// -*- Mode: Java; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// 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/.

Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "PlacesUtils",
                                  "resource://gre/modules/PlacesUtils.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "FormHistory",
                                  "resource://gre/modules/FormHistory.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Downloads",
                                  "resource://gre/modules/Downloads.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Promise",
                                  "resource://gre/modules/Promise.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Task",
                                  "resource://gre/modules/Task.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "console",
                                  "resource://gre/modules/Console.jsm");

function Sanitizer() {}

Sanitizer.prototype = {
  // warning to the caller: this one may raise an exception (e.g. bug #265028)
  clearItem: function (aItemName) {
    if (this.items[aItemName].canClear) {
      this.items[aItemName].clear();
    }
  },

  canClearItem: function (aItemName, aCallback, aArg) {
    let canClear = this.items[aItemName].canClear;
    if (typeof canClear == "function") {
      canClear(aCallback, aArg);
      return false;
    }

    aCallback(aItemName, canClear, aArg);
    return canClear;
  },
  
  prefDomain: "",
  isShutDown: false,
  
  getNameFromPreference: function (aPreferenceName) {
    return aPreferenceName.substr(this.prefDomain.length);
  },
  
  /**
   * Deletes privacy sensitive data in a batch, according to user preferences.
   * Returns a promise which is resolved if no errors occurred.  If an error
   * occurs, a message is reported to the console and all other items are still
   * cleared before the promise is finally rejected.
   */
  sanitize: function () {
    var deferred = Promise.defer();
    var psvc = Components.classes["@mozilla.org/preferences-service;1"]
                         .getService(Components.interfaces.nsIPrefService);
    var branch = psvc.getBranch(this.prefDomain);
    var seenError = false;

    // Cache the range of times to clear
    if (this.ignoreTimespan) {
      // If we ignore timespan, clear everything
      var range = null;
    } else {
      range = this.range || Sanitizer.getClearRange();
    }

    let itemCount = Object.keys(this.items).length;
    let onItemComplete = function() {
      if (!--itemCount) {
        seenError ? deferred.reject() : deferred.resolve();
      }
    };
    for (var itemName in this.items) {
      let item = this.items[itemName];
      item.range = range;
      item.isShutDown = this.isShutDown;
      if ("clear" in item && branch.getBoolPref(itemName)) {
        let clearCallback = (itemName, aCanClear) => {
          // Some of these clear() may raise exceptions (see bug #265028)
          // to sanitize as much as possible, we catch and store them,
          // rather than fail fast.
          // Callers should check returned errors and give user feedback
          // about items that could not be sanitized
          let item = this.items[itemName];
          try {
            if (aCanClear)
              item.clear();
          } catch(er) {
            seenError = true;
            console.error("Error sanitizing " + itemName + ": " + er + "\n");
          }
          onItemComplete();
        };
        this.canClearItem(itemName, clearCallback);
      } else {
        onItemComplete();
      }
    }

    return deferred.promise;
  },
  
  // Time span only makes sense in certain cases.  Consumers who want
  // to only clear some private data can opt in by setting this to false,
  // and can optionally specify a specific range.  If timespan is not ignored,
  // and range is not set, sanitize() will use the value of the timespan
  // pref to determine a range
  ignoreTimespan : true,
  range : null,

  items: {
    cache: {
      clear: function() {
        var cache = Cc["@mozilla.org/netwerk/cache-storage-service;1"]
                      .getService(Ci.nsICacheStorageService);
        try {
          // Cache doesn't consult timespan, nor does it have the
          // facility for timespan-based eviction.  Wipe it.
          cache.clear();
        } catch(er) {}

        var imageCache = Cc["@mozilla.org/image/tools;1"].
                         getService(Ci.imgITools).getImgCacheForDocument(null);
        try {
          imageCache.clearCache(false); // true=chrome, false=content
        } catch(er) {}
      },

      get canClear() {
        return true;
      }
    },

    cookies: {
      clear: function () {
        var cookieMgr = Components.classes["@mozilla.org/cookiemanager;1"]
                                  .getService(Ci.nsICookieManager);
        if (this.range) {
          // Iterate through the cookies and delete any created after our cutoff.
          var cookiesEnum = cookieMgr.enumerator;
          while (cookiesEnum.hasMoreElements()) {
            var cookie = cookiesEnum.getNext().QueryInterface(Ci.nsICookie2);

            if (cookie.creationTime > this.range[0]) {
              // This cookie was created after our cutoff, clear it
              cookieMgr.remove(cookie.host, cookie.name, cookie.path,
                               false, cookie.originAttributes);
            }
          }
        } else {
          // Remove everything
          cookieMgr.removeAll();
        }

