/* 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 EXPORTED_SYMBOLS = ["WebNavigation"];

const { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
const { AppConstants } = ChromeUtils.import(
  "resource://gre/modules/AppConstants.jsm"
);

ChromeUtils.defineModuleGetter(
  this,
  "BrowserWindowTracker",
  "resource:///modules/BrowserWindowTracker.jsm"
);
ChromeUtils.defineModuleGetter(
  this,
  "PrivateBrowsingUtils",
  "resource://gre/modules/PrivateBrowsingUtils.jsm"
);
ChromeUtils.defineModuleGetter(
  this,
  "UrlbarUtils",
  "resource:///modules/UrlbarUtils.jsm"
);
ChromeUtils.defineModuleGetter(
  this,
  "ClickHandlerParent",
  "resource:///actors/ClickHandlerParent.jsm"
);

// Maximum amount of time that can be passed and still consider
// the data recent (similar to how is done in nsNavHistory,
// e.g. nsNavHistory::CheckIsRecentEvent, but with a lower threshold value).
const RECENT_DATA_THRESHOLD = 5 * 1000000;

var Manager = {
  // Map[string -> Map[listener -> URLFilter]]
  listeners: new Map(),

  init() {
    // Collect recent tab transition data in a WeakMap:
    //   browser -> tabTransitionData
    this.recentTabTransitionData = new WeakMap();

    // Collect the pending created navigation target events that still have to
    // pair the message received from the source tab to the one received from
    // the new tab.
    this.createdNavigationTargetByOuterWindowId = new Map();

    Services.obs.addObserver(this, "urlbar-user-start-navigation", true);

    Services.obs.addObserver(this, "webNavigation-createdNavigationTarget");

    if (AppConstants.MOZ_BUILD_APP == "browser") {
      ClickHandlerParent.addContentClickListener(this);
    }

    Services.mm.addMessageListener("Extension:DOMContentLoaded", this);
    Services.mm.addMessageListener("Extension:StateChange", this);
    Services.mm.addMessageListener("Extension:DocumentChange", this);
    Services.mm.addMessageListener("Extension:HistoryChange", this);
    Services.mm.addMessageListener("Extension:CreatedNavigationTarget", this);

    Services.mm.loadFrameScript(
      "resource://gre/modules/WebNavigationContent.js",
      true
    );
  },

  uninit() {
    // Stop collecting recent tab transition data and reset the WeakMap.
    Services.obs.removeObserver(this, "urlbar-user-start-navigation");
    Services.obs.removeObserver(this, "webNavigation-createdNavigationTarget");

    if (AppConstants.MOZ_BUILD_APP == "browser") {
      ClickHandlerParent.removeContentClickListener(this);
    }

    Services.mm.removeMessageListener("Extension:StateChange", this);
    Services.mm.removeMessageListener("Extension:DocumentChange", this);
    Services.mm.removeMessageListener("Extension:HistoryChange", this);
    Services.mm.removeMessageListener("Extension:DOMContentLoaded", this);
    Services.mm.removeMessageListener(
      "Extension:CreatedNavigationTarget",
      this
    );

    Services.mm.removeDelayedFrameScript(
      "resource://gre/modules/WebNavigationContent.js"
    );
    Services.mm.broadcastAsyncMessage("Extension:DisableWebNavigation");

    this.recentTabTransitionData = new WeakMap();
    this.createdNavigationTargetByOuterWindowId.clear();
  },

  addListener(type, listener, filters, context) {
    if (this.listeners.size == 0) {
      this.init();
    }

    if (!this.listeners.has(type)) {
      this.listeners.set(type, new Map());
    }
    let listeners = this.listeners.get(type);
    listeners.set(listener, { filters, context });
  },

  removeListener(type, listener) {
    let listeners = this.listeners.get(type);
    if (!listeners) {
      return;
    }
    listeners.delete(listener);
    if (listeners.size == 0) {
      this.listeners.delete(type);
    }

    if (this.listeners.size == 0) {
      this.uninit();
    }
  },

  /**
   * Support nsIObserver interface to observe the urlbar autocomplete events used
   * to keep track of the urlbar user interaction.
   */
  QueryInterface: ChromeUtils.generateQI([
    "nsIObserver",
    "nsISupportsWeakReference",
  ]),

