/**
* @license Apache-2.0
*
* Copyright (c) 2019 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*    http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

'use strict';

var net = require( 'net' );
var passThrough = require( '@stdlib/streams/node/transform' );
var stdout = require( '@stdlib/streams/node/stdout' );
var objectKeys = require( '@stdlib/utils/keys' );
var REPL = require( './../../lib' );

// Define a counter for keeping track of connections:
var connections = 0;

// Initialize a socket database:
var sockets = {};

// Create a pass through stream which pipes to `stdout` as one of its destinations:
var ostream = passThrough();
ostream.pipe( stdout );

// Define REPL options, leveraging the fact that a socket connection is a duplex stream:
var opts = {
	'output': ostream,
	'isTTY': true
};

// Create a new REPL instance:
var repl = new REPL( opts );

// Listen for when the REPL exits:
repl.on( 'exit', onExit );

function onExit() {
	var keys;
	var key;
	var i;

	// When a REPL exits, we can close all currently open sockets...
	keys = objectKeys( sockets );
	for ( i = 0; i < keys.length; i++ ) {
		key = keys[ i ];
		ostream.unpipe( socket );
		sockets[ key ].end();
		delete sockets[ key ];
	}
}

// Create a new TCP server:
var server = net.createServer( onSocket );

// Start listening for TCP connections:
server.listen( 1337 );

function onSocket( socket ) {
	var id;

	connections += 1;
	id = connections;

	sockets[ id ] = socket;
	socket.on( 'end', onEnd );

	// Start streaming REPL data to the socket:
	ostream.pipe( socket );

	function onEnd() {
		delete sockets[ id ];
		ostream.unpipe( socket );
	}
}