3

const class_name = [ "armor", "infantry", "anti-tank", "artillery" ]
const class_name_cap = [ "Armor", "Infantry", "Anti-tank", "Artillery" ]
const firepower_name = [ "0", "1", "2", "3", "TF", "DF", "SF" ]
const speed_name = [ "zero", "leg", "motorized", "mechanized", "recon" ]
const speed_name_cap = [ "Zero", "Leg", "Motorized", "Mechanized", "Recon" ]

const die_face_hit = [ 0, '\u2776', '\u2777', '\u2778', '\u2779', '\u277A', '\u277B' ]
const die_face_miss = [ 0, '\u2460', '\u2461', '\u2462', '\u2463', '\u2464', '\u2465' ]

const month_names_1940 = [ "",
	"September 1940",
	"October 1940",
	"November 1940",
	"December 1940",
	"January 1940",
	"February 1940",
]

const month_names = [ "",
	"April 1941",
	"May 1941",
	"June 1941",
	"July 1941",
	"August 1941",
	"September 1941",
	"October 1941",
	"November 1941",
	"December 1941",
	"January 1942",
	"February 1942",
	"March 1942",
	"April 1942",
	"May 1942",
	"June 1942",
	"July 1942",
	"August 1942",
	"September 1942",
	"October 1942",
	"November 1942",
]

function current_month_name() {
	if (game.scenario === "1940")
		return month_names_1940[game.month]
	else
		return month_names[game.month]
}

const SF = 6
const DF = 5
const TF = 4

const ARMOR = 0
const INFANTRY = 1
const ANTITANK = 2
const ARTILLERY = 3

const TRAIL = 1
const TRACK = 2
const HIGHWAY = 4

const FIREPOWER_MATRIX = [
	[ SF, DF, SF, TF ],
	[ SF, SF, DF, TF ],
	[ DF, SF, SF, TF ],
	[ SF, DF, DF, SF ],
]

// Off board return to refit holding
const AXIS_REFIT = 102
const ALLIED_REFIT = 48

// Off board reinforcements to engaged base!
const AXIS_QUEUE = 127
const ALLIED_QUEUE = 49

// Free deployment holding box
const DEPLOY = 1
const ELIMINATED = 2

// Off board optional 1942 Malta reinforcements
const MALTA = 4

const EL_AGHEILA = 151
const ALEXANDRIA = 74
const BENGHAZI = 54
const TOBRUK = 37
const BARDIA = 40
const MERSA_BREGA = 152
const JALO_OASIS = 204
const JARABUB_OASIS = 187
const SIWA_OASIS = 213
const SIDI_OMAR = 89
const SOLLUM = 65

const BARDIA_FT_CAPUZZO = 122

const SS_NONE = 0
const SS_BASE = 1
const SS_BARDIA = 2
const SS_BENGHAZI = 3
const SS_TOBRUK = 4
const SS_OASIS = 5

const MF_AXIS = 0
const MF_ALLIED = 1
const MF_VISIBLE = 2
const MF_REVEAL = 3

const EGYPT = regions.Egypt
const LIBYA = regions.Libya
const LIBYA_NO_TOBRUK = LIBYA.filter(r => r !== TOBRUK)

function calc_distance(a, b) {
	let ax = a % hexw, ay = (a / hexw)|0, az = -ax - ay
	let bx = b % hexw, by = (b / hexw)|0, bz = -bx - by
	return max(abs(bx-ax), abs(by-ay), abs(bz-az))
}

function calc_distance_map(supply) {
	let map = new Array(hexcount)
	for (let x = 0; x < hexcount; ++x)
		map[x] = calc_distance(supply, x)
	return map
}

const distance_to = {
	[EL_AGHEILA]: calc_distance_map(EL_AGHEILA),
	[ALEXANDRIA]: calc_distance_map(ALEXANDRIA),
	[BENGHAZI]: calc_distance_map(BENGHAZI),
	[TOBRUK]: calc_distance_map(TOBRUK),
	[BARDIA]: calc_distance_map(BARDIA),
}

function to_side(a, b, s) {
	if (s < 3)
		return a * 3 + s
	return b * 3 + s - 3
}

function to_side_id(a, b) {
	if (a > b) {
		let c = b
		b = a
		a = c
	}
	if (a + hexnext[0] === b)
		return a * 3 + 0
	else if (a + hexnext[1] === b)
		return a * 3 + 1
	else if (a + hexnext[2] === b)
		return a * 3 + 2
	throw new Error("not a hexside " + a + " to " + b)
}

function is_map_hex(x) {
	return x >= first_hex && x <= last_hex && hex_exists[x] === 1
}

function is_hex_or_adjacent_to(x, where) {
	if (x === where)
		return true
	for (let s = 0; s < 6; ++s) {
		let y = where + hexnext[s]
		if (is_map_hex(y) && x === y)
			return true
	}
	return false
}

// === STATE CACHES ===

const first_axis_unit = 0
const last_axis_unit = 33
const first_allied_unit = 34
const last_allied_unit = 93
const unit_count = 94

var presence_invalid = true
var presence_axis = new Array(hexcount).fill(0)
var presence_allied = new Array(hexcount).fill(0)

var supply_axis_invalid = true
var supply_axis_network = new Array(hexcount).fill(0)
var supply_axis_line = new Array(sidecount).fill(0)

var supply_allied_invalid = true
var supply_allied_network = new Array(hexcount).fill(0)
var supply_allied_line = new Array(sidecount).fill(0)

var supply_bardia_invalid = true
var supply_bardia_network = new Array(hexcount).fill(0)
var supply_bardia_line = new Array(sidecount).fill(0)

var supply_benghazi_invalid = true
var supply_benghazi_network = new Array(hexcount).fill(0)
var supply_benghazi_line = new Array(sidecount).fill(0)

var supply_tobruk_invalid = true
var supply_tobruk_network = new Array(hexcount).fill(0)
var supply_tobruk_line = new Array(sidecount).fill(0)

var supply_temp_network = new Array(hexcount).fill(0)
var supply_temp_line = new Array(sidecount).fill(0)

var first_friendly_unit, last_friendly_unit
var first_enemy_unit, last_enemy_unit

function set_active_player() {
	clear_undo()
	if (game.active !== game.phasing) {
		game.active = game.phasing
		update_aliases()
	}
}

function set_passive_player() {
	clear_undo()
	let nonphasing = (game.phasing === AXIS ? ALLIED : AXIS)
	if (game.active !== nonphasing) {
		game.active = nonphasing
		update_aliases()
	}
}

function set_enemy_player() {
	if (is_active_player())
		set_passive_player()
	else
		set_active_player()
}

function is_active_player() {
	return game.active === game.phasing
}

function is_passive_player() {
	return game.active !== game.phasing
}

function is_axis_player() {
	return game.active === AXIS
}

function is_allied_player() {
	return game.active === ALLIED
}

function update_aliases() {
	if (game.active === AXIS) {
		first_friendly_unit = first_axis_unit
		last_friendly_unit = last_axis_unit
		first_enemy_unit = first_allied_unit
		last_enemy_unit = last_allied_unit
	} else {
		first_friendly_unit = first_allied_unit
		last_friendly_unit = last_allied_unit
		first_enemy_unit = first_axis_unit
		last_enemy_unit = last_axis_unit
	}
}

function invalidate_caches() {
	presence_invalid = true
	supply_axis_invalid = true
	supply_allied_invalid = true
	supply_tobruk_invalid = true
	supply_bardia_invalid = true
	supply_benghazi_invalid = true
}

function load_state(state) {
	if (game !== state) {
		game = state
		invalidate_caches()
		update_aliases()
	}
}

// === UNIT STATE ===

// location (8 bits), supply source (3 bits), steps lost (2 bits), disrupted (1 bit)

function apply_select(u) {
	if (game.selected === u)
		game.selected = -1
	else
		game.selected = u
}

function pop_selected() {
	let u = game.selected
	game.selected = -1
	return u
}

const UNIT_DISRUPTED_SHIFT = 0
const UNIT_DISRUPTED_MASK = 1 << UNIT_DISRUPTED_SHIFT

const UNIT_STEPS_SHIFT = 1
const UNIT_STEPS_MASK = 3 << UNIT_STEPS_SHIFT

const UNIT_SUPPLY_SHIFT = 3
const UNIT_SUPPLY_MASK = 7 << UNIT_SUPPLY_SHIFT

const UNIT_HEX_SHIFT = 6
const UNIT_HEX_MASK = 255 << UNIT_HEX_SHIFT

function is_unit_disrupted(u) {
	return (game.units[u] & UNIT_DISRUPTED_MASK) === UNIT_DISRUPTED_MASK
}

function is_unit_undisrupted(u) {
	return (game.units[u] & UNIT_DISRUPTED_MASK) !== UNIT_DISRUPTED_MASK
}

function set_unit_disrupted(u) {
	invalidate_caches()
	game.units[u] |= UNIT_DISRUPTED_MASK
}

function clear_unit_disrupted(u) {
	invalidate_caches()
	game.units[u] &= ~UNIT_DISRUPTED_MASK
}

function unit_hex(u) {
	return (game.units[u] & UNIT_HEX_MASK) >> UNIT_HEX_SHIFT
}

function set_unit_hex(u, x) {
	invalidate_caches()
	game.units[u] = (game.units[u] & ~UNIT_HEX_MASK) | (x << UNIT_HEX_SHIFT)
}

function is_unit_supplied(u) {
	return ((game.units[u] & UNIT_SUPPLY_MASK) >> UNIT_SUPPLY_SHIFT) !== 0
}

function is_unit_unsupplied(u) {
	return ((game.units[u] & UNIT_SUPPLY_MASK) >> UNIT_SUPPLY_SHIFT) === 0
}

function unit_supply(u) {
	return (game.units[u] & UNIT_SUPPLY_MASK) >> UNIT_SUPPLY_SHIFT
}

function set_unit_supply(u, src) {
	game.units[u] = (game.units[u] & ~UNIT_SUPPLY_MASK) | (src << UNIT_SUPPLY_SHIFT)
}

function unit_lost_steps(u) {
	return (game.units[u] & UNIT_STEPS_MASK) >> UNIT_STEPS_SHIFT
}

function set_unit_lost_steps(u, n) {
	game.units[u] = (game.units[u] & ~UNIT_STEPS_MASK) | (n << UNIT_STEPS_SHIFT)
}

function unit_steps(u) {
	return unit_max_steps[u] - unit_lost_steps(u)
}

function set_unit_steps(u, n) {
	set_unit_lost_steps(u, unit_max_steps[u] - n)
}

function is_unit_moved(u) {
	return set_has(game.moved, u)
}

function set_unit_moved(u) {
	set_add(game.moved, u)
}

function is_unit_fired(u) {
	return set_has(game.fired, u)
}

function set_unit_fired(u) {
	set_add(game.fired, u)
}

function eliminate_unit(u) {
	invalidate_caches()
	game.units[u] = 0
	set_unit_hex(u, ELIMINATED)
	hide_unit(u)
}

function is_unit_eliminated(u) {
	return unit_hex(u) === ELIMINATED
}

function reduce_unit(u) {
	let s = unit_steps(u)
	let hp = unit_hp_per_step(u)
	if (s === 1)
		eliminate_unit(u)
	else
		set_unit_steps(u, s - 1)
	return hp
}

function replace_unit(u) {
	let lost = unit_lost_steps(u)
	set_unit_lost_steps(u, lost - 1)
}

function reveal_units_in_hex(x) {
	for (let u = 0; u < unit_count; ++u)
		if (unit_hex(u) === x)
			set_add(game.revealed, u)
}

function hide_friendly_units_in_hex(x) {
	for (let u = first_friendly_unit; u <= last_friendly_unit; ++u)
		if (unit_hex(u) === x)
			set_delete(game.revealed, u)
}

function hide_units_in_hex(x) {
	for (let u = 0; u < unit_count; ++u)
		if (unit_hex(u) === x)
			set_delete(game.revealed, u)
}

function hide_unit(u) {
	set_delete(game.revealed, u)
}

// === UNIT DATA ===

function find_unit(name) {
	for (let u = 0; u < unit_count; ++u)
		if (unit_name[u] === name)
			return u
	throw new Error("cannot find named block: " + name + unit_name)
}

function is_axis_unit(u) {
	return u >= first_axis_unit && u <= last_axis_unit
}

function is_german_unit(u) {
	return (u >= 14 && u <= 33)
}

function is_elite_unit(u) {
	return unit_elite[u]
}

function is_artillery_unit(u) {
	return unit_class[u] === ARTILLERY
}

function unit_cv(u) {
	if (is_elite_unit(u))
		return unit_steps(u) * 2
	return unit_steps(u)
}

function unit_hp_per_step(u) {
	return is_elite_unit(u) ? 2 : 1
}

function unit_hp(u) {
	return unit_steps(u) * unit_hp_per_step(u)
}

// === MAP STATE ===

function friendly_base() {
	if (is_axis_player())
		return EL_AGHEILA
	return ALEXANDRIA
}

function friendly_queue() {
	if (is_axis_player())
		return AXIS_QUEUE
	return ALLIED_QUEUE
}

function friendly_refit() {
	if (is_axis_player())
		return AXIS_REFIT
	return ALLIED_REFIT
}

function update_presence() {
	presence_invalid = false
	presence_axis.fill(0)
	for (let u = first_axis_unit; u <= last_axis_unit; ++u) {
		let x = unit_hex(u)
		if (x >= first_hex && x <= last_hex) {
			if (is_unit_disrupted(u))
				presence_axis[x] |= 1
			else
				presence_axis[x] |= 2
		}
	}
	presence_allied.fill(0)
	for (let u = first_allied_unit; u <= last_allied_unit; ++u) {
		let x = unit_hex(u)
		if (x >= first_hex && x <= last_hex) {
			if (is_unit_disrupted(u))
				presence_allied[x] |= 1
			else
				presence_allied[x] |= 2
		}
	}
}

function count_friendly_units_in_hex(x) {
	let n = 0
	for (let u = first_friendly_unit; u <= last_friendly_unit; ++u)
		if (unit_hex(u) === x)
			n++
	return n
}

function any_friendly_undisrupted_unit_in_hex(x) {
	for (let u = first_friendly_unit; u <= last_friendly_unit; ++u)
		if (is_unit_undisrupted(u) && unit_hex(u) === x)
			return u
	throw Error("ASSERT: hex must have friendly undisrupted unit")
}

function has_friendly_unit_in_raw_hex(x) {
	for (let u = first_friendly_unit; u <= last_friendly_unit; ++u)
		if (unit_hex(u) === x)
			return true
	return false
}

function for_each_friendly_unit_in_month(month, fn) {
	for (let u = first_friendly_unit; u <= last_friendly_unit; ++u)
		if (unit_hex(u) === hexdeploy + month)
			fn(u)
}

function has_axis_unit(x) {
	if (presence_invalid)
		update_presence()
	return presence_axis[x] !== 0
}

function has_allied_unit(x) {
	if (presence_invalid)
		update_presence()
	return presence_allied[x] !== 0
}

function has_undisrupted_axis_unit(x) {
	if (presence_invalid)
		update_presence()
	return (presence_axis[x] & 2) !== 0
}

function has_disrupted_axis_unit(x) {
	if (presence_invalid)
		update_presence()
	return (presence_axis[x] & 1) !== 0
}

function has_undisrupted_allied_unit(x) {
	if (presence_invalid)
		update_presence()
	return (presence_allied[x] & 2) !== 0
}

function has_disrupted_allied_unit(x) {
	if (presence_invalid)
		update_presence()
	return (presence_allied[x] & 1) !== 0
}

function has_unshielded_disrupted_axis_unit(x) {
	if (presence_invalid)
		update_presence()
	return presence_axis[x] === 1
}

function has_unshielded_disrupted_allied_unit(x) {
	if (presence_invalid)
		update_presence()
	return presence_allied[x] === 1
}

function is_axis_hex(x) {
	if (presence_invalid)
		update_presence()
	return (presence_axis[x] !== 0) && (presence_allied[x] === 0)
}

function is_allied_hex(x) {
	if (presence_invalid)
		update_presence()
	return (presence_axis[x] === 0) && (presence_allied[x] !== 0)
}

function is_battle_hex(x) {
	// battle hex if both sides present and at least one is undisrupted
	// disrupted units from both sides can peacefully co-exist
	if (presence_invalid)
		update_presence()
	let a = presence_axis[x]
	let b = presence_allied[x]
	return (a > 1 && b > 0) || (b > 1 && a > 0)
}

function is_enemy_hex(x) {
	if (game.active === ALLIED)
		return is_axis_hex(x)
	return is_allied_hex(x)
}

function has_friendly_unit(x) {
	if (game.active === AXIS)
		return has_axis_unit(x)
	return has_allied_unit(x)
}

function has_undisrupted_friendly_unit(x) {
	if (game.active === AXIS)
		return has_undisrupted_axis_unit(x)
	return has_undisrupted_allied_unit(x)
}

function has_disrupted_friendly_unit(x) {
	if (game.active === AXIS)
		return has_disrupted_axis_unit(x)
	return has_disrupted_allied_unit(x)
}

function has_enemy_unit(x) {
	if (game.active === ALLIED)
		return has_axis_unit(x)
	return has_allied_unit(x)
}

function has_undisrupted_enemy_unit(x) {
	if (game.active === ALLIED)
		return has_undisrupted_axis_unit(x)
	return has_undisrupted_allied_unit(x)
}

function has_unshielded_disrupted_enemy_unit(x) {
	if (game.active === ALLIED)
		return has_unshielded_disrupted_axis_unit(x)
	return has_unshielded_disrupted_allied_unit(x)
}

function has_unshielded_disrupted_friendly_unit(x) {
	if (game.active === ALLIED)
		return has_unshielded_disrupted_allied_unit(x)
	return has_unshielded_disrupted_axis_unit(x)
}

function is_enemy_rout_hex(x) {
	return has_undisrupted_friendly_unit(x) && has_unshielded_disrupted_enemy_unit(x)
}

function is_friendly_rout_hex(x) {
	return has_undisrupted_enemy_unit(x) && has_unshielded_disrupted_friendly_unit(x)
}

function is_new_battle_hex(a) {
	if (is_battle_hex(a))
		return !set_has(game.axis_hexes, a) && !set_has(game.allied_hexes, a)
	return false
}

function claim_hexside_control(side) {
	if (is_axis_player()) {
		set_add(game.axis_sides, side)
		set_delete(game.allied_sides, side)
	} else {
		set_add(game.allied_sides, side)
		set_delete(game.axis_sides, side)
	}
}

function release_hex_control(a) {
	// no longer a battle hex: release hexsides if possible
	set_delete(game.axis_hexes, a)
	set_delete(game.allied_hexes, a)
	for_each_adjacent_hex(a, b => {
		if (!is_battle_hex(b)) {
			let side = to_side_id(a, b)
			set_delete(game.axis_sides, side)
			set_delete(game.allied_sides, side)
		}
	})
	hide_units_in_hex(a)
}

function claim_hex_control_for_defender(a) {
	// a new battle hex: claim hex and hexsides for defender

	if (is_axis_player())
		set_add(game.allied_hexes, a)
	else
		set_add(game.axis_hexes, a)

	for_each_adjacent_hex(a, b => {
		let side = to_side_id(a, b)
		if (side_limit[side] > 0) {
			if (is_axis_player()) {
				if (!set_has(game.axis_sides, side))
					set_add(game.allied_sides, side)
			} else {
				if (!set_has(game.allied_sides, side))
					set_add(game.axis_sides, side)
			}
		}
	})
}

function capture_fortress(fortress, capacity) {
	if (!is_fortress_friendly_controlled(fortress)) {
		if (has_undisrupted_friendly_unit(fortress) && !has_enemy_unit(fortress)) {
			invalidate_caches()
			let fresh = set_fortress_friendly_controlled(fortress)
			if (fresh) {
				log(`Captured #${fortress}!`)
				if (is_axis_player()) {
					let award = capacity
					log(`Awarded ${award} bonus supply.`)
					game.axis_award += award
				} else {
					let award = Math.floor(capacity / 2)
					log(`Awarded ${award} bonus supply.`)
					game.allied_award += award
				}
			} else {
				log(`Recaptured #${fortress}!`)
				if (is_allied_player()) {
					let award = capacity
					log(`Canceled ${award} bonus supply.`)
					game.axis_award -= award
				} else {
					let award = Math.floor(capacity / 2)
					log(`Canceled ${award} bonus supply.`)
					game.allied_award -= award
				}
			}
		}
	}
}

// === FORTRESSES ===

function fortress_bit(fortress) {
	if (fortress === BARDIA) return 1
	if (fortress === BENGHAZI) return 2
	if (fortress === TOBRUK) return 4
	return 0
}

function is_fortress_allied_controlled(fortress) {
	return (game.fortress & fortress_bit(fortress)) !== 0
}

function is_fortress_axis_controlled(fortress) {
	return (game.fortress & fortress_bit(fortress)) === 0
}

function set_fortress_axis_controlled(fortress) {
	game.fortress &= ~fortress_bit(fortress)
}

function set_fortress_allied_controlled(fortress) {
	game.fortress |= fortress_bit(fortress)
}

function toggle_fortress_captured(fortress) {
	let bit = fortress_bit(fortress) << 3
	let old = game.fortress & bit
	game.fortress ^= bit
	return old === 0
}

function clear_fortresses_captured() {
	game.fortress &= 7
}

function is_fortress_friendly_controlled(fortress) {
	if (is_axis_player())
		return is_fortress_axis_controlled(fortress)
	return !is_fortress_axis_controlled(fortress)
}

function set_fortress_friendly_controlled(fortress) {
	if (is_axis_player())
		set_fortress_axis_controlled(fortress)
	else
		set_fortress_allied_controlled(fortress)
	return toggle_fortress_captured(fortress)
}

function is_port_besieged(port) {
	if (port === EL_AGHEILA || port === ALEXANDRIA)
		return false
	return is_fortress_besieged(port)
}

function is_fortress_besieged(fortress) {
	let result = false
	let besieged = is_fortress_axis_controlled(fortress) ? has_allied_unit : has_axis_unit
	for_each_adjacent_hex(fortress, x => {
		if (besieged(x))
			result = true
	})
	return result
}

// === ITERATORS ===

function for_each_adjacent_hex(here, fn) {
	for (let s = 0; s < 6; ++s) {
		let next = here + hexnext[s]
		if (is_map_hex(next))
			fn(next, to_side(here, next, s))
	}
}

function for_each_hex_and_adjacent_hex(here, fn) {
	fn(here)
	for (let s = 0; s < 6; ++s) {
		let next = here + hexnext[s]
		if (is_map_hex(next))
			fn(next)
	}
}

function for_each_axis_unit(fn) {
	for (let u = first_axis_unit; u <= last_axis_unit; ++u)
		fn(u)
}

function for_each_axis_unit_on_map(fn) {
	for (let u = first_axis_unit; u <= last_axis_unit; ++u)
		if (is_map_hex(unit_hex(u)))
			fn(u)
}

function for_each_allied_unit(fn) {
	for (let u = first_allied_unit; u <= last_allied_unit; ++u)
		fn(u)
}

function for_each_allied_unit_on_map(fn) {
	for (let u = first_allied_unit; u <= last_allied_unit; ++u)
		if (is_map_hex(unit_hex(u)))
			fn(u)
}

function for_each_friendly_unit_on_map(fn) {
	for (let u = first_friendly_unit; u <= last_friendly_unit; ++u)
		if (is_map_hex(unit_hex(u)))
			fn(u)
}

function for_each_enemy_unit_on_map(fn) {
	for (let u = first_enemy_unit; u <= last_enemy_unit; ++u)
		if (is_map_hex(unit_hex(u)))
			fn(u)
}

function for_each_friendly_unit_in_hex(x, fn) {
	for (let u = first_friendly_unit; u <= last_friendly_unit; ++u)
		if (unit_hex(u) === x)
			fn(u)
}

function for_each_undisrupted_friendly_unit_in_hex(x, fn) {
	for (let u = first_friendly_unit; u <= last_friendly_unit; ++u)
		if (is_unit_undisrupted(u) && unit_hex(u) === x)
			fn(u)
}

function has_undisrupted_and_unmoved_friendly_unit(x) {
	if (has_undisrupted_friendly_unit(x)) {
		for (let u = first_friendly_unit; u <= last_friendly_unit; ++u)
			if (unit_hex(u) === x && !is_unit_moved(u))
				return true
	}
	return false
}

function for_each_undisrupted_and_unmoved_friendly_unit_in_hex(x, fn) {
	for (let u = first_friendly_unit; u <= last_friendly_unit; ++u)
		if (is_unit_undisrupted(u) && unit_hex(u) === x && !is_unit_moved(u))
			fn(u)
}

function count_hex_or_adjacent_that_has_any_unit_that_can_move(here) {
	let n = 0
	for_each_hex_and_adjacent_hex(here, x => {
		if (has_undisrupted_and_unmoved_friendly_unit(x)) {
			if (!has_enemy_unit(x) || can_any_disengage(x)) {
				n++
				return
			}
		}
	})
	return n
}

function for_each_enemy_unit_in_hex(x, fn) {
	for (let u = first_enemy_unit; u <= last_enemy_unit; ++u)
		if (unit_hex(u) === x)
			fn(u)
}

function for_each_undisrupted_enemy_unit_in_hex(x, fn) {
	for (let u = first_enemy_unit; u <= last_enemy_unit; ++u)
		if (is_unit_undisrupted(u) && unit_hex(u) === x)
			fn(u)
}

function count_and_reveal_battle_hexes() {
	let n = 0
	for (let x of all_hexes) {
		if (is_battle_hex(x)) {
			reveal_units_in_hex(x)
			++n
		}
	}
	return n
}

function has_friendly_units_in_battle() {
	let result = false
	for_each_undisrupted_friendly_unit_in_hex(game.battle, u => {
		if (!is_unit_retreating(u))
			result = true
	})
	return result
}

function count_normal_steps_in_battle() {
	let steps = [ 0, 0, 0, 0 ]
	for_each_undisrupted_friendly_unit_in_hex(game.battle, u => {
		if (!is_elite_unit(u))
			if (!is_unit_retreating(u))
				steps[unit_class[u]] += unit_steps(u)
	})
	return steps
}

function count_elite_steps_in_battle() {
	let steps = [ 0, 0, 0, 0 ]
	for_each_undisrupted_friendly_unit_in_hex(game.battle, u => {
		if (is_elite_unit(u))
			if (!is_unit_retreating(u))
				steps[unit_class[u]] += unit_steps(u)
	})
	return steps
}

function count_hp_in_battle() {
	let hp = [ 0, 0, 0, 0 ]
	for_each_undisrupted_enemy_unit_in_hex(game.battle, u => {
		if (!is_unit_retreating(u))
			hp[unit_class[u]] += unit_hp(u)
	})
	return hp
}

function count_normal_steps_in_pursuit() {
	let steps = 0
	for_each_undisrupted_enemy_unit_in_hex(game.pursuit, u => {
		if (!is_elite_unit(u))
			steps += unit_steps(u)
	})
	return steps
}

function count_elite_steps_in_pursuit() {
	let steps = 0
	for_each_undisrupted_enemy_unit_in_hex(game.pursuit, u => {
		if (is_elite_unit(u))
			steps += unit_steps(u)
	})
	return steps
}

function count_hp_in_pursuit() {
	let hp = 0
	for_each_undisrupted_enemy_unit_in_hex(game.pursuit, u => {
		hp += unit_hp(u)
	})
	return hp
}

function count_normal_steps_in_rout() {
	let steps = 0
	for_each_enemy_unit_in_hex(game.pursuit, u => {
		if (!is_elite_unit(u))
			steps += unit_steps(u)
	})
	return steps
}

function count_elite_steps_in_rout() {
	let steps = 0
	for_each_enemy_unit_in_hex(game.pursuit, u => {
		if (is_elite_unit(u))
			steps += unit_steps(u)
	})
	return steps
}

function count_hp_in_rout() {
	let hp = 0
	for_each_enemy_unit_in_hex(game.pursuit, u => {
		hp += unit_hp(u)
	})
	return hp
}

// === SUPPLY CARDS ===

function draw_supply_card(pile) {
	clear_undo()
	let x = random(pile[0] + pile[1])
	if (x < pile[0]) {
		pile[0] --
		return 0
	} else {
		pile[1] --
		return 1
	}
}

function deal_axis_supply_cards(n) {
	let cur = game.axis_hand[REAL] + game.axis_hand[DUMMY]
	if (cur + n > 16)
		n = 16 - cur
	if (n > 0) {
		log(`Axis drew ${n} cards.`)
		for (let i = 0; i < n; ++i)
			game.axis_hand[draw_supply_card(game.draw_pile)]++
	}
}

function deal_allied_supply_cards(n) {
	let cur = game.allied_hand[REAL] + game.allied_hand[DUMMY]
	if (cur + n > 16)
		n = 16 - cur
	if (n > 0) {
		log(`Allied drew ${n} cards.`)
		for (let i = 0; i < n; ++i)
			game.allied_hand[draw_supply_card(game.draw_pile)]++
	}
}

function shuffle_cards() {
	clear_undo()
	let real = game.axis_hand[REAL] + game.allied_hand[REAL]
	let dummy = game.axis_hand[DUMMY] + game.axis_hand[DUMMY]
	game.draw_pile[0] = 28 - real
	game.draw_pile[1] = 14 - dummy
}

// === SUPPLY NETWORK ===

var supply_friendly_hexes, supply_friendly_sides, supply_friendly, supply_enemy, supply_net, supply_line
var supply_visited = new Array(hexcount).fill(0)
var supply_memo = new Set()

// PASS 1: Forward scan from source to compute potential supply net and valid hex side crossings.
// Simple uniform cost search.

