var express = require('express');
var path = require('path');

var app = express();
var port = 8888;

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'ejs');

// include static files
app.use(express.static(path.join(__dirname, 'public')));

// upload destination setup
app.set('files', path.join(__dirname, '/public/files'));

var index = require('./routes/index');

// router
app.get('/upload', index.list);
app.post('/upload', index.submit(app.get('files')));
app.get('/file/:id/download', index.download(app.get('files')));

var server = app.listen(port);
console.log("Listening on port: " + port);

var io = require('socket.io')(server);
app.set('socketio', io); // store a reference to the io object, can be passed to routes

var formidable = require('formidable');
var fs = require('fs');
var path = require('path');

var fileUploaded = new Map(); // store uploaded files

exports.list = function (req, res) {
  res.render('index', {
    title: "File upload",
    fileUploaded: fileUploaded
  });
};

exports.submit = function (dir) {
  return function (req, res, next) {
    var form = new formidable.IncomingForm();

    // high level formidable API
    form.uploadDir = dir; // set destination
    form.hash = 'md5'; // use hash algorithm, we can get hash value by 'file.hash'
    form.parse(req, function (err, fields, files) {
      // console.log(fields);
      // console.log(files);
      files.file.lastModifiedDate = files.file.lastModifiedDate.toLocaleString();
      var f = {
        newName: fields.name.length == 0
          ? files.file.name
          : fields.name + path.extname(files.file.name),
        file: files.file
      };
      if (fileUploaded.has(files.file.hash)) {
        form.emit('aborted'); // doesn't work!?
        console.log('aborted');
      } else {
        fileUploaded.set(files.file.hash, f); // add to map
      }

      fs.rename(files.file.path, path.join(form.uploadDir, files.file.name), function (err) {
        if (err) {
          console.log(err);
        }
        res.redirect('/upload');
        console.log('Finished.');
      });
    });

    var io = req.app.get('socketio'); // get reference to socket.io

    // listening progress event and send data to client
    form.on('progress', function (bytesReceived, bytesExpected) {
      var percent = Math.floor(bytesReceived / bytesExpected * 100);
      console.log(percent);

      var progress = {
        name: 'progress',
        percent: percent
      };

      // emit event : progress
      io.emit('progress', progress); //notify all client, no session here
    });
  }
};

exports.download = function (dir) {
  return function (req, res, next) {
    var id = req.params.id;
    var file = fileUploaded.get(id);
    var targetPath = path.join(dir, file.file.name);

    // second parameter can be used to specify file name
    res.download(targetPath, file.newName);
  };
};

// client validation
function validateInput() {
	var uploadButton = document.forms[0].upload;
	uploadButton.onclick = function () {
		var file = document.forms[0].file.value;
		if (file.length == 0) {
			document.getElementById('uploadProgress').innerText = 'No file selectd!';
			return false;
		}
		var name = document.forms[0].name.value;
		if (name.length != 0) {
			var invalidChars = name.match(/[^a-zA-Z0-9_()\u4e00-\u9fa5]+/g); // match invalid file name
			if (invalidChars.length != 0) {
				document.getElementById('uploadProgress').innerText = 'Invalid file name!';
				return false;
			}
		}
	}
}

// communication between client and server using socket.io
function getUploadProgressFromServer() {
	var socket = io.connect("http://localhost:8888");
	var uploadProgress = document.getElementById("uploadProgress");
	var bar = document.getElementById('bar');

	socket.on("progress", function (data) {
		if ("progress" === data.name) {
			uploadProgress.innerText = data.percent + '%';
			bar.style.width = data.percent / 100 * document.body.offsetWidth + 'px';
		} else {
			console.log("There is nothing.", data);
		}
	});
}