// Main interface with the servers

import * as electronRemote from '@electron/remote';
const electronConsole = electronRemote.getGlobal('console') as Console;
import Logger from '../../logger/logger';
const LOG = Logger.create(__filename, electronConsole);

import { EventEmitter } from "stream";

import ClientController from "./client-controller";

import * as socketio from 'socket.io-client';

import * as crypto from 'crypto';

import DBCache from './db-cache';
import { ServerConfig } from './data-types';
import { IAddServerData } from './elements/overlay-add-server';

export default class Controller extends EventEmitter {
	public servers: ClientController[] = [];

	constructor() {
		super();
	}

	async _connectFromConfig(serverConfig: ServerConfig): Promise<ClientController> {
		LOG.debug(`connecting to server#${serverConfig.serverId} at ${serverConfig.url}`);

		let server = new ClientController(serverConfig);

		await DBCache.clearAllMemberStatus(server.id);

		this.servers.push(server);
	
		// Forward server events through this event emitter
		let serverEvents = [
			'connected',
			'disconnected',
			'verified',
			'new-message',
			'update-server',
			'deleted-members',
			'updated-members',
			'added-members',
			'deleted-channels',
			'updated-channels',
			'added-channels',
			'deleted-messages',
			'updated-messages',
			'added-messages',
		];
		for (let event of serverEvents) {
			server.on(event, (...args) => {
				this.emit(event, server, ...args);
			});
		}
		return server;
	}

	async init(): Promise<void> {
		this.servers = [];

		let serverConfigs = await DBCache.getServerConfigs();

		// TODO: HTML prompt if no server configs
		if (serverConfigs.length == 0) {
			LOG.warn('no server configs found in client-side db');
		}

		for (let serverConfig of serverConfigs) {
			await this._connectFromConfig(serverConfig);
		}
	}

	static _socketEmitTimeout(socket: socketio.Socket, ms: number, name: string, ...args: any[]) { // see also client-controller.js
		let socketArgs = args.slice(0, args.length - 1);
		let respond = args[args.length - 1];

		let cutoff =  false;
		let timeout = setTimeout(() => {
			cutoff = true;
			respond('emit timeout');
		}, ms);

		socket.emit(name, ...socketArgs, (...respondArgs: any[]) => {
			if (cutoff) {
				return;
			}
			clearTimeout(timeout);
			respond(...respondArgs);
		});
	}

	async addNewServer(serverConfig: IAddServerData, displayName: string, avatarBuff: Buffer): Promise<ClientController> {
		const { name, url, cert, token } = serverConfig;
		LOG.debug('Adding new server', { name, url, cert, token, displayName, avatarBuff });
		

		let socket = await new Promise<socketio.Socket>((resolve, reject) => {
			let socket = socketio.connect(url, {
				forceNew: true,
				ca: cert, // verifies the server's identity
				reconnection: false, // a bit stricter for registration
			});
			socket.on('connect_error', (e) => {
				LOG.error('connect error', e);
				reject(new Error('unable to connect to server'));
			});
			socket.on('connect', () => {
				resolve(socket);
			});
		});
		try {
			// Create a new Public/Private key pair to identify ourselves with this server
			let { publicKey, privateKey } = await new Promise((resolve, reject) => {
				crypto.generateKeyPair('rsa', { modulusLength: 4096 }, (err, publicKey, privateKey) => {
					if (err) {
						reject(err);
					} else {
						resolve({ publicKey, privateKey });
					}
				});
			});

			return await new Promise((resolve, reject) => {
				let clientPublicKeyDerBuff = publicKey.export({ type: 'spki', format: 'der' });
				Controller._socketEmitTimeout(socket, 5000, 'register-with-token',
					token, clientPublicKeyDerBuff, displayName, avatarBuff, async (errStr, member) => {
						if (errStr) {
							reject(new Error(errStr));
						} else {
							try {
								let serverConfig: ServerConfig | null = null;
								await DBCache.queueTransaction(async () => {
									let publicKeyPem = publicKey.export({ type: 'spki', format: 'pem' });
									let privateKeyPem = privateKey.export({ type: 'pkcs8', format: 'pem' });
									let identityId = await DBCache.addIdentity(publicKeyPem, privateKeyPem);
									let serverId = await DBCache.addServer(url, cert, name);
									await DBCache.addServerIdentity(serverId, identityId);
									serverConfig = await DBCache.getServerConfig(serverId, identityId);
								});
								if (serverConfig == null) {
									throw new Error('unable to get server config');
								}
								let server = await this._connectFromConfig(serverConfig);
								resolve(server);
							} catch (e) {
								reject(e);
							}
						}
					}
				);
			});
		} finally {
			socket.disconnect();
		}
	}

	async removeServer(server: ClientController): Promise<void> {
		await DBCache.removeServer(server.id);
		this.servers = this.servers.filter(s => s != server);
	}
}