/* -*- tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
/* 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";

let devtools_ = Cu.import("resource://gre/modules/devtools/Loader.jsm", {}).devtools;
let { createExtraActors, appendExtraActors } = devtools_.require("devtools/server/actors/common");

/* Root actor for the remote debugging protocol. */

/**
 * Create a remote debugging protocol root actor.
 *
 * @param aConnection
 *     The DebuggerServerConnection whose root actor we are constructing.
 *
 * @param aParameters
 *     The properties of |aParameters| provide backing objects for the root
 *     actor's requests; if a given property is omitted from |aParameters|, the
 *     root actor won't implement the corresponding requests or notifications.
 *     Supported properties:
 *
 *     - tabList: a live list (see below) of tab actors. If present, the
 *       new root actor supports the 'listTabs' request, providing the live
 *       list's elements as its tab actors, and sending 'tabListChanged'
 *       notifications when the live list's contents change. One actor in
 *       this list must have a true '.selected' property.
 *
 *     - addonList: a live list (see below) of addon actors. If present, the
 *       new root actor supports the 'listAddons' request, providing the live
 *       list's elements as its addon actors, and sending 'addonListchanged'
 *       notifications when the live list's contents change.
 *
 *     - globalActorFactories: an object |A| describing further actors to
 *       attach to the 'listTabs' reply. This is the type accumulated by
 *       DebuggerServer.addGlobalActor. For each own property |P| of |A|,
 *       the root actor adds a property named |P| to the 'listTabs'
 *       reply whose value is the name of an actor constructed by
 *       |A[P]|.
 *
 *     - onShutdown: a function to call when the root actor is disconnected.
 *
 * Instance properties:
 *
 * - applicationType: the string the root actor will include as the
 *      "applicationType" property in the greeting packet. By default, this
 *      is "browser".
 *
 * Live lists:
 *
 * A "live list", as used for the |tabList|, is an object that presents a
 * list of actors, and also notifies its clients of changes to the list. A
 * live list's interface is two properties:
 *
 * - getList: a method that returns a promise to the contents of the list.
 *
 * - onListChanged: a handler called, with no arguments, when the set of
 *             values the iterator would produce has changed since the last
 *             time 'iterator' was called. This may only be set to null or a
 *             callable value (one for which the typeof operator returns
 *             'function'). (Note that the live list will not call the
 *             onListChanged handler until the list has been iterated over
 *             once; if nobody's seen the list in the first place, nobody
 *             should care if its contents have changed!)
 *
 * When the list changes, the list implementation should ensure that any
 * actors yielded in previous iterations whose referents (tabs) still exist
 * get yielded again in subsequent iterations. If the underlying referent
 * is the same, the same actor should be presented for it.
 *
 * The root actor registers an 'onListChanged' handler on the appropriate
 * list when it may need to send the client 'tabListChanged' notifications,
 * and is careful to remove the handler whenever it does not need to send
 * such notifications (including when it is disconnected). This means that
 * live list implementations can use the state of the handler property (set
 * or null) to install and remove observers and event listeners.
 *
 * Note that, as the only way for the root actor to see the members of the
 * live list is to begin an iteration over the list, the live list need not
 * actually produce any actors until they are reached in the course of
 * iteration: alliterative lazy live lists.
 */
function RootActor(aConnection, aParameters) {
  this.conn = aConnection;
  this._parameters = aParameters;
  this._onTabListChanged = this.onTabListChanged.bind(this);
  this._onAddonListChanged = this.onAddonListChanged.bind(this);
  this._extraActors = {};
}

RootActor.prototype = {
  constructor: RootActor,
  applicationType: "browser",

  /**
   * Return a 'hello' packet as specified by the Remote Debugging Protocol.
   */
  sayHello: function() {
    return {
      from: this.actorID,
      applicationType: this.applicationType,
      /* This is not in the spec, but it's used by tests. */
      testConnectionPrefix: this.conn.prefix,
      traits: {
        sources: true,
        editOuterHTML: true,
        // Wether the server-side highlighter actor exists and can be used to
        // remotely highlight nodes (see server/actors/highlighter.js)
        highlightable: true,
        // Wether the inspector actor implements the getImageDataFromURL
        // method that returns data-uris for image URLs. This is used for image
        // tooltips for instance
        urlToImageDataResolver: true,
        networkMonitor: true,
        // Wether the storage inspector actor to inspect cookies, etc.
        storageInspector: true,
        // Wether storage inspector is read only
        storageInspectorReadOnly: true,
        // Wether conditional breakpoints are supported
        conditionalBreakpoints: true
      }
    };
  },

  /**
   * This is true for the root actor only, used by some child actors
   */
  get isRootActor() true,

  /**
   * The (chrome) window, for use by child actors
   */
  get window() Services.wm.getMostRecentWindow(DebuggerServer.chromeWindowType),

  /**
   * URL of the chrome window.
   */
  get url() { return this.window ? this.window.document.location.href : null; },

  /**
   * Getter for the best nsIWebProgress for to watching this window.
   */
  get webProgress() {
    return this.window
      .QueryInterface(Ci.nsIInterfaceRequestor)
      .getInterface(Ci.nsIDocShell)
      .QueryInterface(Ci.nsIInterfaceRequestor)
      .getInterface(Ci.nsIWebProgress);
  },

  /**
   * Disconnects the actor from the browser window.
   */
  disconnect: function() {
    /* Tell the live lists we aren't watching any more. */
    if (this._parameters.tabList) {
      this._parameters.tabList.onListChanged = null;
    }
    if (this._parameters.addonList) {
      this._parameters.addonList.onListChanged = null;
    }
    if (typeof this._parameters.onShutdown === 'function') {
      this._parameters.onShutdown();
    }
    this._extraActors = null;
  },

