/*
 * Default text - jQuery plugin for html5 dragging files from desktop to browser
 *
 * Author: Weixi Yen
 *
 * Email: [Firstname][Lastname]@gmail.com
 *
 * Copyright (c) 2010 Resopollution
 *
 * Licensed under the MIT license:
 *   http://www.opensource.org/licenses/mit-license.php
 *
 * Project home:
 *   http://www.github.com/weixiyen/jquery-filedrop
 *
 * Version:  0.1.0
 *
 * Features:
 *      Allows sending of extra parameters with file.
 *      Works with Firefox 3.6+
 *      Future-compliant with HTML5 spec (will work with Webkit browsers and IE9)
 * Usage:
 * 	See README at project homepage
 *
 */
(function($) {

  jQuery.event.props.push("dataTransfer");

  var opts = {},
      default_opts = {
      url: '',
      refresh: 1000,
      paramname: 'userfile',
      maxfiles: 25,           // Ignored if queuefiles is set > 0
      maxfilesize: 1,         // MB file size limit
      queuefiles: 0,          // Max files before queueing (for large volume uploads)
      queuewait: 200,         // Queue wait time if full
      data: {},
      drop: empty,
      dragEnter: empty,
      dragOver: empty,
      dragLeave: empty,
      docEnter: empty,
      docOver: empty,
      docLeave: empty,
      beforeEach: empty,
      afterAll: empty,
      rename: empty,
      error: function(err, file, i) {
        alert(err);
      },
      uploadStarted: empty,
      uploadFinished: empty,
      progressUpdated: empty,
      speedUpdated: empty
      },
      errors = ["BrowserNotSupported", "TooManyFiles", "FileTooLarge"],
      doc_leave_timer, stop_loop = false,
      files_count = 0,
      files;

  $.fn.filedrop = function(options) {
    opts = $.extend({}, default_opts, options);

    this.bind('drop', drop).bind('dragenter', dragEnter).bind('dragover', dragOver).bind('dragleave', dragLeave);
    $(document).bind('drop', docDrop).bind('dragenter', docEnter).bind('dragover', docOver).bind('dragleave', docLeave);
  };

  function drop(e) {
    opts.drop(e);
    files = e.dataTransfer.files;
    if (files === null || files === undefined) {
      opts.error(errors[0]);
      return false;
    }
    files_count = files.length;
    upload();
    e.preventDefault();
    return false;
  }

  function getBuilder(filename, filedata, mime, boundary) {
    var dashdash = '--',
        crlf = '\r\n',
        builder = '';

    if (opts.data) {
      var params = $.param(opts.data).split(/&/);

      $.each(params, function() {
        var pair = this.split(/=/, 2);
        var name = decodeURI(pair[0]);
        var val = decodeURI(pair[1]);

        builder += dashdash;
        builder += boundary;
        builder += crlf;
        builder += 'Content-Disposition: form-data; name="' + name + '"';
        builder += crlf;
        builder += crlf;
        builder += val;
        builder += crlf;
      });
    }

    builder += dashdash;
    builder += boundary;
    builder += crlf;
    builder += 'Content-Disposition: form-data; name="' + opts.paramname + '"';
    builder += '; filename="' + filename + '"';
    builder += crlf;

    builder += 'Content-Type: ' + mime;
    builder += crlf;
    builder += crlf;

    builder += filedata;
    builder += crlf;

    builder += dashdash;
    builder += boundary;
    builder += dashdash;
    builder += crlf;
    return builder;
  }

  function progress(e) {
    if (e.lengthComputable) {
      var percentage = Math.round((e.loaded * 100) / e.total);
      if (this.currentProgress != percentage) {

        this.currentProgress = percentage;
        opts.progressUpdated(this.index, this.file, this.currentProgress);

        var elapsed = new Date().getTime();
        var diffTime = elapsed - this.currentStart;
        if (diffTime >= opts.refresh) {
          var diffData = e.loaded - this.startData;
          var speed = diffData / diffTime; // KB per second
          opts.speedUpdated(this.index, this.file, speed);
          this.startData = e.loaded;
          this.currentStart = elapsed;
        }
      }
    }
  }

  // Respond to an upload
  function upload() {

    stop_loop = false;

    if (!files) {
      opts.error(errors[0]);
      return false;
    }

    var filesDone = 0,
        filesRejected = 0;

    if (files_count > opts.maxfiles && opts.queuefiles === 0) {
      opts.error(errors[1]);
      return false;
    }

    // Define queues to manage upload process
    var workQueue = [];
    var processingQueue = [];
    var doneQueue = [];

    // Add everything to the workQueue
    for (var i = 0; i < files_count; i++) {
      workQueue.push(i);
    }

    // Helper function to enable pause of processing to wait
    // for in process queue to complete
    var pause = function(timeout) {
        setTimeout(process, timeout);
        return;
    }

    // Process an upload, recursive
    var process = function() {

	        var fileIndex;

	        if (stop_loop) return false;

	        // Check to see if are in queue mode
	        if (opts.queuefiles > 0 && processingQueue.length >= opts.queuefiles) {

	          return pause(opts.queuewait);