// NOTE: trace direction is from supply to unit
function is_supply_line_blocked(here, next, side) {
	// impassable hexside
	if (side_limit[side] === 0)
		return true

	// into enemy hex
	if (supply_enemy[next] > 1 && supply_friendly[next] === 0)
		return true

	// into battle hex
	if (is_battle_hex(next)) {
		// through friendly hex sides
		if (!set_has(supply_friendly_sides, side))
			return true
	}

	// out of battle hex
	if (is_battle_hex(here)) {
		// only defender (own control)
		if (!set_has(supply_friendly_hexes, here))
			return true
		// through friendly hex sides
		if (!set_has(supply_friendly_sides, side))
			return true
	}

	return false
}

const TRACE_HIGHWAY = 0
const TRACE_TRACK_1 = 1
const TRACE_TRAIL_1 = 2
const TRACE_TRACK_2 = 3
const TRACE_STOP = 7
const TRACE_ABORT = 8

// from supply source outwards
function forward_supply_next_move_type(here_move, road) {
	if (here_move === TRACE_HIGHWAY) {
		if (road === HIGHWAY) return TRACE_HIGHWAY
		if (road === TRACK) return TRACE_TRACK_1
		if (road === TRAIL) return TRACE_TRAIL_1
		return TRACE_STOP
	}
	else if (here_move === TRACE_TRACK_1) {
		if (road === HIGHWAY) return TRACE_TRACK_2
		if (road === TRACK) return TRACE_TRACK_2
		if (road === TRAIL) return TRACE_STOP
		return TRACE_ABORT
	}
	else if (here_move === TRACE_TRAIL_1) {
		if (road === HIGHWAY) return TRACE_STOP
		if (road === TRACK) return TRACE_STOP
		if (road === TRAIL) return TRACE_STOP
		return TRACE_ABORT
	}
	else if (here_move === TRACE_TRACK_2) {
		if (road === HIGHWAY) return TRACE_STOP
		if (road === TRACK) return TRACE_STOP
		if (road === TRAIL) return TRACE_ABORT
		return TRACE_ABORT
	}
	return TRACE_ABORT
}

function trace_supply_network_1(start)
{
	let search_order = []

	supply_net[start] = 1

	supply_visited.fill(8)

	let queue = [ (start << 3) | TRACE_HIGHWAY ]

	while (queue.length > 0) {
		let item = queue.shift()
		let here = item >> 3
		let here_move = item & 7

		for (let s = 0; s < 6; ++s) {
			let next = here + hexnext[s]

			// can't go off-map
			if (next < first_hex || next > last_hex || !hex_exists[next])
				continue

			let side = to_side(here, next, s)
			if (is_supply_line_blocked(here, next, side))
				continue

			let next_move = forward_supply_next_move_type(here_move, side_road[side])
			if (next_move === TRACE_ABORT)
				continue

			supply_line[side] = 1

			// already seen (at same or better)
			if (next_move >= supply_visited[next])
				continue

			// new supply chain at undisrupted friendly unit
			if (supply_friendly[next] > 1)
				next_move = TRACE_HIGHWAY

			supply_visited[next] = next_move

			if (supply_friendly[next] > 0 && !supply_net[next])
				search_order.push(next)

			supply_net[next] = 1

			if (next_move !== TRACE_STOP)
				queue.push((next << 3) | next_move)
		}
	}

	return search_order
}

// PASS 2: Filter net to only include supply lines used by units.
// This is a recursive search to find _all_ possible paths.

const BACK_HEAD = 0
const BACK_STOP = 7
const BACK_ABORT = 8

const BACK_HIGHWAY_1 = 1
const BACK_HIGHWAY_2 = 2
const BACK_HIGHWAY_3 = 3

const BACK_TRACK_1 = 4
const BACK_TRACK_2 = 5
const BACK_TRACK_3 = BACK_STOP

const BACK_TRAIL_1 = 6
const BACK_TRAIL_2 = BACK_STOP
const BACK_TRAIL_3 = BACK_ABORT

// from unit back to supply source
// TODO - double check all!
function backward_supply_next_move_type(here_move, road) {
	if (here_move === BACK_HEAD) {
		if (road === HIGHWAY) return BACK_HIGHWAY_1
		if (road === TRACK) return BACK_TRACK_1
		if (road === TRAIL) return BACK_TRAIL_1
		return BACK_STOP
	}
	if (here_move === BACK_HIGHWAY_1) {
		if (road === HIGHWAY) return BACK_HIGHWAY_2
		if (road === TRACK) return BACK_TRACK_2
		if (road === TRAIL) return BACK_TRAIL_2
		return BACK_ABORT
	}
	if (here_move === BACK_HIGHWAY_2) {
		if (road === HIGHWAY) return BACK_HIGHWAY_3
		if (road === TRACK) return BACK_TRACK_3
		if (road === TRAIL) return BACK_TRAIL_3
		return BACK_ABORT
	}
	if (here_move === BACK_HIGHWAY_3) {
		if (road === HIGHWAY) return BACK_HIGHWAY_3
		if (road === TRACK) return BACK_ABORT
		if (road === TRAIL) return BACK_ABORT
		return BACK_ABORT
	}
	if (here_move === BACK_TRACK_1) {
		if (road === HIGHWAY) return BACK_TRACK_2
		if (road === TRACK) return BACK_TRACK_2
		if (road === TRAIL) return BACK_TRAIL_2
		return BACK_ABORT
	}
	if (here_move === BACK_TRACK_2) {
		if (road === HIGHWAY) return BACK_TRACK_3
		if (road === TRACK) return BACK_TRACK_3
		if (road === TRAIL) return BACK_TRAIL_3
		return BACK_ABORT
	}
	if (here_move === BACK_TRAIL_1) {
		if (road === HIGHWAY) return BACK_TRAIL_2
		if (road === TRACK) return BACK_TRAIL_2
		if (road === TRAIL) return BACK_TRAIL_2
		return BACK_ABORT
	}
	return BACK_ABORT
}

function path_includes(list, x) {
	for (var i = list.length - 1; i >= 0; --i)
		if (list[i] === x)
			return true
	return false
}

function trace_unit_supply_line(full_path, path, here, here_move, ssrc, from_dir) {
	// CORRECT (but slow): let memo_idx = supply_memo_idx_slow(full_path, here, here_move * 6 + from_dir)
	// CRC32-C we pray for no collisions!
	let memo_idx = supply_memo_idx_crc32c(full_path, here, here_move * 6 + from_dir)
	if (supply_memo.has(memo_idx)) {
		return true
	}

	path.push(here)
	if (supply_friendly[here] > 1)
		full_path.push(here)

	let supplied = false

	for (let s = 0; s < 6; ++s) {
		let next = here + hexnext[s]

		// can't go off-map
		if (next < first_hex || next > last_hex)
			continue

		// already seen
		if (path_includes(full_path, next)) // supply chain - heads (can't loop back)
			continue
		if (path_includes(path, next)) // supply chain - intermediate links (can't double back from _same_ head)
			continue

		// not part of supply network (from pass 1)
		if (!supply_net[next])
			continue

		// supply line blocked (from pass 1)
		let side = to_side(here, next, s)
		if (!supply_line[side])
			continue

		let next_move = backward_supply_next_move_type(here_move, side_road[side])
		if (next_move === TRACE_ABORT)
			continue

		// reached supply source
		if (next === ssrc) {
			supply_net[next] = 2
			supply_line[side] = 2
			supplied = true
			continue
		}

		// new supply chain at undisrupted friendly unit
		if (supply_friendly[next] > 1)
			next_move = BACK_HEAD

		// on highway but cannot depart from it (traveled too far on non-highway already)!
		if (next_move === BACK_STOP && hex_road[next] === HIGHWAY)
			next_move = BACK_HIGHWAY_3

		if (trace_unit_supply_line(full_path, supply_friendly[next] > 1 ? [] : path, next, next_move, ssrc, s)) {
			supply_line[side] = 2
			supplied = true
		}
	}

	path.pop()
	if (supply_friendly[here] > 1)
		full_path.pop()

	if (supplied) {
		supply_net[here] = 2
		supply_memo.add(memo_idx)
	}

	return supplied
}

// finalize state after pass 2
function trace_supply_network_3() {
	for (let i = 0; i < sidecount; ++i) {
		if (supply_line[i] === 2)
			supply_line[i] = 1
		else
			supply_line[i] = 0
	}
	for (let i = 0; i < hexcount; ++i) {
		if (supply_net[i] === 2)
			supply_net[i] = 1
		else
			supply_net[i] = 0
	}
}

function trace_supply_network(start) {
	check_timeout()

	supply_net.fill(0)
	supply_line.fill(0)

	// Pass 1: Find hexes that are in supply range.

	let search_order = trace_supply_network_1(start)

	// Pass 2: Filter hexes that have actual supply lines from units.
	supply_memo.clear()
	for (let x of search_order) {
		if (supply_friendly[x] > 0 && x !== start) {
			trace_unit_supply_line([], [], x, BACK_HEAD, start, 0)
		}
	}

	trace_supply_network_3()

	supply_net[start] = 1
}

function trace_fortress_network(fortress, ss) {
	check_timeout()

	supply_net.fill(0)
	supply_line.fill(0)

	if (supply_enemy[fortress] > 1 && supply_friendly[fortress] <= 1)
		return

	// Pass 1: Find hexes that could hold units supplied by fortress.
	trace_supply_network_1(fortress)

	// Pass 2: Filter hexes that have actual supply lines from units.
	supply_memo.clear()
	for (let u = 0; u < unit_count; ++u) {
		if (unit_supply(u) === ss) {
			let x = unit_hex(u)
			if (is_map_hex(x) && x !== fortress) {
				trace_unit_supply_line([], [], x, BACK_HEAD, fortress, 0)
			}
		}
	}

	trace_supply_network_3()
	supply_net[fortress] = 1
}

function init_trace_supply(net, line, friendly) {
	if (presence_invalid)
		update_presence()
	supply_net = net
	supply_line = line
	if (friendly === AXIS) {
		supply_friendly_hexes = game.axis_hexes
		supply_friendly_sides = game.axis_sides
		supply_friendly = presence_axis
		supply_enemy = presence_allied
	} else {
		supply_friendly_hexes = game.allied_hexes
		supply_friendly_sides = game.allied_sides
		supply_friendly = presence_allied
		supply_enemy = presence_axis
	}
}

// For supplied hex checks during deployment and fortress assignment
function trace_supply_to_base_or_fortress(source) {
	init_trace_supply(supply_temp_network, supply_temp_line, game.active)
	supply_net.fill(0)
	supply_line.fill(0)
	trace_supply_network_1(source)
}

function can_trace_supply_to_base_or_fortress(from) {
	return supply_net[from] > 0
}

function update_axis_supply() {
	supply_axis_invalid = false
	init_trace_supply(supply_axis_network, supply_axis_line, AXIS)
	trace_supply_network(EL_AGHEILA)
}

function update_allied_supply() {
	supply_allied_invalid = false
	init_trace_supply(supply_allied_network, supply_allied_line, ALLIED)
	trace_supply_network(ALEXANDRIA)
}

function update_bardia_supply() {
	supply_bardia_invalid = false
	init_trace_supply(supply_bardia_network, supply_bardia_line, is_fortress_axis_controlled(BARDIA) ? AXIS : ALLIED)
	trace_fortress_network(BARDIA, SS_BARDIA)
}

function update_benghazi_supply() {
	supply_benghazi_invalid = false
	init_trace_supply(supply_benghazi_network, supply_benghazi_line, is_fortress_axis_controlled(BENGHAZI) ? AXIS : ALLIED)
	trace_fortress_network(BENGHAZI, SS_BENGHAZI)
}

function update_tobruk_supply() {
	supply_tobruk_invalid = false
	init_trace_supply(supply_tobruk_network, supply_tobruk_line, is_fortress_axis_controlled(TOBRUK) ? AXIS : ALLIED)
	trace_fortress_network(TOBRUK, SS_TOBRUK)
}

function axis_supply_line() {
	if (supply_axis_invalid)
		update_axis_supply()
	return supply_axis_line
}

function axis_supply_network() {
	if (supply_axis_invalid)
		update_axis_supply()
	return supply_axis_network
}

function allied_supply_line() {
	if (supply_allied_invalid)
		update_allied_supply()
	return supply_allied_line
}

function allied_supply_network() {
	if (supply_allied_invalid)
		update_allied_supply()
	return supply_allied_network
}

function bardia_supply_line() {
	if (supply_bardia_invalid)
		update_bardia_supply()
	return supply_bardia_line
}

function bardia_supply_network() {
	if (supply_bardia_invalid)
		update_bardia_supply()
	return supply_bardia_network
}

function benghazi_supply_line() {
	if (supply_benghazi_invalid)
		update_benghazi_supply()
	return supply_benghazi_line
}

function benghazi_supply_network() {
	if (supply_benghazi_invalid)
		update_benghazi_supply()
	return supply_benghazi_network
}

function tobruk_supply_line() {
	if (supply_tobruk_invalid)
		update_tobruk_supply()
	return supply_tobruk_line
}

function tobruk_supply_network() {
	if (supply_tobruk_invalid)
		update_tobruk_supply()
	return supply_tobruk_network
}

function unit_supply_line(who) {
	// Use saved supply line during withdrawal regroup moves.
	if (is_active_player() && game.withdraw && game.withdraw.supply_line) {
		switch (unit_supply(who)) {
		case SS_BARDIA: return game.withdraw.bardia_line
		case SS_BENGHAZI: return game.withdraw.benghazi_line
		case SS_TOBRUK: return game.withdraw.tobruk_line
		}
		return game.withdraw.supply_line
	}

	switch (unit_supply(who)) {
	case SS_BARDIA: return bardia_supply_line()
	case SS_BENGHAZI: return benghazi_supply_line()
	case SS_TOBRUK: return tobruk_supply_line()
	}
	if (is_axis_unit(who))
		return axis_supply_line()
	return allied_supply_line()
}

function unit_supply_network(who) {
	switch (unit_supply(who)) {
	case SS_BARDIA: return bardia_supply_network()
	case SS_BENGHAZI: return benghazi_supply_network()
	case SS_TOBRUK: return tobruk_supply_network()
	}
	if (is_axis_unit(who))
		return axis_supply_network()
	return allied_supply_network()
}

function unit_supply_distance(who) {
	switch (unit_supply(who)) {
	case SS_BARDIA: return distance_to[BARDIA]
	case SS_BENGHAZI: return distance_to[BENGHAZI]
	case SS_TOBRUK: return distance_to[TOBRUK]
	}
	if (is_axis_unit(who))
		return distance_to[EL_AGHEILA]
	return distance_to[ALEXANDRIA]
}

function unit_supply_source(who) {
	switch (unit_supply(who)) {
	case SS_BARDIA: return BARDIA
	case SS_BENGHAZI: return BENGHAZI
	case SS_TOBRUK: return TOBRUK
	}
	if (is_axis_unit(who))
		return EL_AGHEILA
	return ALEXANDRIA
}

function hex_supply_source(x) {
	// TODO: overlapping fortress supply?
	let who = any_friendly_undisrupted_unit_in_hex(x)
	return unit_supply_source(who)
}

function hex_supply_network(x) {
	// TODO: overlapping fortress supply?
	let who = any_friendly_undisrupted_unit_in_hex(x)
	return unit_supply_network(who)
}

function src_supply_network(src) {
	if (src === EL_AGHEILA) return axis_supply_network()
	if (src === ALEXANDRIA) return allied_supply_network()
	if (src === BARDIA) return bardia_supply_network()
	if (src === BENGHAZI) return benghazi_supply_network()
	if (src === TOBRUK) return tobruk_supply_network()
}

function friendly_supply_network() {
	if (is_axis_player())
		return axis_supply_network()
	return allied_supply_network()
}

function friendly_supply_line() {
	if (is_axis_player())
		return axis_supply_line()
	return allied_supply_line()
}

function query_friendly_supply_network_from_to(src, x, y) {
	let save_x
	let save_y
	if (is_axis_player()) {
		init_trace_supply(supply_temp_network, supply_temp_line, AXIS)
		if (x) save_x = presence_axis[x]
		if (y) save_y = presence_axis[y]
		if (x) presence_axis[x] = 0
		if (y) presence_axis[y] = 2
		trace_supply_network(src)
		if (x) presence_axis[x] = save_x
		if (y) presence_axis[y] = save_y
	} else {
		init_trace_supply(supply_temp_network, supply_temp_line, ALLIED)
		if (x) save_x = presence_allied[x]
		if (y) save_y = presence_allied[y]
		if (x) presence_allied[x] = 0
		if (y) presence_allied[y] = 2
		trace_supply_network(src)
		if (x) presence_allied[x] = save_x
		if (y) presence_allied[y] = save_y
	}
	return supply_temp_network
}

function query_friendly_supply_network(src) {
	if (is_axis_player())
		init_trace_supply(supply_temp_network, supply_temp_line, AXIS)
	else
		init_trace_supply(supply_temp_network, supply_temp_line, ALLIED)
	trace_supply_network(src)
	return supply_temp_network
}

// === PATHING ===

const own_seen = new Array(hexcount)
const own_supply_line = new Array(sidecount)

function search_own_supply_line(here, ssrc, sline, sdist) {
	own_seen.fill(0)
	own_supply_line.fill(0)
	search_own_supply_line_rec([], here, ssrc, sline, sdist)
}

function search_own_supply_line_rec(path, here, ssrc, sline, sdist) {
	own_seen[here] = 1
	for (let s = 0; s < 6; ++s) {
		let next = here + hexnext[s]

		// can't go off-map
		if (next < first_hex || next > last_hex)
			continue

		// already seen
		if (own_seen[next])
			continue

		let side = to_side(here, next, s)

		// must follow supply line
		if (sline[side] === 0)
			continue

		// reached supply source
		if (next === ssrc) {
			for (let x of path)
				own_supply_line[x] = 1
			own_supply_line[side] = 1
			continue
		}

		path.push(side)
		search_own_supply_line_rec(path, next, ssrc, sline, sdist)
		path.pop()
	}
	own_seen[here] = 0
}

const path_from = [ new Array(hexcount), new Array(hexcount), new Array(hexcount), null, new Array(hexcount) ]
const path_cost = [ new Array(hexcount), new Array(hexcount), new Array(hexcount), null, new Array(hexcount) ]
const path_valid = new Array(hexcount)

// normal move: may not leave battle hex. may engage any enemy. may move freely.
// normal withdrawal: may not leave battle hex. may engage disrupted enemy. must follow supply lines.
// retreat move: must leave battle hex via friendly side. may ignore disrupted enemy. may move freely.
// retreat withdrawal: must leave battle hex via friendly side. may ignore disrupted enemy. must follow supply lines.

// TODO: cache search results from previous invocation

function search_move(start, speed) {
	search_path_bfs(path_from[0], path_cost[0], start, 0, speed, false, null, null)
	search_path_bfs(path_from[1], path_cost[1], start, 1, speed + 1, false, null, null)
	search_path_bfs(path_from[2], path_cost[2], start, 2, speed + 2, false, null, null)
	search_path_bfs(path_from[4], path_cost[4], start, 4, speed + 4, false, null, null)
}

function search_move_retreat(start, speed) {
	search_path_bfs(path_from[0], path_cost[0], start, 0, speed, true, null, null)
	search_path_bfs(path_from[1], path_cost[1], start, 1, speed + 1, true, null, null)
	search_path_bfs(path_from[2], path_cost[2], start, 2, speed + 2, true, null, null)
	search_path_bfs(path_from[4], path_cost[4], start, 4, speed + 4, true, null, null)
}

function search_withdraw_fast(who, bonus) {
	let sline = unit_supply_line(who)
	let sdist = unit_supply_distance(who)
	let speed = unit_speed[who] + bonus
	let start = unit_hex(who)

	// This is a fast variant that allows following any supply line.
	// Only used when iterating all withdrawal permutations to find
	// possible valid group/regroup moves.

	search_path_bfs(path_from[0], path_cost[0], start, 0, speed, false, sline, sdist)
	search_path_bfs(path_from[1], path_cost[1], start, 1, speed + 1, false, sline, sdist)
	search_path_bfs(path_from[2], path_cost[2], start, 2, speed + 2, false, sline, sdist)
	search_path_bfs(path_from[4], path_cost[4], start, 4, speed + 4, false, sline, sdist)
}

function search_withdraw(who, bonus) {
	let ssrc = unit_supply_source(who)
	let sline = unit_supply_line(who)
	let sdist = unit_supply_distance(who)
	let speed = unit_speed[who] + bonus
	let start = unit_hex(who)

	search_own_supply_line(start, ssrc, sline, sdist)

	search_path_bfs(path_from[0], path_cost[0], start, 0, speed, false, own_supply_line, sdist)
	search_path_bfs(path_from[1], path_cost[1], start, 1, speed + 1, false, own_supply_line, sdist)
	search_path_bfs(path_from[2], path_cost[2], start, 2, speed + 2, false, own_supply_line, sdist)
	search_path_bfs(path_from[4], path_cost[4], start, 4, speed + 4, false, own_supply_line, sdist)
}

function search_withdraw_retreat(who, bonus) {
	let ssrc = unit_supply_source(who)
	let sline = unit_supply_line(who)
	let sdist = unit_supply_distance(who)
	let speed = unit_speed[who] + bonus
	let start = unit_hex(who)

	search_own_supply_line(start, ssrc, sline, sdist)

	search_path_bfs(path_from[0], path_cost[0], start, 0, speed, true, own_supply_line, sdist)
	search_path_bfs(path_from[1], path_cost[1], start, 1, speed + 1, true, own_supply_line, sdist)
	search_path_bfs(path_from[2], path_cost[2], start, 2, speed + 2, true, own_supply_line, sdist)
	search_path_bfs(path_from[4], path_cost[4], start, 4, speed + 4, true, own_supply_line, sdist)
}

function search_redeploy(start) {
	search_path_redeploy_bfs(path_cost[0], start, 0)
	search_path_redeploy_bfs(path_cost[1], start, 1)
	search_path_redeploy_bfs(path_cost[2], start, 2)
	search_path_redeploy_bfs(path_cost[4], start, 4)
}

// Breadth First Search
function search_path_bfs(from, cost, start, road, max_cost, retreat, sline, sdist) {
	let path_enemy, enemy_sides
	let exit1, exit2

	if (presence_invalid)
		update_presence()
	if (is_axis_player()) {
		path_enemy = presence_allied
		enemy_sides = game.allied_sides
		exit1 = exit2 = 175
	} else {
		path_enemy = presence_axis
		enemy_sides = game.axis_sides
		exit1 = 99
		exit2 = 148
	}

	from.fill(0)
	cost.fill(15)
	cost[start] = 0

	if (hex_road[start] < road)
		return

	let queue = [ start << 4 ]

	while (queue.length > 0) {
		let item = queue.shift()
		let here = item >> 4
		let here_cost = item & 15
		let next_cost = here_cost + 1

		for (let s = 0; s < 6; ++s) {
			let next = here + hexnext[s]

			// can't go off-map
			if (next < first_hex || next > last_hex || !hex_exists[next])
				continue

			// can't enter own map edge
			if (next === exit1 || next === exit2)
				continue

			// already seen
			if (cost[next] < 15)
				continue

			let side = to_side(here, next, s)
			let max_side = side_limit[side]

			// can't cross this hexside
			if (max_side === 0)
				continue

			// must stay on road for current bonus
			if (side_road[side] < road)
				continue

			if (sline) {
				// must follow supply line
				if (sline[side] === 0)
					continue

				// may not increase distance to supply source (except Bardia/Ft. Capuzzo)
				if (sdist[next] > sdist[here] && side !== BARDIA_FT_CAPUZZO)
					continue
			}

			let next_enemy = path_enemy[next]
			if (retreat) {
				// must cross friendly hex-side to disengage
				if (here === start && set_has(enemy_sides, side))
					continue
				// may only ignore unshielded disrupted units
				if (next_enemy & 2) // has undisrupted enemy
					continue
			} else {
				if (sline) {
					// may only engage unshielded disrupted units
					if (next_enemy & 2) // has undisrupted enemy
						continue
				}
				// check hexside limit when engaging enemy units
				if (next_enemy)
					if ((game.side_limit[side] | 0) >= max_side)
						continue
			}

			from[next] = here
			cost[next] = next_cost

			if (!retreat) {
				// must stop when engaging enemy units
				if (next_enemy)
					continue
			}