  /**
   * Observe webNavigation-createdNavigationTarget (to fire the onCreatedNavigationTarget
   * related to windows or tabs opened from the main process) topics.
   *
   * @param {nsIAutoCompleteInput|Object} subject
   * @param {string} topic
   * @param {string|undefined} data
   */
  observe: function(subject, topic, data) {
    if (topic == "urlbar-user-start-navigation") {
      this.onURLBarUserStartNavigation(subject.wrappedJSObject);
    } else if (topic == "webNavigation-createdNavigationTarget") {
      // The observed notification is coming from privileged JavaScript components running
      // in the main process (e.g. when a new tab or window is opened using the context menu
      // or Ctrl/Shift + click on a link).
      const {
        createdTabBrowser,
        url,
        sourceFrameID,
        sourceTabBrowser,
      } = subject.wrappedJSObject;

      this.fire(
        "onCreatedNavigationTarget",
        createdTabBrowser,
        {},
        {
          sourceTabBrowser,
          sourceFrameId: sourceFrameID,
          url,
        }
      );
    }
  },

  /**
   * Recognize the type of urlbar user interaction (e.g. typing a new url,
   * clicking on an url generated from a searchengine or a keyword, or a
   * bookmark found by the urlbar autocompletion).
   *
   * @param {object} acData
   *   The data for the autocompleted item.
   * @param {object} [acData.result]
   *   The result information associated with the navigation action.
   * @param {UrlbarUtils.RESULT_TYPE} [acData.result.type]
   *   The result type associated with the navigation action.
   * @param {UrlbarUtils.RESULT_SOURCE} [acData.result.source]
   *   The result source associated with the navigation action.
   */
  onURLBarUserStartNavigation(acData) {
    let tabTransitionData = {
      from_address_bar: true,
    };

    if (!acData.result) {
      tabTransitionData.typed = true;
    } else {
      switch (acData.result.type) {
        case UrlbarUtils.RESULT_TYPE.KEYWORD:
          tabTransitionData.keyword = true;
          break;
        case UrlbarUtils.RESULT_TYPE.SEARCH:
          tabTransitionData.generated = true;
          break;
        case UrlbarUtils.RESULT_TYPE.URL:
          if (acData.result.source == UrlbarUtils.RESULT_SOURCE.BOOKMARKS) {
            tabTransitionData.auto_bookmark = true;
          } else {
            tabTransitionData.typed = true;
          }
          break;
        case UrlbarUtils.RESULT_TYPE.REMOTE_TAB:
          // Remote tab are autocomplete results related to
          // tab urls from a remote synchronized Firefox.
          tabTransitionData.typed = true;
          break;
        case UrlbarUtils.RESULT_TYPE.TAB_SWITCH:
        // This "switchtab" autocompletion should be ignored, because
        // it is not related to a navigation.
        // Fall through.
        case UrlbarUtils.RESULT_TYPE.OMNIBOX:
        // "Omnibox" should be ignored as the add-on may or may not initiate
        // a navigation on the item being selected.
        // Fall through.
        case UrlbarUtils.RESULT_TYPE.TIP:
          // "Tip" should be ignored since the tip will only initiate navigation
          // if there is a valid buttonUrl property, which is optional.
          throw new Error(
            `Unexpectedly received notification for ${acData.result.type}`
          );
        default:
          Cu.reportError(
            `Received unexpected result type ${acData.result.type}, falling back to typed transition.`
          );
          // Fallback on "typed" if the type is unknown.
          tabTransitionData.typed = true;
      }
    }

    this.setRecentTabTransitionData(tabTransitionData);
  },

  /**
   * Keep track of a recent user interaction and cache it in a
   * map associated to the current selected tab.
   *
   * @param {object} tabTransitionData
   * @param {boolean} [tabTransitionData.auto_bookmark]
   * @param {boolean} [tabTransitionData.from_address_bar]
   * @param {boolean} [tabTransitionData.generated]
   * @param {boolean} [tabTransitionData.keyword]
   * @param {boolean} [tabTransitionData.link]
   * @param {boolean} [tabTransitionData.typed]
   */
  setRecentTabTransitionData(tabTransitionData) {
    let window = BrowserWindowTracker.getTopWindow();
    if (
      window &&
      window.gBrowser &&
      window.gBrowser.selectedTab &&
      window.gBrowser.selectedTab.linkedBrowser
    ) {
      let browser = window.gBrowser.selectedTab.linkedBrowser;

