forbid illegal cross-map retreats

1 files changed, 13 insertions, 0 deletions

diff --git a/rules.js b/rules.js
index 5461392..ab7b143 100644
--- a/rules.js
+++ b/rules.js
@@ -2202,6 +2202,17 @@ function search_retreat_distance(from, range) {
 	return seen
 }
 
+function is_illegal_cross_map_retreat(from, to) {
+	if ((is_flanders_space(from) && is_bohemia_space(to)) || (is_flanders_space(to) && is_bohemia_space(from))) {
+		for (let p of game.selected) {
+			let pow = piece_power[p]
+			if (pow !== P_FRANCE && pow !== P_AUSTRIA)
+				return true
+		}
+	}
+	return false
+}
+
 // search all possible retreat paths of given length
 function search_retreat_possible_dfs(result, seen, here, range) {
 	for (let next of data.cities.adjacent[here]) {
@@ -2209,6 +2220,8 @@ function search_retreat_possible_dfs(result, seen, here, range) {
 			continue
 		if (has_any_piece(next))
 			continue
+		if (is_illegal_cross_map_retreat(here, next))
+			continue
 		if (range === 1) {
 			set_add(result, next)
 		} else {