Search legal group withdrawal moves.

TODO: Fortress supply!
TODO: Withdrawal Regroup moves.

3 files changed, 153 insertions, 35 deletions

diff --git a/play.html b/play.html
index fc55ec3..ae183d7 100644
--- a/play.html
+++ b/play.html
@@ -484,7 +484,7 @@ svg .side.allied_supply.axis_supply {
 }
 
 .unit.disrupted {
-	border-color: dimgray;
+	border-color: black;
 }
 
 .unit.unsupplied {
diff --git a/play.js b/play.js
index fa9bd19..43ba4bc 100644
--- a/play.js
+++ b/play.js
@@ -883,6 +883,9 @@ function on_update() {
 	action_button("end_buildup", "End buildup")
 	action_button("end_turn", "End turn")
 
+	confirm_action_button("confirm_end_turn", "End turn",
+		"End turn without performing any moves?")
+
 	action_button("undo", "Undo")
 }
 
diff --git a/rules.js b/rules.js
index 4feba56..6dae240 100644
--- a/rules.js
+++ b/rules.js
@@ -1445,7 +1445,6 @@ function tobruk_supply_network() {
 }
 
 function unit_supply_line(who) {
-	// TODO: allow oasis supplied units to trace to base?
 	switch (unit_supply(who)) {
 	case SS_BARDIA: return bardia_supply_line()
 	case SS_BENGHAZI: return benghazi_supply_line()
@@ -1457,7 +1456,6 @@ function unit_supply_line(who) {
 }
 
 function unit_supply_distance(who) {
-	// TODO: allow oasis supplied units to trace to base?
 	switch (unit_supply(who)) {
 	case SS_BARDIA: return distance_to[BARDIA]
 	case SS_BENGHAZI: return distance_to[BENGHAZI]
@@ -1480,6 +1478,32 @@ function friendly_supply_network() {
 	return allied_supply_network()
 }
 
+function query_friendly_supply_network(x, y) {
+	// TODO: fortress supply
+	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] = 1
+		trace_supply_network(EL_AGHEILA)
+		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] = 1
+		trace_supply_network(ALEXANDRIA)
+		if (x) presence_allied[x] = save_x
+		if (y) presence_allied[y] = save_y
+	}
+	return supply_temp_network
+}
+
 // === PATHING ===
 
 const path_from = [ new Array(hexcount), new Array(hexcount), new Array(hexcount), null, new Array(hexcount) ]
@@ -1762,6 +1786,41 @@ function find_valid_regroup_destinations(from, rommel) {
 	}
 }
 
+// === WITHDRAWAL CHECKS ===
+
+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_legal_withdrawal_from(x) {
+	if (is_battle_hex(x)) {
+		// can retreat, will always reduce supply network
+		return can_all_units_disengage_and_withdraw(x);
+	} else {
+		// non-retreat withdrawal, check if network is reduced after we leave this hex
+		let ref_net = friendly_supply_network()
+		let new_net = query_friendly_supply_network(x, 0)
+		if (is_network_reduced(ref_net, new_net))
+			return true
+	}
+	return false
+}
+
+function is_legal_withdrawal_to(from, to) {
+	if (is_battle_hex(from)) {
+		return true
+	} else {
+		let ref_net = friendly_supply_network()
+		let new_net = query_friendly_supply_network(from, to)
+		if (is_network_reduced(ref_net, new_net))
+			return true
+	}
+	return false
+}
+
 // === MINEFIELDS ===
 
 function visit_hex(x) {
@@ -2359,8 +2418,7 @@ states.select_moves = {
 			view.prompt = `Designate ${game.turn_option} move.`
 		}
 		gen_action('group')
-		if (game.turn_option !== 'pass')
-			gen_action('regroup') // TODO: needs work...
+		gen_action('regroup')
 		if (game.turn_option === 'pass')
 			gen_action('end_turn')
 	},
@@ -2376,6 +2434,9 @@ states.select_moves = {
 		clear_undo()
 		reveal_visited_minefields()
 		goto_final_supply_check()
+	},
+	confirm_end_turn() {
+		this.end_turn()
 	}
 }
 