      // Get recent tab transition data to update if any.
      let prevData = this.getAndForgetRecentTabTransitionData(browser);

      let newData = Object.assign(
        { time: Date.now() },
        prevData,
        tabTransitionData
      );
      this.recentTabTransitionData.set(browser, newData);
    }
  },

  /**
   * Retrieve recent data related to a recent user interaction give a
   * given tab's linkedBrowser (only if is is more recent than the
   * `RECENT_DATA_THRESHOLD`).
   *
   * NOTE: this method is used to retrieve the tab transition data
   * collected when one of the `onCommitted`, `onHistoryStateUpdated`
   * or `onReferenceFragmentUpdated` events has been received.
   *
   * @param {XULBrowserElement} browser
   * @returns {object}
   */
  getAndForgetRecentTabTransitionData(browser) {
    let data = this.recentTabTransitionData.get(browser);
    this.recentTabTransitionData.delete(browser);

    // Return an empty object if there isn't any tab transition data
    // or if it's less recent than RECENT_DATA_THRESHOLD.
    if (!data || data.time - Date.now() > RECENT_DATA_THRESHOLD) {
      return {};
    }

    return data;
  },

  /**
   * Receive messages from the WebNavigationContent.js framescript
   * over message manager events.
   */
  receiveMessage({ name, data, target }) {
    switch (name) {
      case "Extension:StateChange":
        this.onStateChange(target, data);
        break;

      case "Extension:DocumentChange":
        this.onDocumentChange(target, data);
        break;

      case "Extension:HistoryChange":
        this.onHistoryChange(target, data);
        break;

      case "Extension:DOMContentLoaded":
        this.onLoad(target, data);
        break;

      case "Extension:CreatedNavigationTarget":
        this.onCreatedNavigationTarget(target, data);
        break;
    }
  },

  onContentClick(target, data) {
    // We are interested only on clicks to links which are not "add to bookmark" commands
    if (data.href && !data.bookmark) {
      let ownerWin = target.ownerGlobal;
      let where = ownerWin.whereToOpenLink(data);
      if (where == "current") {
        this.setRecentTabTransitionData({ link: true });
      }
    }
  },

  onCreatedNavigationTarget(browser, data) {
    const { createdOuterWindowId, isSourceTab, sourceFrameId, url } = data;

    // We are going to receive two message manager messages for a single
    // onCreatedNavigationTarget event related to a window.open that is happening
    // in the child process (one from the source tab and one from the created tab),
    // the unique createdWindowId (the outerWindowID of the created docShell)
    // to pair them together.
    const pairedMessage = this.createdNavigationTargetByOuterWindowId.get(
      createdOuterWindowId
    );

    if (!isSourceTab) {
      if (pairedMessage) {
        // This should not happen, print a warning before overwriting the unexpected pending data.
        Services.console.logStringMessage(
          `Discarding onCreatedNavigationTarget for ${createdOuterWindowId}: ` +
            "unexpected pending data while receiving the created tab data"
        );
      }

