"use strict";

import { EventEmitter, once } from 'events';
import net from 'net';

import Connection from '../transport/Connection.mjs';

import Peer from './Peer.mjs';

class PeerServer extends EventEmitter {
	constructor(our_id) {
		super();
		
		this.our_id = our_id;
		
		this.peers = [];
	}
	
	/**
	 * Starts the PeerServer listening on the given port and bind address.
	 * @param	{Number}	[port=5252]		The port number to listen on.
	 * @param	{String}	[host="::"]		The address to bind to.
	 * @return	{Promise<void>}				A Promise that resolves when the server setup is complete.
	 */
	listen(port = 5252, host="::") {
		return new Promise((resolve, reject) => {
			this.server = net.createServer(async (client) => {
				await this.handle_client(client);
			});
			
			this.server.once("error", reject);
			this.server.on("error", this.handle_error);
			this.server.listen({
				host,
				port,
				exclusive: false
			}, () => {
				this.server.off("error", reject);
				resolve();
			});
		});
	}
	
	handle_error(error) {
		throw error;
	}
	
	async handle_client(client) {
		const peer = new Peer(this, await Connection.Wrap(client));
		this.peers.push(peer);
		peer.on("message", this.handle_message.bind(this, peer));
		peer.on("destroy", this.handle_destroy.bind(this, peer));
		await once(peer, "connect");
	}
	
	async handle_message(peer, message) {
		this.emit("message", peer, message);
		this.emit(`message-${message.event}`, peer, message.message);
	}
	
	async handle_destroy(peer) {
		const index = this.peers.indexOf(peer);
		if(index > -1)
			this.peers.splice(index, 1);
		
		this.emit("disconnect", peer.remote_endpoint);
	}
	
	/**
	 * Returns a list of all currently known peer addresses.
	 * @return	{{address:string,port:number}[]}
	 */
	peer_addresses() {
		return this.peers.map((peer) => peer.remote_endpoint)
			.filter(el => typeof el.addr === "string" && typeof el.port === "number");
	}
	
	
	/**
	 * Shuts the server down.
	 * This does not disconnect any existing peers!
	 * @return {Promise} A Promise that resolves once the server has been shutdown.
	 */
	shutdown_server() {
		return new Promise((resolve, _reject) => {
			this.server.close(resolve);
		});
	}
	
	/**
	 * Stops the PeerServer and gracefully (if possible) disconnects all existing peers.
	 * @return	{Promise}	A Promise that resolves once the shutdown process has completed.
	 */
	async destroy() {
		await this.shutdown_server();
		await Promise.all(...this.peers.map(peer => peer.destroy()));
	}
}

export default PeerServer;