/* Copyright 2012 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/* globals Components, Services, XPCOMUtils, PdfjsChromeUtils,
           PdfjsContentUtils, PdfStreamConverter */

'use strict';

var EXPORTED_SYMBOLS = ['PdfJs'];

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

const PREF_PREFIX = 'pdfjs';
const PREF_DISABLED = PREF_PREFIX + '.disabled';
const PREF_MIGRATION_VERSION = PREF_PREFIX + '.migrationVersion';
const PREF_PREVIOUS_ACTION = PREF_PREFIX + '.previousHandler.preferredAction';
const PREF_PREVIOUS_ASK = PREF_PREFIX +
                          '.previousHandler.alwaysAskBeforeHandling';
const PREF_DISABLED_PLUGIN_TYPES = 'plugin.disable_full_page_plugin_for_types';
const TOPIC_PDFJS_HANDLER_CHANGED = 'pdfjs:handlerChanged';
const TOPIC_PLUGINS_LIST_UPDATED = 'plugins-list-updated';
const TOPIC_PLUGIN_INFO_UPDATED = 'plugin-info-updated';
const PDF_CONTENT_TYPE = 'application/pdf';

Cu.import('resource://gre/modules/XPCOMUtils.jsm');
Cu.import('resource://gre/modules/Services.jsm');

var Svc = {};
XPCOMUtils.defineLazyServiceGetter(Svc, 'mime',
                                   '@mozilla.org/mime;1',
                                   'nsIMIMEService');
XPCOMUtils.defineLazyServiceGetter(Svc, 'pluginHost',
                                   '@mozilla.org/plugin/host;1',
                                   'nsIPluginHost');
XPCOMUtils.defineLazyModuleGetter(this, 'PdfjsChromeUtils',
                                  'resource://pdf.js/PdfjsChromeUtils.jsm');
XPCOMUtils.defineLazyModuleGetter(this, 'PdfjsContentUtils',
                                  'resource://pdf.js/PdfjsContentUtils.jsm');

function getBoolPref(aPref, aDefaultValue) {
  try {
    return Services.prefs.getBoolPref(aPref);
  } catch (ex) {
    return aDefaultValue;
  }
}

function getIntPref(aPref, aDefaultValue) {
  try {
    return Services.prefs.getIntPref(aPref);
  } catch (ex) {
    return aDefaultValue;
  }
}

function isDefaultHandler() {
 if (Services.appinfo.processType === Services.appinfo.PROCESS_TYPE_CONTENT) {
   return PdfjsContentUtils.isDefaultHandlerApp();
 }
 return PdfjsChromeUtils.isDefaultHandlerApp();
}

function initializeDefaultPreferences() {
  var DEFAULT_PREFERENCES =
{
  "showPreviousViewOnLoad": true,
  "defaultZoomValue": "",
  "sidebarViewOnLoad": 0,
  "enableHandToolOnLoad": false,
  "enableWebGL": false,
  "pdfBugEnabled": false,
  "disableRange": false,
  "disableStream": false,
  "disableAutoFetch": false,
  "disableFontFace": false,
  "disableTextLayer": false,
  "useOnlyCssZoom": false,
  "externalLinkTarget": 0,
  "enhanceTextSelection": false,
  "renderer": "canvas",
  "renderInteractiveForms": false,
  "disablePageLabels": false
}


  var defaultBranch = Services.prefs.getDefaultBranch(PREF_PREFIX + '.');
  var defaultValue;
  for (var key in DEFAULT_PREFERENCES) {
    defaultValue = DEFAULT_PREFERENCES[key];
    switch (typeof defaultValue) {
      case 'boolean':
        defaultBranch.setBoolPref(key, defaultValue);
        break;
      case 'number':
        defaultBranch.setIntPref(key, defaultValue);
        break;
      case 'string':
        defaultBranch.setCharPref(key, defaultValue);
        break;
    }
  }
}

