Add finite prebattle shop stock

scripts/core/campaign_state.gd

@@ -3,7 +3,7 @@ class_name CampaignState
 
 const SAVE_PATH := "user://campaign_save.json"
 const MANUAL_SAVE_PATH := "user://campaign_manual_save.json"
-const SAVE_VERSION := 3
+const SAVE_VERSION := 4
 
 var save_version := SAVE_VERSION
 var campaign_id := ""
@@ -26,6 +26,7 @@ var flags := {}
 var joined_officers: Array[String] = []
 var applied_post_battle_choices := {}
 var pending_post_battle_choice_scenario_id := ""
+var shop_purchases := {}
 
 
 func load_campaign(path: String) -> bool:
@@ -136,6 +137,7 @@ func start_new(scenario_id: String) -> void:
 	joined_officers.clear()
 	applied_post_battle_choices.clear()
 	pending_post_battle_choice_scenario_id = ""
+	shop_purchases.clear()
 	for officer_id in initial_joined_officers:
 		joined_officers.append(officer_id)
 
@@ -341,12 +343,31 @@ func get_inventory_snapshot() -> Dictionary:
 	return inventory.duplicate(true)
 
 
-func try_buy_item(item_id: String, price: int) -> bool:
+func get_shop_purchase_count(scenario_id: String, item_id: String) -> int:
+	var scenario_key := str(scenario_id)
+	var item_key := str(item_id)
+	if scenario_key.is_empty() or item_key.is_empty():
+		return 0
+	if not shop_purchases.has(scenario_key) or typeof(shop_purchases[scenario_key]) != TYPE_DICTIONARY:
+		return 0
+	return int(shop_purchases[scenario_key].get(item_key, 0))
+
+
+func try_buy_item(item_id: String, price: int, scenario_id: String = "", stock_limit: int = -1) -> bool:
 	if item_id.is_empty() or price <= 0 or gold < price:
 		return false
+	var scenario_key := str(scenario_id)
+	if stock_limit >= 0 and not scenario_key.is_empty() and get_shop_purchase_count(scenario_key, item_id) >= stock_limit:
+		return false
 	var previous_count := int(inventory.get(item_id, 0))
+	var previous_shop_purchases: Dictionary = shop_purchases.duplicate(true)
 	gold -= price
 	inventory[item_id] = previous_count + 1
+	if stock_limit >= 0 and not scenario_key.is_empty():
+		if not shop_purchases.has(scenario_key) or typeof(shop_purchases[scenario_key]) != TYPE_DICTIONARY:
+			shop_purchases[scenario_key] = {}
+		var scenario_purchases: Dictionary = shop_purchases[scenario_key]
+		scenario_purchases[item_id] = int(scenario_purchases.get(item_id, 0)) + 1
 	if save_game():
 		return true
 	gold += price
@@ -354,6 +375,7 @@ func try_buy_item(item_id: String, price: int) -> bool:
 		inventory[item_id] = previous_count
 	else:
 		inventory.erase(item_id)
+	shop_purchases = previous_shop_purchases
 	return false
 
 
@@ -795,7 +817,8 @@ func to_dict() -> Dictionary:
 		"flags": flags.duplicate(true),
 		"joined_officers": joined_officers.duplicate(),
 		"applied_post_battle_choices": applied_post_battle_choices.duplicate(true),
-		"pending_post_battle_choice_scenario_id": pending_post_battle_choice_scenario_id
+		"pending_post_battle_choice_scenario_id": pending_post_battle_choice_scenario_id,
+		"shop_purchases": shop_purchases.duplicate(true)
 	}
 
 
@@ -811,6 +834,7 @@ func _apply_save_data(parsed: Dictionary) -> void:
 	flags = _copy_dictionary(parsed.get("flags", {}))
 	applied_post_battle_choices = _copy_dictionary(parsed.get("applied_post_battle_choices", {}))
 	pending_post_battle_choice_scenario_id = str(parsed.get("pending_post_battle_choice_scenario_id", ""))
+	shop_purchases = _copy_dictionary(parsed.get("shop_purchases", {}))
 	joined_officers.clear()
 	var saved_joined = parsed.get("joined_officers", initial_joined_officers)
 	for officer_id in saved_joined: