import { Room, RoomServerMessage, RoomMessage } from "./store/room";

export interface RoomConnectionData {
	ws_url: string;
	auth_token: string;
}

export type MessageHandler = (msg: RoomServerMessage) => void;

export default class RoomClient {
	private ws: WebSocket;
	public info: Room;
	public backlog: RoomServerMessage[];

	private onMessage?: MessageHandler;
	private buffer: RoomServerMessage[];

	constructor(_ws: WebSocket, _info: Room) {
		this.info = _info;
		this.buffer = [];
		this.backlog = [];
		this.ws = _ws;
		this.ws.addEventListener("message", this._received.bind(this));
	}

	private _received(ev: MessageEvent) {
		let data = JSON.parse(ev.data);
		if (this.onMessage) {
			return this.onMessage(data);
		}
		// Save messages in a buffer if no handler is set
		this.buffer.push(data);
	}

	public setMessageHandler(handler: MessageHandler) {
		// Set as handler for all future messages
		this.onMessage = handler;
		// If we have messages in our buffer, send them over
		for (const msg of this.buffer) {
			handler(msg);
		}
		// Empty buffer
		this.buffer = [];
	}

	public static connect(wsdata: RoomConnectionData): Promise<RoomClient> {
		return new Promise((resolve, reject) => {
			let ws = new WebSocket(wsdata.ws_url);
			const onMessage = (ev: MessageEvent) => {
				// Unregister handler
				ws.removeEventListener("message", onMessage);
				// Parse message
				let data = JSON.parse(ev.data) as RoomServerMessage;
				if ("error" in data) {
					reject(data.error);
				}
				if (data.room) {
					let client = new RoomClient(ws, data.room);
					// Check for backlog
					if (data.backlog) {
						client.backlog = data.backlog;
					}
					resolve(client);
				} else {
					reject("missing room info");
				}
			};
			ws.addEventListener("message", onMessage);
			ws.addEventListener("open", ev => {
				// Send authentication
				ws.send(JSON.stringify({ token: wsdata.auth_token }));
			});
		});
	}
}