        // Clear plugin data.
        const phInterface = Ci.nsIPluginHost;
        const FLAG_CLEAR_ALL = phInterface.FLAG_CLEAR_ALL;
        let ph = Cc["@mozilla.org/plugin/host;1"].getService(phInterface);

        // Determine age range in seconds. (-1 means clear all.) We don't know
        // that this.range[1] is actually now, so we compute age range based
        // on the lower bound. If this.range results in a negative age, do
        // nothing.
        let age = this.range ? 
                  (Date.now() / 1000 - this.range[0] / 1000000) :
                  -1;
        if (!this.range || age >= 0) {
          let tags = ph.getPluginTags();
          for (let i = 0; i < tags.length; i++) {
            try {
              ph.clearSiteData(tags[i], null, FLAG_CLEAR_ALL, age);
            } catch(e) {
              // If the plugin doesn't support clearing by age, clear everything.
              if (e.result == Components.results.NS_ERROR_PLUGIN_TIME_RANGE_NOT_SUPPORTED) {
                try {
                  ph.clearSiteData(tags[i], null, FLAG_CLEAR_ALL, -1);
                } catch(e) {
                  // Ignore errors from the plugin
                }
              }
            }
          }
        }
      },

      get canClear() {
        return true;
      }
    },

    offlineApps: {
      clear: function () {
        Components.utils.import("resource:///modules/offlineAppCache.jsm");
        OfflineAppCacheHelper.clear();
        if (!this.range || this.isShutDown) {
          Components.utils.import("resource:///modules/QuotaManager.jsm");
          QuotaManagerHelper.clear(this.isShutDown);
        }
      },

      get canClear() {
        return true;
      }
    },

    history: {
      clear: function () {
        if (this.range) {
          PlacesUtils.history.removeVisitsByFilter({
            beginDate: new Date(this.range[0] / 1000),
            endDate: new Date(this.range[1] / 1000)
          }).catch(Components.utils.reportError);;
        } else {
          // Remove everything.
          PlacesUtils.history.clear()
                     .catch(Components.utils.reportError);
        }

        try {
          var os = Components.classes["@mozilla.org/observer-service;1"]
                             .getService(Components.interfaces.nsIObserverService);
          os.notifyObservers(null, "browser:purge-session-history", "");
        } catch(e) {}

        // Clear last URL of the Open Web Location dialog
        var prefs = Components.classes["@mozilla.org/preferences-service;1"]
                              .getService(Components.interfaces.nsIPrefBranch);
        try {
          prefs.clearUserPref("general.open_location.last_url");
        } catch(e) {}
      },

      get canClear()
      {
        // bug 347231: Always allow clearing history due to dependencies on
        // the browser:purge-session-history notification. (like error console)
        return true;
      }
    },

    formdata: {
      clear: function () {
        // Clear undo history of all searchBars
        var windowManager = Components.classes['@mozilla.org/appshell/window-mediator;1']
                                      .getService(Components.interfaces.nsIWindowMediator);
        var windows = windowManager.getEnumerator("navigator:browser");
        while (windows.hasMoreElements()) {
          let currentDocument = windows.getNext().document;
          let searchBar = currentDocument.getElementById("searchbar");
          if (searchBar) {
            searchBar.textbox.reset();
          }
          let findBar = currentDocument.getElementById("FindToolbar");
          if (findBar) {
            findBar.clear();
          }
        }

        let change = { op: "remove" };
        if (this.range) {
          [ change.firstUsedStart, change.firstUsedEnd ] = this.range;
        }
        FormHistory.update(change);
      },

