if (!Array.prototype.filter) {
    Array.prototype.filter = function(fun/*, thisArg*/) {
      'use strict';
  
      if (this === void 0 || this === null) {
        throw new TypeError();
      }
  
      var t = Object(this);
      var len = t.length >>> 0;
      if (typeof fun !== 'function') {
        throw new TypeError();
      }
  
      var res = [];
      var thisArg = arguments.length >= 2 ? arguments[1] : void 0;
      for (var i = 0; i < len; i++) {
        if (i in t) {
          var val = t[i];
  
          // NOTE: Technically this should Object.defineProperty at
          //       the next index, as push can be affected by
          //       properties on Object.prototype and Array.prototype.
          //       But that method's new, and collisions should be
          //       rare, so use the more-compatible alternative.
          if (fun.call(thisArg, val, i, t)) {
            res.push(val);
          }
        }
      }
  
      return res;
    };
  }
  
  if (!String.prototype.startsWith) {
    String.prototype.startsWith = function(searchString, position) {
      position = position || 0;
      return this.indexOf(searchString, position) === position;
    };
  }
  
  
  /**
   * Stack for holding previous commands for retrieval with the up arrow. 
   * Stores data in localStorage. Won't push consecutive duplicates.
   *
   * @author   Jake Gully, chimpytk@gmail.com
   * @license  MIT License
   */
  
  /**
   * Constructor
   * @param {string}  id       Unique id for this stack
   * @param {integer} max_size Number of commands to store
   */
  function CmdStack(id, max_size) {
    "use strict";
  
    var instance_id = id,
        cur = 0,
        arr = []; // This is a fairly meaningless name but
                  // makes it sound like this function was
                  // written by a pirate.  I'm keeping it.
  
    if (typeof id !== 'string') {
      throw 'Stack error: id should be a string.';
    }
  
    if (typeof max_size !== 'number') {
      throw 'Stack error: max_size should be a number.';
    }
  
  
    /**
     * Store the array in localstorage
     */
    function setArray(arr) {
      localStorage['cmd_stack_' + instance_id] = JSON.stringify(arr);
    }
  
    /**
     * Load array from localstorage
     */
    function getArray() {
      if (!localStorage['cmd_stack_' + instance_id]) {
        arr = [];
        setArray(arr);
      }
  
      try {
        arr = JSON.parse(localStorage['cmd_stack_' + instance_id]);
      } catch (err) {
        return [];
      }
      return arr;
    }
  
    /**
     * Push a command to the array
     * @param  {string} cmd Command to append to stack
     */
    function push(cmd) {
      arr = getArray();
      
      // don't push if same as last command
      if (cmd === arr[arr.length - 1]) {
        return false;
      }
  
      arr.push(cmd);
  
      // crop off excess
      while (arr.length > max_size) {
        arr.shift();
      }
  
      cur = arr.length;
      setArray(arr);
    }
  
    /**
     * Get previous command from stack (up key)
     * @return {string} Retrieved command string
     */
    function prev() {
      cur -= 1;
  
      if (cur < 0) {
        cur = 0;
      }
  
      return arr[cur];
    }
  
    /**
     * Get next command from stack (down key)
     * @return {string} Retrieved command string
     */
    function next() {
      cur = cur + 1;
  
      // Return a blank string as last item
      if (cur === arr.length) {
        return "";
      }
  
      // Limit
      if (cur > (arr.length - 1)) {
        cur = (arr.length - 1);
      }
  
      return arr[cur];
    }
  
    /**
     * Move cursor to last element
     */
    function reset() {
      arr = getArray();
      cur = arr.length;
    }
  
    /**
     * Is stack empty
     * @return {Boolean} True if stack is empty
     */
    function isEmpty() {
      arr = getArray();
      return (arr.length === 0);
    }
    
    /**
     * Empty array and remove from localstorage
     */
    function empty() {
      arr = undefined;
      localStorage.clear();
      reset();
    }
  
    /**
     * Get current cursor location
     * @return {integer} Current cursor index
     */
    function getCur() {
      return cur;
    }
  
    /**
     * Get entire stack array
     * @return {array} The stack array
     */
    function getArr() {
      return arr;
    }
  
    /**
     * Get size of the stack
     * @return {Integer} Size of stack
     */
    function getSize(){
      return arr.size;
    }
  
    return {
      push: push,
      prev: prev,
      next: next,
      reset: reset,
      isEmpty: isEmpty,
      empty: empty,
      getCur: getCur,
      getArr: getArr,
      getSize: getSize
    };
  }
  
