import express from "express";
import cors from "cors";
import * as http from "http";
import { EventEmitter } from "events";
import { Server, Socket } from "socket.io";

const pendingMessageEvents: { [id: string]: EventEmitter } = {};
let messageId = 0;

export class MSeriesServer {
    public static readonly PORT: number = 5000;
    private app: express.Application;
    private server: http.Server;
    private io: Server;
    private port: string | number;

    constructor() {
        this.createApp();
        this.config();
        this.createServer();
        this.sockets();
        this.listen();
    }

    private createApp(): void {
        this.app = express();
        this.app.use(cors());
    }

    private createServer(): void {
        this.server = http.createServer(this.app);
    }

    private config(): void {
        this.port = process.env.PORT || MSeriesServer.PORT;
    }

    private sockets(): void {
        this.io = new Server(this.server, {
            cors: {
                origin: '*',
            }, 
            serveClient: false,
            pingTimeout: 1 * 60 * 1000,
            maxHttpBufferSize:1e9,
            
        });
    }

    private listen(): void {
        this.io.on("connect", (socket: Socket) => {
            console.log("Connected client on port %s.", this.port);
            socket.on("message", (m: { id: string, payload: string }) => {
                console.log(`[server](message): ${m.id}`);

                pendingMessageEvents[m.id].emit("response", m.payload);
            });

            socket.on("disconnect", (reason) => {
                console.log("Client disconnected: " + reason);
            });
        });

        this.server.listen(this.port, () => {
            console.log("Running server on port %s", this.port);
        });
    }

    public getApp(): express.Application {
        return this.app;
    }

    public sendMessage(msg: string) {
        const currentMessageId = messageId++;

        return new Promise((resolve, reject) => {
            console.log(`[server] send message: ${currentMessageId}`);
            this.io.emit("message", {
                id: currentMessageId,
                payload: msg
            });

            pendingMessageEvents[currentMessageId] = new EventEmitter();
            pendingMessageEvents[currentMessageId].on("response", (response) => {
                resolve(response);
            })
        })

    }
}