/*
 * This Source Code is subject to the terms of the Mozilla Public License
 * version 2.0 (the "License"). You can obtain a copy of the License at
 * http://mozilla.org/MPL/2.0/.
 */

#filter substitution

/**
 * @fileOverview Stores Adblock Plus data to be attached to a window.
 */

var EXPORTED_SYMBOLS = ["RequestNotifier"];

const Cc = Components.classes;
const Ci = Components.interfaces;
const Cr = Components.results;
const Cu = Components.utils;

let baseURL = "resource://@ADDON_CHROME_NAME@/modules/";
Cu.import(baseURL + "Utils.jsm");
Cu.import(baseURL + "FilterClasses.jsm");
Utils.runAsync(Cu.import, Cu, baseURL + "ContentPolicy.jsm");  // delay to avoid circular imports

let nodeData = new WeakMap();
let windowStats = new WeakMap();
let windowSelection = new WeakMap();

/**
 * List of notifiers in use - these notifiers need to receive notifications on
 * new requests.
 * @type RequestNotifier[]
 */
let activeNotifiers = [];

/**
 * Creates a notifier object for a particular window. After creation the window
 * will first be scanned for previously saved requests. Once that scan is
 * complete only new requests for this window will be reported.
 * @param {Window} wnd  window to attach the notifier to
 * @param {Function} listener  listener to be called whenever a new request is found
 * @param {Object} [listenerObj]  "this" pointer to be used when calling the listener
 */
function RequestNotifier(wnd, listener, listenerObj)
{
  this.window = wnd;
  this.listener = listener;
  this.listenerObj = listenerObj || null;
  activeNotifiers.push(this);
  if (wnd)
    this.startScan(wnd);
  else
    this.scanComplete = true;
}
RequestNotifier.prototype =
{
  /**
   * The window this notifier is associated with.
   * @type Window
   */
  window: null,

  /**
   * The listener to be called when a new request is found.
   * @type Function
   */
  listener: null,

  /**
   * "this" pointer to be used when calling the listener.
   * @type Object
   */
  listenerObj: null,

  /**
   * Will be set to true once the initial window scan is complete.
   * @type Boolean
   */
  scanComplete: false,

  /**
   * Shuts down the notifier once it is no longer used. The listener
   * will no longer be called after that.
   */
  shutdown: function()
  {
    delete this.window;
    delete this.listener;
    delete this.listenerObj;

    for (let i = activeNotifiers.length - 1; i >= 0; i--)
      if (activeNotifiers[i] == this)
        activeNotifiers.splice(i, 1);
  },

  /**
   * Notifies listener about a new request.
   */
  notifyListener: function(/**Window*/ wnd, /**Node*/ node, /**RequestEntry*/ entry)
  {
    this.listener.call(this.listenerObj, wnd, node, entry, this.scanComplete);
  },

  /**
   * Number of currently posted scan events (will be 0 when the scan finishes
   * running).
   */
  eventsPosted: 0,

  /**
   * Starts the initial scan of the window (will recurse into frames).
   * @param {Window} wnd  the window to be scanned
   */
  startScan: function(wnd)
  {
    let currentThread = Utils.threadManager.currentThread;

    let doc = wnd.document;
    let walker = doc.createTreeWalker(doc, Ci.nsIDOMNodeFilter.SHOW_ELEMENT, null, false);

    let runnable =
    {
      notifier: null,

      run: function()
      {
        if (!this.notifier.listener)
          return;

        let node = walker.currentNode;
        let data = nodeData.get(node);
        if (typeof data != "undefined")
          for (let i = data.length - 1; i >= 0; i--)
            this.notifier.notifyListener(wnd, node, data[i]);

        if (walker.nextNode())
          currentThread.dispatch(runnable, Ci.nsIEventTarget.DISPATCH_NORMAL);
        else
        {
          // Done with the current window, start the scan for its frames
          for (let i = 0; i < wnd.frames.length; i++)
            this.notifier.startScan(wnd.frames[i]);

          this.notifier.eventsPosted--;
          if (!this.notifier.eventsPosted)
          {
            this.notifier.scanComplete = true;
            this.notifier.notifyListener(wnd, null, null);
          }

          this.notifier = null;
        }
      }
    };
    runnable.notifier = this;

    // Process each node in a separate event on current thread to allow other
    // events to process
    this.eventsPosted++;
    currentThread.dispatch(runnable, Ci.nsIEventTarget.DISPATCH_NORMAL);
  }
};

RequestNotifier.storeSelection = function(/**Window*/ wnd, /**String*/ selection)
{
  windowSelection.set(wnd, selection);
};
RequestNotifier.getSelection = function(/**Window*/ wnd) /**String*/
{
  if (windowSelection.has(wnd))
    return windowSelection.get(wnd);
  else
    return null;
};