  /* The 'listTabs' request and the 'tabListChanged' notification. */

  /**
   * Handles the listTabs request. The actors will survive until at least
   * the next listTabs request.
   */
  onListTabs: function() {
    let tabList = this._parameters.tabList;
    if (!tabList) {
      return { from: this.actorID, error: "noTabs",
               message: "This root actor has no browser tabs." };
    }

    /*
     * Walk the tab list, accumulating the array of tab actors for the
     * reply, and moving all the actors to a new ActorPool. We'll
     * replace the old tab actor pool with the one we build here, thus
     * retiring any actors that didn't get listed again, and preparing any
     * new actors to receive packets.
     */
    let newActorPool = new ActorPool(this.conn);
    let tabActorList = [];
    let selected;
    return tabList.getList().then((tabActors) => {
      for (let tabActor of tabActors) {
        if (tabActor.selected) {
          selected = tabActorList.length;
        }
        tabActor.parentID = this.actorID;
        newActorPool.addActor(tabActor);
        tabActorList.push(tabActor);
      }

      /* DebuggerServer.addGlobalActor support: create actors. */
      if (!this._globalActorPool) {
        this._globalActorPool = new ActorPool(this.conn);
        this._createExtraActors(this._parameters.globalActorFactories, this._globalActorPool);
        this.conn.addActorPool(this._globalActorPool);
      }

      /*
       * Drop the old actorID -> actor map. Actors that still mattered were
       * added to the new map; others will go away.
       */
      if (this._tabActorPool) {
        this.conn.removeActorPool(this._tabActorPool);
      }
      this._tabActorPool = newActorPool;
      this.conn.addActorPool(this._tabActorPool);

      let reply = {
        "from": this.actorID,
        "selected": selected || 0,
        "tabs": [actor.form() for (actor of tabActorList)],
      };

      /* If a root window is accessible, include its URL. */
      if (this.url) {
        reply.url = this.url;
      }

      /* DebuggerServer.addGlobalActor support: name actors in 'listTabs' reply. */
      this._appendExtraActors(reply);

      /*
       * Now that we're actually going to report the contents of tabList to
       * the client, we're responsible for letting the client know if it
       * changes.
       */
      tabList.onListChanged = this._onTabListChanged;

      return reply;
    });
  },

  onTabListChanged: function () {
    this.conn.send({ from: this.actorID, type:"tabListChanged" });
    /* It's a one-shot notification; no need to watch any more. */
    this._parameters.tabList.onListChanged = null;
  },

  onListAddons: function () {
    let addonList = this._parameters.addonList;
    if (!addonList) {
      return { from: this.actorID, error: "noAddons",
               message: "This root actor has no browser addons." };
    }

    return addonList.getList().then((addonActors) => {
      let addonActorPool = new ActorPool(this.conn);
      for (let addonActor of addonActors) {
          addonActorPool.addActor(addonActor);
      }

      if (this._addonActorPool) {
        this.conn.removeActorPool(this._addonActorPool);
      }
      this._addonActorPool = addonActorPool;
      this.conn.addActorPool(this._addonActorPool);

      addonList.onListChanged = this._onAddonListChanged;

      return {
        "from": this.actorID,
        "addons": [addonActor.form() for (addonActor of addonActors)]
      };
    });
  },

  onAddonListChanged: function () {
    this.conn.send({ from: this.actorID, type: "addonListChanged" });
    this._parameters.addonList.onListChanged = null;
  },

  /* This is not in the spec, but it's used by tests. */
  onEcho: function (aRequest) {
    /*
     * Request packets are frozen. Copy aRequest, so that
     * DebuggerServerConnection.onPacket can attach a 'from' property.
     */
    return JSON.parse(JSON.stringify(aRequest));
  },

  onProtocolDescription: function (aRequest) {
    return protocol.dumpProtocolSpec()
  },

  /* Support for DebuggerServer.addGlobalActor. */
  _createExtraActors: createExtraActors,
  _appendExtraActors: appendExtraActors,

  /* ThreadActor hooks. */

  /**
   * Prepare to enter a nested event loop by disabling debuggee events.
   */
  preNest: function() {
    // Disable events in all open windows.
    let e = Services.wm.getEnumerator(null);
    while (e.hasMoreElements()) {
      let win = e.getNext();
      let windowUtils = win.QueryInterface(Ci.nsIInterfaceRequestor)
                           .getInterface(Ci.nsIDOMWindowUtils);
      windowUtils.suppressEventHandling(true);
      windowUtils.suspendTimeouts();
    }
  },

  /**
   * Prepare to exit a nested event loop by enabling debuggee events.
   */
  postNest: function(aNestData) {
    // Enable events in all open windows.
    let e = Services.wm.getEnumerator(null);
    while (e.hasMoreElements()) {
      let win = e.getNext();
      let windowUtils = win.QueryInterface(Ci.nsIInterfaceRequestor)
                           .getInterface(Ci.nsIDOMWindowUtils);
      windowUtils.resumeTimeouts();
      windowUtils.suppressEventHandling(false);
    }
  }
};

RootActor.prototype.requestTypes = {
  "listTabs": RootActor.prototype.onListTabs,
  "listAddons": RootActor.prototype.onListAddons,
  "echo": RootActor.prototype.onEcho,
  "protocolDescription": RootActor.prototype.onProtocolDescription
};