			// enough movement allowance to keep going
			if (next_cost < max_cost)
				queue.push(next << 4 | next_cost)
		}
	}
}

function search_path_redeploy_bfs(cost, start, road) {
	let path_enemy, friendly_network, enemy_network, enemy_sides
	let exit1, exit2

	if (presence_invalid)
		update_presence()
	if (is_axis_player()) {
		path_enemy = presence_allied
		friendly_network = game.buildup.axis_network
		enemy_network = game.buildup.allied_network
		enemy_sides = game.allied_sides
		exit1 = exit2 = 175
	} else {
		path_enemy = presence_axis
		friendly_network = game.buildup.allied_network
		enemy_network = game.buildup.axis_network
		enemy_sides = game.axis_sides
		exit1 = 99
		exit2 = 148
	}

	cost.fill(63)
	cost[start] = 0

	if (hex_road[start] < road)
		return

	let queue = [ start << 6 ]

	while (queue.length > 0) {
		let item = queue.shift()
		let here = item >> 6
		let here_cost = item & 63
		let next_cost = here_cost + 1

		for (let s = 0; s < 6; ++s) {
			let next = here + hexnext[s]

			// can't go off-map
			if (next < first_hex || next > last_hex || !hex_exists[next])
				continue

			// can't enter own map edge
			if (next === exit1 || next === exit2)
				continue

			// already seen
			if (cost[next] < 63)
				continue

			let side = to_side(here, next, s)
			let max_side = side_limit[side]

			// can't cross this hexside
			if (max_side === 0)
				continue

			// must stay on road for current bonus
			if (side_road[side] < road)
				continue

			// must stay within supply network, and not enter enemy network
			if (!friendly_network[next] || enemy_network[next])
				continue

			// may not move into or through battle hexes
			let next_enemy = path_enemy[next]
			if (next_enemy)
				continue

			// if disengaging from battle, must not cross enemy hexside
			if (here === start && path_enemy[here] && set_has(enemy_sides, side))
				continue

			cost[next] = next_cost

			// don't care about distance (need to find home base for refit)
			if (next_cost < 63)
				queue.push(next << 6 | next_cost)
		}
	}
}

function can_move_to(to, speed) {
	if (path_cost[4][to] <= speed + 4)
		return true
	if (path_cost[2][to] <= speed + 2)
		return true
	if (path_cost[1][to] <= speed + 1)
		return true
	if (path_cost[0][to] <= speed)
		return true
	return false
}

function move_road(to, speed) {
	if (path_cost[4][to] <= speed + 4)
		return 4
	if (path_cost[2][to] <= speed + 2)
		return 2
	if (path_cost[1][to] <= speed + 1)
		return 1
	return 0
}

function fastest_undisrupted_and_unmoved_friendly_unit_in_hex(from) {
	let max_speed = 0
	let who = -1
	for_each_undisrupted_and_unmoved_friendly_unit_in_hex(from, u => {
		let s = unit_speed[u]
		if (s > max_speed) {
			who = u
			max_speed = s
		}
	})
	return who
}

function max_speed_of_undisrupted_and_unmoved_friendly_unit_in_hex(from) {
	let max_speed = 0
	for_each_undisrupted_and_unmoved_friendly_unit_in_hex(from, u => {
		let s = unit_speed[u]
		if (s > max_speed)
			max_speed = s
	})
	return max_speed
}

function find_valid_regroup_destinations(from, rommel) {
	let speed = max_speed_of_undisrupted_and_unmoved_friendly_unit_in_hex(from)
	if (speed > 0) {
		search_move(from, speed + 1 + rommel)
		for (let x of all_hexes)
			if (!path_valid[x])
				if (can_move_to(x, speed + 1 + rommel))
					path_valid[x] = 1
	}
}

// === WITHDRAWAL CHECKS ===

function is_friendly_hexside(side) {
	if (is_axis_player())
		return set_has(game.axis_sides, side)
	return set_has(game.allied_sides, side)
}

function is_enemy_hexside(side) {
	if (is_allied_player())
		return set_has(game.axis_sides, side)
	return set_has(game.allied_sides, side)
}

function unit_has_supply_line(who) {
	let snet = unit_supply_network(who)
	if (snet[unit_hex(who)])
		return true
	return false
}

function is_move_closer(sdist, from, to, side) {
	return side === BARDIA_FT_CAPUZZO || sdist[to] <= sdist[from]
}

function can_unit_withdraw(who) {
	let result = false
	if (unit_has_supply_line(who)) {
		let ssrc = unit_supply_source(who)
		let sline = unit_supply_line(who)
		let sdist = unit_supply_distance(who)
		let from = unit_hex(who)
		search_own_supply_line(from, ssrc, sline, sdist)
		for_each_adjacent_hex(from, to => {
			let side = to_side_id(from, to)
			if (side_limit[side] > 0 && !has_undisrupted_enemy_unit(to))
				if (own_supply_line[side] && is_move_closer(sdist, from, to, side))
					result = true
		})
	}
	return result
}

function can_unit_disengage_and_withdraw(who) {
	let result = false
	if (unit_has_supply_line(who)) {
		let ssrc = unit_supply_source(who)
		let sline = unit_supply_line(who)
		let sdist = unit_supply_distance(who)
		let from = unit_hex(who)
		search_own_supply_line(from, ssrc, sline, sdist)
		for_each_adjacent_hex(from, to => {
			let side = to_side_id(from, to)
			if (side_limit[side] > 0 && !is_enemy_hexside(side) && !has_undisrupted_enemy_unit(to))
				if (own_supply_line[side] && is_move_closer(sdist, from, to, side))
					result = true
		})
	}
	return result
}

function can_unit_disengage_and_move(who) {
	let from = unit_hex(who)
	let result = false
	for_each_adjacent_hex(from, to => {
		let side = to_side_id(from, to)
		if (side_limit[side] > 0 && !is_enemy_hexside(side) && !has_undisrupted_enemy_unit(to))
			result = true
	})
	return result
}

function can_unit_disengage_and_withdraw_to(who, to, extra) {
	if (unit_has_supply_line(who)) {
		search_withdraw_retreat(who, extra)
		return can_move_to(to, unit_speed[who] + extra)
	}
	return false
}

function can_unit_disengage_and_move_to(who, to, extra) {
	search_move_retreat(unit_hex(who), unit_speed[who] + extra)
	return can_move_to(to, unit_speed[who] + extra)
}

function can_all_units_disengage_and_withdraw(from) {
	let result = true
	for_each_friendly_unit_in_hex(from, u => {
		if (result === true && !can_unit_disengage_and_withdraw(u))
			result = false
	})
	return result
}

function can_all_undisrupted_units_disengage_and_withdraw(from) {
	if (!has_undisrupted_friendly_unit(from))
		return false
	let result = true
	for_each_undisrupted_friendly_unit_in_hex(from, u => {
		if (result === true && !can_unit_disengage_and_withdraw(u))
			result = false
	})
	return result
}

function can_all_undisrupted_units_withdraw(from) {
	if (!has_undisrupted_friendly_unit(from))
		return false
	let result = true
	for_each_undisrupted_friendly_unit_in_hex(from, u => {
		if (result === true && !can_unit_withdraw(u))
			result = false
	})
	return result
}

function is_network_reduced(reference, candidate) {
	for (let x = first_hex; x <= last_hex; ++x)
		if (reference[x] - candidate[x] === 1)
			return true
	return false
}

function is_valid_withdrawal_group_move_from(x) {
	if (is_battle_hex(x)) {
		// can retreat, will always reduce supply network
		return can_all_undisrupted_units_disengage_and_withdraw(x)
	} else {
		// non-retreat withdrawal, check if network is reduced after we leave this hex
		if (!has_disrupted_friendly_unit(x) && can_all_undisrupted_units_withdraw(x)) {
			// All units in hex have the same supply source
			let src = hex_supply_source(x)
			let net = hex_supply_network(x)
			let new_net = query_friendly_supply_network_from_to(src, x, 0)
			if (is_network_reduced(net, new_net))
				return true
		}
	}
	return false
}

function is_valid_withdrawal_group_move_to(src, net, from, to) {
	if (is_battle_hex(from)) {
		return true
	} else {
		let new_net = query_friendly_supply_network_from_to(src, from, to)
		if (is_network_reduced(net, new_net))
			return true
	}
	return false
}

function list_valid_withdrawal_group_moves_to(src, net, from, speed) {
	let result = []
	for (let to of all_hexes)
		if (to != from)
			if (can_move_to(to, speed) && is_valid_withdrawal_group_move_to(src, net, game.from1, to))
				result.push(to)
	return result
}

function is_valid_withdrawal_regroup_move_from(x) {
	// 0 = never, 1 = maybe, 2 = always
	if (is_battle_hex(x)) {
		// can retreat, will always reduce supply network
		if (can_all_undisrupted_units_disengage_and_withdraw(x))
			return 2
	} else {
		// non-retreat withdrawal, check if network is reduced after we leave this hex
		if (can_all_undisrupted_units_withdraw(x)) {
			let src = hex_supply_source(x)
			let net = hex_supply_network(x)
			let new_net = query_friendly_supply_network_from_to(src, x, 0)
			if (is_network_reduced(net, new_net))
				return 2
			// does not reduce network by itself, but maybe in cooperation with other hex withdrawals?
			return 1
		}
	}
	return 0
}

function is_valid_withdrawal_regroup_permutation(src) {
	let net = src_supply_network(src)
	let new_net = query_friendly_supply_network(src)
	return is_network_reduced(net, new_net)
}

function includes_mandatory_hex(from, mandatory) {
	if (mandatory.length === 0)
		return true
	for (let m of mandatory)
		if (is_hex_or_adjacent_to(from, m))
			return true
	return false
}

function list_valid_withdrawal_regroup_command_points() {
	let mandatory = []
	let always = []
	let test = []
	let maybe = null

	for (let fortress of FORTRESS_HEX_LIST) {
		if (is_mandatory_combat(fortress)) {
			set_add(mandatory, fortress)
			for_each_hex_and_adjacent_hex(fortress, x => {
				let status = is_valid_withdrawal_regroup_move_from(x)
				if (status === 2)
					set_add(always, x)
				else if (status === 1)
					set_add(test, x)
			})
		}
	}

	if (mandatory.length === 0) {
		for (let x of all_hexes) {
			let status = is_valid_withdrawal_regroup_move_from(x)
			if (status === 2)
				set_add(always, x)
			else if (status === 1)
				set_add(test, x)
		}
	}

	// console.log("WITHDRAW REGROUP CANDIDATES", always, test)

	if (is_axis_player())
		maybe = list_withdrawal_permutations(EL_AGHEILA, test)
	else
		maybe = list_withdrawal_permutations(ALEXANDRIA, test)
	// TODO: fortress supply

	let from = []
	let m, n

	// Usable command points
	for (let here of all_hexes) {
		if (!includes_mandatory_hex(here, mandatory))
			continue
		if (here in maybe)
			set_add(from, here)
		else if (!is_enemy_hex(here)) {
			m = n = 0
			for_each_hex_and_adjacent_hex(here, x => {
				// Must include at least one valid withdrawal hex to evacuate fully
				if (set_has(always, x))
					m++
				// TODO: allow one-hex regroup moves? (failed forced march abuse)
				// Must include at least two hexes to qualify as a regroup move
				if (has_undisrupted_friendly_unit(x))
					n++
			})
			if (m >= 1 && n >= 2)
				set_add(from, here)
		}
	}

	return { from, always, maybe, to: null, evacuate: null }
}

function count_bits(v) {
	let c = 0
	for (; v; ++c)
		v &= v - 1
	return c
}

function list_withdrawal_permutations(src, maybe) {
	let rommel1 = (game.rommel === 1) ? 1 : 0
	let result = {}
	let hexes

	// impossible...
	if (maybe.length < 2)
		return {}

	// console.log("LIST WITHDRAWAL REGROUPS", maybe)

	// List all possible command points with more than one 'maybe' hex
	let cmd_maybe = {}
	let cmd_points = {}
	for (let here of all_hexes) {
		if (!is_enemy_hex(here)) {
			hexes = null
			for_each_hex_and_adjacent_hex(here, x => {
				if (set_has(maybe, x) && hex_supply_source(x) === src) {
					if (!hexes)
						hexes = []
					set_add(hexes, x)
				}
			})
			if (hexes && hexes.length > 1) {
				let key = hexes.join(",")
				cmd_maybe[key] = hexes
				if (!(key in cmd_points))
					cmd_points[key] = []
				cmd_points[key].push(here)
			}
		}
	}

	// For each unique set of "maybe" command points,
	// find all permutations of removing more than one "maybe" hex.
	if (presence_invalid)
		update_presence()
	let presence_friendly = is_axis_player() ? presence_axis : presence_allied

	for (let key in cmd_maybe) {
		hexes = cmd_maybe[key]
		let n = hexes.length
		let n2 = 1 << n
		path_valid.fill(1)
		for (let bits = 3; bits < n2; ++bits) {
			if (count_bits(bits) >= 2) {
				// Evacuate presence for testing
				for (let i = 0; i < n; ++i)
					if (bits & (1 << i))
						presence_friendly[hexes[i]] &= 1 // clear 'undisrupted'

				// Find the hexes that all units in the evacuated hexes can reach
				for (let i = 0; i < n; ++i) {
					if (bits & (1 << i)) {
						let from = hexes[i]
						let who = slowest_undisrupted_friendly_unit(from)
						let speed = unit_speed[who]

						// NOTE: Inaccurate withdrawal search...
						// It may yield false positives that will result
						// in having to undo if you pick an option that
						// required withdrawal along supply lines not
						// one's own. This should be very unlikely.
						if (true)
							search_withdraw_fast(who, 1 + rommel1)
						else
							search_withdraw(who, 1 + rommel1)

						for (let to = 0; to < hexcount; ++to)
							if (!can_move_to(to, speed + 1 + rommel1))
								path_valid[to] = 0
					}
				}

				// Test supply net for all possible destinations
				for (let x of all_hexes) {
					if (path_valid[x]) {
						let save_x = presence_friendly[x]
						presence_friendly[x] = 2
						if (is_valid_withdrawal_regroup_permutation(src)) {
							for (let here of cmd_points[key]) {
								if (!(here in result))
									result[here] = []
								set_add(result[here], x)
							}
						}
						presence_friendly[x] = save_x
					}
				}

				// Restore presence
				for (let i = 0; i < n; ++i)
					if (bits & (1 << i))
						presence_friendly[hexes[i]] |= 2 // set 'undisrupted'
			}
		}
	}

	// console.log("MAYBE", result)
	return result
}

function list_valid_withdrawal_regroup_destinations() {
	let rommel1 = (game.rommel === 1) ? 1 : 0

	// Find hexes that can be reached by ALL units of ONE always-hex
	// ... that also reduces the network (either by full retreat, or checking move)
	let result = []

	for_each_hex_and_adjacent_hex(game.from1, from => {
		if (set_has(game.regroup.always, from)) {
			if (is_battle_hex(from)) {
				let who = slowest_undisrupted_friendly_unit(from)
				let speed = unit_speed[who]
				search_withdraw_retreat(who, 1 + rommel1)
				for (let to of all_hexes) {
					if (to != from && can_move_to(to, speed + 1 + rommel1)) {
						set_add(result, to)
					}
				}
			} else {
				let who = slowest_undisrupted_friendly_unit(from)
				let speed = unit_speed[who]
				let src = unit_supply_source(who)
				let net = unit_supply_network(who)
				search_withdraw(who, 1 + rommel1)
				for (let to of all_hexes) {
					if (to != from && can_move_to(to, speed + 1 + rommel1)) {
						if (is_valid_withdrawal_group_move_to(src, net, from, to))
							set_add(result, to)
					}
				}
			}
		}
	})

	// List hexes that can be reached by ALL units of one valid permutation of maybe-hexes.
	if (game.from1 in game.regroup.maybe) {
		for (let to of game.regroup.maybe[game.from1])
			set_add(result, to)
	}

	game.withdraw.to = result
}

function gen_withdrawal_regroup_destination() {
	for (let x of game.withdraw.to)
		gen_action_hex(x)
}

// === MINEFIELDS ===

function visit_hex(x) {
	let mf_enemy = (game.active === AXIS) ? MF_ALLIED : MF_AXIS
	if (set_has(game.minefields[mf_enemy], x))
		set_add(game.minefields[MF_REVEAL], x)
}

function visit_path(from, to, speed) {
	let road = move_road(to, speed)
	while (to && to !== from) {
		visit_hex(to)
		to = path_from[road][to]
	}
}

function reveal_visited_minefields() {
	for (let x of game.minefields[MF_REVEAL]) {
		log(`Minefield at #${x}.`)
		set_delete(game.minefields[MF_AXIS], x)
		set_delete(game.minefields[MF_ALLIED], x)
		set_add(game.minefields[MF_VISIBLE], x)
	}
	set_clear(game.minefields[MF_REVEAL])
}

// === SUPPLY COMMITMENT & TURN OPTION ===

function goto_turn_option() {
	game.commit = [ 0, 0 ]
	game.state = 'turn_option'
}

function player_hand() {
	return is_axis_player() ? game.axis_hand : game.allied_hand
}

states.turn_option = {
	inactive: "turn option",
	prompt() {
		if (game.commit[0] === 0 && game.commit[1] === 0)
			view.prompt = `Turn Option: Committed zero supply.`
		else if (game.commit[1] === 0)
			view.prompt = `Turn Option: Committed ${game.commit[0]} real supply.`
		else if (game.commit[0] === 0)
			view.prompt = `Turn Option: Committed ${game.commit[1]} dummy supply.`
		else
			view.prompt = `Turn Option: Committed ${game.commit[0]} real and ${game.commit[1]} dummy supply.`

		let hand = player_hand()
		if (game.commit[0] + game.commit[1] < 3) {
			if (hand[REAL] > 0)
				gen_action('real_card')
			if (hand[DUMMY] > 0)
				gen_action('dummy_card')
		}

		if (game.commit[0] === 1)
			view.actions.basic = 1
		else
			view.actions.basic = 0
		if (game.commit[0] === 2)
			view.actions.offensive = view.actions.assault = 1
		else
			view.actions.offensive = view.actions.assault = 0
		if (game.commit[0] === 3)
			view.actions.blitz = 1
		else
			view.actions.blitz = 0
		if (game.commit[0] === 0)
			view.actions.pass = 1
		else
			view.actions.pass = 0
	},
	basic() {
		push_undo()
		apply_turn_option('basic')
	},
	offensive() {
		push_undo()
		apply_turn_option('offensive')
	},
	assault() {
		push_undo()
		apply_turn_option('assault')
	},
	blitz() {
		push_undo()
		apply_turn_option('blitz')
	},
	pass() {
		push_undo()
		apply_turn_option('pass')
	},
	real_card() {
		push_undo()
		let hand = player_hand()
		hand[REAL]--
		game.commit[0]++
	},
	dummy_card() {
		push_undo()
		let hand = player_hand()
		hand[DUMMY]--
		game.commit[1]++
	},
}

function apply_turn_option(option) {
	game.turn_option = option

	log_br()

	let n = game.commit[0] + game.commit[1]
	if (n === 0)
		log(`Played zero supply cards.`)
	else if (n === 1)
		log(`Played one supply card.`)
	else if (n === 2)
		log(`Played two supply cards.`)
	else if (n === 3)
		log(`Played three supply cards.`)
	log_br()

	if (game.turn_option === 'pass')
		game.passed++
	else
		game.passed = 0

	goto_move_phase()
}

// === PLAYER TURN ===

function goto_player_turn() {
	set_active_player()

	log_h2(game.phasing)

	// paranoid resetting of state
	game.side_limit = {}
	game.rommel = 0
	game.from1 = game.from2 = 0
	game.to1 = game.to2 = 0

	// reset moved and fired flags
	set_clear(game.fired)
	set_clear(game.moved)

	game.commit = null

	goto_initial_supply_check()
}

function end_player_turn() {
	// Forget partial retreats
	set_clear(game.partial_retreats)

	// Reveal supply cards
	if (game.commit[0] + game.commit[1] > 0) {
		log_br()
		if (game.commit[0] === 0 && game.commit[1] === 0)
			log(`Revealed zero supply.`)
		else if (game.commit[1] === 0)
			log(`Revealed ${game.commit[0]} real supply.`)
		else if (game.commit[0] === 0)
			log(`Revealed ${game.commit[1]} dummy supply.`)
		else
			log(`Revealed ${game.commit[0]} real and ${game.commit[1]} dummy supply.`)
		log_br()
	}

	game.commit = null

	if (check_sudden_death_victory())
		return

	if (game.passed === 2) {
		game.passed = 0
		return end_month()
	}

	if (game.phasing === AXIS)
		game.phasing = ALLIED
	else
		game.phasing = AXIS

	goto_player_turn()
}

// === FORTRESS SUPPLY ===

function union_fortress_network(result, fort) {
	for (let i = first_hex; i <= last_hex; ++i)
		result[i] |= fort[i]
}

function union_fortress_line(result, fort) {
	for (let i = 0; i < sidecount; ++i)
		result[i] |= fort[i]
}

function union_axis_network() {
	let net = axis_supply_network().slice()
	if (net[BARDIA] === 0 && is_fortress_axis_controlled(BARDIA))
		union_fortress_network(net, bardia_supply_network())
	if (net[BENGHAZI] === 0 && is_fortress_axis_controlled(BENGHAZI))
		union_fortress_network(net, benghazi_supply_network())
	if (net[TOBRUK] === 0 && is_fortress_axis_controlled(TOBRUK))
		union_fortress_network(net, tobruk_supply_network())
	return net
}

function union_allied_network() {
	let net = allied_supply_network().slice()
	if (net[BARDIA] === 0 && is_fortress_allied_controlled(BARDIA))
		union_fortress_network(net, bardia_supply_network())
	if (net[BENGHAZI] === 0 && is_fortress_allied_controlled(BENGHAZI))
		union_fortress_network(net, benghazi_supply_network())
	if (net[TOBRUK] === 0 && is_fortress_allied_controlled(TOBRUK))
		union_fortress_network(net, tobruk_supply_network())
	return net
}

function union_axis_line() {
	let net = axis_supply_network()
	let line = axis_supply_line().slice()
	if (net[BARDIA] === 0 && is_fortress_axis_controlled(BARDIA))
		union_fortress_line(line, bardia_supply_line())
	if (net[BENGHAZI] === 0 && is_fortress_axis_controlled(BENGHAZI))
		union_fortress_line(line, benghazi_supply_line())
	if (net[TOBRUK] === 0 && is_fortress_axis_controlled(TOBRUK))
		union_fortress_line(line, tobruk_supply_line())
	return line
}

function union_allied_line() {
	let net = allied_supply_network()
	let line = allied_supply_line().slice()
	if (net[BARDIA] === 0 && is_fortress_allied_controlled(BARDIA))
		union_fortress_line(line, bardia_supply_line())
	if (net[BENGHAZI] === 0 && is_fortress_allied_controlled(BENGHAZI))
		union_fortress_line(line, benghazi_supply_line())
	if (net[TOBRUK] === 0 && is_fortress_allied_controlled(TOBRUK))
		union_fortress_line(line, tobruk_supply_line())
	return line
}

const FORTRESS_HEX_LIST = [ BARDIA, BENGHAZI, TOBRUK ]
const FORTRESS_SRC_LIST = [ SS_BARDIA, SS_BENGHAZI, SS_TOBRUK ]

function all_friendly_unsupplied_units() {
	let result = []
	for_each_friendly_unit_on_map(u => {
		if (is_unit_unsupplied(u))
			result.push(u)
	})
	return result
}

function goto_fortress_supply(state) {
	game.state = state
	game.assign = 0
	game.summary = [ 0, 0, 0 ]
	resume_fortress_supply()
}

function resume_fortress_supply() {
	while (game.assign < 3) {
		if (assign_fortress_supply())
			return
		game.assign++
	}
	end_fortress_supply()
}

function end_fortress_supply() {
	for (let ix = 0; ix < 3; ++ix)
		if (game.summary[ix] > 0)
			log(`Assigned ${game.summary[ix]} #${FORTRESS_HEX_LIST[ix]} supply.`)
	game.summary = null

	game.assign = 0
	if (game.state === 'initial_fortress_supply')
		game.state = 'initial_oasis_supply'
	else if (game.state === 'final_fortress_supply')
		game.state = 'final_oasis_supply'
	else if (game.state === 'buildup_fortress_supply')
		game.state = 'buildup_oasis_supply'
	else if (game.state === 'end_game_fortress_supply')
		game.state = 'end_game_oasis_supply'
	resume_oasis_supply()
}

function list_fortress_supply_candidates(fortress) {
	let dist = distance_to[fortress]
	let list = []
	trace_supply_to_base_or_fortress(fortress)
	for_each_friendly_unit_on_map(u => {
		if (is_unit_unsupplied(u))
			if (can_trace_supply_to_base_or_fortress(unit_hex(u)))
				list.push(u)
	})
	list.sort((a,b) => dist[unit_hex(a)] - dist[unit_hex(b)])
	return list
}

function auto_assign_fortress_supply(list, fortress, ss, ix) {
	let dist = distance_to[fortress]
	while (list.length > 0 && game.capacity[ix] > 0) {
		let d0 = dist[unit_hex(list[0])]
		let n = 0
		for (let u of list)
			if (dist[unit_hex(u)] === d0)
				++n
		if (n <= game.capacity[ix]) {
			game.summary[ix] += n
			for (let u of list)
				if (dist[unit_hex(u)] === d0)
					set_unit_supply(u, ss)
			game.capacity[ix] -= n
			list = list.slice(n)
		} else {
			return true
		}
	}
	return false
}

function assign_fortress_supply() {
	let ix = game.assign
	let ss = FORTRESS_SRC_LIST[ix]
	let fortress = FORTRESS_HEX_LIST[ix]
	let base_net = friendly_supply_network()

	// Isolated friendly fortress with capacity!
	if (!base_net[fortress] && is_fortress_friendly_controlled(fortress) && game.capacity[ix] > 0) {
		let list = list_fortress_supply_candidates(fortress)
		if (auto_assign_fortress_supply(list, fortress, ss, ix))
			return true
	}

	return false
}

const xxx_fortress_supply = {
	inactive: "supply check",
	prompt() {
		let ix = game.assign
		let fortress = FORTRESS_HEX_LIST[ix]
		view.prompt = `Supply Check: Assign fortress supply to ${hex_name[fortress]} (${game.capacity[ix]} capacity left).`
		if (game.capacity[ix] > 0) {
			let list = list_fortress_supply_candidates(fortress)
			if (list.length > 0) {
				let dist = distance_to[fortress]
				let d0 = dist[unit_hex(list[0])]
				for (let u of list)
					if (dist[unit_hex(u)] === d0)
						gen_action_unit(u)
			}
		}
		gen_action('next')
	},
	unit(who) {
		let ix = game.assign
		let ss = FORTRESS_SRC_LIST[ix]
		push_undo()
		game.capacity[ix]--
		game.summary[ix] ++
		set_unit_supply(who, ss)
	},
	next() {
		push_undo()
		game.assign++
		resume_fortress_supply()
	},
}

states.initial_fortress_supply = xxx_fortress_supply
states.final_fortress_supply = xxx_fortress_supply
states.buildup_fortress_supply = xxx_fortress_supply
states.end_game_fortress_supply = xxx_fortress_supply

