extends Node
class_name ShipInventory

signal inventory_changed
signal ammunition_changed

const CARGO_SIZE := 20
const WEAPON_SLOT_COUNT := 3
const STARTING_MISSILE_AMMUNITION := 2
const MISSILE_CRAFT_PARTS_COST := 50.0
const MISSILE_BUY_BASE_COST := 10
const MISSILE_DEFINITIONS := [preload("res://resources/items/missile_launcher.tres"), preload("res://resources/items/unguided_missile.tres")]
const MODULE_SLOT_COUNT := 5
const EXTENSION_SLOT_COUNT := 5
const MODULE_CATEGORIES := [ItemDefinition.Category.SHIELD, ItemDefinition.Category.ARMOR, ItemDefinition.Category.ENGINE, ItemDefinition.Category.REACTOR, ItemDefinition.Category.COMPUTER]
const MODULE_NAMES := ["Tarcze", "Pancerz", "Silnik", "Reaktor", "Komputer"]
const STARTING_AMMUNITION := 50
const AMMUNITION_CRAFT_AMOUNT := 100
const AMMUNITION_CRAFT_PARTS_COST := 50.0
const AMMUNITION_BUY_AMOUNT := 100
const AMMUNITION_BUY_BASE_COST := 20

var ammunition: int = STARTING_AMMUNITION
var missile_ammunition: int = STARTING_MISSILE_AMMUNITION

var cargo: Array[ItemInstance] = []
var weapon_slots: Array[ItemInstance] = []
var module_slots: Array[ItemInstance] = []
var extension_slots: Array[ItemInstance] = []

@onready var ship: CharacterBody2D = get_parent()

func _ready() -> void:
	add_to_group("ship_inventory")
	cargo.resize(CARGO_SIZE)
	weapon_slots.resize(WEAPON_SLOT_COUNT)
	module_slots.resize(MODULE_SLOT_COUNT)
	extension_slots.resize(EXTENSION_SLOT_COUNT)
	if GameState.restart_inventory.is_empty():
		_add_starter_items()
	else:
		cargo.assign(GameState.restart_inventory["cargo"])
		weapon_slots.assign(GameState.restart_inventory["weapon"])
		weapon_slots.resize(WEAPON_SLOT_COUNT)
		_restore_modules(GameState.restart_inventory)
		ammunition = int(GameState.restart_inventory.get("ammunition", STARTING_AMMUNITION))
		missile_ammunition = int(GameState.restart_inventory.get("missile_ammunition", STARTING_MISSILE_AMMUNITION))
		GameState.restart_inventory.clear()
	_remove_extension_addons()
	_recalculate_ship_stats()
	inventory_changed.emit()

func get_cargo_used() -> int:
	var used := 0
	for item in cargo:
		if item != null:
			used += 1
	return used

func preserve_for_restart() -> void:
	# Copy the slot arrays; resources retain levels and individual modifiers.
	GameState.restart_inventory = {
		"cargo": cargo.duplicate(),
		"weapon": weapon_slots.duplicate(),
		"module": module_slots.duplicate(),
		"extension": extension_slots.duplicate(),
		"ammunition": ammunition,
		"missile_ammunition": missile_ammunition,
	}

func consume_ammunition() -> bool:
	if ammunition <= 0:
		return false
	ammunition -= 1
	ammunition_changed.emit()
	return true

func can_craft_ammunition() -> bool:
	return GameState.captain.parts >= AMMUNITION_CRAFT_PARTS_COST

func craft_ammunition() -> bool:
	if not can_craft_ammunition():
		return false
	GameState.captain.parts -= AMMUNITION_CRAFT_PARTS_COST
	ammunition += AMMUNITION_CRAFT_AMOUNT
	GameState.captain.emit_changed()
	ammunition_changed.emit()
	return true

func get_item(slot_kind: String, index: int) -> ItemInstance:
	var slots := _get_slots(slot_kind)
	if index < 0 or index >= slots.size():
		return null
	return slots[index]