      // Store a weak reference to the browser XUL element, so that we don't prevent
      // it to be garbage collected if it has been destroyed.
      const browserWeakRef = Cu.getWeakReference(browser);

      this.createdNavigationTargetByOuterWindowId.set(createdOuterWindowId, {
        browserWeakRef,
        data,
      });

      return;
    }

    if (!pairedMessage) {
      // The sourceTab should always be received after the message coming from the created
      // top level frame because the "webNavigation-createdNavigationTarget-from-js" observers
      // subscribed by WebNavigationContent.js are going to be executed in reverse order
      // (See http://searchfox.org/mozilla-central/rev/f54c1723be/xpcom/ds/nsObserverList.cpp#76)
      // and the observer subscribed to the created target will be the last one subscribed
      // to the ObserverService (and the first one to be triggered).
      Services.console.logStringMessage(
        `Discarding onCreatedNavigationTarget for ${createdOuterWindowId}: ` +
          "received source tab data without any created tab data available"
      );

      return;
    }

    this.createdNavigationTargetByOuterWindowId.delete(createdOuterWindowId);

    let sourceTabBrowser = browser;
    let createdTabBrowser = pairedMessage.browserWeakRef.get();

    if (!createdTabBrowser) {
      Services.console.logStringMessage(
        `Discarding onCreatedNavigationTarget for ${createdOuterWindowId}: ` +
          "the created tab has been already destroyed"
      );

      return;
    }

    this.fire(
      "onCreatedNavigationTarget",
      createdTabBrowser,
      {},
      {
        sourceTabBrowser,
        sourceFrameId,
        url,
      }
    );
  },

  onStateChange(browser, data) {
    let stateFlags = data.stateFlags;
    if (stateFlags & Ci.nsIWebProgressListener.STATE_IS_WINDOW) {
      let url = data.requestURL;
      if (stateFlags & Ci.nsIWebProgressListener.STATE_START) {
        this.fire("onBeforeNavigate", browser, data, { url });
      } else if (stateFlags & Ci.nsIWebProgressListener.STATE_STOP) {
        if (Components.isSuccessCode(data.status)) {
          this.fire("onCompleted", browser, data, { url });
        } else {
          let error = `Error code ${data.status}`;
          this.fire("onErrorOccurred", browser, data, { error, url });
        }
      }
    }
  },

  onDocumentChange(browser, data) {
    let extra = {
      url: data.location,
      // Transition data which is coming from the content process.
      frameTransitionData: data.frameTransitionData,
      tabTransitionData: this.getAndForgetRecentTabTransitionData(browser),
    };

    this.fire("onCommitted", browser, data, extra);
  },

  onHistoryChange(browser, data) {
    let extra = {
      url: data.location,
      // Transition data which is coming from the content process.
      frameTransitionData: data.frameTransitionData,
      tabTransitionData: this.getAndForgetRecentTabTransitionData(browser),
    };

    if (data.isReferenceFragmentUpdated) {
      this.fire("onReferenceFragmentUpdated", browser, data, extra);
    } else if (data.isHistoryStateUpdated) {
      this.fire("onHistoryStateUpdated", browser, data, extra);
    }
  },

  onLoad(browser, data) {
    this.fire("onDOMContentLoaded", browser, data, { url: data.url });
  },

  fire(type, browser, data, extra) {
    let listeners = this.listeners.get(type);
    if (!listeners) {
      return;
    }

    let details = {
      browser,
      frameId: data.frameId,
    };

    if (data.parentFrameId !== undefined) {
      details.parentFrameId = data.parentFrameId;
    }

    for (let prop in extra) {
      details[prop] = extra[prop];
    }

    for (let [listener, { filters, context }] of listeners) {
      if (
        context &&
        !context.privateBrowsingAllowed &&
        PrivateBrowsingUtils.isBrowserPrivate(browser)
      ) {
        continue;
      }
      // Call the listener if the listener has no filter or if its filter matches.
      if (!filters || filters.matches(extra.url)) {
        listener(details);
      }
    }
  },
};

const EVENTS = [
  "onBeforeNavigate",
  "onCommitted",
  "onDOMContentLoaded",
  "onCompleted",
  "onErrorOccurred",
  "onReferenceFragmentUpdated",
  "onHistoryStateUpdated",
  "onCreatedNavigationTarget",
];

var WebNavigation = {};

for (let event of EVENTS) {
  WebNavigation[event] = {
    addListener: Manager.addListener.bind(Manager, event),
    removeListener: Manager.removeListener.bind(Manager, event),
  };
}