  
  /**
   * HTML5 Command Line Terminal
   *
   * @author   Jake Gully (chimpytk@gmail.com)
   * @license  MIT License
   */
  
  (function (root, factory) {
    if ( typeof define === 'function' && define.amd ) {
      define(factory);
    } else if ( typeof exports === 'object' ) {
      module.exports = factory();
    } else {
      root.Cmd = factory();
    }
  }(this, function () {
    "use strict";
  
    var Cmd = function (user_config) {
      this.keys_array    = [9, 13, 38, 40, 27],
      this.style         = 'dark',
      this.popup         = false,
      this.prompt_str    = '$ ',
      this.speech_synth_support = ('speechSynthesis' in window && typeof SpeechSynthesisUtterance !== 'undefined'),
      this.options       = {
        busy_text:           'Communicating...',
        external_processor:  function() {},
        filedrop_enabled:    false,
        file_upload_url:     'ajax/uploadfile.php',
        history_id:          'cmd_history',
        remote_cmd_list_url: '',
        selector:            '#cmd',
        tabcomplete_url:     '',
        talk:                false,
        unknown_cmd:         'Unrecognised command',
        typewriter_time:     32
      },
      this.voices = false;
      this.remote_commands = [];
      this.all_commands = [];
      this.local_commands = [
        'clear',
        'clr',
        'cls',
        'clearhistory',
        'invert',
        'shh',
        'talk'
      ];
      this.autocompletion_attempted = false;
  
      $.extend(this.options, user_config);
  
      if (this.options.remote_cmd_list_url) {
        $.ajax({
          url: this.options.remote_cmd_list_url,
          context: this,
          dataType: 'json',
          method: 'GET',
          success: function (data) {
            this.remote_commands = data;
            this.all_commands = $.merge(this.remote_commands, this.local_commands)
          }
        });
      } else {
        this.all_commands = this.local_commands;
      }
  
      if (!$(this.options.selector).length) {
        throw 'Cmd err: Invalid selector.';
      }
  
      this.cmd_stack = new CmdStack(this.options.history_id, 30);
  
      if (this.cmd_stack.isEmpty()) {
        this.cmd_stack.push('secretmagicword!');
      }
  
      this.cmd_stack.reset();
      this.setupDOM();
      this.input.focus();
    }
  
    // ====== Layout / IO / Alter Interface =========
  
    /**
     * Create DOM elements, add click & key handlers
     */
    Cmd.prototype.setupDOM = function() {
      this.wrapper = $(this.options.selector).addClass('cmd-interface');
  
      this.container = $('<div/>')
      .addClass('cmd-container')
      .appendTo(this.wrapper);
  
      if (this.options.filedrop_enabled) {
        setupFiledrop(); // adds dropzone div
      }
  
      this.clearScreen(); // adds output, input and prompt
  
      $(this.options.selector).on('click', $.proxy(this.focusOnInput, this));
      $(window).resize($.proxy(this.resizeInput, this));
  
      this.wrapper.keydown($.proxy(this.handleKeyDown, this));
      this.wrapper.keyup($.proxy(this.handleKeyUp, this));
      this.wrapper.keydown($.proxy(this.handleKeyPress, this));
    }
  
    /**
     * Changes the input type
     */
    Cmd.prototype.showInputType = function(input_type) {
      switch (input_type) {
        case 'password':
          this.input = $('<input/>')
            .attr('type', 'password')
            .attr('maxlength', 512)
            .addClass('cmd-in');
          break;
        case 'textarea':
          this.input = $('<textarea/>')
            .addClass('cmd-in')
          break;
        default:
          this.input = $('<input/>')
            .attr('type', 'text')
            .attr('maxlength', 512)
            .addClass('cmd-in');
      }
  
      this.container.children('.cmd-in').remove();
  
      this.input.appendTo(this.container)
        .attr('title', 'Chimpcom input');
  
      this.focusOnInput();
    }
  
    /**
     * Takes the client's input and the server's output
     * and displays them appropriately.
     *
     * @param   string  cmd_in      The command as entered by the user
     * @param   string  cmd_out     The server output to write to screen
     */
    Cmd.prototype.displayOutput = function(cmd_out) {
      if (typeof cmd_out !== 'string') {
        cmd_out = 'Error: invalid cmd_out returned.';
      }
  
      if (this.output.html())  {
        this.output.append('<br>');
      }
  
      this.output.append(cmd_out + '<br>');
  
      if (this.options.talk) {
        this.speakOutput(cmd_out);
      }
  
      this.cmd_stack.reset();
  
      this.input.val('').removeAttr('disabled');
  
      this.enableInput();
      this.focusOnInput();
      this.activateAutofills();
    }
  