/**
 * Attaches request data to a DOM node.
 * @param {Node} node   node to attach data to
 * @param {Window} topWnd   top-level window the node belongs to
 * @param {Integer} contentType   request type, one of the Policy.type.* constants
 * @param {String} docDomain  domain of the document that initiated the request
 * @param {Boolean} thirdParty  will be true if a third-party server has been requested
 * @param {String} location   the address that has been requested
 * @param {Filter} filter   filter applied to the request or null if none
 */
RequestNotifier.addNodeData = function(/**Node*/ node, /**Window*/ topWnd, /**Integer*/ contentType, /**String*/ docDomain, /**Boolean*/ thirdParty, /**String*/ location, /**Filter*/ filter)
{
  return new RequestEntry(node, topWnd, contentType, docDomain, thirdParty, location, filter);
}

/**
 * Retrieves the statistics for a window.
 * @result {Object} Object with the properties items, blocked, whitelisted, hidden, filters containing statistics for the window (might be null)
 */
RequestNotifier.getWindowStatistics = function(/**Window*/ wnd)
{
  if (windowStats.has(wnd.document))
    return windowStats.get(wnd.document);
  else
    return null;
}

/**
 * Retrieves the request entry associated with a DOM node.
 * @param {Node} node
 * @param {Boolean} noParent  if missing or false, the search will extend to the parent nodes until one is found that has data associated with it
 * @param {Integer} [type] request type to be looking for
 * @param {String} [location] request location to be looking for
 * @result {[Node, RequestEntry]}
 * @static
 */
RequestNotifier.getDataForNode = function(node, noParent, type, location)
{
  while (node)
  {
    let data = nodeData.get(node);
    if (typeof data != "undefined")
    {
      // Look for matching entry starting at the end of the list (most recent first)
      for (let i = data.length - 1; i >= 0; i--)
      {
        let entry = data[i];
        if ((typeof type == "undefined" || entry.type == type) &&
            (typeof location == "undefined" || entry.location == location))
        {
          return [node, entry];
        }
      }
    }

    // If we don't have any match on this node then maybe its parent will do
    if ((typeof noParent != "boolean" || !noParent) &&
        node.parentNode instanceof Ci.nsIDOMElement)
    {
      node = node.parentNode;
    }
    else
    {
      node = null;
    }
  }

  return null;
};

function RequestEntry(node, topWnd, contentType, docDomain, thirdParty, location, filter)
{
  this.type = contentType;
  this.docDomain = docDomain;
  this.thirdParty = thirdParty;
  this.location = location;
  this.filter = filter;

  this.attachToNode(node);

  // Update window statistics
  if (!windowStats.has(topWnd.document))
  {
    windowStats.set(topWnd.document, {
      items: 0,
      hidden: 0,
      blocked: 0,
      whitelisted: 0,
      filters: {}
    });
  }

  let stats = windowStats.get(topWnd.document);
  if (filter && filter instanceof ElemHideFilter)
    stats.hidden++;
  else
    stats.items++;
  if (filter)
  {
    if (filter instanceof BlockingFilter)
      stats.blocked++;
    else if (filter instanceof WhitelistFilter)
      stats.whitelisted++;

    if (filter.text in stats.filters)
      stats.filters[filter.text]++;
    else
      stats.filters[filter.text] = 1;
  }

  // Notify listeners
  for each (let notifier in activeNotifiers)
    if (!notifier.window || notifier.window == topWnd)
      notifier.notifyListener(topWnd, node, this);
}
RequestEntry.prototype =
{
  /**
   * Content type of the request (one of the nsIContentPolicy constants)
   * @type Integer
   */
  type: null,
  /**
   * Domain name of the requesting document
   * @type String
   */
  docDomain: null,
  /**
   * True if the request goes to a different domain than the domain of the containing document
   * @type Boolean
   */
  thirdParty: false,
  /**
   * Address being requested
   * @type String
   */
  location: null,
  /**
   * Filter that was applied to this request (if any)
   * @type Filter
   */
  filter: null,
  /**
   * String representation of the content type, e.g. "subdocument"
   * @type String
   */
  get typeDescr() Policy.typeDescr[this.type],
  /**
   * User-visible localized representation of the content type, e.g. "frame"
   * @type String
   */
  get localizedDescr() Policy.localizedDescr[this.type],

  /**
   * Attaches this request object to a DOM node.
   */
  attachToNode: function(/**Node*/ node)
  {
    let existingData = nodeData.get(node);
    if (typeof existingData != "undefined")
    {
      // Add the new entry to the existing data
      existingData.push(this);
    }
    else
    {
      // Associate the node with a new array
      nodeData.set(node, [this]);
    }
  }
};