class_name ResearchPanel
extends PanelContainer

const RESEARCH_ROW_SCENE: PackedScene = preload("res://core/research/research_row.tscn")

@onready var _title_label: Label = $ScrollContainer/VBoxContainer/TitleLabel
@onready var _research_rows_container: VBoxContainer = $ScrollContainer/VBoxContainer/ResearchRows
@onready var _buy_worker_button: Button = $ScrollContainer/VBoxContainer/HBoxContainer/BuyWorkerButton

var _game_state: LevelGameState
var _research_rows: Dictionary = {}
var _active_research_id: StringName = &""

func _ready() -> void:
	_game_state = find_parent("LevelGameState")
	if _game_state == null:
		push_error("ResearchPanel: Could not find LevelGameState parent")
		return
	
	_game_state.research_xp_changed.connect(_on_research_xp_changed)
	_game_state.research_level_up.connect(_on_research_level_up)
	_game_state.currency_changed.connect(_on_currency_changed)
	_game_state.research_workers_changed.connect(_on_research_workers_changed)
	
	_build_research_rows()
	_refresh_all()
	_refresh_worker_button()

func _build_research_rows() -> void:
	for child in _research_rows_container.get_children():
		child.queue_free()
	_research_rows.clear()
	_active_research_id = &""
	
	if _game_state.research_catalogue:
		for research in _game_state.research_catalogue.get_all_research():
			var row: ResearchRow = RESEARCH_ROW_SCENE.instantiate()
			_research_rows_container.add_child(row)
			row.setup(research)
			row.active_changed.connect(_on_research_active_changed.bind(research.id))
			_research_rows[research.id] = row
	
	_load_active_research_state()

func _refresh_all() -> void:
	for row in _research_rows.values():
		_refresh_row(row)

func _refresh_row(row: ResearchRow) -> void:
	var research_id: StringName = row.get_research_id()
	var xp: BigNumber = _game_state.get_research_xp(research_id)
	var level: int = _game_state.get_research_level(research_id)
	var research: ResearchData = _game_state.research_catalogue.get_research_by_id(research_id)
	
	if research != null:
		var progress: float = research.get_xp_progress(xp)
		var multiplier: float = research.get_multiplier_for_level(level)
		var xp_current: BigNumber = xp.subtract(research.get_total_xp_for_level(level))
		var xp_needed: BigNumber = research.get_xp_required_for_level_big(level + 1)
		
		row.update_display(level, progress, multiplier, xp_current, xp_needed)

func _on_research_xp_changed(research_id: StringName, _new_xp: BigNumber) -> void:
	if _research_rows.has(research_id):
		_refresh_row(_research_rows[research_id])

func _on_research_level_up(research_id: StringName, _old_level: int, _new_level: int) -> void:
	if _research_rows.has(research_id):
		_refresh_row(_research_rows[research_id])

func _on_research_active_changed(is_active: bool, research_id: StringName) -> void:
	if is_active:
		if _active_research_id != &"" and _active_research_id != research_id:
			var existing_row: ResearchRow = _research_rows.get(_active_research_id)
			if existing_row != null:
				existing_row.set_active(false, false)
		_active_research_id = research_id
		_save_active_research_state()
	else:
		if _active_research_id == research_id:
			_active_research_id = &""
			_save_active_research_state()

func _load_active_research_state() -> void:
	if _game_state == null:
		return
	
	var save_data: Dictionary = _game_state.get_external_save_data("research_active")
	if save_data.has("active_research_id"):
		var loaded_id: String = String(save_data.get("active_research_id", ""))
		if not loaded_id.is_empty():
			_active_research_id = StringName(loaded_id)
			var row: ResearchRow = _research_rows.get(_active_research_id)
			if row != null:
				row.set_active(true, false)

func _save_active_research_state() -> void:
	if _game_state == null:
		return
	
	var save_data: Dictionary = {}
	if _active_research_id != &"":
		save_data["active_research_id"] = String(_active_research_id)
	_game_state.set_external_save_data("research_active", save_data)

func get_active_research_id() -> StringName:
	return _active_research_id

func is_research_active(research_id: StringName) -> bool:
	return _active_research_id == research_id

func activate_research(research_id: StringName) -> void:
	if _research_rows.has(research_id):
		var row: ResearchRow = _research_rows[research_id]
		row.set_active(true)

func _on_currency_changed(currency_id: StringName, _new_amount: BigNumber) -> void:
	if currency_id == &"worker":
		_refresh_worker_button()

func _on_research_workers_changed(_new_count: int) -> void:
	_refresh_worker_button()

func _can_buy_worker() -> bool:
	if _game_state == null:
		return false
	
	var worker_currency: BigNumber = _game_state.get_currency_amount_by_id(&"worker")
	
	return worker_currency.mantissa >= 1.0

func _buy_worker() -> void:
	if _game_state == null:
		return
	
	_game_state.assign_worker_to_research()

func _on_buy_worker_pressed() -> void:
	_buy_worker()
	_refresh_worker_button()

func _refresh_worker_button() -> void:
	if _buy_worker_button == null:
		return
	
	if _game_state == null:
		_buy_worker_button.disabled = true
		return
	
	var can_buy: bool = _can_buy_worker()
	_buy_worker_button.disabled = not can_buy
	
	var worker_currency: BigNumber = _game_state.get_currency_amount_by_id(&"worker")
	var research_workers: int = _game_state.get_research_workers()
	_buy_worker_button.text = "Assign Worker to Research (%d available, %d assigned)" % [int(worker_currency.mantissa), research_workers]