Fix placement possibility checks for old guard and grand battery.

1 files changed, 31 insertions, 4 deletions

diff --git a/rules.js b/rules.js
index 51c71e4..137e3ff 100644
--- a/rules.js
+++ b/rules.js
@@ -923,17 +923,44 @@ function can_place_detachment(p, hq) {
 	let x = piece_hex(p)
 	if (x === AVAILABLE_P1 || x === AVAILABLE_P2) {
 		if (pieces_are_associated(p, hq)) {
-			if (p === GRAND_BATTERY || p === OLD_GUARD) {
+
+			if (p === GRAND_BATTERY) {
+				if (hq === NAPOLEON_HQ && piece_mode(NAPOLEON_HQ))
+					return can_place_detachment_grand_battery()
+				return false
+			}
+
+			if (p === OLD_GUARD) {
 				if (hq === NAPOLEON_HQ && piece_mode(NAPOLEON_HQ))
-					return can_place_detachment_anywhere()
-			} else {
-				return can_place_detachment_anywhere()
+					return can_place_detachment_old_guard()
+				return false
 			}
+
+			return can_place_detachment_anywhere()
 		}
 	}
 	return false
 }
 
+function can_place_detachment_grand_battery() {
+	for (let p of friendly_units()) {
+		let x = piece_hex(p)
+		if (calc_distance(piece_hex(NAPOLEON_HQ), x) <= 3)
+			if (!hex_has_any_piece(x, p1_det))
+				return true
+	}
+	return false
+}
+
+function can_place_detachment_old_guard() {
+	let result = false
+	for_each_within_x3(piece_hex(NAPOLEON_HQ), (next) => {
+		if (!is_enemy_zoc(next) && is_empty_hex(next))
+			result = true
+	})
+	return result
+}
+
 states.place_detachment_hq = {
 	inactive: "place detachments",
 	prompt() {