func get_ammunition_buy_cost() -> int:
	return AMMUNITION_BUY_BASE_COST * maxi(1, GameState.system_level)

func can_buy_ammunition() -> bool:
	return GameState.captain.credits >= get_ammunition_buy_cost()

func buy_ammunition() -> bool:
	if not can_buy_ammunition():
		return false
	GameState.captain.credits -= get_ammunition_buy_cost()
	ammunition += AMMUNITION_BUY_AMOUNT
	GameState.captain.emit_changed()
	ammunition_changed.emit()
	return true

func add_item(item: ItemInstance) -> bool:
	if item == null or item.definition == null:
		return false
	if item.definition.category == ItemDefinition.Category.ACTIVE_EXTENSION:
		item.additional_modifiers.clear()
		item.rarity = 0
	for index in cargo.size():
		if cargo[index] == null:
			cargo[index] = item
			inventory_changed.emit()
			return true
	return false

func delete_cargo_item(index: int) -> bool:
	if index < 0 or index >= cargo.size() or cargo[index] == null:
		return false
	cargo[index] = null
	GameState.captain.parts += 10.0
	GameState.captain.emit_changed()
	inventory_changed.emit()
	return true

func can_move_item(from_kind: String, from_index: int, to_kind: String, to_index: int) -> bool:
	var source := _get_slots(from_kind)
	var destination := _get_slots(to_kind)
	if from_index < 0 or from_index >= source.size() or to_index < 0 or to_index >= destination.size():
		return false
	if from_kind == to_kind and from_index == to_index:
		return false
	var item := source[from_index]
	if item == null or item.definition == null:
		return false
	if not _accepts_item(to_kind, to_index, item):
		return false
	var displaced := destination[to_index]
	if displaced != null and displaced.definition != null:
		if not _accepts_item(from_kind, from_index, displaced):
			return false
	return true

func _accepts_item(kind: String, index: int, item: ItemInstance) -> bool:
	if kind == "weapon":
		return item.definition.category == ItemDefinition.Category.WEAPON
	if kind == "module":
		return item.definition.category == MODULE_CATEGORIES[index]
	if kind == "extension":
		return item.definition.category == ItemDefinition.Category.ACTIVE_EXTENSION and item.definition.active_ability != null
	return kind == "cargo"

func get_missile_count() -> int:
	return missile_ammunition

func get_missile_cooldown(item: ItemInstance) -> float:
	var reduction := item.get_stat_total("missile_cooldown_reduction")
	for equipped in weapon_slots + module_slots:
		if equipped != null and equipped != item:
			reduction += equipped.get_stat_total("missile_cooldown_reduction")
	return maxf(1.0, 5.0 - reduction)

func consume_missile() -> bool:
	if missile_ammunition <= 0:
		return false
	missile_ammunition -= 1
	ammunition_changed.emit()
	return true

func can_craft_missile() -> bool:
	return GameState.captain.parts >= MISSILE_CRAFT_PARTS_COST

func get_missile_buy_cost() -> int:
	return MISSILE_BUY_BASE_COST * maxi(1, GameState.system_level)

func can_buy_missile() -> bool:
	return GameState.captain.credits >= get_missile_buy_cost()

func craft_missile() -> bool:
	if not can_craft_missile():
		return false
	GameState.captain.parts -= MISSILE_CRAFT_PARTS_COST
	missile_ammunition += 1
	GameState.captain.emit_changed()
	ammunition_changed.emit()
	return true

func buy_missile() -> bool:
	if not can_buy_missile():
		return false
	GameState.captain.credits -= get_missile_buy_cost()
	missile_ammunition += 1
	GameState.captain.emit_changed()
	ammunition_changed.emit()
	return true

