extends Node

signal decks_loaded()
signal deck_saved(deck: Deck)
signal deck_deleted(deck_id: String)
signal progress_updated(deck_id: String)

const DECKS_DIR = "user://data/decks/"
const PROGRESS_FILE = "user://data/progress/progress.json"

var decks: Array[Deck] = []
var progress_data: Dictionary = {}
var user_id: String = "local"

func _ready() -> void:
	_ensure_directories_exist()
	load_all_decks()
	load_progress()

func _ensure_directories_exist() -> void:
	DirAccess.make_dir_recursive_absolute("user://data/decks/")
	DirAccess.make_dir_recursive_absolute("user://data/progress/")

func load_all_decks() -> void:
	decks.clear()
	var dir = DirAccess.open(DECKS_DIR)

	if not dir:
		push_warning("Could not open decks directory, creating it...")
		_ensure_directories_exist()
		decks_loaded.emit()
		return

	dir.list_dir_begin()
	var file_name = dir.get_next()

	while file_name != "":
		if file_name.ends_with(".json"):
			var deck = load_deck_from_file(DECKS_DIR + file_name)
			if deck:
				decks.append(deck)
		file_name = dir.get_next()

	dir.list_dir_end()

	decks.sort_custom(func(a, b): return a.updated_at > b.updated_at)

	print("Loaded %d deck(s)" % decks.size())
	decks_loaded.emit()

func load_deck_from_file(file_path: String) -> Deck:
	print("Loading Deck From File: ", file_path)
	var file = FileAccess.open(file_path, FileAccess.READ)
	if not file:
		push_error("Failed to open deck file: " + file_path)
		return null
	
	var json_string = file.get_as_text()
	file.close()

	var json = JSON.new()
	var error = json.parse(json_string)

	if error != OK:
		push_error("Failed to parse JSON in file: %s (Error: %s)" % [file_path, json.get_error_message()])
		return null

	var deck = Deck.new()
	deck.from_dict(json.data)
	return deck

func save_deck(deck: Deck) -> bool:
	if not deck:
		push_error("Cannot save null deck")
		return false

	deck.updated_at = Time.get_datetime_string_from_system(true, true) + "Z"

	var file_path = DECKS_DIR + deck.id + ".json"
	print("Saving Deck to: ", file_path)
	var file = FileAccess.open(file_path, FileAccess.WRITE)

	if not file:
		push_error("Failed to create deck file: " + file_path)
		return false

	var deck_dict = deck.to_dict()
	var json_string = JSON.stringify(deck_dict, "\t")
	file.store_string(json_string)
	file.close()

	var found = false
	for i in range(decks.size()):
		if decks[i].id == deck.id:
			decks[i] = deck
			found = true
			break

	if not found:
		decks.append(deck)

	decks.sort_custom(func(a, b): return a.updated_at > b.updated_at)

	print("Saved deck: %s (%d cards)" % [deck.name, deck.get_card_count()])
	deck_saved.emit(deck)
	return true

func delete_deck(deck_id: String) -> bool:
	var file_path = DECKS_DIR + deck_id + ".json"

	if FileAccess.file_exists(file_path):
		var error = DirAccess.remove_absolute(file_path)
		if error != OK:
			push_error("Failed to delete deck file: " + file_path)
			return false

	for i in range(decks.size()):
		if decks[i].id == deck_id:
			decks.remove_at(i)
			break

	if progress_data.has(deck_id):
		progress_data.erase(deck_id)
		save_progress()

	print("Deleted deck: " + deck_id)
	deck_deleted.emit(deck_id)
	return true

func get_deck_by_id(deck_id: String) -> Deck:
	for deck in decks:
		if deck.id == deck_id:
			return deck
	return null

func load_progress() -> void:
	if not FileAccess.file_exists(PROGRESS_FILE):
		print("No progress file found, starting fresh")
		return

	var file = FileAccess.open(PROGRESS_FILE, FileAccess.READ)
	if not file:
		push_error("Failed to open progress file")
		return

	var json_string = file.get_as_text()
	file.close()

	var json = JSON.new()
	var error = json.parse(json_string)

	if error != OK:
		push_error("Failed to parse progress JSON")
		return

	var data = json.data
	user_id = data.get("user_id", "local")

	var deck_progress = data.get("deck_progress", {})
	for deck_id in deck_progress.keys():
		var progress = Progress.new()
		progress.from_dict(deck_progress[deck_id])
		progress_data[deck_id] = progress

	print("Loaded progress for %d deck(s)" % progress_data.size())

func save_progress() -> void:
	var deck_progress = {}
	for deck_id in progress_data.keys():
		deck_progress[deck_id] = progress_data[deck_id].to_dict()