    /**
     * Take an input string and output it to the screen
     */
    Cmd.prototype.displayInput = function(cmd_in) {
      cmd_in = cmd_in.replace(/&/g, "&amp;")
        .replace(/</g, "&lt;")
        .replace(/>/g, "&gt;")
        .replace(/"/g, "&quot;")
        .replace(/'/g, "&#039;");
  
      this.output.append('<span class="prompt">' + this.prompt_str + '</span> ' +
        '<span class="grey_text">' + cmd_in + '</span>');
    }
  
    /**
     * Set the prompt string
     * @param {string} new_prompt The new prompt string
     */
    Cmd.prototype.setPrompt = function(new_prompt) {
      if (typeof new_prompt !== 'string') {
        throw 'Cmd error: invalid prompt string.';
      }
  
      this.prompt_str = new_prompt;
      this.prompt_elem.html(this.prompt_str);
    }
  
    /**
     * Post-file-drop dropzone reset
     */
    Cmd.prototype.resetDropzone = function() {
      dropzone.css('display', 'none');
    }
  
    /**
     * Add file drop handlers
     */
    Cmd.prototype.setupFiledrop = function() {
      this.dropzone = $('<div/>')
      .addClass('dropzone')
      .appendTo(wrapper)
      .filedrop({
        url: this.options.file_upload_url,
        paramname: 'dropfile', // POST parameter name used on serverside to reference file
        maxfiles: 10,
        maxfilesize: 2, // MBs
        error: function (err, file) {
          switch (err) {
          case 'BrowserNotSupported':
            alert('Your browser does not support html5 drag and drop.');
            break;
          case 'TooManyFiles':
            this.displayInput('[File Upload]');
            this.displayOutput('Too many files!');
            this.resetDropzone();
            break;
          case 'FileTooLarge':
            // FileTooLarge also has access to the file which was too large
            // use file.name to reference the filename of the culprit file
            this.displayInput('[File Upload]');
            this.displayOutput('File too big!');
            this.resetDropzone();
            break;
          default:
            this.displayInput('[File Upload]');
            this.displayOutput('Fail D:');
            this.resetDropzone();
            break;
          }
        },
        dragOver: function () { // user dragging files over #dropzone
          this.dropzone.css('display', 'block');
        },
        dragLeave: function () { // user dragging files out of #dropzone
          this.resetDropzone();
        },
        docOver: function () { // user dragging files anywhere inside the browser document window
          this.dropzone.css('display', 'block');
        },
        docLeave: function () { // user dragging files out of the browser document window
          this.resetDropzone();
        },
        drop: function () { // user drops file
          this.dropzone.append('<br>File dropped.');
        },
        uploadStarted: function (i, file, len) {
          this.dropzone.append('<br>Upload started...');
          // a file began uploading
          // i = index => 0, 1, 2, 3, 4 etc
          // file is the actual file of the index
          // len = total files user dropped
        },
        uploadFinished: function (i, file, response, time) {
          // response is the data you got back from server in JSON format.
          if (response.error !== '') {
            upload_error = response.error;
          }
          this.dropzone.append('<br>Upload finished! ' + response.result);
        },
        progressUpdated: function (i, file, progress) {
          // this function is used for large files and updates intermittently
          // progress is the integer value of file being uploaded percentage to completion
          this.dropzone.append('<br>File uploading...');
        },
        speedUpdated: function (i, file, speed) { // speed in kb/s
          this.dropzone.append('<br>Upload speed: ' + speed);
        },
        afterAll: function () {
          // runs after all files have been uploaded or otherwise dealt with
          if (upload_error !== '') {
            this.displayInput('[File Upload]');
            this.displayOutput('Error: ' + upload_error);
          } else {
            this.displayInput('[File Upload]');
            this.displayOutput('[File Upload]', 'Success!');
          }
  
          upload_error = '';
  
          this.dropzone.css('display', 'none');
          this.resetDropzone();
        }
      });
    }
  
    /**
     * [invert description]
     * @return {[type]} [description]
     */
    Cmd.prototype.invert = function() {
      this.wrapper.toggleClass('inverted');
    }
  
  
  
