var spawn = require('child_process').spawn;
var fs = require("fs");

var http = require('http');
var mime=require("mime");
var server = http.createServer(function (req, res) {
	var format = req.url.replace(/\/(.*)\.(.*?)/, "$2");
  	var url    = req.url.replace(/\/(.*)\.(.*?)/, "$1");
	if ( ! /^.*\.[a-z0-9]{3,5}$/.test(req.url) ) {
	   format="mp4";
	   url     = req.url.replace(/\/(.*)/, "$1");
	}
	var file = url.replace(/[\/:?!&?=\.]/g, "")+"."+format;
	var mimeType=mime.lookup(file);
	var args = ["-o", "downloads/"+file];
	if (format==="m4a") {
		args.push("-x");
		args.push("--audio-format");
		args.push(format);
	}
	else if (format==="mp3") {
		args.push("-x");
		args.push("--audio-format");
		args.push(format);
	}
	else if (format==="opus") {
		args.push("-x");
		args.push("--audio-format");
		args.push(format);
	} else {
		args.push("-f");
		args.push(format);
	}
	args.push(url);
	var job = spawn('./youtube-dl',args);
	console.log(args.join(" "));
	job.on('close', function (code, signal) {
		var fileStream = fs.createReadStream("downloads/"+file);
		pipeReadstream ( req, res, fileStream, mimeType, file,  function ( err ) { 
		console.log(err);
		});
	});

	job.stdout.on('data', function (data) {
	  console.log('stdout: ' + data);
	});

	job.stderr.on('data', function (data) {
	  console.log('stderr: ' + data);
	});
});

server.listen(8567);
	
  // pipe some stream as HTTP response
function pipeReadstream( req, res, readStream, mimeType, filename, cb ) {
	var headWritten = false;   
	
	readStream.on('data', function(data) {
	    if ( !headWritten ) {
		res.writeHead(200, {'Content-disposition':'attachment; filename='+filename,'Content-Type': mimeType });
		headWritten = true; 
	    }
	    var flushed = res.write( data );
	    // Pause the read stream when the write stream gets saturated
	    if( !flushed ){
		readStream.pause();
	    }
	});

	res.on('drain', function() {
	    // Resume the read stream when the write stream gets hungry 
	    readStream.resume();
	});

	readStream.on('end', function() {
	    res.end();
	});

	readStream.on('error', function(err) {
	    cb ( err );        
	});   

}