// Register/unregister a constructor as a factory.
function Factory() {}
Factory.prototype = {
  register: function register(targetConstructor) {
    var proto = targetConstructor.prototype;
    this._classID = proto.classID;

    var factory = XPCOMUtils._getFactory(targetConstructor);
    this._factory = factory;

    var registrar = Cm.QueryInterface(Ci.nsIComponentRegistrar);
    registrar.registerFactory(proto.classID, proto.classDescription,
                              proto.contractID, factory);

    if (proto.classID2) {
      this._classID2 = proto.classID2;
      registrar.registerFactory(proto.classID2, proto.classDescription,
                                proto.contractID2, factory);
    }
  },

  unregister: function unregister() {
    var registrar = Cm.QueryInterface(Ci.nsIComponentRegistrar);
    registrar.unregisterFactory(this._classID, this._factory);
    if (this._classID2) {
      registrar.unregisterFactory(this._classID2, this._factory);
    }
    this._factory = null;
  }
};

var PdfJs = {
  QueryInterface: XPCOMUtils.generateQI([Ci.nsIObserver]),
  _registered: false,
  _initialized: false,

  init: function init(remote) {
    if (Services.appinfo.processType !==
        Services.appinfo.PROCESS_TYPE_DEFAULT) {
      throw new Error('PdfJs.init should only get called ' +
                      'in the parent process.');
    }
    PdfjsChromeUtils.init();
    if (!remote) {
      PdfjsContentUtils.init();
    }
    this.initPrefs();
    this.updateRegistration();
  },

  initPrefs: function initPrefs() {
    if (this._initialized) {
      return;
    }
    this._initialized = true;

    if (!getBoolPref(PREF_DISABLED, true)) {
      this._migrate();
    }

    // Listen for when pdf.js is completely disabled or a different pdf handler
    // is chosen.
    Services.prefs.addObserver(PREF_DISABLED, this, false);
    Services.prefs.addObserver(PREF_DISABLED_PLUGIN_TYPES, this, false);
    Services.obs.addObserver(this, TOPIC_PDFJS_HANDLER_CHANGED, false);
    Services.obs.addObserver(this, TOPIC_PLUGINS_LIST_UPDATED, false);
    Services.obs.addObserver(this, TOPIC_PLUGIN_INFO_UPDATED, false);

    initializeDefaultPreferences();
  },

  updateRegistration: function updateRegistration() {
    if (this.enabled) {
      this._ensureRegistered();
    } else {
      this._ensureUnregistered();
    }
  },

  uninit: function uninit() {
    if (this._initialized) {
      Services.prefs.removeObserver(PREF_DISABLED, this);
      Services.prefs.removeObserver(PREF_DISABLED_PLUGIN_TYPES, this);
      Services.obs.removeObserver(this, TOPIC_PDFJS_HANDLER_CHANGED);
      Services.obs.removeObserver(this, TOPIC_PLUGINS_LIST_UPDATED);
      Services.obs.removeObserver(this, TOPIC_PLUGIN_INFO_UPDATED);
      this._initialized = false;
    }
    this._ensureUnregistered();
  },

  _migrate: function migrate() {
    const VERSION = 2;
    var currentVersion = getIntPref(PREF_MIGRATION_VERSION, 0);
    if (currentVersion >= VERSION) {
      return;
    }
    // Make pdf.js the default pdf viewer on the first migration.
    if (currentVersion < 1) {
      this._becomeHandler();
    }
    if (currentVersion < 2) {
      // cleaning up of unused database preference (see #3994)
      Services.prefs.clearUserPref(PREF_PREFIX + '.database');
    }
    Services.prefs.setIntPref(PREF_MIGRATION_VERSION, VERSION);
  },

  _becomeHandler: function _becomeHandler() {
    let handlerInfo = Svc.mime.getFromTypeAndExtension(PDF_CONTENT_TYPE, 'pdf');
    let prefs = Services.prefs;
    if (handlerInfo.preferredAction !== Ci.nsIHandlerInfo.handleInternally &&
        handlerInfo.preferredAction !== false) {
      // Store the previous settings of preferredAction and
      // alwaysAskBeforeHandling in case we need to revert them in a hotfix that
      // would turn pdf.js off.
      prefs.setIntPref(PREF_PREVIOUS_ACTION, handlerInfo.preferredAction);
      prefs.setBoolPref(PREF_PREVIOUS_ASK, handlerInfo.alwaysAskBeforeHandling);
    }

    let handlerService = Cc['@mozilla.org/uriloader/handler-service;1'].
                         getService(Ci.nsIHandlerService);