	var data = {
		"version": "1.0",
		"user_id": user_id,
		"deck_progress": deck_progress
	}

	var file = FileAccess.open(PROGRESS_FILE, FileAccess.WRITE)
	if not file:
		push_error("Failed to save progress file")
		return

	var json_string = JSON.stringify(data, "\t")
	file.store_string(json_string)
	file.close()

	print("Saved progress for %d deck(s)" % progress_data.size())

func get_or_create_progress(deck_id: String) -> Progress:
	if not progress_data.has(deck_id):
		var progress = Progress.new()
		progress.deck_id = deck_id
		progress_data[deck_id] = progress

	return progress_data[deck_id]

func record_quiz_result(deck_id: String, card_id: String, is_correct: bool) -> void:
	var progress = get_or_create_progress(deck_id)
	progress.record_answer(card_id, is_correct)
	save_progress()
	progress_updated.emit(deck_id)

func get_progress(deck_id: String) -> Progress:
	return progress_data.get(deck_id, null)


func download_deck_from_api(api_url: String) -> void:
	print("Downloading deck from API: " + api_url)

	var http_request = HTTPRequest.new()
	add_child(http_request)

	http_request.request_completed.connect(_on_api_deck_downloaded.bind(http_request))
	var error = http_request.request(api_url)

	if error != OK:
		push_error("Failed to start HTTP request: " + str(error))
		http_request.queue_free()

func _on_api_deck_downloaded(result: int, response_code: int, headers: PackedStringArray, body: PackedByteArray, http_request: HTTPRequest) -> void:
	if not http_request:
		return

	if result != HTTPRequest.RESULT_SUCCESS:
		push_error("HTTP request failed with result: " + str(result))
		http_request.queue_free()
		return

	if response_code != 200:
		push_error("API returned error code: " + str(response_code))
		http_request.queue_free()
		return

	var json_string = body.get_string_from_utf8()
	var json = JSON.new()
	var parse_error = json.parse(json_string)

	if parse_error != OK:
		push_error("Failed to parse API response JSON")
		http_request.queue_free()
		return

	var deck = Deck.new()
	deck.from_dict(json.data)
	save_deck(deck)

	print("Successfully downloaded and saved deck: " + deck.name)
	http_request.queue_free()

func upload_deck_to_api(deck: Deck, api_url: String, auth_token: String = "") -> void:
	print("Uploading deck to API: " + deck.name)

	var http_request = HTTPRequest.new()
	add_child(http_request)

	http_request.request_completed.connect(_on_api_deck_uploaded.bind(http_request))

	var headers = ["Content-Type: application/json"]
	if auth_token != "":
		headers.append("Authorization: Bearer " + auth_token)

	var deck_dict = deck.to_dict()
	var json_string = JSON.stringify(deck_dict)

	var error = http_request.request(api_url, headers, HTTPClient.METHOD_POST, json_string)

	if error != OK:
		push_error("Failed to start HTTP upload request: " + str(error))
		http_request.queue_free()

func _on_api_deck_uploaded(result: int, response_code: int, headers: PackedStringArray, body: PackedByteArray, http_request: HTTPRequest) -> void:
	if not http_request:
		return

	if result != HTTPRequest.RESULT_SUCCESS:
		push_error("HTTP upload failed with result: " + str(result))
		http_request.queue_free()
		return

	if response_code == 200 or response_code == 201:
		print("Deck successfully uploaded to API!")
		# Optionally parse response to get the deck ID from server
		var json_string = body.get_string_from_utf8()
		print("Server response: " + json_string)
	else:
		push_error("API returned error code: " + str(response_code))

	http_request.queue_free()

func browse_decks_from_api(api_url: String) -> void:
	print("Browsing decks from API: " + api_url)

	var http_request = HTTPRequest.new()
	add_child(http_request)
	http_request.request_completed.connect(_on_api_decks_browsed.bind(http_request))

	var error = http_request.request(api_url)
	if error != OK:
		push_error("Failed to start browse request: " + str(error))
		http_request.queue_free()

func _on_api_decks_browsed(result: int, response_code: int, headers: PackedStringArray, body: PackedByteArray, http_request: HTTPRequest) -> void:
	if not http_request:
		return

	if result != HTTPRequest.RESULT_SUCCESS or response_code != 200:
		push_error("Browse request failed")
		http_request.queue_free()
		return

	var json_string = body.get_string_from_utf8()
	var json = JSON.new()

	if json.parse(json_string) == OK:
		var decks_list = json.data
		print("Found %d decks from API" % decks_list.size())

		for deck_data in decks_list:
			print("  - " + deck_data.get("deck", {}).get("name", "Unknown"))

	http_request.queue_free()