text: /* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
  /* vim:set ts=2 sw=2 sts=2 et: */
  /* This Source Code Form is subject to the terms of the Mozilla Public
   * License, v. 2.0. If a copy of the MPL was not distributed with this
   * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  "use strict";
  
  const { Worker } = require('./worker');
  const { Loader } = require('./loader');
  const hiddenFrames = require('../hidden-frame');
  const observers = require('../observer-service');
  const unload = require('../unload');
  
  /**
   * This trait is layered on top of `Worker` and in contrast to symbiont
   * Worker constructor requires `content` option that represents content
   * that will be loaded in the provided frame, if frame is not provided
   * Worker will create hidden one.
   */
  const Symbiont = Worker.resolve({
      constructor: '_initWorker',
      destroy: '_workerDestroy'
    }).compose(Loader, {
    
    /**
     * The constructor requires all the options that are required by
     * `require('content').Worker` with the difference that the `frame` option
     * is optional. If `frame` is not provided, `contentURL` is expected.
     * @param {Object} options
     * @param {String} options.contentURL
     *    URL of a content to load into `this._frame` and create worker for.
     * @param {Element} [options.frame]
     *    iframe element that is used to load `options.contentURL` into.
     *    if frame is not provided hidden iframe will be created.
     */
    constructor: function Symbiont(options) {
      options = options || {};
  
      if ('contentURL' in options)
          this.contentURL = options.contentURL;
      if ('contentScriptWhen' in options)
        this.contentScriptWhen = options.contentScriptWhen;
      if ('contentScriptFile' in options)
        this.contentScriptFile = options.contentScriptFile;
      if ('contentScript' in options)
        this.contentScript = options.contentScript;
      if ('allow' in options)
        this.allow = options.allow;
      if ('onError' in options)
          this.on('error', options.onError);
      if ('onMessage' in options)
          this.on('message', options.onMessage);
      if ('frame' in options) {
        this._initFrame(options.frame);
      }
      else {
        let self = this;
        this._hiddenFrame = hiddenFrames.HiddenFrame({
          onReady: function onFrame() {
            self._initFrame(this.element);
          }
        });
        hiddenFrames.add(this._hiddenFrame);
      }
  
      unload.ensure(this._public, "destroy");
    },
    
    destroy: function destroy() {
      this._workerDestroy();
      this._unregisterListener();
      this._frame = null;
      if (this._hiddenFrame) {
        hiddenFrames.remove(this._hiddenFrame);
        this._hiddenFrame = null;
      }
    },
    
    /**
     * XUL iframe or browser elements with attribute `type` being `content`.
     * Used to create `ContentSymbiont` from.
     * @type {nsIFrame|nsIBrowser}
     */
    _frame: null,
    
    /**
     * Listener to the `'frameReady"` event (emitted when `iframe` is ready).
     * Removes listener, sets right permissions to the frame and loads content.
     */
    _initFrame: function _initFrame(frame) {
      if (this._loadListener)
        this._unregisterListener();
      
      this._frame = frame;
      frame.docShell.allowJavascript = this.allow.script;
      frame.setAttribute("src", this._contentURL);
  
      // Inject `addon` object in document if we load a document from
      // one of our addon folder and if no content script are defined. bug 612726
      let isDataResource =
        typeof this._contentURL == "string" &&
        this._contentURL.indexOf(require("@packaging").uriPrefix) == 0;
      let hasContentScript =
        (Array.isArray(this.contentScript) ? this.contentScript.length > 0
                                               : !!this.contentScript) ||
        (Array.isArray(this.contentScriptFile) ? this.contentScriptFile.length > 0
                                               : !!this.contentScriptFile);
      // If we have to inject `addon` we have to do it before document
      // script execution, so during `start`:
      this._injectInDocument = isDataResource && !hasContentScript;
      if (this._injectInDocument)
        this.contentScriptWhen = "start";
  
      if ((frame.contentDocument.readyState == "complete" ||
          (frame.contentDocument.readyState == "interactive" &&
           this.contentScriptWhen != 'end' )) &&
          frame.contentDocument.location == this._contentURL) {
        // In some cases src doesn't change and document is already ready
        // (for ex: when the user moves a widget while customizing toolbars.)
        this._onInit();
        return;
      }
      
      let self = this;
      
      if ('start' == this.contentScriptWhen) {
        this._loadEvent = 'start';
        observers.add('document-element-inserted', 
          this._loadListener = function onStart(doc) {
            
            let window = doc.defaultView;
            if (window && window == frame.contentWindow) {
              self._unregisterListener();
              self._onInit();
            }
            
          });
        return;
      }
      
      let eventName = 'end' == this.contentScriptWhen ? 'load' : 'DOMContentLoaded';
      let self = this;
      this._loadEvent = eventName;
      frame.addEventListener(eventName, 
        this._loadListener = function _onReady(event) {
        
          if (event.target != frame.contentDocument)
            return;
          self._unregisterListener();
          
          self._onInit();
          
        }, true);
      
    },
    
    /**
     * Unregister listener that watchs for document being ready to be injected.
     * This listener is registered in `Symbiont._initFrame`.
     */
    _unregisterListener: function _unregisterListener() {
      if (!this._loadListener)
        return;
      if (this._loadEvent == "start") {
        observers.remove('document-element-inserted', this._loadListener);
      }
      else {
        this._frame.removeEventListener(this._loadEvent, this._loadListener,
                                        true);
      }
      this._loadListener = null;
    },
    
    /**
     * Called by Symbiont itself when the frame is ready to load  
     * content scripts according to contentScriptWhen. Overloaded by Panel. 
     */
    _onInit: function () {
      this._initWorker({ window: this._frame.contentWindow });
    }
    
  });
  exports.Symbiont = Symbiont;
  