    // ====== Handlers ==============================
  
    /**
     * Do something
     */
    Cmd.prototype.handleInput = function(input_str) {
      var cmd_array = input_str.split(' ');
      var shown_input = input_str;
  
      if (this.input.attr('type') === 'password') {
        shown_input = new Array(shown_input.length + 1).join("•");
      }
  
      this.displayInput(shown_input);
  
      switch (cmd_array[0]) {
        case '':
          this.displayOutput('');
          break;
        case 'clear':
        case 'cls':
        case 'clr':
          this.clearScreen();
          break;
        case 'clearhistory':
          this.cmd_stack.empty();
          this.cmd_stack.reset();
          this.displayOutput('Command history cleared. ');
          break;
        case 'invert':
          this.invert();
          this.displayOutput('Shazam.');
          break;
        case 'shh':
          if (this.options.talk) {
            window.speechSynthesis.cancel();
            this.options.talk = false;
            this.displayOutput('Speech stopped. Talk mode is still enabled. Type TALK to disable talk mode.');
            this.options.talk = true;
          } else {
            this.displayOutput('Ok.');
          }
          break;
        case 'talk':
          if (!this.speech_synth_support) {
            this.displayOutput('You browser doesn\'t support speech synthesis.');
            return false;
          }
  
          this.options.talk = !this.options.talk;
          this.displayOutput((this.options.talk ? 'Talk mode enabled.' : 'Talk mode disabled.'));
          break;
        default:
          if (typeof this.options.external_processor !== 'function') {
            this.displayOutput(this.options.unknown_cmd);
            return false;
          }
  
          var result = this.options.external_processor(input_str, this);
  
          switch (typeof result) {
            // If undefined, external handler should
            // call handleResponse when done
            case 'boolean':
              if (!result) {
                this.displayOutput(this.options.unknown_cmd);
              }
              break;
            // If we get a response object, deal with it directly
            case 'object':
              this.handleResponse(result);
              break;
            // If we have a string, output it. This shouldn't
            // really happen but it might be useful
            case 'string':
              this.displayOutput(result);
              break;
            default:
              this.displayOutput(this.options.unknown_cmd);
          }
      }
    }
  
    /**
     * Handle JSON responses. Used as callback by external command handler
     * @param  {object} res Chimpcom command object
     */
    Cmd.prototype.handleResponse = function(res) {
      if (res.redirect !== undefined) {
        document.location.href = res.redirect;
      }
  
      if (res.openWindow !== undefined) {
        window.open(res.openWindow, '_blank', res.openWindowSpecs);
      }
  
      if (res.log !== undefined && res.log !== '') {
        console.log(res.log);
      }
  
      if (res.show_pass === true) {
        this.showInputType('password');
      } else {
        this.showInputType();
      }
  
      this.displayOutput(res.cmd_out);
  
      if (res.cmd_fill !== '') {
        this.wrapper.children('.cmd-container').children('.cmd-in').first().val(res.cmd_fill);
      }
    }
  
    /**
     * Handle keypresses
     */
    Cmd.prototype.handleKeyPress = function(e) {
      var keyCode = e.keyCode || e.which,
        input_str = this.input.val(),
        autocompletions;
  
      if (keyCode === 9) { //tab
        this.tabComplete(input_str);
      } else {
        this.autocompletion_attempted = false;
        if (this.autocomplete_ajax) {
          this.autocomplete_ajax.abort();
        }
  
        if (keyCode === 13) { // enter
          if (this.input.attr('disabled')) {
            return false;
          }
  
          if (e.ctrlKey) {
            this.cmd_stack.push(input_str);
            this.goToURL(input_str);
          } else {
            this.disableInput();
  
            // push command to stack if using text input, i.e. no passwords
            if (this.input.get(0).type === 'text') {
              this.cmd_stack.push(input_str);
            }
  
            this.handleInput(input_str);
          }
        } else if (keyCode === 38) { // up arrow
          if (input_str !== "" && this.cmd_stack.cur === (this.cmd_stack.getSize() - 1)) {
            this.cmd_stack.push(input_str);
          }
  
          this.input.val(this.cmd_stack.prev());
        } else if (keyCode === 40) { // down arrow
          this.input.val(this.cmd_stack.next());
        } else if (keyCode === 27) { // esc
          if (this.container.css('opacity') > 0.5) {
            this.container.animate({'opacity': 0}, 300);
          } else {
            this.container.animate({'opacity': 1}, 300);
          }
        }
      }
    }
  
