extends Node
class_name WsGatewayClient
## WebSocket gateway client for real-time presence and chat.
##
## Manages connection to the AGP gateway endpoint (/api/ws or /v1/ws).
## Handles JWT authentication, presence heartbeat, DM/world channel
## subscriptions, and event dispatch.

signal connected
signal disconnected
signal authenticated(user_id: int, username: String)
signal presence_changed(user_id: int, status: String)
signal chat_message_received(channel: String, id: int, data: Dictionary)
signal subscribed(channel: String, id: int)
signal unsubscribed(channel: String, id: int)
signal gateway_error(message: String)

enum ConnectionState {
	DISCONNECTED,
	CONNECTING,
	CONNECTED,
	AUTHENTICATED,
	CLOSING
}

var _peer: WebSocketPeer = WebSocketPeer.new()
var _state: ConnectionState = ConnectionState.DISCONNECTED
var _token: String = ""
var _authenticated_user_id: int = 0
var _authenticated_username: String = ""
var _heartbeat_timer: float = 0.0
var _heartbeat_interval: float = 25.0
var _last_url: String = ""

var is_connected_to_gateway: bool:
	get:
		return _state == ConnectionState.CONNECTED or _state == ConnectionState.AUTHENTICATED

var is_authenticated: bool:
	get:
		return _state == ConnectionState.AUTHENTICATED

var user_id: int:
	get:
		return _authenticated_user_id

var username: String:
	get:
		return _authenticated_username


func _process(delta: float) -> void:
	if _state == ConnectionState.DISCONNECTED:
		return

	_peer.poll()
	var peer_state := _peer.get_ready_state()

	match peer_state:
		WebSocketPeer.STATE_OPEN:
			if _state == ConnectionState.CONNECTING:
				_state = ConnectionState.CONNECTED
				connected.emit()
				# If token was provided, send auth frame if not already sent via query param
				if _token != "" and _state != ConnectionState.AUTHENTICATED:
					send_json_message({"type": "auth", "token": _token})

			# Process incoming packets
			while _peer.get_available_packet_count() > 0:
				var packet := _peer.get_packet()
				_handle_packet(packet)

			# Send periodic heartbeat
			if _state == ConnectionState.AUTHENTICATED:
				_heartbeat_timer += delta
				if _heartbeat_timer >= _heartbeat_interval:
					_heartbeat_timer = 0.0
					send_heartbeat()

		WebSocketPeer.STATE_CLOSING:
			_state = ConnectionState.CLOSING

		WebSocketPeer.STATE_CLOSED:
			if _state != ConnectionState.DISCONNECTED:
				var code := _peer.get_close_code()
				var reason := _peer.get_close_reason()
				_cleanup()
				disconnected.emit()


## Connect to the WebSocket gateway.
## If ws_url is empty, derives ws:// or wss:// from base_http_url + "/api/ws".
func connect_gateway(base_http_url: String = "http://127.0.0.1:8000", token: String = "") -> Error:
	_cleanup()
	_token = token

	var url: String
	if base_http_url.begins_with("ws://") or base_http_url.begins_with("wss://"):
		url = base_http_url
	else:
		var ws_scheme := "wss://" if base_http_url.begins_with("https://") else "ws://"
		var stripped := base_http_url.replace("https://", "").replace("http://", "").rstrip("/")
		url = ws_scheme + stripped + "/api/ws"

	if token != "":
		url += "?token=" + token.uri_encode()

	_last_url = url
	_peer = WebSocketPeer.new()
	var err := _peer.connect_to_url(url)
	if err == OK:
		_state = ConnectionState.CONNECTING
	else:
		_state = ConnectionState.DISCONNECTED
		gateway_error.emit("Failed to initiate connection: %d" % err)
	return err


## Disconnect from the WebSocket gateway.
func disconnect_gateway(code: int = 1000, reason: String = "Normal closure") -> void:
	if _state != ConnectionState.DISCONNECTED and _peer != null:
		_peer.close(code, reason)
	_cleanup()
	disconnected.emit()


## Send a ping frame.
func send_ping() -> void:
	send_json_message({"type": "ping"})


## Send presence heartbeat.
func send_heartbeat() -> void:
	send_json_message({"type": "heartbeat"})


## Subscribe to world chat events.
func subscribe_world(world_id: int) -> void:
	send_json_message({"type": "subscribe", "channel": "world", "id": world_id})


## Unsubscribe from world chat events.
func unsubscribe_world(world_id: int) -> void:
	send_json_message({"type": "unsubscribe", "channel": "world", "id": world_id})


## Subscribe to DM conversation events.
func subscribe_dm(conversation_id: int) -> void:
	send_json_message({"type": "subscribe", "channel": "dm", "id": conversation_id})


## Unsubscribe from DM conversation events.
func unsubscribe_dm(conversation_id: int) -> void:
	send_json_message({"type": "unsubscribe", "channel": "dm", "id": conversation_id})


## Send any dictionary as a JSON text packet.
func send_json_message(data: Dictionary) -> Error:
	if _peer.get_ready_state() != WebSocketPeer.STATE_OPEN:
		return ERR_UNCONFIGURED
	var text := JSON.stringify(data)
	return _peer.send_text(text)


func _handle_packet(packet: PackedByteArray) -> void:
	var text := packet.get_string_from_utf8()
	var parsed: Variant = JSON.parse_string(text)
	if not (parsed is Dictionary):
		return
	var msg: Dictionary = parsed as Dictionary
	var msg_type: String = str(msg.get("type", ""))

	match msg_type:
		"auth_ok":
			_state = ConnectionState.AUTHENTICATED
			_authenticated_user_id = int(msg.get("user_id", 0))
			_authenticated_username = str(msg.get("username", ""))
			authenticated.emit(_authenticated_user_id, _authenticated_username)

		"presence":
			var uid: int = int(msg.get("user_id", 0))
			var p_status: String = str(msg.get("status", "offline"))
			presence_changed.emit(uid, p_status)

		"chat_message":
			var channel: String = str(msg.get("channel", ""))
			var target_id: int = int(msg.get("id", 0))
			var data: Dictionary = msg.get("data", {}) if msg.get("data") is Dictionary else {}
			chat_message_received.emit(channel, target_id, data)

		"subscribed":
			var channel: String = str(msg.get("channel", ""))
			var id: int = int(msg.get("id", 0))
			subscribed.emit(channel, id)

		"unsubscribed":
			var channel: String = str(msg.get("channel", ""))
			var id: int = int(msg.get("id", 0))
			unsubscribed.emit(channel, id)

		"error":
			var err_msg: String = str(msg.get("message", "Unknown error"))
			gateway_error.emit(err_msg)


func _cleanup() -> void:
	_state = ConnectionState.DISCONNECTED
	_authenticated_user_id = 0
	_authenticated_username = ""
	_heartbeat_timer = 0.0