func move_item(from_kind: String, from_index: int, to_kind: String, to_index: int) -> bool:
	if not can_move_item(from_kind, from_index, to_kind, to_index):
		return false
	var source := _get_slots(from_kind)
	var destination := _get_slots(to_kind)
	var displaced := destination[to_index]
	destination[to_index] = source[from_index]
	source[from_index] = displaced
	_remove_extension_addons()
	_recalculate_ship_stats()
	inventory_changed.emit()
	return true

func _get_slots(slot_kind: String) -> Array[ItemInstance]:
	match slot_kind:
		"cargo":
			return cargo
		"weapon":
			return weapon_slots
		"module":
			return module_slots
		"extension":
			return extension_slots
	return []

func _recalculate_ship_stats() -> void:
	var bonuses := {}
	for item in weapon_slots + module_slots:
		if item == null or item.definition == null:
			continue
		for stat_key in ["shield_on_damage_percent", "scanner_range", "max_hull", "max_shields", "max_energy", "max_speed", "energy_regeneration", "shield_regeneration", "hull_percent", "shield_percent", "damage_percent", "speed_percent", "experience_percent", "credits_percent", "critical_chance_percent", "critical_damage_percent"]:
			bonuses[stat_key] = float(bonuses.get(stat_key, 0.0)) + item.get_stat_total(stat_key)
	ship.call("apply_equipment_bonuses", bonuses)

func _add_starter_items() -> void:
	var definition := load("res://resources/items/plasma_cannon.tres") as ItemDefinition
	if definition == null:
		push_warning("Could not load starter plasma cannon")
		return
	var item := ItemInstance.new()
	item.definition = definition
	item.item_level = 1
	weapon_slots[0] = item

func _remove_extension_addons() -> void:
	for item in cargo + extension_slots:
		if item != null and item.definition.category == ItemDefinition.Category.ACTIVE_EXTENSION:
			item.additional_modifiers.clear()
			item.rarity = 0

func _restore_modules(saved: Dictionary) -> void:
	if saved.has("extension"):
		extension_slots.assign(saved["extension"])
		extension_slots.resize(EXTENSION_SLOT_COUNT)
	for item in saved.get("module", []):
		if item == null or item.definition == null:
			continue
		var index := MODULE_CATEGORIES.find(item.definition.category)
		if index >= 0 and module_slots[index] == null:
			module_slots[index] = item
		elif item.definition.category == ItemDefinition.Category.ACTIVE_EXTENSION and extension_slots.has(null):
			extension_slots[extension_slots.find(null)] = item
		else:
			add_item(item)

func get_item_comparison(item: ItemInstance, equipped: ItemInstance) -> Array[Dictionary]:
	var before := _comparison_stats(_comparison_bonuses())
	var after := _comparison_stats(_comparison_bonuses(item, equipped))
	var rows: Array[Dictionary] = []
	for key in before:
		var difference: float = float(after[key]["value"]) - float(before[key]["value"])
		if is_zero_approx(difference):
			continue
		rows.append({"key": key, "name": before[key]["name"], "delta": difference, "unit": before[key]["unit"]})
	return rows

func _comparison_bonuses(incoming: ItemInstance = null, outgoing: ItemInstance = null) -> Dictionary:
	var bonuses := {}
	for item in weapon_slots + module_slots:
		if item == null or item == outgoing:
			continue
		_add_comparison_bonuses(bonuses, item)
	if incoming != null:
		_add_comparison_bonuses(bonuses, incoming)
	return bonuses

func _add_comparison_bonuses(bonuses: Dictionary, item: ItemInstance) -> void:
	for key in ["max_hull", "max_shields", "max_energy", "max_speed", "scanner_range", "hull_percent", "shield_percent", "speed_percent", "damage_percent", "critical_damage_percent", "critical_chance_percent", "shield_on_damage_percent", "energy_regeneration", "shield_regeneration", "missile_cooldown_reduction", "experience_percent", "credits_percent"]:
		bonuses[key] = float(bonuses.get(key, 0.0)) + item.get_stat_total(key)