// === OASIS SUPPLY ===

const OASIS_HEX_LIST = [ JALO_OASIS, JARABUB_OASIS, SIWA_OASIS ]

function resume_oasis_supply() {
	while (game.assign < 3) {
		if (assign_oasis_supply())
			return
		game.assign++
	}
	end_oasis_supply()
}

function end_oasis_supply() {
	if (game.state === 'initial_oasis_supply')
		goto_initial_supply_check_recover()
	else if (game.state === 'final_oasis_supply')
		goto_final_supply_check_disrupt()
	else if (game.state === 'buildup_oasis_supply')
		goto_buildup_supply_check_recover()
	else if (game.state === 'end_game_oasis_supply')
		goto_end_game_supply_check_recover()
}

function assign_oasis_supply() {
	let ix = game.assign
	if (game.oasis[ix] > 0) {
		let oasis = OASIS_HEX_LIST[ix]
		let enemy_battle = is_axis_player() ? game.allied_hexes : game.axis_hexes
		if (has_friendly_unit(oasis)) {
			if (!set_has(enemy_battle, oasis)) {
				let n = count_friendly_units_in_hex(oasis)
				if (n > 1)
					return true
				if (n === 1) {
					for_each_friendly_unit_in_hex(oasis, u => {
						game.oasis[ix] = 0
						log(`Assigned #${oasis} supply.`)
						set_unit_supply(u, SS_OASIS)
					})
				}
			}
		}
	}
	return false
}

const xxx_oasis_supply = {
	inactive: "supply check",
	prompt() {
		let ix = game.assign
		let oasis = OASIS_HEX_LIST[ix]
		view.prompt = `Supply Check: Assign oasis supply to ${hex_name[oasis]}.`
		for_each_friendly_unit_in_hex(oasis, u => {
			gen_action_unit(u)
		})
	},
	unit(who) {
		let ix = game.assign
		let oasis = OASIS_HEX_LIST[ix]
		push_undo()
		game.oasis[ix] = 0
		log(`Assigned #${oasis} supply.`)
		set_unit_supply(who, SS_OASIS)
		game.assign++
		resume_oasis_supply()
	},
}

states.initial_oasis_supply = xxx_oasis_supply
states.final_oasis_supply = xxx_oasis_supply
states.buildup_oasis_supply = xxx_oasis_supply
states.end_game_oasis_supply = xxx_oasis_supply

// === INITIAL SUPPLY CHECK ===

function goto_initial_supply_check() {
	let base_net = friendly_supply_network()
	for_each_friendly_unit_on_map(u => {
		if (base_net[unit_hex(u)])
			set_unit_supply(u, SS_BASE)
		else
			set_unit_supply(u, SS_NONE)
	})

	if (is_axis_player())
		game.capacity = [ 1, 1, 2 ]
	else
		game.capacity = [ 2, 2, 5 ]
	game.oasis = [ 1, 1, 1 ]

	goto_fortress_supply('initial_fortress_supply')
}

function goto_initial_supply_check_recover() {
	let summary = []
	for (let u of game.recover) {
		if (is_unit_supplied(u) && is_unit_disrupted(u) && !is_battle_hex(unit_hex(u))) {
			set_add(summary, unit_hex(u))
			clear_unit_disrupted(u)
		}
	}
	for (let x of summary)
		log(`Recovered at #${x}.`)

	// remember enemy units that can recover on their next turn
	set_clear(game.recover)
	for_each_enemy_unit_on_map(u => {
		if (is_unit_disrupted(u))
			set_add(game.recover, u)
	})

	goto_initial_supply_check_rout()
}

function goto_initial_supply_check_rout() {
	let rout = false
	for (let x of all_hexes)
		if (is_enemy_rout_hex(x))
			rout = true
	if (rout)
		game.state = 'initial_supply_check_rout'
	else
		goto_turn_option()
}

states.initial_supply_check_rout = {
	inactive: "supply check",
	prompt() {
		view.prompt = `Initial Supply Check: Rout!`
		for (let x of all_hexes)
			if (is_enemy_rout_hex(x))
				gen_action_hex(x)
	},
	hex(where) {
		goto_rout(where, true, goto_initial_supply_check_rout)
	}
}

// === FINAL SUPPLY CHECK ===

function goto_final_supply_check() {
	set_active_player()

	set_clear(game.fired)

	log_br()

	capture_fortress(BARDIA, 2)
	capture_fortress(BENGHAZI, 2)
	capture_fortress(TOBRUK, 5)

	// Raiders!
	for (let [u, side] of game.raiders) {
		let x = unit_hex(u)
		if (is_map_hex(x) && is_enemy_hexside(side)) {
			log(`Disrupted raider at #${x}.`)
			set_unit_disrupted(u)
		}
	}
	game.raiders.length = 0

	// Unsupplied and in danger of disruption!
	game.disrupt = all_friendly_unsupplied_units()

	// Now in supply!
	let base_net = friendly_supply_network()
	let summary = []
	for (let u of game.disrupt) {
		if (base_net[unit_hex(u)]) {
			set_add(summary, unit_hex(u))
			set_unit_supply(u, SS_BASE)
		}
	}
	for (let x of summary)
		log(`Restored supply at #${x}.`)

	// Assign leftover fortress and oasis supply
	goto_fortress_supply('final_fortress_supply')
}

function goto_final_supply_check_disrupt() {
	let summary = []
	for (let u of game.disrupt) {
		if (is_unit_unsupplied(u) && is_unit_undisrupted(u)) {
			set_add(summary, unit_hex(u))
			set_unit_disrupted(u)
		}
	}
	for (let x of summary)
		log(`Disrupted at #${x}.`)

	game.disrupt = null
	goto_final_supply_check_rout()
}

function goto_final_supply_check_rout() {
	let rout = false
	for (let x of all_hexes)
		if (is_friendly_rout_hex(x))
			rout = true
	if (rout)
		game.state = 'final_supply_check_rout'
	else
		end_player_turn()
}

states.final_supply_check_rout = {
	inactive: "supply check",
	prompt() {
		view.prompt = `Final Supply Check: Rout!`
		for (let x of all_hexes)
			if (is_friendly_rout_hex(x))
				gen_action_hex(x)
	},
	hex(where) {
		goto_rout(where, false, goto_final_supply_check_rout)
	}
}

function save_withdrawal_supply_lines() {
	game.withdraw = {}

	game.withdraw.supply_net = friendly_supply_network().slice()
	game.withdraw.supply_line = friendly_supply_line().slice()

	// Units assigned fortress supply MUST withdraw using fortress supply lines,
	// even if they are currently in the base supply network.

	if (is_fortress_friendly_controlled(BARDIA)) {
		game.withdraw.bardia_net = bardia_supply_network().slice()
		game.withdraw.bardia_line = bardia_supply_line().slice()
	}

	if (is_fortress_friendly_controlled(BENGHAZI)) {
		game.withdraw.benghazi_net = benghazi_supply_network().slice()
		game.withdraw.benghazi_line = benghazi_supply_line().slice()
	}

	if (is_fortress_friendly_controlled(TOBRUK)) {
		game.withdraw.tobruk_net = tobruk_supply_network().slice()
		game.withdraw.tobruk_line = tobruk_supply_line().slice()
	}
}

// === MOVEMENT PHASE ===

function push_move_summary(from, to, via, forced) {
	let mm = (from) | (to << 8) | (via << 16) | (forced << 24)
	if (game.summary === null)
		game.summary = {}
	game.summary[mm] = (game.summary[mm]|0) + 1
}

function flush_move_summary() {
	if (game.summary === null)
		return
	log_br()
	if (!game.from1 && !game.from2) {
		log(`Passed.`)
	} else if (!game.from2 && !game.to1) {
		log(`Moved from #${game.from1}`)
	} else if (!game.from2 && game.to1) {
		log(`Moved to #${game.to1}`)
	} else {
		log(`Moved`)
	}

	let keys = Object.keys(game.summary).map(Number).sort((a,b)=>a-b)
	for (let mm of keys) {
		let n = game.summary[mm]
		let from = (mm) & 255
		let to = (mm >>> 8 ) & 255
		let via = (mm >>> 16) & 255
		let forced = (mm >>> 24) & 1
		if (!game.from2 && !game.to1 && from === game.from1) {
			log(`>${n} to #${to}`)
		} else if (!game.from2 && game.to1 && to === game.to1) {
			log(`>${n} from #${from}`)
		} else {
			log(`>${n} #${from} to #${to}`)
		}
		if (via) {
			if (forced)
				log(`>>via #${via} *`)
			else
				log(`>>via #${via}`)
		}
	}
	log_br()
	game.summary = null
}

function flush_withdraw_summary() {
	log("Withdrew\n")
	for (let key in game.summary) {
		let n = game.summary[key]
		let to = +key
		if (to === 0)
			log(`>${n} eliminated`)
		else
			log(`>${n} to #${to}`)
	}
	game.summary = null
}

function goto_move_phase() {
	set_clear(game.fired)
	game.used = 0
	game.forced = []
	game.state = 'select_moves'

	if (game.phasing === AXIS && game.scenario !== "1940" && game.rommel === 0)
		if (game.turn_option !== 'offensive' && game.turn_option !== 'blitz')
			game.rommel = 1

	if (game.turn_option === 'pass') {
		try {
			save_withdrawal_supply_lines()
			game.group = list_valid_withdrawal_group_moves()
			game.regroup = list_valid_withdrawal_regroup_command_points()
		} catch (err) {
			if (err !== "TIMEOUT")
				throw err
			game.state = 'select_moves_timeout'
		}
	} else {
		game.group = list_valid_group_moves()
		game.regroup = list_valid_regroup_moves()
	}
}

function show_move_commands() {
	if (game.from1 && game.from2)
		view.selected_hexes = [ game.from1, game.from2 ]
	else if (game.from1)
		view.selected_hexes = game.from1
}

function has_valid_group_move_left() {
	if (!game.group)
		return false
	if (game.group.length > 1)
		return true
	if (game.group.length > 0) {
		if (!game.from1)
			return true
		if (!game.to1)
			return true
	}
	return false
}

function has_valid_regroup_move_left() {
	if (game.regroup) {
		if (game.turn_option === 'pass')
			return game.regroup.from.length > 0
		return game.regroup.length > 0
	}
	return false
}

states.select_moves = {
	inactive: "movement",
	prompt() {
		show_move_commands()
		if (game.turn_option === 'offensive') {
			if (game.from1)
				view.prompt = `Movement: Designate second offensive move.`
			else
				view.prompt = `Movement: Designate first offensive move.`
		} else if (game.turn_option === 'blitz') {
			view.prompt = `Movement: Designate first blitz move.`
		} else {
			view.prompt = `Movement: Designate ${game.turn_option} move.`
		}

		if (game.state === 'select_moves_timeout') {
			if (game.group && !game.regroup)
				view.prompt = "Movement: Computation timed out. Regroup moves not available."
			else
				view.prompt = "Movement: Computation timed out. Some moves may not be available."
		}

		let can_group_move = has_valid_group_move_left() ? 1 : 0
		let can_regroup_move = has_valid_regroup_move_left() ? 1 : 0

		if (game.phasing === AXIS && game.scenario !== "1940" && game.rommel === 0) {
			if (game.turn_option === 'offensive' || game.turn_option === 'blitz') {
				view.actions.group = can_group_move
				view.actions.regroup = can_regroup_move
			}
			view.actions.group_rommel = can_group_move
			view.actions.regroup_rommel = can_regroup_move
		} else {
			view.actions.group = can_group_move
			view.actions.regroup = can_regroup_move
		}

		if (game.turn_option === 'pass') {
			if (has_mandatory_withdrawals())
				view.actions.end_turn = 0
			else
				view.actions.end_turn = 1
		} else if (!can_group_move && !can_regroup_move) {
			gen_action('end_move')
		}
	},
	group_rommel() {
		push_undo()
		game.rommel = (game.from1 === 0) ? 1 : 2
		game.state = 'group_move_from'
	},
	group() {
		push_undo()
		game.state = 'group_move_from'
	},
	regroup_rommel() {
		push_undo()
		game.rommel = (game.from1 === 0) ? 1 : 2
		game.state = 'regroup_move_command_point'
	},
	regroup() {
		push_undo()
		game.state = 'regroup_move_command_point'
	},
	end_move() {
		end_movement()
	},
	end_turn() {
		game.summary = null
		game.group = null
		game.regroup = null
		game.withdraw = null
		goto_combat_phase()
	},
}

states.select_moves_timeout = states.select_moves

function list_valid_group_moves() {
	let result = []
	for (let x of all_hexes) {
		if (has_undisrupted_and_unmoved_friendly_unit(x)) {
			if (!has_enemy_unit(x) || can_any_disengage(x))
				set_add(result, x)
		}
	}
	if (has_friendly_unit_in_raw_hex(friendly_queue()))
		set_add(result, friendly_queue())
	return result
}

function list_valid_withdrawal_group_moves() {
	let result = []
	let mandatory = false
	if (is_mandatory_combat(BARDIA) && is_valid_withdrawal_group_move_from(BARDIA)) {
		set_add(result, BARDIA)
		mandatory = true
	}
	if (is_mandatory_combat(BENGHAZI) && is_valid_withdrawal_group_move_from(BENGHAZI)) {
		set_add(result, BENGHAZI)
		mandatory = true
	}
	if (is_mandatory_combat(TOBRUK) && is_valid_withdrawal_group_move_from(TOBRUK)) {
		set_add(result, TOBRUK)
		mandatory = true
	}
	try {
		if (!mandatory) {
			for (let x of all_hexes) {
				if (has_undisrupted_friendly_unit(x)) {
					if (is_valid_withdrawal_group_move_from(x))
						set_add(result, x)
				}
			}
		}
	} catch (err) {
		if (err !== "TIMEOUT")
			throw err
	}
	return result
}

function list_valid_regroup_moves() {
	let result = []
	for (let x of all_hexes) {
		if (!is_enemy_hex(x)) {
			let n = count_hex_or_adjacent_that_has_any_unit_that_can_move(x)
			// TODO: allow one-hex regroup moves? (failed forced march abuse)
			if (n >= 2)
				set_add(result, x)
		}
	}
	return result
}

states.group_move_from = {
	inactive: "movement",
	prompt() {
		show_move_commands()
		view.prompt = `Group Move: Select group to move.`
		for (let x of game.group)
			if (x !== game.from1 || game.to1)
				gen_action_hex(x)
	},
	hex(x) {
		push_undo()
		if (game.from1 === 0) {
			game.from1 = x
			print_move_1()
		} else {
			game.from2 = x
			print_move_2()
		}

		if (x === friendly_queue()) {
			for_each_friendly_unit_in_hex(friendly_queue(), u => {
				push_move_summary(friendly_queue(), friendly_base(), 0, 0)
				set_unit_hex(u, friendly_base())
				set_unit_moved(u)
			})
		}

		if (game.turn_option === 'offensive' && !game.from2)
			game.state = 'select_moves'
		else
			goto_move()

		if (game.turn_option === 'pass') {
			// Precalculate valid withdrawal move destinations here
			if (!is_battle_hex(game.from1)) {
				let rommel1 = (game.rommel === 1) ? 1 : 0

				// Note: All units in hex have the same supply source.
				let who = fastest_undisrupted_friendly_unit(game.from1)
				let src = unit_supply_source(who)
				let net = unit_supply_network(who)

				// console.log("CALC WITHDRAWAL DESTINATIONS")
				search_withdraw(who, 1 + rommel1)
				game.withdraw.to = list_valid_withdrawal_group_moves_to(src, net, game.from1, unit_speed[who] + 1 + rommel1)
				// console.log("DONE")
			} else {
				// console.log("CALC WITHDRAWAL SKIPPED: full retreat")
			}
		}
	},
}

states.regroup_move_command_point = {
	inactive: "movement",
	prompt() {
		show_move_commands()
		view.prompt = `Regroup Move: Select the command point hex.`
		if (game.turn_option !== 'pass') {
			for (let x of game.regroup)
				gen_action_hex(x)
		} else {
			for (let x of game.regroup.from)
				gen_action_hex(x)
		}
	},
	hex(x) {
		push_undo()
		if (game.from1 === 0)
			game.from1 = x
		else
			game.from2 = x
		game.state = 'regroup_move_destination'
		if (game.turn_option === 'pass')
			list_valid_withdrawal_regroup_destinations()
	},
}

states.regroup_move_destination = {
	inactive: "movement",
	prompt() {
		show_move_commands()
		view.prompt = `Regroup Move: Select the destination hex.`
		let cp, rommel
		if (game.from2 === 0)
			cp = game.from1, rommel = (game.rommel === 1 ? 1 : 0)
		else
			cp = game.from2, rommel = (game.rommel === 2 ? 1 : 0)

		if (game.turn_option !== 'pass') {
			path_valid.fill(0)
			for_each_hex_and_adjacent_hex(cp, x => {
				find_valid_regroup_destinations(x, rommel)
			})
			for (let x of all_hexes)
				if (path_valid[x])
					gen_action_hex(x)
		} else {
			gen_withdrawal_regroup_destination()
		}
	},
	hex(x) {
		push_undo()
		if (game.from2 === 0) {
			game.to1 = x
			print_move_1()
		} else {
			game.to2 = x
			print_move_2()
		}
		if (game.turn_option === 'offensive' && !game.from2)
			game.state = 'select_moves'
		else
			goto_move()
	},
}

function end_movement() {

	// TODO: track whether a regroup move has affected more than one hex
	// scan summary to detect (only bother if forced march is involved)
	// TODO: convert single hex regroup move to group move for forced march attempts

	flush_move_summary()

	game.group = null
	game.regroup = null
	game.withdraw = null
	game.from1 = game.from2 = game.to1 = game.to2 = 0
	goto_forced_marches()
}

// === GROUP AND REGROUP MOVEMENT ===

function search_current_move(who, is_retreat) {
	let rommel1 = (game.rommel === 1) ? 1 : 0
	let rommel2 = (game.rommel === 2) ? 1 : 0
	let from = unit_hex(who)
	let speed = unit_speed[who]
	if (game.turn_option !== 'pass') {
		if (is_retreat)
			search_move_retreat(from, speed + 1 + (rommel1 | rommel2))
		else
			search_move(from, speed + 1 + (rommel1 | rommel2))
	} else {
		if (is_retreat)
			search_withdraw_retreat(who, 1 + rommel1)
		else
			search_withdraw(who, 1 + rommel1)
	}
}

function print_move_1() {
	if (game.rommel === 1) {
		if (game.from1 && game.to1)
			log(`Regroup move with Rommel\nfrom #${game.from1}\nto #${game.to1}.`)
		else if (game.from1)
			log(`Group move with Rommel\nfrom #${game.from1}.`)
	} else {
		if (game.from1 && game.to1)
			log(`Regroup move\nfrom #${game.from1}\nto #${game.to1}.`)
		else if (game.from1)
			log(`Group move\nfrom #${game.from1}.`)
	}
}

function print_move_2() {
	if (game.rommel === 2) {
		if (game.from2 && game.to2)
			log(`Regroup (R) move\nfrom #${game.from2}\nto #${game.to2}.`)
		else if (game.from2)
			log(`Group (R) move\nfrom #${game.from2}.`)
	} else {
		if (game.from2 && game.to2)
			log(`Regroup move\nfrom #${game.from2}\nto #${game.to2}.`)
		else if (game.from2)
			log(`Group move\nfrom #${game.from2}.`)
	}
}

function goto_move() {
	log_br()
	game.state = 'move'
}

function is_withdraw_network_reduced() {
	if (game.withdraw.supply_net) {
		if (is_network_reduced(game.withdraw.supply_net, friendly_supply_network()))
			return true
		if (game.withdraw.bardia_net && is_network_reduced(game.withdraw.bardia_net, bardia_supply_network()))
			return true
		if (game.withdraw.benghazi_net && is_network_reduced(game.withdraw.benghazi_net, benghazi_supply_network()))
			return true
		if (game.withdraw.tobruk_net && is_network_reduced(game.withdraw.tobruk_net, tobruk_supply_network()))
			return true
	}
	return false
}

function can_end_move() {
	if (game.turn_option !== 'pass')
		return true

	if (game.to1) {
		// must retreat from mandatory combat!
		for (let fortress of FORTRESS_HEX_LIST) {
			if (is_hex_or_adjacent_to(game.from1, fortress))
				if (is_mandatory_combat(fortress) && set_has(game.regroup.always, fortress))
					return !has_friendly_unit(fortress)
		}

		// quick check
		for (let x of game.regroup.always)
			if (!has_friendly_unit(x))
				return true

		// full check
		return is_withdraw_network_reduced()
	} else {
		if (!has_friendly_unit(game.from1))
			return true
	}
}

function gen_action_end_move() {
	if (game.turn_option === 'offensive') {
		if (game.used !== 3)
			gen_action('confirm_end_move')
		else
			gen_action('end_move')
	} else {
		if (game.used !== 1)
			gen_action('confirm_end_move')
		else
			gen_action('end_move')
	}
}

states.move = {
	inactive: "movement",
	prompt() {
		let rommel1 = (game.rommel === 1) ? 1 : 0
		let rommel2 = (game.rommel === 2) ? 1 : 0

		if (game.selected < 0) {
			let can_move = false

			// Select Group Move 1
			if (!game.to1 && game.from1) {
				if (!is_battle_hex(game.from1)) {
					for_each_undisrupted_and_unmoved_friendly_unit_in_hex(game.from1, u => {
						gen_action_unit(u)
						can_move = true
					})
				}
			}

			// Select Group Move 2
			if (!game.to2 && game.from2) {
				if (!is_battle_hex(game.from2)) {
					for_each_undisrupted_and_unmoved_friendly_unit_in_hex(game.from2, u => {
						gen_action_unit(u)
						can_move = true
					})
				}
			}

			// Select Regroup Move 1
			if (game.to1) {
				for_each_hex_and_adjacent_hex(game.from1, from => {
					if (!has_enemy_unit(from) && from !== game.to1) {
						let fastest = fastest_undisrupted_and_unmoved_friendly_unit_in_hex(from)
						if (fastest >= 0) {
							search_current_move(fastest, false)
							for_each_undisrupted_and_unmoved_friendly_unit_in_hex(from, u => {
								if (can_move_to(game.to1, unit_speed[u] + 1 + rommel1)) {
									gen_action_unit(u)
									can_move = true
								}
							})
						}
					}
				})
			}

			// Select Regroup Move 2
			if (game.to2) {
				for_each_hex_and_adjacent_hex(game.from2, from => {
					if (!has_enemy_unit(from) && from !== game.to2) {
						let fastest = fastest_undisrupted_and_unmoved_friendly_unit_in_hex(from)
						if (fastest >= 0) {
							search_current_move(fastest, false)
							for_each_undisrupted_and_unmoved_friendly_unit_in_hex(from, u => {
								if (can_move_to(game.to2, unit_speed[u] + 1 + rommel2)) {
									gen_action_unit(u)
									can_move = true
								}
							})
						}
					}
				})
			}

			// Overrun
			let has_overrun_hex = false
			for (let x of all_hexes) {
				if (is_enemy_rout_hex(x)) {
					has_overrun_hex = true
					break
				}
			}

			if (has_overrun_hex) {
				if (can_move)
					view.prompt = `Movement: Select unit to move, or hex to overrun.`
				else
					view.prompt = `Movement: Select hex to overrun.`
				gen_action('overrun')
			} else {
				if (can_select_retreat_hex()) {
					if (can_move)
						view.prompt = `Movement: Select unit to move, or retreat after all other movement.`
					else
						view.prompt = `Movement: You may retreat.`
					gen_action('retreat')
					if (can_end_move())
						gen_action_end_move()
				} else {
					if (can_move)
						view.prompt = `Movement: Select unit to move.`
					else
						view.prompt = `Movement: Done.`
					if (can_end_move())
						gen_action_end_move()
				}
			}
		} else {
			view.prompt = `Movement: Select destination.`

			// Deselect
			gen_action_unit(game.selected)

			// Move
			if (game.turn_option !== 'pass') {
				search_move(unit_hex(game.selected), unit_speed[game.selected] + 1 + (rommel1 | rommel2))
				gen_move()
			} else {
				search_withdraw(game.selected, 1 + rommel1)
				gen_withdraw()
			}
		}
	},
	unit(who) {
		apply_select(who)
	},
	forced_march(to) {
		this.hex(to)
	},
	hex(to) {
		apply_move(to, false)
	},
	retreat() {
		push_undo()
		log_br()
		game.state = 'retreat_from'
	},
	overrun() {
		push_undo()
		flush_move_summary()
		game.state = 'overrun'

		if (false) {
			let n = 0
			let where = 0
			for (let x of all_hexes) {
				if (is_enemy_rout_hex(x)) {
					n ++
					where = x
				}
			}
			if (n === 1)
				return goto_overrun(where)
		}
	},
	confirm_end_move() {
		this.end_move()
	},
	end_move() {
		end_movement()
	}
}

states.overrun = {
	inactive: "movement",
	prompt() {
		view.prompt = `Movement: Select hex to overrun.`
		for (let x of all_hexes)
			if (is_enemy_rout_hex(x))
				gen_action_hex(x)
	},
	hex(where) {
		// return to move state afterwards
		game.state = 'move'
		goto_overrun(where)
	},
}

function goto_overrun(where) {
	goto_rout(where, true, null)
}

function do_gen_move_to(_from, to, speed) {
	if (can_move_to(to, speed)) {
		gen_action_hex(to)
	} else if (can_move_to(to, speed + 1)) {
		if (!view.actions.hex || !set_has(view.actions.hex, to))
			gen_action_forced_march(to)
	}
}

function gen_move() {
	let rommel1 = game.rommel === 1 ? 1 : 0
	let rommel2 = game.rommel === 2 ? 1 : 0
	let speed = unit_speed[game.selected]
	let from = unit_hex(game.selected)

	// view.path = {}

	if (rommel1) {
		if (!game.to1 && game.from1 === from)
			for (let to of all_hexes)
				if (to != from)
					do_gen_move_to(from, to, speed + 1)
		if (game.to1 && is_hex_or_adjacent_to(from, game.from1))
			do_gen_move_to(from, game.to1, speed + 1)
	}

	if (rommel2) {
		if (!game.to2 && game.from2 === from)
			for (let to of all_hexes)
				if (to != from)
					do_gen_move_to(from, to, speed + 1)
		if (game.to2 && is_hex_or_adjacent_to(from, game.from2))
			do_gen_move_to(from, game.to2, speed + 1)
	}

	if (!rommel1) {
		if (!game.to1 && game.from1 === from)
			for (let to of all_hexes)
				if (to != from)
					do_gen_move_to(from, to, speed)
		if (game.to1 && is_hex_or_adjacent_to(from, game.from1))
			do_gen_move_to(from, game.to1, speed)
	}

	if (!rommel2) {
		if (!game.to2 && game.from2 === from)
			for (let to of all_hexes)
				if (to != from)
					do_gen_move_to(from, to, speed)
		if (game.to2 && is_hex_or_adjacent_to(from, game.from2))
			do_gen_move_to(from, game.to2, speed)
	}
}

function gen_withdraw() {
	let rommel1 = (game.rommel === 1) ? 1 : 0
	let speed = unit_speed[game.selected]
	let from = unit_hex(game.selected)