    // Change and save mime handler settings.
    handlerInfo.alwaysAskBeforeHandling = false;
    handlerInfo.preferredAction = Ci.nsIHandlerInfo.handleInternally;
    handlerService.store(handlerInfo);

    // Also disable any plugins for pdfs.
    var stringTypes = '';
    var types = [];
    if (prefs.prefHasUserValue(PREF_DISABLED_PLUGIN_TYPES)) {
      stringTypes = prefs.getCharPref(PREF_DISABLED_PLUGIN_TYPES);
    }
    if (stringTypes !== '') {
      types = stringTypes.split(',');
    }

    if (types.indexOf(PDF_CONTENT_TYPE) === -1) {
      types.push(PDF_CONTENT_TYPE);
    }
    prefs.setCharPref(PREF_DISABLED_PLUGIN_TYPES, types.join(','));

    // Update the category manager in case the plugins are already loaded.
    let categoryManager = Cc['@mozilla.org/categorymanager;1'];
    categoryManager.getService(Ci.nsICategoryManager).
                    deleteCategoryEntry('Goanna-Content-Viewers',
                                        PDF_CONTENT_TYPE,
                                        false);
  },

  // nsIObserver
  observe: function observe(aSubject, aTopic, aData) {
    this.updateRegistration();
    if (Services.appinfo.processType ===
        Services.appinfo.PROCESS_TYPE_DEFAULT) {
      let jsm = 'resource://pdf.js/PdfjsChromeUtils.jsm';
      let PdfjsChromeUtils = Components.utils.import(jsm, {}).PdfjsChromeUtils;
      PdfjsChromeUtils.notifyChildOfSettingsChange();
    }
  },

  /**
   * pdf.js is only enabled if it is both selected as the pdf viewer and if the
   * global switch enabling it is true.
   * @return {boolean} Whether or not it's enabled.
   */
  get enabled() {
    var disabled = getBoolPref(PREF_DISABLED, true);
    if (disabled) {
      return false;
    }

    // Check if the 'application/pdf' preview handler is configured properly.
    if (!isDefaultHandler()) {
      return false;
    }

    // Check if we have disabled plugin handling of 'application/pdf' in prefs
    if (Services.prefs.prefHasUserValue(PREF_DISABLED_PLUGIN_TYPES)) {
      let disabledPluginTypes =
        Services.prefs.getCharPref(PREF_DISABLED_PLUGIN_TYPES).split(',');
      if (disabledPluginTypes.indexOf(PDF_CONTENT_TYPE) >= 0) {
        return true;
      }
    }

    // Check if there is an enabled pdf plugin.
    // Note: this check is performed last because getPluginTags() triggers
    // costly plugin list initialization (bug 881575)
    let tags = Cc['@mozilla.org/plugin/host;1'].
                  getService(Ci.nsIPluginHost).
                  getPluginTags();
    let enabledPluginFound = tags.some(function(tag) {
      if (tag.disabled) {
        return false;
      }
      let mimeTypes = tag.getMimeTypes();
      return mimeTypes.some(function(mimeType) {
        return mimeType === PDF_CONTENT_TYPE;
      });
    });

    // Use pdf.js if pdf plugin is not present or disabled
    return !enabledPluginFound;
  },

  _ensureRegistered: function _ensureRegistered() {
    if (this._registered) {
      return;
    }
    this._pdfStreamConverterFactory = new Factory();
    Cu.import('resource://pdf.js/PdfStreamConverter.jsm');
    this._pdfStreamConverterFactory.register(PdfStreamConverter);

    this._registered = true;
  },

  _ensureUnregistered: function _ensureUnregistered() {
    if (!this._registered) {
      return;
    }
    this._pdfStreamConverterFactory.unregister();
    Cu.unload('resource://pdf.js/PdfStreamConverter.jsm');
    delete this._pdfStreamConverterFactory;

    this._registered = false;
  }
};