From 39b805a7da253435c5c8c694cb60b49f43adc83e Mon Sep 17 00:00:00 2001
From: Tor Andersson <tor@ccxvii.net>
Date: Mon, 3 Oct 2022 12:54:55 +0200
Subject: Verify group and regroup options as valid retreat hexes.

The pass turn option already has strict checks. Add similar disengagement
hexside checks when listing valid group and regroup moves.
---
 rules.js | 29 +++++++++++++++++++----------
 1 file changed, 19 insertions(+), 10 deletions(-)

diff --git a/rules.js b/rules.js
index 5dca9fe..adbf7d5 100644
--- a/rules.js
+++ b/rules.js
@@ -952,11 +952,11 @@ function for_each_undisrupted_and_unmoved_friendly_unit_in_hex(x, fn) {
 			fn(u)
 }
 
-function count_hex_or_adjacent_has_undisrupted_and_unmoved_friendly_unit(here) {
+function count_hex_or_adjacent_that_has_any_unit_that_can_move(here) {
 	let n = 0
 	for_each_hex_and_adjacent_hex(here, x => {
-		for (let u = first_friendly_unit; u <= last_friendly_unit; ++u) {
-			if (is_unit_undisrupted(u) && !is_unit_moved(u) && unit_hex(u) === x) {
+		if (has_undisrupted_and_unmoved_friendly_unit(x)) {
+			if (!has_enemy_unit(x) || can_any_disengage(x)) {
 				n++
 				return
 			}
@@ -3043,8 +3043,10 @@ states.select_moves = {
 function list_valid_group_moves() {
 	let result = []
 	for (let x of all_hexes) {
-		if (has_undisrupted_and_unmoved_friendly_unit(x))
-			set_add(result, x)
+		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())
@@ -3081,7 +3083,7 @@ function list_valid_regroup_moves() {
 	let result = []
 	for (let x of all_hexes) {
 		if (!is_enemy_hex(x)) {
-			let n = count_hex_or_adjacent_has_undisrupted_and_unmoved_friendly_unit(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)
@@ -3947,13 +3949,20 @@ function can_unit_retreat(who) {
 	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) {
-			if (can_unit_retreat(u))
-				result = true
-		}
+		if (result === false && can_unit_retreat(u))
+			result = true
 	})
 	return result
 }
-- 
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