	        } else {

	          // Take first thing off work queue
	          fileIndex = workQueue[0];
	          workQueue.splice(0, 1);

	          // Add to processing queue
	          processingQueue.push(fileIndex);

	        }

	        try {
	          if (beforeEach(files[fileIndex]) != false) {
	            if (fileIndex === files_count) return;
	            var reader = new FileReader(),
	                max_file_size = 1048576 * opts.maxfilesize;

	            reader.index = fileIndex;
	            if (files[fileIndex].size > max_file_size) {
	              opts.error(errors[2], files[fileIndex], fileIndex);
	              // Remove from queue
	              processingQueue.forEach(function(value, key) {
	                if (value === fileIndex) processingQueue.splice(key, 1);
	              });
	              filesRejected++;
	              return true;
	            }
	            reader.onloadend = send;
	            reader.readAsBinaryString(files[fileIndex]);

	          } else {
	            filesRejected++;
	          }
	        } catch (err) {
	          // Remove from queue
	          processingQueue.forEach(function(value, key) {
	            if (value === fileIndex) processingQueue.splice(key, 1);
	          });
	          opts.error(errors[0]);
	          return false;
	        }

	        // If we still have work to do,
	        if (workQueue.length > 0) {
	          process();
	        }

        };

    var send = function(e) {

      var fileIndex = ((typeof(e.srcElement) === "undefined") ? e.target : e.srcElement).index

      // Sometimes the index is not attached to the
      // event object. Find it by size. Hack for sure.
      if (e.target.index == undefined) {
        e.target.index = getIndexBySize(e.total);
      }

      var xhr = new XMLHttpRequest(),
          upload = xhr.upload,
          file = files[e.target.index],
          index = e.target.index,
          start_time = new Date().getTime(),
          boundary = '------multipartformboundary' + (new Date).getTime(),
          builder;

      newName = rename(file.name);
      mime = file.type
      if (typeof newName === "string") {
        builder = getBuilder(newName, e.target.result, mime, boundary);
      } else {
        builder = getBuilder(file.name, e.target.result, mime, boundary);
      }

      upload.index = index;
      upload.file = file;
      upload.downloadStartTime = start_time;
      upload.currentStart = start_time;
      upload.currentProgress = 0;
      upload.startData = 0;
      upload.addEventListener("progress", progress, false);

      xhr.open("POST", opts.url, true);
      xhr.setRequestHeader('content-type', 'multipart/form-data; boundary=' + boundary);

      xhr.sendAsBinary(builder);

      opts.uploadStarted(index, file, files_count);

      xhr.onload = function() {
        if (xhr.responseText) {
          var now = new Date().getTime(),
              timeDiff = now - start_time,
              result = opts.uploadFinished(index, file, jQuery.parseJSON(xhr.responseText), timeDiff);
          filesDone++;

          // Remove from processing queue
          processingQueue.forEach(function(value, key) {
            if (value === fileIndex) processingQueue.splice(key, 1);
          });

          // Add to donequeue
          doneQueue.push(fileIndex);

          if (filesDone == files_count - filesRejected) {
            afterAll();
          }
          if (result === false) stop_loop = true;
        }
      };

    }

    // Initiate the processing loop
    process();

  }

  function getIndexBySize(size) {
    for (var i = 0; i < files_count; i++) {
      if (files[i].size == size) {
        return i;
      }
    }

    return undefined;
  }

  function rename(name) {
    return opts.rename(name);
  }

  function beforeEach(file) {
    return opts.beforeEach(file);
  }

  function afterAll() {
    return opts.afterAll();
  }

  function dragEnter(e) {
    clearTimeout(doc_leave_timer);
    e.preventDefault();
    opts.dragEnter(e);
  }

  function dragOver(e) {
    clearTimeout(doc_leave_timer);
    e.preventDefault();
    opts.docOver(e);
    opts.dragOver(e);
  }

  function dragLeave(e) {
    clearTimeout(doc_leave_timer);
    opts.dragLeave(e);
    e.stopPropagation();
  }

  function docDrop(e) {
    e.preventDefault();
    opts.docLeave(e);
    return false;
  }

  function docEnter(e) {
    clearTimeout(doc_leave_timer);
    e.preventDefault();
    opts.docEnter(e);
    return false;
  }

  function docOver(e) {
    clearTimeout(doc_leave_timer);
    e.preventDefault();
    opts.docOver(e);
    return false;
  }

  function docLeave(e) {
    doc_leave_timer = setTimeout(function() {
      opts.docLeave(e);
    }, 200);
  }

  function empty() {}

  try {
    if (XMLHttpRequest.prototype.sendAsBinary) return;
    XMLHttpRequest.prototype.sendAsBinary = function(datastr) {
      function byteValue(x) {
        return x.charCodeAt(0) & 0xff;
      }
      var ords = Array.prototype.map.call(datastr, byteValue);
      var ui8a = new Uint8Array(ords);
      this.send(ui8a.buffer);
    }
  } catch (e) {}

})(jQuery);