	// view.path = {}

	// Group Move Withdraw
	if (!game.to1) {
		for (let to of all_hexes) {
			if (to != from) {
				if (can_move_to(to, speed + rommel1) && set_has(game.withdraw.to, to)) {
					gen_action_hex(to)
				} else if (can_move_to(to, speed + 1 + rommel1) && set_has(game.withdraw.to, to)) {
					gen_action_forced_march(to)
				}
			}
		}
	}

	// Regroup Move Withdraw
	if (game.to1) {
		if (can_move_to(game.to1, speed + rommel1)) {
			gen_action_hex(game.to1)
		} else if (can_move_to(game.to1, speed + 1 + rommel1)) {
			gen_action_forced_march(game.to1)
		}
	}
}

function apply_move(to, is_retreat) {
	let rommel1 = game.rommel === 1 ? 1 : 0
	let rommel2 = game.rommel === 2 ? 1 : 0
	let who = pop_selected()
	let from = unit_hex(who)
	let speed = unit_speed[who]

	push_undo()

	search_current_move(who, is_retreat)

	if (rommel1) {
		if (!game.to1 && game.from1 === from)
			if (can_move_to(to, speed + 2))
				return move_unit(who, to, speed + 2, 1)
		if (game.to1 === to && is_hex_or_adjacent_to(from, game.from1))
			if (can_move_to(to, speed + 2))
				return move_unit(who, to, speed + 2, 1)
	}

	if (rommel2) {
		if (!game.to2 && game.from2 === from)
			if (can_move_to(to, speed + 2))
				return move_unit(who, to, speed + 2, 2)
		if (game.to2 === to && is_hex_or_adjacent_to(from, game.from2))
			if (can_move_to(to, speed + 2))
				return move_unit(who, to, speed + 2, 2)
	}

	if (!rommel1) {
		if (!game.to1 && game.from1 === from)
			if (can_move_to(to, speed + 1))
				return move_unit(who, to, speed + 1, 1)
		if (game.to1 === to && is_hex_or_adjacent_to(from, game.from1))
			if (can_move_to(to, speed + 1))
				return move_unit(who, to, speed + 1, 1)
	}

	if (!rommel2) {
		if (!game.to2 && game.from2 === from)
			if (can_move_to(to, speed + 1))
				return move_unit(who, to, speed + 1, 2)
		if (game.to2 === to && is_hex_or_adjacent_to(from, game.from2))
			if (can_move_to(to, speed + 1))
				return move_unit(who, to, speed + 1, 2)
	}

	throw Error("bad move")
}

// to check usable alternate paths to enter destination hex
function can_move_via(via, to, speed, road) {
	let cost = path_cost[road][via]
	let side = to_side_id(via, to)
	let max_side = side_limit[side]

	// too far
	if (cost + 1 > speed + road)
		return 0

	// can't cross this hexside
	if (max_side === 0)
		return 0

	// must stay on road for current bonus
	if (side_road[side] < road)
		return 0

	// must stop on enemies
	if (has_enemy_unit(via))
		return 0

	// may not exceed hexside limit
	if (has_enemy_unit(to))
		if ((game.side_limit[side] | 0) >= max_side)
			return 0

	if (cost + 1 === speed + road)
		return 2
	return 1
}

function is_forced_march_move(from, to, speed) {
	let result = true
	if (hex_road[from] >= 0 && path_cost[0][to] < speed + 0)
		result = false
	if (hex_road[from] >= 1 && path_cost[1][to] < speed + 1)
		result = false
	if (hex_road[from] >= 2 && path_cost[2][to] < speed + 2)
		result = false
	if (hex_road[from] >= 4 && path_cost[4][to] < speed + 4)
		result = false
	return result
}

function move_via(who, to, speed, move) {
	let from = unit_hex(who)
	game.hexside = {
		who: who,
		to: to,
		via: [],
		forced: [],
		move: move
	}
	for_each_adjacent_hex(to, (via, side) => {
		let forced = false
		let unforced = false

		if (game.turn_option === 'pass')
			if (!own_supply_line[side])
				return

		function check_road(bonus) {
			if (hex_road[from] >= bonus) {
				let k = can_move_via(via, to, speed, bonus)
				if (k === 2)
					forced = true
				else if (k === 1)
					unforced = true
			}
		}
		check_road(4)
		check_road(2)
		check_road(1)
		check_road(0)
		if (unforced) {
			game.hexside.via.push(via)
			game.hexside.forced.push(0)
		} else if (forced) {
			game.hexside.via.push(via)
			game.hexside.forced.push(1)
		}
	})
	return game.hexside.via.length === 1
}

function is_engagement_move(to) {
	if (game.retreat > 0) {
		// retreating units may co-exist with disrupted enemy units
		return has_undisrupted_enemy_unit(to)
	}
	return has_enemy_unit(to)
}

function move_unit(who, to, speed, move) {
	let from = unit_hex(who)

	game.used |= move

	if (is_forced_march_move(from, to, speed) || is_engagement_move(to)) {
		if (move_via(who, to, speed, move)) {
			if (game.hexside.forced[0])
				forced_march_via(who, game.hexside.via[0], to, move)
			else
				engage_via(who, game.hexside.via[0], to, move)
			game.hexside = null
		} else {
			game.state = 'move_via'
		}
	}

	else {
		push_move_summary(from, to, 0, 0)
		visit_path(from, to, speed)
		set_unit_moved(who)
		set_unit_hex(who, to)
	}
}

function resume_move() {
	if (game.retreat > 0)
		game.state = 'retreat_move'
	else
		game.state = 'move'
}

states.move_via = {
	inactive: "movement",
	prompt() {
		view.prompt = `Movement: Select which path to take.`
		view.selected = game.hexside.who
		view.selected_hexes = game.hexside.to

		// view.path = {}

		let rommel = (game.hexside.move === game.rommel) ? 1 : 0
		let who = game.hexside.who
		let from = unit_hex(who)
		let speed = unit_speed[who]
		search_move(from, speed + rommel)

		for (let i = 0; i < game.hexside.via.length; ++i) {
			let x = game.hexside.via[i]
			if (game.hexside.forced[i])
				gen_action_forced_march(x)
			else
				gen_action_hex(x)
		}
	},
	forced_march(via) {
		let rommel = (game.hexside.move === game.rommel) ? 1 : 0
		let who = game.hexside.who
		let from = unit_hex(who)
		let speed = unit_speed[who]
		search_move(from, speed + 1 + rommel)

		forced_march_via(game.hexside.who, via, game.hexside.to, game.hexside.move)
		game.hexside = null
		resume_move()
	},
	hex(via) {
		let rommel = (game.hexside.move === game.rommel) ? 1 : 0
		let who = game.hexside.who
		let from = unit_hex(who)
		let speed = unit_speed[who]
		search_move(from, speed + rommel)

		engage_via(game.hexside.who, via, game.hexside.to, game.hexside.move)
		game.hexside = null
		resume_move()
	}
}

function forced_march_via(who, via, to, move) {
	let speed = unit_speed[who] + (game.rommel === move ? 1 : 0)
	let from = unit_hex(who)
	set_unit_moved(who)
	set_unit_hex(who, via)

	visit_path(from, via, speed)

	// remember where we should advance to / return to
	if ((move === 1 && game.to1) || (move === 2 && game.to2))
		game.forced.push([who, to, from])
	else
		game.forced.push([who, to])

	// attempted force marches affect hexside limits
	if (has_enemy_unit(to)) {
		let side = to_side_id(via, to)
		if (game.side_limit[side])
			game.side_limit[side] = 2
		else
			game.side_limit[side] = 1
	}

	push_move_summary(from, to, via, 1)
}

function engage_via(who, via, to, move) {
	let speed = unit_speed[who] + (game.rommel === move ? 1 : 0)
	let from = unit_hex(who)

	set_unit_moved(who)
	set_unit_hex(who, to)

	visit_path(from, via, speed)
	visit_hex(to)

	if (from !== via)
		push_move_summary(from, to, via, 0)
	else
		push_move_summary(from, to, 0, 0)

	engage_via_hexside(who, via, to)
}

function engage_via_hexside(who, via, to) {
	let side = to_side_id(via, to)
	if (game.side_limit[side])
		game.side_limit[side] = 2
	else
		game.side_limit[side] = 1

	if (is_unit_supplied(who)) {
		claim_hexside_control(side)
	} else {
		// new battle or enemy hexside (is_friendly_hexside is false before claiming control)
		if (!is_friendly_hexside(side))
			game.raiders.push([who, side])
	}

	if (is_new_battle_hex(to)) {
		claim_hex_control_for_defender(to)
		set_add(game.new_battles, to)
	}
}

// === FORCED MARCHES ===

function goto_forced_marches() {
	if (game.forced.length > 0) {
		log(`Forced Marches`)
		game.state = 'forced_marches'
	} else {
		end_forced_marches()
	}
}

function resume_forced_marches() {
	if (game.forced.length > 0) {
		game.state = 'forced_marches'
	} else {
		log_br()
		end_forced_marches()
	}
}

states.forced_marches = {
	inactive: "forced marches",
	prompt() {
		view.prompt = `Forced Marches!`
		for (let [who] of game.forced)
			gen_action_unit(who)
	},
	unit(who) {
		let via = unit_hex(who)
		let ix = game.forced.findIndex(item => who === item[0])
		let to = game.forced[ix][1]
		let from = game.forced[ix][2] || via
		let roll = roll_die()
		if (roll >= 4) {
			log(`>${die_face_hit[roll]} to #${to}`)
			visit_hex(to)
			set_unit_hex(who, to)
			if (has_enemy_unit(to))
				engage_via_hexside(who, via, to)
		} else {
			log(`>${die_face_miss[roll]} disrupted at #${from}`)
			set_unit_hex(who, from)
			if (is_unit_disrupted(who)) {
				reduce_unit(who) // was a retreating unit
				if (is_unit_eliminated(who))
					log(`Eliminated at #${from}.`)
			} else {
				set_unit_disrupted(who)
			}
		}
		array_remove(game.forced, ix)
		resume_forced_marches()
	}
}

function end_forced_marches() {
	game.side_limit = {}
	game.forced = null
	goto_forced_marches_rout()
}

function goto_forced_marches_rout() {
	let rout = false
	for (let x of all_hexes) {
		if (is_friendly_rout_hex(x))
			rout = true
		if (is_enemy_rout_hex(x))
			rout = true
	}
	if (rout)
		game.state = 'forced_marches_rout'
	else
		goto_refuse_battle()
}

states.forced_marches_rout = {
	inactive: "forced marches",
	prompt() {
		view.prompt = `Forced Marches: Rout!`
		for (let x of all_hexes) {
			if (is_friendly_rout_hex(x))
				gen_action_hex(x)
			if (is_enemy_rout_hex(x))
				gen_action_hex(x)
		}
	},
	hex(where) {
		goto_rout(where, is_enemy_rout_hex(where), goto_forced_marches_rout)
	}
}

// === RETREAT ===

function is_valid_retreat_hex(from) {
	if (is_battle_hex(from)) {
		if (game.turn_option === 'pass')
			return can_all_retreat(from)
		else
			return can_any_retreat(from)
	}
	return false
}

function can_unit_retreat(who) {
	let rommel1 = (game.rommel === 1) ? 1 : 0
	let rommel2 = (game.rommel === 2) ? 1 : 0
	let from = unit_hex(who)
	if (!game.to1 && game.from1 === from)
		return can_unit_retreat_group_move(who)
	if (!game.to2 && game.from2 === from)
		return can_unit_retreat_group_move(who)
	if (game.to1 && is_hex_or_adjacent_to(from, game.from1))
		if (can_unit_retreat_regroup_move(who, game.to1, rommel1))
			return true
	if (game.to2 && is_hex_or_adjacent_to(from, game.from2))
		if (can_unit_retreat_regroup_move(who, game.to2, rommel2))
			return true
	return false
}

function can_any_disengage(from) {
	let result = false
	for_each_undisrupted_and_unmoved_friendly_unit_in_hex(from, u => {
		if (result === false && can_unit_disengage_and_move(u))
			result = true
	})
	return result
}

function can_any_retreat(from) {
	let result = false
	for_each_undisrupted_and_unmoved_friendly_unit_in_hex(from, u => {
		if (result === false && can_unit_retreat(u))
			result = true
	})
	return result
}

function can_all_retreat(from) {
	if (!has_undisrupted_friendly_unit(from))
		return false
	let result = true
	for_each_undisrupted_friendly_unit_in_hex(from, u => {
		if (result === true && !is_unit_moved(u) && !can_unit_retreat(u))
			result = false
	})
	return result
}

function can_unit_retreat_group_move(who) {
	if (game.turn_option === 'pass')
		return can_unit_disengage_and_withdraw(who)
	else
		return can_unit_disengage_and_move(who)
}

function can_unit_retreat_regroup_move(who, to, rommel) {
	if (game.turn_option === 'pass')
		return can_unit_disengage_and_withdraw_to(who, to, 1 + rommel)
	else
		return can_unit_disengage_and_move_to(who, to, 1 + rommel)
}

function can_select_retreat_hex() {
	if (!game.to1 && game.from1)
		if (is_valid_retreat_hex(game.from1))
			return true

	if (!game.to2 && game.from2)
		if (is_valid_retreat_hex(game.from2))
			return true

	if (game.to1 && !has_undisrupted_enemy_unit(game.to1)) {
		let result = false
		for_each_hex_and_adjacent_hex(game.from1, x => {
			if (result === false && x !== game.to1 && is_valid_retreat_hex(x))
				result = true
		})
		if (result)
			return true
	}

	if (game.to2 && !has_undisrupted_enemy_unit(game.to2)) {
		let result = false
		for_each_hex_and_adjacent_hex(game.from2, x => {
			if (result === false && x !== game.to2 && is_valid_retreat_hex(x))
				result = true
		})
		if (result)
			return true
	}

	return false
}

states.retreat_from = {
	inactive: "retreat",
	prompt() {
		view.prompt = `Retreat: Select hex to retreat from.`

		if (!game.to1 && game.from1) {
			if (is_valid_retreat_hex(game.from1))
				gen_action_hex(game.from1)
		}

		if (!game.to2 && game.from2) {
			if (is_valid_retreat_hex(game.from2))
				gen_action_hex(game.from2)
		}

		if (game.to1) {
			for_each_hex_and_adjacent_hex(game.from1, x => {
				if (is_valid_retreat_hex(x))
					gen_action_hex(x)
			})
		}

		if (game.to2) {
			for_each_hex_and_adjacent_hex(game.from2, x => {
				if (is_valid_retreat_hex(x))
					gen_action_hex(x)
			})
		}

		if (can_end_move())
			gen_action('end_move')
	},
	hex(x) {
		push_undo()
		goto_retreat_who(x)
	},
	end_move() {
		log_br()
		end_movement()
	}
}

function goto_retreat_who(from) {
	game.retreat = from
	if (game.turn_option === 'pass') {
		game.state = 'retreat_full'
		game.retreat_units = []
		for_each_undisrupted_and_unmoved_friendly_unit_in_hex(game.retreat, u => {
			if (can_unit_retreat(u))
				game.retreat_units.push(u)
		})
	} else {
		game.state = 'retreat_who'
		game.retreat_units = []
	}
}

states.retreat_who = {
	inactive: "retreat",
	prompt() {
		view.prompt = `Retreat: Select units to retreat.`
		let full_retreat = true
		for_each_undisrupted_and_unmoved_friendly_unit_in_hex(game.retreat, u => {
			if (!set_has(game.retreat_units, u))
				full_retreat = false
			if (can_unit_retreat(u))
				gen_action_unit(u)
		})

		if (full_retreat) {
			view.actions.retreat = 1
		} else {
			gen_action('select_all')
			if (game.retreat_units.length > 0)
				view.actions.retreat = 1
			else
				view.actions.retreat = 0
		}
		view.selected = game.retreat_units
	},
	unit(u) {
		set_toggle(game.retreat_units, u)
	},
	select_all() {
		for_each_undisrupted_and_unmoved_friendly_unit_in_hex(game.retreat, u => {
			if (!set_has(game.retreat_units, u))
				if (can_unit_retreat(u))
					set_add(game.retreat_units, u)
		})
	},
	retreat() {
		apply_retreat()
	},
}

states.retreat_full = {
	inactive: "retreat",
	prompt() {
		view.prompt = `Retreat: All units must retreat.`
		view.selected = game.retreat_units
		gen_action('retreat')
	},
	retreat() {
		apply_retreat()
	},
}

function apply_retreat() {
	let full_retreat = true
	for (let u of game.retreat_units)
		hide_unit(u)
	for_each_undisrupted_friendly_unit_in_hex(game.retreat, u => {
		if (!set_has(game.retreat_units, u))
			full_retreat = false
	})
	if (full_retreat) {
		log_h4(`Full retreat from #${game.retreat}`)
		goto_pursuit_fire_during_retreat(game.retreat)
	} else {
		set_add(game.partial_retreats, game.retreat)
		set_passive_player()
		game.state = 'provoke_probe_combat'
	}
}

states.provoke_probe_combat = {
	inactive: "probe combat",
	prompt() {
		view.prompt = `Retreat: You may provoke probe combat at ${hex_name[game.retreat]}.`
		view.selected = game.retreat_units
		gen_action('probe')
		gen_action('pass')
	},
	probe() {
		log_h3(`Probe Combat at #${game.retreat}`)
		set_active_player()
		game.state = 'probe_fire'
		game.battle = game.retreat
		game.hits = [ 0, 0, 0, 0 ]
	},
	pass() {
		end_probe()
	},
}

function end_probe() {
	game.flash = ""
	game.battle = 0
	game.hits = 0

	set_active_player()
	let shielded = false
	for_each_undisrupted_friendly_unit_in_hex(game.retreat, u => {
		if (!set_has(game.retreat_units, u))
			shielded = true
	})
	if (shielded) {
		log_h4(`Partial retreat from #${game.retreat}.`)
		goto_retreat_move()
	} else {
		log_h4(`Full retreat from #${game.retreat}`)
		goto_pursuit_fire_during_retreat(game.retreat)
	}
}

function goto_retreat_move() {
	set_active_player()
	let done = true
	for (let u of game.retreat_units) {
		if (unit_hex(u) === game.retreat) {
			done = false
			break
		}
	}
	if (done)
		end_retreat()
	else
		game.state = 'retreat_move'
}

states.retreat_move = {
	inactive: "retreat",
	prompt() {
		if (game.selected < 0) {
			let done = true
			for (let u of game.retreat_units) {
				if (unit_hex(u) === game.retreat) {
					gen_action_unit(u)
					done = false
				}
			}
			if (done) {
				view.prompt = `Retreat: Done.`
				gen_action('end_retreat')
			} else {
				view.prompt = `Retreat: Select unit to withdraw.`
			}
		} else {
			view.prompt = `Retreat: Select destination.`
			let rommel1 = (game.rommel === 1) ? 1 : 0
			let rommel2 = (game.rommel === 2) ? 1 : 0
			gen_action_unit(game.selected)
			if (game.turn_option === 'pass')
				search_withdraw_retreat(game.selected, 1 + (rommel1 | rommel2))
			else
				search_move_retreat(unit_hex(game.selected), unit_speed[game.selected] + 1 + (rommel1 | rommel2))
			gen_move()
		}
	},
	unit(who) {
		apply_select(who)
	},
	forced_march(to) {
		this.hex(to)
	},
	hex(to) {
		let who = game.selected
		apply_move(to, true)
		set_unit_disrupted(who)
	},
	end_retreat() {
		end_retreat()
	}
}

function end_retreat() {
	if ((game.to1 || game.to2) && game.forced.length > 0) {
		// Don't release in case a forced march regroup teleports units back into battle.
		// Wait until goto_combat_phase to release these hexes.
	} else {
		if (!is_battle_hex(game.retreat))
			release_hex_control(game.retreat)
	}

	game.retreat_units = null

	// mark shielding units as moved
	for_each_undisrupted_friendly_unit_in_hex(game.retreat, u => {
		set_unit_moved(u)
	})

	// no shielding units remain
	if (is_friendly_rout_hex(game.retreat))
		goto_rout(game.retreat, false, end_retreat_2)

	// rear-guard eliminated all enemy units
	else if (is_enemy_rout_hex(game.retreat))
		goto_rout(game.retreat, true, end_retreat_2)
	else
		end_retreat_2()
}

function end_retreat_2() {
	game.retreat = 0
	if (can_select_retreat_hex())
		game.state = 'retreat_from'
	else
		end_movement()
}

// === REFUSE BATTLE ===

function can_select_refuse_battle_hex() {
	for (let x of game.new_battles)
		if (can_all_undisrupted_units_disengage_and_withdraw(x))
			return true
	return false
}

function goto_refuse_battle() {
	set_passive_player()
	if (can_select_refuse_battle_hex()) {
		game.state = 'refuse_battle'
	} else {
		goto_combat_phase()
	}
}

states.refuse_battle = {
	inactive: "refuse battle",
	prompt() {
		view.selected_hexes = game.refuse
		for (let x of game.new_battles)
			if (can_all_undisrupted_units_disengage_and_withdraw(x))
				gen_action_hex(x)
		if (game.refuse > 0) {
			view.prompt = `Refuse Battle: You may retreat from ${hex_name[game.refuse]}.`
			gen_action('retreat')
			gen_action('undo')
		} else {
			view.prompt = `Refuse Battle: Select an attacked hex to refuse battle.`
			gen_action('pass')
		}
	},
	undo() {
		game.refuse = 0
	},
	hex(x) {
		if (x === game.refuse)
			game.refuse = 0
		else
			game.refuse = x
	},
	retreat() {
		log_h4(`Refused battle at #${game.refuse}`)
		set_delete(game.new_battles, game.refuse)
		goto_pursuit_fire_during_refuse_battle(game.refuse)
	},
	pass() {
		goto_combat_phase()
	}
}

function goto_refuse_battle_move() {
	set_passive_player()
	if (has_undisrupted_friendly_unit(game.refuse)) {
		game.state = 'refuse_battle_move'
		game.summary = {}
	} else {
		end_refuse_battle_move()
	}
}

states.refuse_battle_move = {
	inactive: "refuse battle",
	prompt() {
		if (game.selected < 0) {
			let done = true
			for_each_undisrupted_friendly_unit_in_hex(game.refuse, u => {
				gen_action_unit(u)
				done = false
			})
			if (done) {
				view.prompt = `Refuse Battle: Done.`
				gen_action('end_retreat')
			} else {
				view.prompt = `Refuse Battle: Select unit to withdraw.`
			}
		} else {
			view.prompt = `Refuse Battle: Select destination.`
			let speed = unit_speed[game.selected]
			gen_action_unit(game.selected)
			search_withdraw_retreat(game.selected, 0)
			for (let to of all_hexes)
				if (to != game.refuse && can_move_to(to, speed))
					gen_action_hex(to)
		}
	},
	unit(who) {
		apply_select(who)
	},
	hex(to) {
		let who = pop_selected()
		push_undo()
		game.summary[to] = (game.summary[to]|0) + 1
		set_unit_hex(who, to)
		set_unit_disrupted(who)
	},
	end_retreat() {
		flush_withdraw_summary()
		end_refuse_battle_move()
	}
}

function end_refuse_battle_move() {
	if (is_friendly_rout_hex(game.refuse))
		goto_rout(game.refuse, false, end_refuse_battle_move_2)
	else
		end_refuse_battle_move_2()
}

function end_refuse_battle_move_2() {
	release_hex_control(game.refuse)
	game.refuse = 0
	goto_refuse_battle()
}

// === ROUT ===

// rout attrition
// pursuit fire
// withdraw by group move
// eliminated if cannot

function goto_rout(from, enemy, after) {
	// remember state and callback so we can resume after routing
	if (after)
		after = after.name

	game.rout = {
		state: game.state,
		active: game.active,
		after: after,
		from: from,
		attrition: [],
	}

	if (enemy)
		set_enemy_player()

	log_h4(`Routed at #${from}`)

	// RULES: Will be disrupted again, so won't be able to recover.
	for_each_friendly_unit_in_hex(from, u => {
		set_delete(game.recover, u)
	})

	if (can_all_units_disengage_and_withdraw(from)) {
		game.state = 'rout_attrition'
	} else {
		game.state = 'rout_elimination'
		game.summary = 0
	}
}

states.rout_elimination = {
	inactive: "rout",
	prompt() {
		view.prompt = "Rout: Eliminate all units that can not disengage."
		for_each_friendly_unit_in_hex(game.rout.from, u => {
			gen_action_unit(u)
		})
	},
	unit(who) {
		game.summary++
		eliminate_unit(who)
		if (!has_friendly_unit(game.rout.from)) {
			log(`Eliminated ${game.summary} at #${game.rout.from}.`)
			game.summary = null
			end_rout()
		}
	},
}

states.rout_attrition = {
	inactive: "rout",
	prompt() {
		view.prompt = "Rout: All units lose one step of rout attrition."
		for_each_friendly_unit_in_hex(game.rout.from, u => {
			if (!set_has(game.rout.attrition, u))
				gen_action_unit(u)
		})
	},
	unit(who) {
		reduce_unit(who)
		set_add(game.rout.attrition, who)
		let done = true
		for_each_friendly_unit_in_hex(game.rout.from, u => {
			if (!set_has(game.rout.attrition, u))
				done = false
		})
		if (done) {
			let d = 0, e = 0
			for (let u of game.rout.attrition)
				if (is_unit_eliminated(u))
					++e
				else
					++d
			if (d > 0)
				log(`Reduced ${e} at #${game.rout.from}.`)
			if (e > 0)
				log(`Eliminated ${e} at #${game.rout.from}.`)
			game.rout.attrition = null

			if (has_friendly_unit(game.rout.from))
				goto_rout_fire(game.rout.from)
			else
				end_rout()
		}
	},
}

function goto_rout_move() {
	if (has_friendly_unit(game.rout.from)) {
		hide_friendly_units_in_hex(game.rout.from)
		// TODO: auto-eliminate if no withdraw path available
		game.state = 'rout_move'
		game.summary = {}
	} else {
		end_rout()
	}
}

states.rout_move = {
	inactive: "rout",
	prompt() {
		if (game.selected < 0) {
			let done = true
			for_each_friendly_unit_in_hex(game.rout.from, u => {
				gen_action_unit(u)
				done = false
			})
			if (done) {
				view.prompt = `Rout: Done.`
				gen_action('end_rout')
			} else {
				view.prompt = `Rout: Select unit to withdraw.`
			}
		} else {
			view.prompt = `Rout: Select destination.`
			let speed = unit_speed[game.selected]
			let eliminate = true
			search_withdraw_retreat(game.selected, 0)
			for (let to of all_hexes) {
				if (to != game.rout.from && can_move_to(to, speed)) {
					gen_action_hex(to)
					eliminate = false
				}
			}
			// TODO: should already have eliminated?
			if (eliminate)
				gen_action('eliminate')
		}
	},
	unit(who) {
		apply_select(who)
	},
	eliminate() {
		let who = pop_selected()
		push_undo()
		game.summary[0] = (game.summary[0]|0) + 1
		eliminate_unit(who)
	},
	hex(to) {
		let who = pop_selected()
		push_undo()
		game.summary[to] = (game.summary[to]|0) + 1
		set_unit_hex(who, to)
		set_unit_disrupted(who)
	},
	end_rout() {
		flush_withdraw_summary()
		end_rout()
	}
}

function end_rout() {
	log_br()
	game.state = game.rout.state
	release_hex_control(game.rout.from)

	set_delete(game.new_battles, game.rout.from)

	if (game.active !== game.rout.active)
		set_enemy_player()
	let after = game.rout.after
	game.rout = null
	if (after)
		after_rout_table[after]()
}