func _comparison_stats(bonuses: Dictionary) -> Dictionary:
	var stats := {}
	for data in [["max_hull", "base_max_hull", "hull_percent", "Pancerz", "pkt"], ["max_shields", "base_max_shields", "shield_percent", "Tarcze", "pkt"], ["max_speed", "base_max_speed", "speed_percent", "Prędkość", "px/s"]]:
		var value := (float(ship.get(data[1])) + float(bonuses.get(data[0], 0.0))) * (1.0 + float(bonuses.get(data[2], 0.0)) / 100.0)
		stats[data[0]] = {"value": value, "name": data[3], "unit": data[4]}
	for data in [["max_energy", "base_max_energy", "Energia", "pkt"], ["scanner_range", "base_scanner_range", "Zasięg skanera", "px"], ["energy_regeneration", "base_energy_regeneration", "Regeneracja energii", "pkt/s"], ["shield_regeneration", "base_shield_regeneration", "Regeneracja tarcz", "pkt/s"]]:
		stats[data[0]] = {"value": float(ship.get(data[1])) + float(bonuses.get(data[0], 0.0)), "name": data[2], "unit": data[3]}
	var captain_damage := 1.0 + GameState.captain.get_skill_bonus("gunner")
	var damage_factor := (1.0 + float(bonuses.get("damage_percent", 0.0)) / 100.0) * captain_damage
	var critical_factor := preload("res://scripts/captain/captain_balance.gd").BASE_CRITICAL_MULTIPLIER * (1.0 + maxf(0.0, float(bonuses.get("critical_damage_percent", 0.0)) / 100.0))
	for index in weapon_slots.size():
		var weapon := weapon_slots[index]
		if weapon == null:
			continue
		var damage := weapon.get_stat_total("damage") * damage_factor
		var binding: String = ["LPM", "PPM", "ŚPM"][index]
		stats["weapon_damage_%d" % index] = {"value": damage, "name": "Śr. obrażenia [%s]" % binding, "unit": "DMG"}
		stats["weapon_critical_%d" % index] = {"value": damage * critical_factor, "name": "Śr. krytyk [%s]" % binding, "unit": "DMG"}
		if weapon.definition.weapon_kind == ItemDefinition.WeaponKind.MISSILE:
			stats["missile_cooldown_%d" % index] = {"value": -maxf(1.0, 5.0 - float(bonuses.get("missile_cooldown_reduction", 0.0))), "name": "Skrócenie cooldownu [%s]" % binding, "unit": "s"}
	var chance := clampf(GameState.captain.get_skill_bonus("sharp_eye") + float(bonuses.get("critical_chance_percent", 0.0)) / 100.0, 0.0, 1.0)
	stats["critical_chance"] = {"value": chance * 100.0, "name": "Krytyki na 100 strzałów", "unit": "trafień"}
	stats["shield_recovery"] = {"value": maxf(0.0, float(bonuses.get("shield_on_damage_percent", 0.0))), "name": "Odzysk tarcz na 100 DMG", "unit": "pkt"}
	var balance := preload("res://scripts/captain/captain_balance.gd")
	var scale_factor := 1.0 + 0.05 * (clampi(GameState.system_level, 1, 1000) - 1)
	for tier in 3:
		var caption: String = ["wróg", "elita", "boss"][tier]
		stats["xp_%d" % tier] = {"value": roundi(balance.KILL_XP[tier] * scale_factor * maxf(0.0, 1.0 + float(bonuses.get("experience_percent", 0.0)) / 100.0)), "name": "EXP / %s" % caption, "unit": "EXP"}
		stats["credits_%d" % tier] = {"value": roundi(balance.KILL_CREDITS[tier] * scale_factor * maxf(0.0, 1.0 + float(bonuses.get("credits_percent", 0.0)) / 100.0)), "name": "Kredyty / %s" % caption, "unit": "kr"}
	return stats