    /**
     * Prevent default action of special keys
     */
    Cmd.prototype.handleKeyUp = function(e) {
      var key = e.which;
  
      if ($.inArray(key, this.keys_array) > -1) {
        e.preventDefault();
        return false;
      }
  
      return true;
    }
  
    /**
     * Prevent default action of special keys
     */
    Cmd.prototype.handleKeyDown = function(e) {
      var key = e.which;
  
      if ($.inArray(key, this.keys_array) > -1) {
        e.preventDefault();
  
        return false;
      }
      return true;
    }
  
    /**
     * Complete command names when tab is pressed
     */
    Cmd.prototype.tabComplete = function(str) {
      // If we have a space then offload to external processor
      if (str.indexOf(' ') !== -1) {
        if (this.options.tabcomplete_url) {
          if (this.autocomplete_ajax) {
            this.autocomplete_ajax.abort();
          }
  
          this.autocomplete_ajax = $.ajax({
            url: this.options.tabcomplete_url,
            context: this,
            dataType: 'json',
            data: {
              cmd_in: str
            },
            success: function (data) {
              if (data) {
                this.input.val(data);
              }
            }
          });
        }
        this.autocompletion_attempted = false;
        return;
      }
  
      var autocompletions = this.all_commands.filter(function (value) {
        return value.startsWith(str);
      });
  
  
      if (autocompletions.length === 0) {
        return false;
      } else if (autocompletions.length === 1) {
        this.input.val(autocompletions[0]);
      } else {
        if (this.autocompletion_attempted) {
          this.displayOutput(autocompletions.join(', '));
          this.autocompletion_attempted = false;
          this.input.val(str);
          return;
        } else {
          this.autocompletion_attempted = true;
        }
      }
    }
  
  
    // ====== Helpers ===============================
  
    /**
     * Takes a user to a given url. Adds "http://" if necessary.
     */
    Cmd.prototype.goToURL = function(url) {
      if (url.substr(0, 4) !== 'http' && url.substr(0, 2) !== '//') {
        url = 'http://' + url;
      }
  
      if (popup) {
        window.open(url, '_blank');
        window.focus();
      } else {
        // break out of iframe - used by chrome plugin
        if (top.location !== location) {
          top.location.href = document.location.href;
        }
  
        location.href = url;
      }
    }
  
    /**
     * Give focus to the command input and
     * scroll to the bottom of the page
     */
    Cmd.prototype.focusOnInput = function() {
      var cmd_width;
  
      $(this.options.selector).scrollTop($(this.options.selector)[0].scrollHeight);
  
      this.input.focus();
    }
  
    /**
     * Make prompt and input fit on one line
     */
    Cmd.prototype.resizeInput = function() {
      var cmd_width = this.wrapper.width() - this.wrapper.find('.main-prompt').first().width() - 45;
  
      this.input.focus().css('width', cmd_width);
    }
  
    /**
     * Clear the screen
     */
    Cmd.prototype.clearScreen = function() {
      this.container.empty();
  
      this.output = $('<div/>')
        .addClass('cmd-output')
        .appendTo(this.container);
  
      this.prompt_elem = $('<span/>')
        .addClass('main-prompt')
        .addClass('prompt')
        .html(this.prompt_str)
        .appendTo(this.container);
  
      this.input = $('<input/>')
        .addClass('cmd-in')
        .attr('type', 'text')
        .attr('maxlength', 512)
        .appendTo(this.container);
  
      this.showInputType();
  
      this.input.val('');
    }
  
    /**
     * Attach click handlers to 'autofills' - divs which, when clicked,
     * will insert text into the input
     */
    Cmd.prototype.activateAutofills = function() {
      var input = this.input;
  
      this.wrapper
        .find('[data-type=autofill]')
        .on('click', function() {
          input.val($(this).data('autofill'));
        });
    }
  
    /**
     * Temporarily disable input while runnign commands
     */
    Cmd.prototype.disableInput = function() {
      this.input
        .attr('disabled', true)
        .val(this.options.busy_text);
    }
  
    /**
     * Reenable input after running disableInput()
     */
    Cmd.prototype.enableInput = function() {
      this.input
        .removeAttr('disabled')
        .val('');
    }
  
    /**
     * Speak output aloud using speech synthesis API
     *
     * @param {String} output Text to read
     */
    Cmd.prototype.speakOutput = function(output) {
      var msg = new SpeechSynthesisUtterance();
  
      msg.volume = 1; // 0 - 1
      msg.rate   = 1; // 0.1 - 10
      msg.pitch  = 2; // 0 - 2
      msg.lang   = 'en-UK';
      msg.text   = output;
  
      window.speechSynthesis.speak(msg);
    }
  
    return Cmd;
  }));