// ==== COMBAT PHASE ===

function has_mandatory_withdrawals() {
	return (
		(is_mandatory_combat(BARDIA) && is_valid_withdrawal_group_move_from(BARDIA)) ||
		(is_mandatory_combat(BENGHAZI) && is_valid_withdrawal_group_move_from(BENGHAZI)) ||
		(is_mandatory_combat(TOBRUK) && is_valid_withdrawal_group_move_from(TOBRUK))
	)
}

function is_mandatory_combat(fortress) {
	if (is_battle_hex(fortress)) {
		if (game.phasing === AXIS)
			return is_fortress_allied_controlled(fortress)
		else
			return is_fortress_axis_controlled(fortress)
	}
	return false
}

function release_retreat_hex_control() {
	for (let x of all_hexes)
		if (!is_battle_hex(x))
			if (set_has(game.axis_hexes, x) || set_has(game.allied_hexes, x))
				release_hex_control(x)
}

function goto_combat_phase() {
	set_active_player()

	// Release hexes that were retreated from here
	release_retreat_hex_control()

	reveal_visited_minefields()

	if (game.turn_option === 'pass') {
		if (is_mandatory_combat(BARDIA))
			return goto_rout(BARDIA, false, goto_combat_phase)
		if (is_mandatory_combat(BENGHAZI))
			return goto_rout(BENGHAZI, false, goto_combat_phase)
		if (is_mandatory_combat(TOBRUK))
			return goto_rout(TOBRUK, false, goto_combat_phase)
		return end_combat_phase()
	}

	// exception - not mandatory during blitz combat
	if (game.turn_option !== 'second blitz') {
		if (is_mandatory_combat(BARDIA))
			set_add(game.new_battles, BARDIA)
		if (is_mandatory_combat(BENGHAZI))
			set_add(game.new_battles, BENGHAZI)
		if (is_mandatory_combat(TOBRUK))
			set_add(game.new_battles, TOBRUK)
	}

	for (let x of game.new_battles)
		set_add(game.active_battles, x)

	let n = count_and_reveal_battle_hexes()
	if (n > 0) {
		if (n > game.active_battles.length)
			return game.state = 'select_active_battles'
		if (game.turn_option === 'assault')
			return game.state = 'select_assault_battles'
		return goto_select_battle()
	}
	end_combat_phase()
}

states.select_active_battles = {
	inactive: "combat phase",
	prompt() {
		view.prompt = `Combat: Select active battles.`
		view.selected_hexes = game.active_battles
		for (let x of all_hexes) {
			if (!set_has(game.active_battles, x) && is_battle_hex(x))
				gen_action_hex(x)
			if (set_has(game.active_battles, x) && !set_has(game.new_battles, x))
				gen_action_hex(x)
		}
		if (game.active_battles.length === 0)
			gen_action('pass')
		else
			gen_action('next')
		if (game.active_battles.length > game.new_battles.length)
			gen_action('undo')
	},
	undo() {
		game.active_battles = game.new_battles.slice()
	},
	hex(x) {
		set_toggle(game.active_battles, x)
	},
	pass() {
		end_combat_phase()
	},
	next() {
		if (game.active_battles.length > 0) {
			if (game.turn_option === 'assault')
				game.state = 'select_assault_battles'
			else
				goto_select_battle()
		} else {
			end_combat_phase()
		}
	}
}

states.select_assault_battles = {
	inactive: "combat phase",
	prompt() {
		view.prompt = `Combat: Select assault battles.`
		view.selected_hexes = game.assault_battles
		for (let x of game.active_battles)
			gen_action_hex(x)
		if (game.assault_battles.length === 0)
			gen_action('pass')
		else {
			gen_action('undo')
			gen_action('next')
		}
	},
	undo() {
		set_clear(game.assault_battles)
	},
	hex(x) {
		set_toggle(game.assault_battles, x)
	},
	pass() {
		goto_select_battle()
	},
	next() {
		goto_select_battle()
	}
}

function goto_select_battle() {
	if (game.active_battles.length > 0) {
		if (game.active_battles.length > game.assault_battles.length) {
			log_br()
			log("Active battles")
			for (let x of game.active_battles)
				if (!set_has(game.assault_battles, x))
					log(`>#${x}`)
		}

		if (game.assault_battles.length > 0) {
			log_br()
			log("Assault battles")
			for (let x of game.assault_battles)
				log(`>#${x}`)
		}

		// TODO: auto-select here?
		if (game.active_battles.length === 1)
			goto_battle(game.active_battles[0])
		else
			game.state = 'select_battle'
	} else {
		end_combat_phase()
	}
}

states.select_battle = {
	inactive: "combat phase",
	prompt() {
		view.prompt = `Combat: Select next battle.`
		view.active_battles = game.active_battles
		view.assault_battles = game.assault_battles
		for (let x of game.active_battles)
			gen_action_hex(x)
	},
	hex(x) {
		goto_battle(x)
	},
}

function end_combat_phase() {
	if (game.turn_option === 'blitz')
		goto_blitz_turn()
	else
		goto_final_supply_check()
}

function goto_blitz_turn() {
	log_h2(`Blitz Turn`)
	game.used = 0
	if (game.rommel)
		game.rommel = 3
	game.turn_option = 'second blitz'
	goto_move_phase()
}

// === BATTLES ===

// Normal Battle:
//	passive fire
//	active hits
//	active fire
//	passive hits

function is_unit_retreating(u) {
	if (game.retreat_units)
		return set_has(game.retreat_units, u)
	return false
}

function is_assault_battle() {
	return set_has(game.assault_battles, game.battle)
}

function is_fortress_defensive_fire() {
	if ((game.state === 'battle_fire' && is_passive_player()) || (game.state === 'probe_fire' && is_active_player())) {
		if (game.battle === BARDIA)
			return is_fortress_friendly_controlled(BARDIA)
		if (game.battle === BENGHAZI)
			return is_fortress_friendly_controlled(BENGHAZI)
		if (game.battle === TOBRUK)
			return is_fortress_friendly_controlled(TOBRUK)
	}
	return false
}

function is_minefield_offensive_fire() {
	if ((game.state === 'battle_fire' && is_active_player()) || (game.state === 'probe_fire' && is_passive_player())) {
		if (set_has(game.minefields[MF_VISIBLE], game.battle)) {
			// DD advantage is lost if the defender initiated combat
			if (is_axis_player())
				return set_has(game.allied_hexes, game.battle)
			else
				return set_has(game.axis_hexes, game.battle)
		}
	}
	return false
}

function roll_battle_fire(who, tc) {
	let fc = unit_class[who]
	let cv = unit_cv(who)
	let n = 1

	// Double dice during assault
	if (is_assault_battle())
		n *= 2

	// Double dice for non-armor defenders in fortress!
	if (fc !== ARMOR && is_fortress_defensive_fire())
		n *= 2

	let fp = FIREPOWER_MATRIX[fc][tc]
	let result = []
	let total = 0
	for (let k = 0; k < n; ++k) {
		if (k > 0)
			result.push(" ")
		for (let i = 0; i < cv; ++i) {
			let roll = roll_die()
			if (roll >= fp) {
				result.push(die_face_hit[roll])
				++total
			} else {
				result.push(die_face_miss[roll])
			}
		}
	}

	// Double defense in minefields!
	if (fc !== ARTILLERY && is_minefield_offensive_fire())
		total = total / 2

	game.flash = `${class_name_cap[fc]} ${firepower_name[fp]} ${result.join("")} at ${class_name[tc]}.`
	log(game.flash)
	return total
}

function goto_battle(x) {
	game.battle = x

	if (is_assault_battle())
		log_h3(`Assault at #${x}`)
	else
		log_h3(`Battle at #${x}`)

	// goto defensive fire
	log_h4(`Defensive Fire`)
	set_passive_player()
	game.state = 'battle_fire'
	game.hits = [ 0, 0, 0, 0 ]
}

function end_battle() {
	if (!is_battle_hex(game.battle))
		release_hex_control(game.battle)

	set_delete(game.new_battles, game.battle)
	set_delete(game.active_battles, game.battle)
	set_delete(game.assault_battles, game.battle)

	game.flash = ""
	game.battle = 0
	game.hits = 0

	set_active_player()
	if (game.active_battles.length > 0)
		game.state = 'select_battle'
	else
		end_combat_phase()
}

function apply_battle_fire(tc) {
	let who = pop_selected()

	set_unit_fired(who)

	game.hits[tc] += roll_battle_fire(who, tc)

	let hp = count_hp_in_battle()

	// clamp to available hit points
	game.hits[tc] = min(game.hits[tc], hp[tc])
}

function goto_hits() {
	set_enemy_player()

	// round down half-hits from double defense
	game.hits[0] |= 0
	game.hits[1] |= 0
	game.hits[2] |= 0
	game.hits[3] |= 0

	game.flash = "Inflicted " + format_hits() + "."
	log(game.flash)

	if (game.hits[0] + game.hits[1] + game.hits[2] + game.hits[3] > 0) {
		if (game.state === 'battle_fire')
			game.state = 'battle_hits'
		else
			game.state = 'probe_hits'
	} else {
		if (game.state === 'battle_fire')
			end_battle_hits()
		else
			end_probe_hits()
	}
}

function gen_battle_fire() {
	let arty = false
	let done = true
	let hp = count_hp_in_battle()
	if (game.hits[0] < hp[0] || game.hits[1] < hp[1] || game.hits[2] < hp[2] || game.hits[3] < hp[3]) {
		for_each_undisrupted_friendly_unit_in_hex(game.battle, u => {
			if (is_artillery_unit(u) && !is_unit_retreating(u)) {
				if (!is_unit_fired(u)) {
					gen_action_unit(u)
					arty = true
					done = false
				}
			}
		})
		if (!arty) {
			for_each_undisrupted_friendly_unit_in_hex(game.battle, u => {
				if (!is_unit_fired(u) && !is_unit_retreating(u)) {
					gen_action_unit(u)
					done = false
				}
			})
		}
	}
	if (done)
		gen_action('end_fire')
}

function gen_battle_target() {
	let hp = count_hp_in_battle()
	for (let i = 0; i < 4; ++i)
		hp[i] -= game.hits[i]

	let who = game.selected
	let fc = unit_class[who]

	gen_action_unit(who) // deselect

	// armor must target armor if possible
	if (fc === ARMOR && hp[ARMOR] > 0) {
		gen_action('armor')
		return
	}

	// infantry must target infantry if possible
	if (fc === INFANTRY && hp[INFANTRY] > 0) {
		gen_action('infantry')
		return
	}

	if (hp[ARMOR] > 0)
		gen_action('armor')
	if (hp[INFANTRY] > 0)
		gen_action('infantry')
	if (hp[ANTITANK] > 0)
		gen_action('antitank')

	// only artillery may target artillery if other units are alive
	if (hp[ARTILLERY] > 0) {
		if (fc === ARTILLERY || (hp[ARMOR] <= 0 && hp[INFANTRY] <= 0 && hp[ANTITANK] <= 0))
			gen_action('artillery')
	}
}

function apply_auto_target(who) {
	let hp = count_hp_in_battle()
	for (let i = 0; i < 4; ++i)
		hp[i] -= game.hits[i]

	let fc = unit_class[who]

	// armor must target armor if possible
	if (fc === ARMOR && hp[ARMOR] > 0)
		return apply_battle_fire(ARMOR)

	// infantry must target infantry if possible
	if (fc === INFANTRY && hp[INFANTRY] > 0)
		return apply_battle_fire(INFANTRY)

	// only one class remains
	if (fc === ARTILLERY) {
		// Artillery may always target anything
		if (hp[ARMOR] > 0 && hp[INFANTRY] === 0 && hp[ANTITANK] === 0 && hp[ARTILLERY] === 0)
			return apply_battle_fire(ARMOR)
		if (hp[ARMOR] === 0 && hp[INFANTRY] > 0 && hp[ANTITANK] === 0 && hp[ARTILLERY] === 0)
			return apply_battle_fire(INFANTRY)
		if (hp[ARMOR] === 0 && hp[INFANTRY] === 0 && hp[ANTITANK] > 0 && hp[ARTILLERY] === 0)
			return apply_battle_fire(ANTITANK)
		if (hp[ARMOR] === 0 && hp[INFANTRY] === 0 && hp[ANTITANK] === 0 && hp[ARTILLERY] > 0)
			return apply_battle_fire(ARTILLERY)
	} else {
		// Non-artillery may only target artillery if no other targets remain
		if (hp[ARMOR] > 0 && hp[INFANTRY] === 0 && hp[ANTITANK] === 0)
			return apply_battle_fire(ARMOR)
		if (hp[ARMOR] === 0 && hp[INFANTRY] > 0 && hp[ANTITANK] === 0)
			return apply_battle_fire(INFANTRY)
		if (hp[ARMOR] === 0 && hp[INFANTRY] === 0 && hp[ANTITANK] > 0)
			return apply_battle_fire(ANTITANK)
		if (hp[ARMOR] === 0 && hp[INFANTRY] === 0 && hp[ANTITANK] === 0 && hp[ARTILLERY] > 0)
			return apply_battle_fire(ARTILLERY)
	}
}

function gen_battle_hits() {
	let normal_steps = count_normal_steps_in_battle()
	let elite_steps = count_elite_steps_in_battle()
	let done = true
	for_each_undisrupted_friendly_unit_in_hex(game.battle, u => {
		if (!is_unit_retreating(u)) {
			let c = unit_class[u]
			if (is_elite_unit(u)) {
				if (game.hits[c] >= 2) {
					gen_action_unit_hit(u)
					done = false
				}
			} else {
				if (game.hits[c] >= 1) {
					// If mixed elite and non-elite: must assign ALL damage.
					if (elite_steps[c] > 0 && normal_steps[c] === 1 && (game.hits[c] & 1) === 0) {
						// Eliminating the last non-elite must not leave an odd
						// number of hits remaining.
					} else {
						gen_action_unit_hit(u)
						done = false
					}
				}
			}
		}
	})
	if (done)
		gen_action('end_hits')
	return done
}

function apply_battle_hit(who) {
	if (unit_steps(who) === 1) {
		log(`Eliminated ${class_name[unit_class[who]]}.`)
		game.flash = `Eliminated ${class_name[unit_class[who]]} \u2014 `
	} else {
		game.flash = `Reduced ${class_name[unit_class[who]]} \u2014 `
	}
	game.hits[unit_class[who]] -= reduce_unit(who)
	game.flash += format_hits() + " left."
}

states.battle_fire = {
	inactive: "battle fire",
	show_battle: true,
	prompt() {
		if (game.active === game.phasing)
			view.prompt = `Battle: Offensive Fire!`
		else
			view.prompt = `Battle: Defensive Fire!`
		if (game.selected < 0)
			gen_battle_fire()
		else
			gen_battle_target()
	},
	unit(who) {
		apply_select(who)
		if (game.selected >= 0)
			apply_auto_target(who)
	},
	armor() {
		apply_battle_fire(ARMOR)
	},
	infantry() {
		apply_battle_fire(INFANTRY)
	},
	antitank() {
		apply_battle_fire(ANTITANK)
	},
	artillery() {
		apply_battle_fire(ARTILLERY)
	},
	end_fire() {
		goto_hits()
	},
}

states.battle_hits = {
	inactive: "battle hits",
	show_battle: true,
	prompt() {
		if (game.active === game.phasing)
			view.prompt = `Battle: Allocate ${format_hits()} from Defensive Fire.`
		else
			view.prompt = `Battle: Allocate ${format_hits()} from Offensive Fire.`
		gen_battle_hits()
	},
	unit_hit(who) {
		push_undo()
		apply_battle_hit(who)
	},
	end_hits() {
		end_battle_hits()
	},
}

function end_battle_hits() {
	if (is_friendly_rout_hex(game.battle)) {
		goto_rout(game.battle, false, end_battle)
	} else if (game.active === game.phasing && has_friendly_units_in_battle()) {
		// goto offensive fire
		log_h4(`Offensive Fire`)
		game.state = 'battle_fire'
		game.hits = [ 0, 0, 0, 0 ]
	} else {
		end_battle()
	}
}

states.probe_fire = {
	inactive: "probe combat fire",
	show_battle: true,
	prompt() {
		if (game.active !== game.phasing)
			view.prompt = `Probe: Offensive Fire!`
		else
			view.prompt = `Probe: Defensive Fire!`
		if (game.selected < 0)
			gen_battle_fire()
		else
			gen_battle_target()
	},
	unit(who) {
		apply_select(who)
		if (game.selected >= 0)
			apply_auto_target(who)
	},
	armor() {
		apply_battle_fire(ARMOR)
	},
	infantry() {
		apply_battle_fire(INFANTRY)
	},
	antitank() {
		apply_battle_fire(ANTITANK)
	},
	artillery() {
		apply_battle_fire(ARTILLERY)
	},
	end_fire() {
		goto_hits()
	},
}

states.probe_hits = {
	inactive: "probe combat hits",
	show_battle: true,
	prompt() {
		if (game.active !== game.phasing)
			view.prompt = `Probe: Allocate ${format_hits()} from Defensive Fire.`
		else
			view.prompt = `Probe: Allocate ${format_hits()} from Offensive Fire.`
		gen_battle_hits()
	},
	unit_hit(who) {
		push_undo()
		apply_battle_hit(who)
	},
	end_hits() {
		end_probe_hits()
	},
}

function end_probe_hits() {
	// TODO: rout during probe combat?
	if (game.active !== game.phasing && has_friendly_units_in_battle()) {
		// goto offensive fire
		game.state = 'probe_fire'
		game.hits = [ 0, 0, 0, 0 ]
	} else {
		end_probe()
	}
}

// === PURSUIT FIRE ===

// Refuse battle
//	active pursuit fire
//	passive apply hits
//	passive moves

// Retreat
//	passive pursuit fire
//	active apply hits
//	active moves

// Rout
//	non-routing pursuit fire
//	routing apply hits
//	routing moves

function slowest_enemy_unit_speed(where) {
	let r = 5
	for_each_enemy_unit_in_hex(where, u => {
		let s = unit_speed[u]
		if (s < r)
			r = s
	})
	return r
}

function slowest_undisrupted_enemy_unit_speed(where) {
	let r = 5
	for_each_undisrupted_enemy_unit_in_hex(where, u => {
		let s = unit_speed[u]
		if (s < r)
			r = s
	})
	return r
}

function slowest_undisrupted_friendly_unit(where) {
	let who = -1
	let r = 5
	for_each_undisrupted_friendly_unit_in_hex(where, u => {
		let s = unit_speed[u]
		if (s < r) {
			who = u
			r = s
		}
	})
	return who
}

function fastest_undisrupted_friendly_unit(where) {
	let who = -1
	let r = 0
	for_each_undisrupted_friendly_unit_in_hex(where, u => {
		let s = unit_speed[u]
		if (s > r) {
			who = u
			r = s
		}
	})
	return who
}

function fastest_undisrupted_friendly_unit_speed(where) {
	let r = 0
	for_each_undisrupted_friendly_unit_in_hex(where, u => {
		let s = unit_speed[u]
		if (s > r)
			r = s
	})
	return r
}

function has_hidden_friendly_unit(x) {
	for (let u = first_friendly_unit; u <= last_friendly_unit; ++u)
		if (unit_hex(u) === x && !set_has(game.revealed, u))
			return true
	return false
}

function goto_rout_fire(where) {
	set_enemy_player()
	game.hits = 0
	game.pursuit = where
	game.flash = ""

	let slowest = slowest_enemy_unit_speed(game.pursuit)
	let fastest = fastest_undisrupted_friendly_unit_speed(game.pursuit)

	log(`Slowest was ${speed_name[slowest]} unit.`)
	if (slowest <= fastest || has_hidden_friendly_unit(game.pursuit)) {
		game.state = 'rout_fire'
	} else {
		// too fast for pursuit fire, and we already know all the units involved
		set_enemy_player()
		end_rout_fire()
	}
}

function goto_pursuit_fire_during_retreat(where) {
	set_passive_player()
	game.hits = 0
	game.pursuit = where
	game.flash = ""

	let slowest = slowest_undisrupted_enemy_unit_speed(game.pursuit)
	let fastest = fastest_undisrupted_friendly_unit_speed(game.pursuit)

	log(`Slowest was ${speed_name[slowest]} unit.`)
	if (slowest <= fastest) {
		game.state = 'pursuit_fire'
	} else {
		// too fast for pursuit fire, and we already know all the units involved
		end_pursuit_fire()
	}
}

function goto_pursuit_fire_during_refuse_battle(where) {
	set_active_player()
	game.hits = 0
	game.pursuit = where
	let slowest = slowest_undisrupted_enemy_unit_speed(game.pursuit)
	log(`Slowest was ${speed_name[slowest]} unit.`)
	game.state = 'pursuit_fire'
}

function format_hits() {
	if (typeof game.hits === 'number') {
		if (game.hits === 0)
			return "zero hits"
		if (game.hits === 1)
			return "1 hit"
		return game.hits + " hits"
	}

	let n = game.hits[0] + game.hits[1] + game.hits[2] + game.hits[3]
	if (n === 0)
		return `zero hits`

	let s = []
	if (game.hits[ARMOR] > 0)
		s.push(game.hits[ARMOR] + " armor")
	if (game.hits[INFANTRY] > 0)
		s.push(game.hits[INFANTRY] + " infantry")
	if (game.hits[ANTITANK] > 0)
		s.push(game.hits[ANTITANK] + " anti-tank")
	if (game.hits[ARTILLERY] > 0)
		s.push(game.hits[ARTILLERY] + " artillery")

	if (n === 1)
		return s.join(", ") + " hit"
	return s.join(", ") + " hits"
}

function goto_rout_hits() {
	set_enemy_player()
	game.flash = ""
	if (game.hits > 0)
		game.state = 'rout_hits'
	else
		end_rout_fire()
}

function goto_pursuit_hits() {
	set_enemy_player()
	game.flash = ""
	if (game.hits > 0)
		game.state = 'pursuit_hits'
	else
		end_pursuit_fire()
}

function roll_pursuit_fire_imp(who, n, hp) {
	let speed = unit_speed[who]
	if (n === 2) {
		let astr, bstr
		let a = roll_die()
		let b = roll_die()
		if (a >= 4) {
			game.hits++
			astr = die_face_hit[a]
		} else {
			astr = die_face_miss[a]
		}
		if (b >= 4) {
			game.hits++
			bstr = die_face_hit[b]
		} else {
			bstr = die_face_miss[b]
		}
		game.flash = `${speed_name_cap[speed]} fired ${astr}${bstr}.`
	}
	if (n === 1) {
		let astr
		let a = roll_die()
		if (a >= 4) {
			game.hits++
			astr = die_face_hit[a]
		} else {
			astr = die_face_miss[a]
		}
		game.flash = `${speed_name_cap[speed]} fired ${astr}.`
	}
	log(game.flash)
	if (game.hits > hp)
		game.hits = hp
	return game.hits === hp
}

function roll_pursuit_fire(who, n) {
	return roll_pursuit_fire_imp(who, n, count_hp_in_pursuit())
}

function roll_rout_fire(who, n) {
	return roll_pursuit_fire_imp(who, n, count_hp_in_rout())
}

states.pursuit_fire = {
	inactive: "pursuit fire",
	show_pursuit: true,
	prompt() {
		view.prompt = `Pursuit Fire: Fire or withhold.`
		if (game.hits < count_hp_in_pursuit()) {
			let slowest = slowest_undisrupted_enemy_unit_speed(game.pursuit)
			for_each_undisrupted_friendly_unit_in_hex(game.pursuit, u => {
				if (unit_speed[u] >= slowest && !is_unit_fired(u)) {
					gen_action_unit(u)
				}
			})
		}
		gen_action('end_fire')
	},
	unit(who) {
		let slowest = slowest_undisrupted_enemy_unit_speed(game.pursuit)
		roll_pursuit_fire(who, (unit_speed[who] > slowest ? 2 : 1))
		set_unit_fired(who)
	},
	end_fire() {
		goto_pursuit_hits()
	},
}

states.rout_fire = {
	inactive: "rout fire",
	show_pursuit: true,
	prompt() {
		view.prompt = `Pursuit Fire: Fire or withhold.`
		if (game.hits < count_hp_in_rout()) {
			let slowest = slowest_enemy_unit_speed(game.pursuit)
			for_each_undisrupted_friendly_unit_in_hex(game.pursuit, u => {
				if (unit_speed[u] >= slowest && !is_unit_fired(u)) {
					gen_action_unit(u)
				}
			})
		}
		gen_action('end_fire')
	},
	unit(who) {
		let slowest = slowest_enemy_unit_speed(game.pursuit)
		roll_rout_fire(who, (unit_speed[who] > slowest ? 2 : 1))
		set_unit_fired(who)
	},
	end_fire() {
		goto_rout_hits()
	},
}

function gen_pursuit_hits(normal_steps, elite_steps, iterate) {
	let done = true
	iterate(game.pursuit, u => {
		if (is_elite_unit(u)) {
			if (game.hits >= 2) {
				gen_action_unit_hit(u)
				done = false
			}
		} else {
			if (game.hits >= 1) {
				// If mixed elite and non-elite: must assign ALL damage.
				if (elite_steps > 0 && normal_steps === 1 && (game.hits & 1) === 0) {
					// Eliminating the last non-elite must not leave an odd
					// number of hits remaining.
				} else {
					gen_action_unit_hit(u)
					done = false
				}
			}
		}
	})
	if (done)
		gen_action('end_hits')
}

states.pursuit_hits = {
	inactive: "pursuit hits",
	show_pursuit: true,
	prompt() {
		view.prompt = "Pursuit Fire: Allocate " + format_hits() + "."
		let normal_steps = count_normal_steps_in_pursuit()
		let elite_steps = count_elite_steps_in_pursuit()
		gen_pursuit_hits(normal_steps, elite_steps, for_each_undisrupted_friendly_unit_in_hex)
	},
	unit_hit(who) {
		push_undo()
		// TODO: flash?
		let where = unit_hex(who)
		game.hits -= reduce_unit(who)
		if (is_unit_eliminated(who))
			log(`Eliminated at #${where}.`)
	},
	end_hits() {
		end_pursuit_fire()
	},
}

states.rout_hits = {
	inactive: "rout hits",
	show_pursuit: true,
	prompt() {
		view.prompt = "Pursuit Fire: Allocate " + format_hits() + "."
		let normal_steps = count_normal_steps_in_rout()
		let elite_steps = count_elite_steps_in_rout()
		gen_pursuit_hits(normal_steps, elite_steps, for_each_friendly_unit_in_hex)
	},
	unit_hit(who) {
		push_undo()
		// TODO: flash?
		let where = unit_hex(who)
		game.hits -= reduce_unit(who)
		if (is_unit_eliminated(who))
			log(`Eliminated at #${where}.`)
	},
	end_hits() {
		end_rout_fire()
	},
}

function end_pursuit_fire() {
	game.flash = ""
	game.pursuit = 0
	if (game.retreat) {
		goto_retreat_move()
	} else {
		goto_refuse_battle_move()
	}
}

function end_rout_fire() {
	game.flash = ""
	game.pursuit = 0
	goto_rout_move()
}

// === BUILDUP - SUPPLY CHECK ===

function end_month() {
	set_clear(game.fired)
	set_clear(game.moved)

	// Forget captured fortresses (for bonus cards)
	clear_fortresses_captured()

	if (game.month === current_scenario().end)
		return goto_end_game()

	goto_buildup()
}

function goto_buildup() {
	++game.month
	log_h1(current_month_name())

	game.phasing = AXIS
	set_active_player()
	goto_buildup_supply_check()
}

function goto_buildup_supply_check() {
	let base_net = friendly_supply_network()
	for_each_friendly_unit_on_map(u => {
		if (base_net[unit_hex(u)])
			set_unit_supply(u, SS_BASE)
		else
			set_unit_supply(u, SS_NONE)
	})

	if (is_axis_player())
		game.capacity = [ 1, 1, 2 ]
	else
		game.capacity = [ 2, 2, 5 ]
	game.oasis = [ 1, 1, 1 ]

	goto_fortress_supply('buildup_fortress_supply')
}

function goto_buildup_supply_check_recover() {
	let summary = []
	for_each_friendly_unit_on_map(u => {
		if (is_unit_supplied(u) && is_unit_disrupted(u) && !is_battle_hex(unit_hex(u))) {
			set_add(summary, unit_hex(u))
			clear_unit_disrupted(u)
		}
	})
	for (let x of summary)
		log(`Recovered at #${x}.`)
	resume_buildup_eliminate_unsupplied()
}

function resume_buildup_eliminate_unsupplied() {
	game.state = 'buildup_eliminate_unsupplied'
	let done = true
	for_each_friendly_unit_on_map(u => {
		if (is_unit_unsupplied(u))
			done = false
	})
	if (done) {
		if (is_axis_player()) {
			set_enemy_player()
			goto_buildup_supply_check()
		} else {
			goto_buildup_point_determination()
		}
	}
}

states.buildup_eliminate_unsupplied = {
	inactive: "buildup",
	prompt() {
		view.prompt = `Buildup: Eliminate unsupplied units.`
		for_each_friendly_unit_on_map(u => {
			if (is_unit_unsupplied(u))
				gen_action_unit(u)
		})
	},
	unit(u) {
		log(`Eliminated at #${unit_hex(u)}.`)
		eliminate_unit(u)
		resume_buildup_eliminate_unsupplied()
	},
}

// === BUILDUP - POINT DETERMINATION ===

function is_pregame_buildup() {
	return game.scenario === "Gazala" && game.month === 14
}

function goto_pregame_buildup() {
	game.phasing = ALLIED
	init_buildup()
	game.axis_bps = 30
	game.allied_bps = 30
	set_active_player()
	goto_buildup_discard()
}

function init_buildup() {
	game.buildup = {
		// redeployment network
		axis_network: union_axis_network(),
		axis_line: union_axis_line(),
		allied_network: union_allied_network(),
		allied_line: union_allied_line(),

		// extra cards purchased
		axis_cards: 0,
		allied_cards: 0,

		// remaining port capacity for sea redeployment
		bardia: is_fortress_axis_controlled(BARDIA) ? 1 : 2,
		benghazi: is_fortress_axis_controlled(BENGHAZI) ? 1 : 2,
		tobruk: is_fortress_axis_controlled(TOBRUK) ? 2 : 5,

		// for undo tracking
		changed: 0
	}
}

function goto_buildup_point_determination() {
	let axis, allied

	// take union of supply networks?

	init_buildup()

	log_br()
	if (game.scenario === "1940") {
		axis = roll_die()
		allied = roll_die()
		log(`Axis rolled ${axis}.`)
		log(`Allied rolled ${allied}.`)
	} else {
		let axis_a = roll_die()
		let axis_b = roll_die()
		let allied_a = roll_die()
		let allied_b = roll_die()
		axis = axis_a + axis_b
		allied = allied_a + allied_b
		log(`Axis rolled ${axis_a} + ${axis_b}.`)
		log(`Allied rolled ${allied_a} + ${allied_b}.`)
	}

	log(`Received ${axis + allied} BPs.`)
	game.axis_bps += axis + allied
	game.allied_bps += axis + allied

	if (allied <= axis)
		game.phasing = ALLIED
	else
		game.phasing = AXIS

	set_active_player()
	goto_buildup_discard()
}

// === BUILDUP - DISCARD ===

function goto_buildup_discard() {
	log_h2(game.active + " Buildup")

	let hand = player_hand()
	if (hand[REAL] + hand[DUMMY] === 0) {
		goto_buildup_reinforcements()
	} else {
		game.state = 'buildup_discard'
		game.summary = 0
	}
}

states.buildup_discard = {
	inactive: "buildup",
	prompt() {
		view.prompt = "Buildup: Discard any unwanted dummy cards."
		let hand = player_hand()
		if (hand[DUMMY] > 0)
			gen_action('dummy_card')
		gen_action('next')
	},
	dummy_card() {
		push_undo()
		let hand = player_hand()
		hand[DUMMY]--
		game.summary++
	},
	next() {
		log(`${game.active} discarded ${game.summary} dummy supply.`)
		goto_buildup_reinforcements()
	},
}

// === BUILDUP - REINFORCEMENTS ===

function have_scheduled_reinforcements() {
	let refit = friendly_refit()
	for (let u = first_friendly_unit; u <= last_friendly_unit; ++u) {
		let x = unit_hex(u)
		if (x === refit || x === hexdeploy + game.month || x === hexdeploy + game.month + 1)
			return true
	}
}

function goto_buildup_reinforcements() {
	if (have_scheduled_reinforcements())
		game.state = 'buildup_reinforcements'
	else
		goto_buildup_spending()
}

states.buildup_reinforcements = {
	inactive: "buildup",
	prompt() {
		view.prompt = `Buildup: Bring on reinforcements.`

		view.selected = []
		for_each_friendly_unit_in_month(game.month, u => {
			set_add(view.selected, u)
		})
		if (game.month < current_scenario().end) {
			for_each_friendly_unit_in_month(game.month+1, u => {
				set_add(view.selected, u)
			})
		}

		gen_action_hex(friendly_base())
	},
	hex(_base) {
		apply_reinforcements()
		goto_buildup_spending()
	},
}

function apply_reinforcements() {
	let base = friendly_base()
	let refitted = 0
	let scheduled = 0
	let early = 0

	if (is_battle_hex(base))
		base = friendly_queue()

	for_each_friendly_unit_in_hex(friendly_refit(), u => {
		set_unit_hex(u, base)
		refitted++
	})

	for_each_friendly_unit_in_month(game.month, u => {
		set_unit_hex(u, base)
		scheduled++
	})

	if (game.month < current_scenario().end) {
		for_each_friendly_unit_in_month(game.month + 1, u => {
			if (roll_die() <= 2) {
				set_unit_hex(u, base)
				early++
			}
		})
	}

	log(`Reinforcements at #${base}`)
	if (refitted > 0)
		log(`>${refitted} refitted`)
	log(`>${scheduled} on schedule`)
	log(`>${early} early`)
}

// === BUILDUP - SPENDING BPS ===

function goto_buildup_spending() {
	game.state = 'spending_bps'
	game.summary = {
		refit: 0,
		redeployed: {},
		replaced_steps: 0,
		replaced_bps: 0,
		dismantled: 0,
		built: 0,
		cards: 0,
	}
}

function print_buildup_summary() {
	let keys = Object.keys(game.summary.redeployed).map(Number).sort((a,b)=>a-b)
	if (keys.length > 0) {
		log("Redeployed")
		for (let mm of keys) {
			let n = game.summary.redeployed[mm]
			let from = (mm) & 255
			let to = (mm >>> 8 ) & 255
			let sea = (mm >>> 16) & 255
			if (sea)
				log(`>${n} #${from} to #${to} *`)
			else
				log(`>${n} #${from} to #${to}`)
		}
	}

	if (game.summary.refit > 0)
		log(`Returned ${game.summary.refit} for Refit.`)

	if (game.summary.replaced_steps > 0)
		log(`Replaced ${game.summary.replaced_steps} steps for ${game.summary.replaced_bps} BPs.`)

	if (game.summary.dismantled > 0)
		log(`Dismantled ${game.summary.dismantled} minefields.`)
	if (game.summary.built === 1)
		log(`Built 1 minefield.`)
	else if (game.summary.built > 1)
		log(`Built ${game.summary.built} minefields.`)

	let cards = is_axis_player() ? game.buildup.axis_cards : game.buildup.allied_cards
	if (cards === 1)
		log(`Purchased 1 extra card.`)
	else if (cards > 1)
		log(`Purchased ${cards} extra cards.`)

	game.summary = null
}

function push_buildup_summary(from, to, sea) {
	let mm = (from) | (to << 8) | (sea << 16)
	game.summary.redeployed[mm] = (game.summary.redeployed[mm]|0) + 1
}

function available_bps() {
	if (is_axis_player())
		return game.axis_bps
	else
		return game.allied_bps
}

function pay_bps(n) {
	if (is_axis_player())
		game.axis_bps -= n
	else
		game.allied_bps -= n
}

function count_friendly_minefields() {
	let net = friendly_buildup_network()
	let n = 0
	for (let x of friendly_minefields())
		if (net[x] && !is_battle_hex(x))
			++n
	for (let x of game.minefields[MF_VISIBLE])
		if (net[x] && !is_battle_hex(x))
			++n
	return n
}

function replacement_cost(who) {
	let cost = (unit_class[who] === INFANTRY) ? (unit_speed[who] > 1) ? 2 : 1 : 3
	if (is_elite_unit(who))
		return 2 * cost
	return cost
}

function can_redeploy_from(from) {
	if (is_battle_hex(from)) {
		let n = 0
		for_each_undisrupted_friendly_unit_in_hex(from, _u => {
			n++
		})
		return n > 1
	}
	return true
}

function is_port_friendly(where) {
	if (where === BARDIA || where === BENGHAZI || where === TOBRUK)
		return is_fortress_friendly_controlled(where)
	return true
}

function sea_redeploy_cost(from, to) {
	if ((from === BARDIA || to === BARDIA) && game.buildup.bardia === 0)
		return 0
	if ((from === BENGHAZI || to === BENGHAZI) && game.buildup.benghazi === 0)
		return 0
	if ((from === TOBRUK || to === TOBRUK) && game.buildup.tobruk === 0)
		return 0
	if (is_port_friendly(from) && is_port_friendly(to)) {
		let b_from = is_port_besieged(from)
		let b_to = is_port_besieged(to)
		if (b_from && b_to)
			return 0
		if (b_from || b_to) {
			if (is_axis_player())
				return 0
			return 4
		}
		return 1
	}
	return 0
}

function gen_sea_redeployment(from, to) {
	let cost = sea_redeploy_cost(from, to)
	if (cost && cost <= available_bps())
		gen_action_hex(to)
}

function gen_spending_bps() {
	let who = game.selected
	let bps = available_bps()
	let base = friendly_base()
	let from = unit_hex(who)

	// Receive replacement in base
	if (from === base && unit_lost_steps(who) > 0) {
		if (bps >= replacement_cost(who))
			view.actions.replacement = 1
		else
			view.actions.replacement = 0
	}

	if (can_redeploy_from(from)) {
		search_redeploy(from)

		// Return for Refit
		if (from !== base) {
			if (path_cost[0][base] < 63) {
				view.actions.refit = 1
				gen_action_hex(friendly_refit())
			}
		}

		// Redeployment
		if (bps > 0) {
			for (let x of all_hexes)
				if (x !== from && can_move_to(x, 2))
					gen_action_hex(x)
		}

		// Sea Redeployment
		if (from === base) {
			gen_sea_redeployment(base, BARDIA)
			gen_sea_redeployment(base, BENGHAZI)
			gen_sea_redeployment(base, TOBRUK)
		}
		if (from === BARDIA) {
			gen_sea_redeployment(BARDIA, BENGHAZI)
			gen_sea_redeployment(BARDIA, TOBRUK)
			gen_sea_redeployment(BARDIA, base)
		}
		if (from === BENGHAZI) {
			gen_sea_redeployment(BENGHAZI, BARDIA)
			gen_sea_redeployment(BENGHAZI, TOBRUK)
			gen_sea_redeployment(BENGHAZI, base)
		}
		if (from === TOBRUK) {
			gen_sea_redeployment(TOBRUK, BARDIA)
			gen_sea_redeployment(TOBRUK, BENGHAZI)
			gen_sea_redeployment(TOBRUK, base)
		}
	}
}

states.spending_bps = {
	inactive: "buildup",
	prompt() {
		view.prompt = `Buildup: Spend buildup points (${available_bps()} remain).`
		let bps = available_bps()
		for_each_friendly_unit_on_map(u => {
			if (is_unit_undisrupted(u))
				gen_action_unit(u)
		})
		if (game.selected < 0) {
			if (game.month >= 11 && has_friendly_unit_in_raw_hex(MALTA))
				gen_action_hex(MALTA)
			if (count_friendly_minefields() >= 1 || bps >= 15)
				gen_action('minefield')
			if (bps >= 10)
				gen_action('extra_supply_card')
		} else {
			gen_spending_bps()
		}
		gen_action('end_buildup')
	},
	unit(who) {
		if (game.selected < 0) {
			push_undo()
			game.selected = who
			game.buildup.changed = 0
		} else {
			if (who === game.selected) {
				if (unit_hex(who) === friendly_base() && unit_lost_steps(who) > 0 && available_bps() >= replacement_cost(who))
					return this.replacement()
				if (!game.buildup.changed)
					pop_undo()
				else
					game.selected = -1
			} else {
				game.selected = -1
				if (game.buildup.changed)
					push_undo()
				game.selected = who
				game.buildup.changed = 0
			}
		}
	},
	extra_supply_card() {
		push_undo()
		if (is_axis_player())
			game.buildup.axis_cards++
		else
			game.buildup.allied_cards++
		pay_bps(10)
	},
	minefield() {
		push_undo()
		game.state = 'minefield'
	},
	replacement() {
		game.buildup.changed = 1
		game.summary.replaced_steps ++
		game.summary.replaced_bps += replacement_cost(game.selected)
		replace_unit(game.selected)
		pay_bps(replacement_cost(game.selected))
	},
	refit() {
		game.buildup.changed = 1
		game.summary.refit ++
		hide_unit(game.selected)
		set_unit_hex(pop_selected(), friendly_refit())
	},
	hex(to) {
		if (to === MALTA) {
			push_undo()
			log(`Malta Group arrived.`)
			log(`Axis Resupply dropped to 2.`)
			let base = friendly_base()
			if (is_battle_hex(base))
				base = friendly_queue()
			for_each_friendly_unit_in_hex(MALTA, u => {
				set_unit_hex(u, base)
			})
			game.malta = 1
			return
		}

		game.buildup.changed = 1
		let who = game.selected
		let from = unit_hex(who)
		if (to === from) {
			game.selected = -1
		} else if (to === friendly_refit()) {
			game.summary.refit ++
			hide_unit(game.selected)
			set_unit_hex(pop_selected(), friendly_refit())
		} else {
			search_redeploy(from)
			if (can_move_to(to, 2)) {
				push_buildup_summary(from, to, 0)
				pay_bps(1)
			} else {
				push_buildup_summary(from, to, 1)
				if (is_fortress_besieged(from) || is_fortress_besieged(to))
					pay_bps(4)
				else
					pay_bps(1)
				if (from === BARDIA || to === BARDIA)
					game.buildup.bardia--
				if (from === BENGHAZI || to === BENGHAZI)
					game.buildup.benghazi--
				if (from === TOBRUK || to === TOBRUK)
					game.buildup.tobruk--
			}
			set_unit_hex(who, to)
			hide_unit(who)
		}
	},
	end_buildup() {
		end_buildup_spending()
	}
}

function end_buildup_spending() {
	game.selected = -1

	print_buildup_summary()

	let n = available_bps()
	if (n > 20) {
		log(`Lost ${n - 20} unspent BPs.`)
		pay_bps(n - 20)
	}

	log(`Saved ${available_bps()} BPs.`)

	if (is_active_player()) {
		set_enemy_player()
		goto_buildup_discard()
	} else {
		goto_buildup_resupply()
	}
}

function friendly_minefields() {
	return is_axis_player() ? game.minefields[MF_AXIS] : game.minefields[MF_ALLIED]
}

function friendly_buildup_network() {
	return is_axis_player() ? game.buildup.axis_network : game.buildup.allied_network
}

states.minefield = {
	inactive: "buildup",
	prompt() {
		view.prompt = `Buildup: Build a minefield.`
		let mfs = friendly_minefields()
		if (count_friendly_minefields() >= 1)
			gen_action('dismantle')
		if (available_bps() >= 15) {
			let net = friendly_buildup_network()
			for (let x of all_hexes)
				if (net[x] && !is_battle_hex(x) && !set_has(mfs, x))
					gen_action_hex(x)
		}
	},
	dismantle() {
		push_undo()
		if (count_friendly_minefields() >= 2)
			game.state = 'dismantle1'
		else
			game.state = 'dismantle0'
	},
	hex(x) {
		let mfs = friendly_minefields()
		game.summary.built ++
		pay_bps(15)
		set_add(mfs, x)
		game.state = 'spending_bps'
	}
}

states.dismantle0 = {
	inactive: "buildup",
	prompt() {
		view.prompt = `Buildup: Dismantle minefield.`
		let net = friendly_buildup_network()
		for (let x of friendly_minefields())
			if (net[x] && !is_battle_hex(x))
				gen_action_hex(x)
		for (let x of game.minefields[MF_VISIBLE])
			if (net[x] && !is_battle_hex(x))
				gen_action_hex(x)
	},
	hex(x) {
		set_delete(friendly_minefields(), x)
		set_delete(game.minefields[MF_VISIBLE], x)
		game.state = 'spending_bps'
	},
}

states.dismantle1 = {
	inactive: "buildup",
	prompt() {
		view.prompt = `Buildup: Dismantle first minefield to build a new one.`
		let net = friendly_buildup_network()
		for (let x of friendly_minefields())
			if (net[x] && !is_battle_hex(x))
				gen_action_hex(x)
		for (let x of game.minefields[MF_VISIBLE])
			if (net[x] && !is_battle_hex(x))
				gen_action_hex(x)
	},
	hex(x) {
		set_delete(friendly_minefields(), x)
		set_delete(game.minefields[MF_VISIBLE], x)
		game.state = 'dismantle2'
	},
}

states.dismantle2 = {
	inactive: "buildup",
	prompt() {
		view.prompt = `Buildup: Dismantle second minefield to build a new one.`
		let net = friendly_buildup_network()
		for (let x of friendly_minefields())
			if (net[x] && !is_battle_hex(x))
				gen_action_hex(x)
		for (let x of game.minefields[MF_VISIBLE])
			if (net[x] && !is_battle_hex(x))
				gen_action_hex(x)
	},
	hex(x) {
		set_delete(friendly_minefields(), x)
		set_delete(game.minefields[MF_VISIBLE], x)
		game.state = 'dismantle3'
	},
}

states.dismantle3 = {
	inactive: "buildup",
	prompt() {
		view.prompt = `Buildup: Build a new minefield at no cost.`
		let mfs = friendly_minefields()
		let net = friendly_buildup_network()
		for (let x of all_hexes)
			if (net[x] && !is_battle_hex(x) && !set_has(mfs, x) && !set_has(game.minefields[MF_VISIBLE], x))
				gen_action_hex(x)
	},
	hex(x) {
		let mfs = friendly_minefields()
		game.summary.dismantled += 2
		game.summary.built ++
		set_add(mfs, x)
		game.state = 'spending_bps'
	},
}

function goto_buildup_resupply() {
	// Per-scenario allotment
	let axis_resupply = (game.month <= 10 || game.malta) ? 2 : 3
	let allied_resupply = 3

	if (is_pregame_buildup())
		axis_resupply = allied_resupply = 0

	log_h2("Resupply")
	log(`Shuffled supply cards.`)
	shuffle_cards()

	// Extra cards purchased during buildup
	axis_resupply += game.buildup.axis_cards
	allied_resupply += game.buildup.allied_cards

	// Bonus from captured fortresses
	axis_resupply += game.axis_award
	allied_resupply += game.allied_award

	game.axis_award = 0
	game.allied_award = 0

	deal_axis_supply_cards(axis_resupply)
	deal_allied_supply_cards(allied_resupply)

	game.buildup = null

	goto_player_initiative()
}

// === INITIATIVE ===

function goto_player_initiative() {
	log_h2("Initiative")
	game.phasing = AXIS
	set_passive_player()
	game.state = 'allied_player_initiative'
}

states.allied_player_initiative = {
	inactive: "initiative",
	prompt() {
		view.prompt = "Initiative: You may challenge for the initiative."
		let hand = player_hand()
		if (hand[REAL] > 0)
			gen_action('real_card')
		if (hand[DUMMY] > 0)
			gen_action('dummy_card')
		gen_action('pass')
	},
	real_card() {
		log(`Allied player challenged for the initiative.`)
		player_hand()[0]--
		game.phasing = ALLIED
		set_passive_player()
		game.state = 'axis_player_initiative'
	},
	dummy_card() {
		player_hand()[1]--
		log(`Allied player challenged for the initiative.`)
		set_active_player()
		game.state = 'axis_player_initiative'
	},
	pass() {
		log(`Allied player did not challenge for the initiative.`)
		goto_player_turn()
	}
}

states.axis_player_initiative = {
	inactive: "initiative",
	prompt() {
		view.prompt = "Initiative: You may defend your initiative."
		let hand = player_hand()
		if (hand[REAL] > 0)
			gen_action('real_card')
		gen_action('pass')
	},
	real_card() {
		player_hand()[0]--
		log("Axis defends the initiative.")
		if (game.phasing === ALLIED)
			log("Allied card was real.")
		else
			log("Allied card was a dummy.")
		game.phasing = AXIS
		goto_player_turn()
	},
	pass() {
		if (game.phasing === ALLIED)
			log("Allied siezed the initiative.")
		else
			log("Allied card was a dummy.")
		goto_player_turn()
	}
}

// === END GAME SUPPLY CHECK (AFTER LAST MONTH, BEFORE VICTORY CHECK) ===

function goto_end_game() {
	log_h1("End Game")

	game.phasing = AXIS
	set_active_player()
	goto_end_game_supply_check()
}

function goto_end_game_supply_check() {
	let base_net = friendly_supply_network()
	for_each_friendly_unit_on_map(u => {
		if (base_net[unit_hex(u)])
			set_unit_supply(u, SS_BASE)
		else
			set_unit_supply(u, SS_NONE)
	})

	if (is_axis_player())
		game.capacity = [ 1, 1, 2 ]
	else
		game.capacity = [ 2, 2, 5 ]
	game.oasis = [ 1, 1, 1 ]

	goto_fortress_supply('end_game_fortress_supply')
}

function goto_end_game_supply_check_recover() {
	let summary = []
	for_each_friendly_unit_on_map(u => {
		if (is_unit_supplied(u) && is_unit_disrupted(u) && !is_battle_hex(unit_hex(u))) {
			set_add(summary, unit_hex(u))
			clear_unit_disrupted(u)
		}
	})
	for (let x of summary)
		log(`Recovered at #${x}.`)
	resume_end_game_eliminate_unsupplied()
}

function resume_end_game_eliminate_unsupplied() {
	game.state = 'end_game_eliminate_unsupplied'
	let done = true
	for_each_friendly_unit_on_map(u => {
		if (is_unit_unsupplied(u))
			done = false
	})
	if (done) {
		if (is_axis_player()) {
			set_enemy_player()
			goto_end_game_supply_check()
		} else {
			end_game()
		}
	}
}

states.end_game_eliminate_unsupplied = {
	inactive: "buildup",
	prompt() {
		view.prompt = `End Game: Eliminate unsupplied units.`
		for_each_friendly_unit_on_map(u => {
			if (is_unit_unsupplied(u))
				gen_action_unit(u)
		})
	},
	unit(u) {
		log(`Eliminated at #${unit_hex(u)}.`)
		eliminate_unit(u)
		resume_end_game_eliminate_unsupplied()
	},
}

// === VICTORY CHECK ===

const EXIT_EAST_EDGE = [ 99, 148 ]
const EXIT_WEST_EDGE = [ 175 ]
const EXIT_EAST = 47
const EXIT_WEST = 53

function check_sudden_death_victory() {
	// Supplied units that move beyond the map "edge" exit the map.
	// Count the easternmost row of hexes and half-hexes.
	// In the original map this would be the half-hexes and the virtual hexes beyond the edge.
	for (let x of EXIT_EAST_EDGE) {
		for_each_axis_unit(u => {
			if (unit_hex(u) === x && is_unit_supplied(u)) {
				log(`Exited the east map edge.`)
				set_unit_hex(u, EXIT_EAST)
			}
		})
	}

	for (let x of EXIT_WEST_EDGE) {
		for_each_allied_unit(u => {
			if (unit_hex(u) === x && is_unit_supplied(u)) {
				log(`Exited the west map edge.`)
				set_unit_hex(u, EXIT_WEST)
			}
		})
	}

	let axis_exited = 0
	for_each_axis_unit(u => {
		if (unit_hex(u) === EXIT_EAST)
			axis_exited++
	})

	let allied_exited = 0
	for_each_allied_unit(u => {
		if (unit_hex(u) === EXIT_WEST)
			allied_exited++
	})

	if (is_axis_hex(ALEXANDRIA)) {
		log_br()
		log("Axis captured Alexandria!")
		return goto_game_over(AXIS, "Axis Strategic Victory!")
	}
	if (axis_exited >= 3) {
		log_br()
		log("Axis exited three supplied units!")
		return goto_game_over(AXIS, "Axis Strategic Victory!")
	}

	if (is_allied_hex(EL_AGHEILA)) {
		log_br()
		log("Allied captured El Agheila!")
		return goto_game_over(ALLIED, "Allied Strategic Victory!")
	}
	if (is_allied_hex(EL_AGHEILA) || allied_exited >= 3) {
		log_br()
		log("Allied exited three supplied units!")
		return goto_game_over(ALLIED, "Allied Strategic Victory!")
	}

	return false
}

function end_game() {
	let axis = 0
	for_each_axis_unit_on_map(u => {
		axis += is_german_unit(u) ? 1.5 : 1.0
	})

	let allied = 0
	for_each_allied_unit_on_map(_u => {
		allied += 1.0
	})

	if (axis >= allied * 2)
		return goto_game_over(AXIS, "Axis Decisive Victory!")
	if (allied >= axis * 2)
		return goto_game_over(ALLIED, "Allied Decisive Victory!")