@@ -2389,15 +2450,36 @@ states.group_move_from = {
 	prompt() {
 		view.prompt = `Group Move: Select hex to move from.`
 		gen_rommel_move()
-		for (let x of all_hexes) {
-			if (x === game.from1 && !game.to1)
-				continue
-			if (has_undisrupted_friendly_unit(x))
-				gen_action_hex(x)
-		}
-		if (game.turn_option !== 'pass')
+		if (game.turn_option !== 'pass') {
+			for (let x of all_hexes) {
+				if (x === game.from1 && !game.to1)
+					continue
+				if (has_undisrupted_friendly_unit(x))
+					gen_action_hex(x)
+			}
 			if (has_friendly_unit_in_raw_hex(friendly_queue()))
 				gen_action_hex(friendly_queue())
+		} else {
+			// Withdrawal group move
+			let mandatory = false
+			if (is_mandatory_combat(BARDIA)) {
+				gen_action_hex(BARDIA)
+				mandatory = true
+			}
+			if (is_mandatory_combat(BENGHAZI)) {
+				gen_action_hex(BENGHAZI)
+				mandatory = true
+			}
+			if (is_mandatory_combat(TOBRUK)) {
+				gen_action_hex(TOBRUK)
+				mandatory = true
+			}
+			if (!mandatory) {
+				for (let x of all_hexes)
+					if (has_undisrupted_friendly_unit(x) && is_legal_withdrawal_from(x))
+						gen_action_hex(x)
+			}
+		}
 	},
 	rommel() {
 		push_undo()
@@ -2432,13 +2514,18 @@ states.regroup_move_command_point = {
 	prompt() {
 		view.prompt = `Regroup Move: Designate the command point hex.`
 		gen_rommel_move()
-		for (let x of all_hexes) {
-			if (!is_enemy_hex(x)) {
-				let n = count_hex_or_adjacent_has_undisrupted_and_unmoved_friendly_unit(x)
-				// TODO: allow one-hex regroup moves? (failed forced march abuse)
-				if (n >= 2)
-					gen_action_hex(x)
+		if (game.turn_option !== 'pass') {
+			for (let x of all_hexes) {
+				if (!is_enemy_hex(x)) {
+					let n = count_hex_or_adjacent_has_undisrupted_and_unmoved_friendly_unit(x)
+					// TODO: allow one-hex regroup moves? (failed forced march abuse)
+					if (n >= 2)
+						gen_action_hex(x)
+				}
 			}
+		} else {
+			// TODO: Withdrawal regroup moves
+			view.prompt = "TODO"
 		}
 	},
 	rommel() {
@@ -2604,8 +2691,14 @@ states.move = {
 
 			if (has_overrun_hex)
 				gen_action('overrun')
-			else
-				gen_action('end_move')
+			else {
+				if (game.turn_option !== 'pass') {
+					gen_action('end_move')
+				} else {
+					if (!game.to1 && !has_friendly_unit(game.from1))
+						gen_action('end_move')
+				}
+			}
 		} else {
 			view.prompt = `Move: Select hex to move to.`
 
@@ -2613,12 +2706,13 @@ states.move = {
 			gen_action_unit(game.selected)
 
 			// Move
-			if (game.turn_option === 'pass')
-				search_withdraw(game.selected, 1 + (rommel1 | rommel2))
-			else
+			if (game.turn_option !== 'pass') {
 				search_move(unit_hex(game.selected), unit_speed[game.selected] + 1 + (rommel1 | rommel2))
-
-			gen_move()
+				gen_move()
+			} else {
+				search_withdraw(game.selected, 1 + rommel1)
+				gen_withdraw()
+			}
 		}
 	},
 	unit(who) {
@@ -2722,6 +2816,30 @@ function gen_move() {
 	}
 }
 
+function gen_withdraw() {
+	let rommel1 = (game.rommel === 1) ? 1 : 0
+	let speed = unit_speed[game.selected]
+	let from = unit_hex(game.selected)
+
+	if (!game.to1 && game.from1 === from) {
+		for (let to of all_hexes) {
+			if (to != from) {
+				if (can_move_to(to, speed + rommel1) && is_legal_withdrawal_to(game.from1, to))
+					gen_action_hex(to)
+				else if (can_move_to(to, speed + 1 + rommel1) && is_legal_withdrawal_to(game.from1, to))
+					gen_action_forced_march(to)
+			}
+		}
+	}
+
+	if (game.to1 && is_hex_or_adjacent_to(from, game.from1)) {
+		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) {
 	let rommel1 = (game.rommel === 1) ? 1 : 0
 	let rommel2 = (game.rommel === 2) ? 1 : 0
@@ -3426,7 +3544,7 @@ function end_retreat_2() {
 
 function can_select_refuse_battle_hex() {
 	for (let x of game.active_battles)
-		if (can_all_refuse_battle(x))
+		if (can_all_units_disengage_and_withdraw(x))
 			return true
 	return false
 }
@@ -3440,25 +3558,21 @@ function goto_refuse_battle() {
 	}
 }
 
-function can_all_refuse_battle(from) {
+function can_all_units_disengage_and_withdraw(from) {
 	let result = true
 	for_each_undisrupted_friendly_unit_in_hex(from, u => {
-		if (result === true && !can_unit_refuse_battle(u))
+		if (result === true && !can_unit_disengage_and_withdraw(u))
 			result = false
 	})
 	return result
 }
 
-function can_unit_refuse_battle(who) {
-	return can_unit_disengage_and_withdraw(who)
-}
-
 states.refuse_battle = {
 	inactive: "refuse battle",
 	prompt() {
 		view.prompt = `You may Refuse Battle.`
 		for (let x of game.active_battles)
-			if (can_all_refuse_battle(x))
+			if (can_all_units_disengage_and_withdraw(x))
 				gen_action_hex(x)
 		gen_action('pass')
 	},
@@ -3538,7 +3652,8 @@ function end_refuse_battle_move_2() {
 // withdraw by group move
 // eliminated if cannot
 
-function can_rout_from_hex(from) {
+function can_disengage_from(from) {
+	// TODO: check supply lines too...
 	let n = 0
 	for_each_adjacent_hex(from, to => {
 		let side = to_side_id(from, to)
@@ -3575,7 +3690,7 @@ function goto_rout(from, enemy, after) {
 		set_delete(game.recover, u)
 	})
 
-	if (can_rout_from_hex(from))
+	if (can_all_units_disengage_and_withdraw(from))
 		game.state = 'rout_attrition'
 	else
 		game.state = 'rout_elimination'