extends Node
# This script is added as an Autoload named 'GameState'

# ==========================================
# SIGNALS
# ==========================================
signal gold_changed(new_amount: BigNumber)
signal gems_changed(new_amount: BigNumber)

enum CurrencyType { gold, gems }

# ==========================================
# STATE VARIABLES
# ==========================================
var gold: BigNumber = BigNumber.from_float(0.0)
var gems: BigNumber = BigNumber.from_float(0.0)

var last_save_time: int = 0 # Unix timestamp

static var file_name: String = "user://idle_save.json"

func _ready() -> void:
	load_game()

# ==========================================
# STATE MODIFIERS
# ==========================================
func add_gold(amount: BigNumber) -> void:
	gold.add_in_place(amount)
	gold_changed.emit(gold)

func spend_gold(cost: BigNumber) -> bool:
	if gold.is_greater_than(cost) or gold.is_equal_to(cost):
		var negative_cost = BigNumber.new(-cost.mantissa, cost.exponent)
		gold.add_in_place(negative_cost)
		gold_changed.emit(gold)
		return true
	return false

func add_gems(amount: BigNumber) -> void:
	gems.add_in_place(amount)
	gems_changed.emit(gems)

func spend_gems(cost: BigNumber) -> bool:
	if gems.is_greater_than(cost) or gems.is_equal_to(cost):
		var negative_cost = BigNumber.new(-cost.mantissa, cost.exponent)
		gems.add_in_place(negative_cost)
		gems_changed.emit(gems)
		return true
	return false

# ==========================================
# PERSISTENCE (Save/Load)
# ==========================================
func save_game() -> void:
	var save_data = {
		"gold": gold.serialize(),
		"gems": gems.serialize(),
		"last_save_time": Time.get_unix_time_from_system()
	}
	
	var file = FileAccess.open(file_name, FileAccess.WRITE)
	if file:
		file.store_string(JSON.stringify(save_data))

func load_game() -> void:
	if not FileAccess.file_exists(file_name):
		return
		
	var file = FileAccess.open(file_name, FileAccess.READ)
	if file:
		var parsed = JSON.parse_string(file.get_as_text())
		if parsed is Dictionary:
			gold = BigNumber.deserialize(parsed.get("gold", {}))
			gems = BigNumber.deserialize(parsed.get("gems", {}))
			last_save_time = parsed.get("last_save_time", Time.get_unix_time_from_system())