	if (!is_fortress_besieged(TOBRUK)) {
		if (is_fortress_axis_controlled(TOBRUK))
			return goto_game_over(AXIS, "Axis Positional Victory!")
		else
			return goto_game_over(ALLIED, "Allied Positional Victory!")
	}

	if (axis > allied)
		return goto_game_over(AXIS, "Axis Attrition Victory!")
	if (allied > axis)
		return goto_game_over(ALLIED, "Allied Attrition Victory!")

	return goto_game_over("Draw", "No Victory!")
}

// === DEPLOYMENT ===

function goto_free_deployment() {
	log_h2(`${game.active} Deployment`)
	game.state = 'free_deployment'
	if (!has_friendly_unit_in_raw_hex(DEPLOY))
		goto_initial_supply_cards()
	game.selected = []
	game.summary = {}
}

function is_valid_deployment_hex(x, n) {
	if (can_trace_supply_to_base_or_fortress(x))
		return true
	if (x === TOBRUK)
		return count_friendly_units_in_hex(x) + n <= 5
	if (x === JALO_OASIS || x === JARABUB_OASIS || x === SIWA_OASIS)
		return count_friendly_units_in_hex(x) + n <= 1
	return false
}

states.free_deployment = {
	inactive: "setup",
	prompt() {
		let scenario = current_scenario()
		let axis = (game.active === AXIS)

		view.prompt = `Setup: ${game.active} Deployment.`
		view.deploy = 1
		// view.prompt = `Setup: Deploy units in a supplied location in the setup area.`

		let done = true
		for_each_friendly_unit_in_hex(DEPLOY, u => {
			gen_action_unit(u)
			done = false
		})
		if (done)
			gen_action('end_deployment')

		if (game.selected.length > 0) {
			trace_supply_to_base_or_fortress(friendly_base())

			for (let x of (axis ? scenario.axis_deployment : scenario.allied_deployment)) {
				if (!is_enemy_hex(x)) {
					let limit = 0
					if (scenario.deployment_limit)
						limit = scenario.deployment_limit[x] | 0
					if (!limit || count_friendly_units_in_hex(x) + game.selected.length <= limit) {
						if (is_valid_deployment_hex(x, game.selected.length))
							gen_action_hex(x)
					}
				}
			}
		}
	},
	unit(u) {
		set_toggle(game.selected, u)
	},
	hex(to) {
		let list = game.selected
		game.selected = []
		push_undo()
		game.summary[to] = (game.summary[to] | 0) + list.length
		for (let who of list)
			set_unit_hex(who, to)
	},
	end_deployment() {
		log(`Deployed`)
		let keys = Object.keys(game.summary).map(Number).sort((a,b)=>a-b)
		for (let x of keys)
			log(`>${game.summary[x]} at #${x}`)
		game.summary = null

		goto_initial_supply_cards()
	}
}

function goto_initial_supply_cards() {
	game.state = 'initial_supply_cards'
	if (is_axis_player())
		deal_axis_supply_cards(current_scenario().axis_initial_supply)
	else
		deal_allied_supply_cards(current_scenario().allied_initial_supply)
}

states.initial_supply_cards = {
	inactive: "setup",
	prompt() {
		view.prompt = `Setup: You may discard your entire hand and redraw a new one.`
		gen_action('discard')
		gen_action('keep')
	},
	discard() {
		if (is_axis_player()) {
			log(`Axis discarded all cards.`)
			game.axis_hand[REAL] = 0
			game.axis_hand[DUMMY] = 0
			deal_axis_supply_cards(current_scenario().axis_initial_supply)
		} else {
			log(`Allied discarded all cards.`)
			game.allied_hand[REAL] = 0
			game.allied_hand[DUMMY] = 0
			deal_allied_supply_cards(current_scenario().allied_initial_supply)
		}
		end_free_deployment()
	},
	keep() {
		end_free_deployment()
	},
}

function end_free_deployment() {
	set_enemy_player()
	if (has_friendly_unit_in_raw_hex(DEPLOY)) {
		goto_free_deployment()
	} else {
		game.selected = -1
		game.summary = null
		begin_game()
	}
}

function begin_game() {
	log_h1(current_month_name())

	if (game.scenario === "Crusader") {
		game.phasing = ALLIED
	}

	// No buildup first month
	// No initiative first month

	if (is_pregame_buildup())
		goto_pregame_buildup()
	else
		goto_player_turn()
}

// === SETUP ===

function find_axis_units(a) {
	let list = []
	for (let u = first_axis_unit; u <= last_axis_unit; ++u)
		if (unit_appearance[u] === a)
			list.push(u)
	return list
}

function find_allied_units(a) {
	let list = []
	for (let u = first_allied_unit; u <= last_allied_unit; ++u)
		if (unit_appearance[u] === a)
			list.push(u)
	return list
}

function setup_reinforcements(m) {
	for (let u = 0; u < unit_count; ++u) {
		if (unit_appearance[u] === m) {
			if (m === "M")
				set_unit_hex(u, MALTA)
			else
				set_unit_hex(u, hexdeploy + m)
			set_unit_supply(u, SS_BASE)
		}
	}
}

function setup_units(where, steps, list) {
	if (where < 0)
		where = hexdeploy - where
	for (let u of list) {
		if (typeof u === 'string')
			u = find_unit(u)
		set_unit_hex(u, where)
		if (steps < 0)
			set_unit_steps(u, unit_max_steps[u] + steps)
		else if (steps > 0)
			set_unit_steps(u, steps)
		set_unit_supply(u, SS_BASE)
	}
}

function current_scenario() {
	return SCENARIOS[game.scenario]
}

function sort_deployment_for_axis(list) {
	list = list.slice()
	list.sort((a,b) => distance_to[EL_AGHEILA][b] - distance_to[EL_AGHEILA][a])
	return list
}

function sort_deployment_for_allied(list) {
	list = list.slice()
	list.sort((a,b) => distance_to[ALEXANDRIA][b] - distance_to[ALEXANDRIA][a])
	return list
}

const SCENARIOS = {
	"1940": {
		start: 1,
		end: 6,
		axis_deployment: sort_deployment_for_axis([...LIBYA, SIDI_OMAR]),
		allied_deployment: sort_deployment_for_allied(EGYPT),
		axis_initial_supply: 6,
		allied_initial_supply: 3,
	},
	"1941": {
		start: 1,
		end: 10,
		axis_deployment: [],
		allied_deployment: sort_deployment_for_allied([...EGYPT, ...LIBYA]),
		axis_initial_supply: 6,
		allied_initial_supply: 6,
	},
	"Crusader": {
		start: 8,
		end: 10,
		axis_deployment: sort_deployment_for_axis([...LIBYA_NO_TOBRUK, SIDI_OMAR, SOLLUM]),
		allied_deployment: sort_deployment_for_allied([...EGYPT, TOBRUK]),
		axis_initial_supply: 10,
		allied_initial_supply: 12,
		deployment_limit: {
			[TOBRUK]: 5
		},
	},
	"Battleaxe": {
		start: 4,
		end: 10,
		axis_deployment: sort_deployment_for_axis(LIBYA_NO_TOBRUK),
		allied_deployment: sort_deployment_for_allied([...EGYPT, TOBRUK]),
		axis_initial_supply: 4,
		allied_initial_supply: 8,
		deployment_limit: {
			[TOBRUK]: 5
		},
	},
	"1942": {
		start: 11,
		end: 20,
		axis_deployment: [ EL_AGHEILA, MERSA_BREGA ],
		allied_deployment: sort_deployment_for_allied([...EGYPT, ...LIBYA]),
		axis_initial_supply: 5,
		allied_initial_supply: 5,
		deployment_limit: {
			[EL_AGHEILA]: 14,
			[MERSA_BREGA]: 10,
		},
	},
	"Gazala": {
		start: 14,
		end: 15,
		axis_deployment: sort_deployment_for_axis(regions["West Line"]),
		allied_deployment: sort_deployment_for_allied(regions["East Line"]),
		axis_initial_supply: 10,
		allied_initial_supply: 12,
	},
	"Pursuit to Alamein": {
		start: 15,
		end: 20,
		axis_deployment: sort_deployment_for_axis(LIBYA),
		allied_deployment: sort_deployment_for_allied(EGYPT),
		axis_initial_supply: 8,
		allied_initial_supply: 8,
	},
	"1941-42": {
		start: 1,
		end: 20,
		axis_deployment: [],
		allied_deployment: sort_deployment_for_allied([...EGYPT, ...LIBYA]),
		axis_initial_supply: 6,
		allied_initial_supply: 6,
	},
}

const SETUP = {
	"1940" () {
		setup_units(DEPLOY, 0, [ "Pav", "Bre", "Tre", "Bol", "Sav", "Sab", "Fas", "Ita" ])
		setup_units(-3, 0, [ "Ari", "Pis"])
		setup_units(-5, 0, [ "Lit", "Cen"])

		setup_units(DEPLOY, 0, [ "7/7", "7", "7/SG", "4IN/3m" ])
		setup_units(-2, 0, [ "4IN/5", "4IN/11" ])
		setup_units(-4, 0, [ "Matilda/A", "7/4", "4IN/7m", "/Tob" ])
	},

	"1941" () {
		setup_units(EL_AGHEILA, 0, find_axis_units('S'))
		setup_reinforcements(3)
		setup_reinforcements(5)
		setup_reinforcements(7)

		setup_units(DEPLOY, 0, find_allied_units('S'))
		setup_units(TOBRUK, 0, find_allied_units('T'))
		setup_reinforcements(2)
		setup_reinforcements(4)
		setup_reinforcements(6)
		setup_reinforcements(8)
		setup_reinforcements(10)
	},

	"Crusader" () {
		setup_units(DEPLOY, 0, find_axis_units('S'))
		setup_units(DEPLOY, 0, find_axis_units(3))
		setup_units(DEPLOY, 0, find_axis_units(5))
		setup_units(DEPLOY, 0, find_axis_units(7))

		setup_units(DEPLOY, 0, find_allied_units('S'))
		setup_units(DEPLOY, 0, find_allied_units('T'))
		setup_units(DEPLOY, 0, find_allied_units(2))
		setup_units(DEPLOY, 0, find_allied_units(4))
		setup_units(DEPLOY, 0, find_allied_units(6))
		setup_units(DEPLOY, 0, find_allied_units(8))
		setup_units(0, 0, [ "2/3", "2/SG", "9AU/20", "7AU/18" ])
		setup_reinforcements(10)

		set_add(game.minefields[MF_VISIBLE], TOBRUK)
	},

	"Battleaxe" () {
		setup_units(DEPLOY, 0, [ "21/5", "21/3", "15/33", "90/155", "15/115", "88mm/A" ])
		setup_units(DEPLOY, -1, [ "21/104" ])
		setup_units(DEPLOY, 0, [ "Ari", "Lit", "Pav", "Bre", "Tre", "Bol", "Ita" ])
		setup_reinforcements(5)
		setup_reinforcements(7)

		setup_units(DEPLOY, 0, [ "4IN/3m", "9AU/20", "70/14+16", "70/23",
			"7/22G", "7/SG", "7AU/18", "Matilda/A", "/Tob", "/Pol",
			"7/7", "4IN/5", "4IN/7m", "4IN/11", "Matilda/B", "/1AT",
			"7/4", "7" ])
		setup_reinforcements(6)
		setup_reinforcements(8)
		setup_reinforcements(10)
	},

	"1942" () {
		setup_units(DEPLOY, 0, [
			"21/3",
			"15/33",
			"90/580",
			"90/sv288",
			"90/346",
			"88mm/A",
		])
		setup_units(DEPLOY, 2, [
			"21/5",
			"15/8",
			"15/115",
			"90/155"
		])
		setup_units(DEPLOY, 1, [
			"90/361",
			"90/200",
			"88mm/B",
			"50mm",
			"/104"
		])
		setup_units(DEPLOY, 0, [ "Lit" ])
		setup_units(DEPLOY, -1, [ "Ari", "Tri", "Pav", "Bre", "Tre", "Bol", "Sab", "Ita" ])
		setup_reinforcements(17)
		setup_reinforcements(19)
		setup_reinforcements('M')

		setup_units(DEPLOY, 0, [
			"1/2",
			"1SA",
			"7/22G",
			"1/201G",
			"4IN/7m",
			"4IN/3m",
			"1/SG",
			"4IN/11",
			"5IN/29",
			"2#",
		])
		setup_units(TOBRUK, 0, [
			"1/22",
			"/1AT",
			"Matilda/B",
			"1SA/2+5",
			"70/14+16",
			"1SA/1",
			"1SA/3",
			"2SA/4+6",
			"70/23",
			"/Tob",
		])
		setup_units(ALEXANDRIA, 1, [
			"7/4",
			"/32AT",
			"2NZ/4",
			"2NZ/5",
			"2NZ/6",
			"7/SG",
			"4IN/5",
			"/Pol",
		])
		setup_reinforcements(12)
		setup_reinforcements(14)
		setup_reinforcements(16)
		setup_reinforcements(18)
		setup_reinforcements(20)
	},

	"Gazala" () {
		setup_units(DEPLOY, -1, [
			"21/5",
			"15/8",
			"15/115",
			"90/155",
			"88mm/B",
			"50mm",
			"/104",
		])
		setup_units(DEPLOY, 0, [
			"21/3",
			"15/33",
			"90/580",
			"90/sv288",
			"90/346",
			"90/361",
			"90/200",
			"88mm/A",
		])
		setup_units(DEPLOY, 0, [ "Lit" ])
		setup_units(DEPLOY, -1, [
			"Ari", "Tri", "Pav", "Bre", "Tre", "Bol", "Sab", "Ita"
		])

		setup_units(DEPLOY, 0, [
			"Grant",
			"/1AT",
			"1/22",
			"Matilda/B",
			"1SA",
			"1/201G",
			"4IN/7m",
			"4IN/3m",
			"1/SG",
			"1SA/2+5",
			"70/14+16",
			"1SA/1",
			"1SA/3",
			"2SA/4+6",
			"70/23",
			"4IN/11",
			"5IN/29",
			"6#/A",
			"2#",
			"/Tob",
		])
		setup_units(ALEXANDRIA, 1, [
			"1/2",
			"7/4",
			"/32AT",
			"2NZ/4",
			"2NZ/5",
			"2NZ/6",
			"7/SG",
			"7/22G",
			"4IN/5",
			"/Pol",
		])
		setup_units(ALEXANDRIA, 0, [
			"10IN/161m",
			"8IN/18",
			"/B",
			"FF/2",
			"5IN/9+10",
			"10IN/21+25",
		])
	},

	"Pursuit to Alamein" () {
		setup_units(DEPLOY, 0, [
			"21/3",
			"15/33",
		])
		setup_units(DEPLOY, -1, [
			"21/5",
			"15/8",
			"15/115",
			"90/346",
			"90/sv288",
			"90/361",
			"90/200",
			"88mm/A",
			"88mm/B",
			"50mm",
		])
		setup_units(DEPLOY, 3, [
			"Ari",
			"Tri",
			"Pav",
			"Bre",
			"Tre",
		])
		setup_units(DEPLOY, 2, [
			"Lit",
			"Bol",
		])
		setup_units(DEPLOY, 1, [
			"Sab",
			"Ita",
		])
		setup_reinforcements(17)
		setup_reinforcements(19)
		setup_reinforcements('M')

		setup_units(DEPLOY, 0, [
			"10IN/161m",
			"10IN/21+25",
			"70/14+16",
			"8IN/18",
			"/B",
		])
		setup_units(DEPLOY, -1, [
			"1/22",
			"7/4",
			"2NZ/4",
			"2NZ/5",
			"2NZ/6",
			"1SA/2+5",
			"1SA/1",
			"1SA/3",
			"70/23",
			"5IN/29",
			"6#/A",
		])
		setup_units(ALEXANDRIA, 1, [
			"Grant",
			"1/2",
			"/1AT",
			"1SA",
			"7/SG",
			"1/SG",
			"FF/2",
			"5IN/9+10",
			"4IN/5",
			"4IN/11",
			"/Pol",
			"2#",
		])
		setup_reinforcements(16)
		setup_reinforcements(18)
		setup_reinforcements(20)
	},

	"1941-42" () {
		SETUP["1941"]()

		setup_reinforcements(11)
		setup_reinforcements(17)
		setup_reinforcements(19)
		setup_reinforcements('M')

		setup_reinforcements(12)
		setup_reinforcements(14)
		setup_reinforcements(16)
		setup_reinforcements(18)
		setup_reinforcements(20)
	},

}

function setup_fortress(scenario, fortress) {
	if (scenario.allied_deployment.includes(fortress))
		set_fortress_allied_controlled(fortress)
	if (scenario.axis_deployment.includes(fortress))
		set_fortress_axis_controlled(fortress)
}

function setup(scenario_name) {
	let scenario = SCENARIOS[scenario_name]
	game.month = scenario.start

	log_h1(scenario_name)

	SETUP[scenario_name]()

	setup_fortress(scenario, BARDIA)
	setup_fortress(scenario, BENGHAZI)
	setup_fortress(scenario, TOBRUK)

	game.phasing = AXIS
	set_active_player()

	goto_free_deployment()
}

// === PUBLIC FUNCTIONS ===

exports.roles = [ "Axis", "Allied" ]

exports.scenarios = [
	"1940",
	"1941",
	"1942",
	"Battleaxe",
	"Crusader",
	"Gazala",
	"Pursuit to Alamein",
	"1941-42"
]

exports.setup = function (seed, scenario, _options) {
	load_state({
		seed: seed,
		log: [],
		undo: [],

		state: null,
		phasing: AXIS,
		active: AXIS,
		selected: -1,

		scenario: scenario,
		month: 0,

		draw_pile: [ 28, 14 ],	// 28 real supply + 14 dummy supply
		axis_hand: [ 0, 0 ],
		allied_hand: [ 0, 0 ],

		axis_bps: 0,
		allied_bps: 0,

		units: new Array(unit_count).fill(0),
		revealed: [],
		moved: [],
		fired: [],
		raiders: [],
		recover: [],

		// axis/allied/visible/to-be-revealed
		minefields: [[],[],[],[]], // revealed to both players

		// fortress control
		fortress: 7,
		axis_award: 0,
		allied_award: 0,
		assign: 0,

		// fortress and oasis supply capacity
		capacity: [ 0, 0, 0 ],
		oasis: [ 0, 0, 0 ],

		// battle hexes (defender)
		axis_hexes: [],
		allied_hexes: [],

		// hexside control (for battle hexes)
		axis_sides: [],
		allied_sides: [],

		// current turn option and selected moves
		commit: null,
		turn_option: null,
		passed: 0,
		side_limit: {},
		used: 0,
		forced: null,
		rommel: 0,
		from1: 0,
		to1: 0,
		from2: 0,
		to2: 0,

		// retreat
		partial_retreats: [], // remember partial retreats to forbid initiating combat
		retreat: 0,
		retreat_units: null,

		// refuse battle
		refuse: 0,

		// rout
		rout: null,

		// combat
		new_battles: [],
		active_battles: [],
		assault_battles: [],
		pursuit: 0,
		battle: 0,
		hits: null,
		flash: null,

		// misc states
		group: null,
		regroup: null,
		disrupt: null,
		withdraw: null,
		hexside: null,
		buildup: null,

		// logging
		summary: null,
	})

	setup(scenario)

	return game
}

exports.view = function(state, current) {
	timeout = Date.now() + TIMEOUT // don't think too long!
	load_state(state)

	let scenario = current_scenario()

	view = {
		month: game.month,
		start: scenario.start,
		end: scenario.end,
		units: game.units,
		revealed: game.revealed,
		moved: game.moved,
		fortress: game.fortress,
		axis_hand: game.axis_hand[REAL] + game.axis_hand[DUMMY],
		allied_hand: game.allied_hand[REAL] + game.allied_hand[DUMMY],
		phasing: game.phasing,
		commit: game.commit ? (game.commit[0] + game.commit[1]) : -1,
		axis_hexes: game.axis_hexes,
		allied_hexes: game.allied_hexes,
		axis_sides: game.axis_sides,
		allied_sides: game.allied_sides,
	}

	let player_minefields = null
	if (current === AXIS) {
		view.cards = game.axis_hand
		if (game.minefields[MF_AXIS].length > 0)
			player_minefields = game.minefields[MF_AXIS]
	}
	else if (current === ALLIED) {
		view.cards = game.allied_hand
		if (game.minefields[MF_ALLIED].length > 0)
			player_minefields = game.minefields[MF_ALLIED]
	}
	if (game.minefields[MF_VISIBLE].length > 0) {
		if (player_minefields)
			view.minefields = game.minefields[MF_VISIBLE].concat(player_minefields)
		else
			view.minefields = game.minefields[MF_VISIBLE]
	} else {
		if (player_minefields)
			view.minefields = player_minefields
	}

	if (current === game.active)
		view.selected = game.selected

	if (states[game.state].show_battle) {
		view.battle = game.battle
		view.retreat = game.retreat_units
	}
	if (states[game.state].show_pursuit)
		view.pursuit = game.pursuit
	if (view.battle || view.pursuit) {
		view.hits = game.hits
		view.flash = game.flash
		if (game.fired.length > 0)
			view.fired = game.fired
	}

	return common_view(current)
}

exports.query = function (state, _player, q) {
	timeout = Date.now() + TIMEOUT // don't think too long!
	if (q === 'supply') {
		load_state(state)
		if (game.buildup) {
			return {
				axis_supply: game.buildup.axis_network,
				axis_supply_line: game.buildup.axis_line,
				allied_supply: game.buildup.allied_network,
				allied_supply_line: game.buildup.allied_line,
			}
		} else {
			return {
				axis_supply: union_axis_network(),
				axis_supply_line: union_axis_line(),
				allied_supply: union_allied_network(),
				allied_supply_line: union_allied_line(),
			}
		}
	}
	return null
}

function gen_action_unit(u) {
	gen_action('unit', u)
}

function gen_action_unit_hit(u) {
	gen_action('unit_hit', u)
}

function gen_action_hex(x) {
	gen_action('hex', x)
}

function gen_action_forced_march(x) {
	gen_action('forced_march', x)
}

// === COMMON TEMPLATE ===

function roll_die() {
	clear_undo()
	return random(6) + 1
}

function log_br() {
	if (game.log.length > 0 && game.log[game.log.length-1] !== "")
		game.log.push("")
}

function log(msg) {
	game.log.push(msg)
}

function log_h1(msg) {
	log_br()
	log(".h1 " + msg)
	log_br()
}

function log_h2(msg) {
	log_br()
	log(".h2 " + msg)
	log_br()
}

function log_h3(msg) {
	log_br()
	log(".h3 " + msg)
	log_br()
}

function log_h4(msg) {
	log_br()
	log(".h4 " + msg)
}

function gen_action(action, argument) {
	if (argument !== undefined) {
		if (!(action in view.actions)) {
			view.actions[action] = [ argument ]
		} else {
			set_add(view.actions[action], argument)
		}
	} else {
		view.actions[action] = 1
	}
}

function goto_game_over(result, victory) {
	game.state = 'game_over'
	game.active = "None"
	game.result = result
	game.victory = victory
	log_br()
	log(game.victory)
	return true
}

states.game_over = {
	get inactive() {
		return game.victory
	},
	prompt() {
		view.prompt = game.victory
	}
}

exports.action = function (state, current, action, arg) {
	timeout = Date.now() + TIMEOUT // don't think too long!
	load_state(state)
	let S = states[game.state]
	if (S && action in S) {
		S[action](arg, current)
	} else {
		if (action === 'undo' && game.undo && game.undo.length > 0)
			pop_undo()
		else
			throw new Error("Invalid action: " + action)
	}
	return game
}

function common_view(current) {
	view.log = game.log
	if (game.state === 'game_over') {
		view.prompt = game.victory
	} else if (current === 'Observer' || game.active !== current) {
		let inactive = states[game.state].inactive || game.state
		view.prompt = `Waiting for ${game.active} \u2014 ${inactive}...`
	} else {
		view.actions = {}
		if (states[game.state])
			states[game.state].prompt()
		else
			view.prompt = "Unknown state: " + game.state
		if (view.actions.undo === undefined) {
			if (game.undo && game.undo.length > 0)
				view.actions.undo = 1
			else
				view.actions.undo = 0
		}
	}
	return view
}

// === COMMON LIBRARY ===

function random(range) {
	// An MLCG using integer arithmetic with doubles.
	// https://www.ams.org/journals/mcom/1999-68-225/S0025-5718-99-00996-5/S0025-5718-99-00996-5.pdf
	// m = 2**35 − 31
	return (game.seed = game.seed * 200105 % 34359738337) % range
}

// remove item at index (faster than splice)

function array_remove(array, index) {
	let n = array.length
	for (let i = index + 1; i < n; ++i)
		array[i - 1] = array[i]
	array.length = n - 1
}

// insert item at index (faster than splice)
function array_insert(array, index, item) {
	for (let i = array.length; i > index; --i)
		array[i] = array[i - 1]
	array[index] = item
}

function set_clear(set) {
	set.length = 0
}

function set_has(set, item) {
	let a = 0
	let b = set.length - 1
	while (a <= b) {
		let m = (a + b) >> 1
		let x = set[m]
		if (item < x)
			b = m - 1
		else if (item > x)
			a = m + 1
		else
			return true
	}
	return false
}

function set_add(set, item) {
	let a = 0
	let b = set.length - 1
	while (a <= b) {
		let m = (a + b) >> 1
		let x = set[m]
		if (item < x)
			b = m - 1
		else if (item > x)
			a = m + 1
		else
			return
	}
	array_insert(set, a, item)
}

function set_delete(set, item) {
	let a = 0
	let b = set.length - 1
	while (a <= b) {
		let m = (a + b) >> 1
		let x = set[m]
		if (item < x)
			b = m - 1
		else if (item > x)
			a = m + 1
		else {
			array_remove(set, m)
			return
		}
	}
}

function set_toggle(set, item) {
	let a = 0
	let b = set.length - 1
	while (a <= b) {
		let m = (a + b) >> 1
		let x = set[m]
		if (item < x)
			b = m - 1
		else if (item > x)
			a = m + 1
		else {
			array_remove(set, m)
			return
		}
	}
	array_insert(set, a, item)
}

// Fast deep copy for objects without cycles
function object_copy(original) {
	if (Array.isArray(original)) {
		let n = original.length
		let copy = new Array(n)
		for (let i = 0; i < n; ++i) {
			let v = original[i]
			if (typeof v === "object" && v !== null)
				copy[i] = object_copy(v)
			else
				copy[i] = v
		}
		return copy
	} else {
		let copy = {}
		for (let i in original) {
			let v = original[i]
			if (typeof v === "object" && v !== null)
				copy[i] = object_copy(v)
			else
				copy[i] = v
		}
		return copy
	}
}

function clear_undo() {
	if (game.undo.length > 0)
		game.undo = []
}

function push_undo() {
	let copy = {}
	for (let k in game) {
		let v = game[k]
		if (k === "undo")
			continue
		else if (k === "log")
			v = v.length
		else if (typeof v === "object" && v !== null)
			v = object_copy(v)
		copy[k] = v
	}
	game.undo.push(copy)
}

function pop_undo() {
	let save_log = game.log
	let save_undo = game.undo
	let state = save_undo.pop()
	save_log.length = state.log
	state.log = save_log
	state.undo = save_undo
	load_state(state)
}