      canClear: function(aCallback, aArg) {
        var windowManager = Components.classes['@mozilla.org/appshell/window-mediator;1']
                                      .getService(Components.interfaces.nsIWindowMediator);
        var windows = windowManager.getEnumerator("navigator:browser");
        while (windows.hasMoreElements()) {
          let currentDocument = windows.getNext().document;
          let searchBar = currentDocument.getElementById("searchbar");
          if (searchBar) {
            let transactionMgr = searchBar.textbox.editor.transactionManager;
            if (searchBar.value ||
                transactionMgr.numberOfUndoItems ||
                transactionMgr.numberOfRedoItems) {
              aCallback("formdata", true, aArg);
              return false;
            }
          }
          let findBar = currentDocument.getElementById("FindToolbar");
          if (findBar && findBar.canClear) {
            aCallback("formdata", true, aArg);
            return false;
          }
        }

        let count = 0;
        let countDone = {
          handleResult: function(aResult) {
            count = aResult;
          },
          handleError: function(aError) {
            Components.utils.reportError(aError);
          },
          handleCompletion: function(aReason) {
            aCallback("formdata", aReason == 0 && count > 0, aArg);
          }
        };
        FormHistory.count({}, countDone);
        return false;
      }
    },

    downloads: {
      clear: Task.async(function* (range) {
        let refObj = {};
        try {
          let filterByTime = null;
          if (range) {
            // Convert microseconds back to milliseconds for date comparisons.
            let rangeBeginMs = range[0] / 1000;
            let rangeEndMs = range[1] / 1000;
            filterByTime = download => {
              return download.startTime >= rangeBeginMs &&
                     download.startTime <= rangeEndMs;
            }
          }

          // Clear all completed/cancelled downloads
          let list = yield Downloads.getList(Downloads.ALL);
          list.removeFinished(filterByTime);
        } finally {}
      }),

      get canClear() {
        //Clearing is always possible with JSTransfers
        return true;
      }
    },

    passwords: {
      clear: function () {
        var pwmgr = Components.classes["@mozilla.org/login-manager;1"]
                              .getService(Components.interfaces.nsILoginManager);
        // Passwords are timeless, and don't respect the timeSpan setting
        pwmgr.removeAllLogins();
      },

      get canClear() {
        var pwmgr = Components.classes["@mozilla.org/login-manager;1"]
                              .getService(Components.interfaces.nsILoginManager);
        // count all logins
        var count = pwmgr.countLogins("", "", "");
        return (count > 0);
      }
    },

    sessions: {
      clear: function () {
        // clear all auth tokens
        var sdr = Components.classes["@mozilla.org/security/sdr;1"]
                            .getService(Components.interfaces.nsISecretDecoderRing);
        sdr.logoutAndTeardown();

        // clear FTP and plain HTTP auth sessions
        var os = Components.classes["@mozilla.org/observer-service;1"]
                           .getService(Components.interfaces.nsIObserverService);
        os.notifyObservers(null, "net:clear-active-logins", null);
      },

      get canClear() {
        return true;
      }
    },

    siteSettings: {
      clear: function () {
        // Clear site-specific permissions like "Allow this site to open popups"
        var pm = Components.classes["@mozilla.org/permissionmanager;1"]
                           .getService(Components.interfaces.nsIPermissionManager);
        pm.removeAll();

        // Clear site-specific settings like page-zoom level
        var cps = Components.classes["@mozilla.org/content-pref/service;1"]
                            .getService(Components.interfaces.nsIContentPrefService2);
        cps.removeAllDomains(null);

        // Clear "Never remember passwords for this site", which is not handled by
        // the permission manager
        var pwmgr = Components.classes["@mozilla.org/login-manager;1"]
                              .getService(Components.interfaces.nsILoginManager);
        var hosts = pwmgr.getAllDisabledHosts();
        for each (var host in hosts) {
          pwmgr.setLoginSavingEnabled(host, true);
        }
      },

      get canClear() {
        return true;
      }
    },

    connectivityData: {
      clear: function () {
        // Clear site security settings
        var sss = Components.classes["@mozilla.org/ssservice;1"]
                            .getService(Components.interfaces.nsISiteSecurityService);
        sss.clearAll();
      },

      get canClear() {
        return true;
      }
    }
  }
};



// "Static" members
Sanitizer.prefDomain          = "privacy.sanitize.";
Sanitizer.prefShutdown        = "sanitizeOnShutdown";
Sanitizer.prefDidShutdown     = "didShutdownSanitize";

// Time span constants corresponding to values of the privacy.sanitize.timeSpan
// pref.  Used to determine how much history to clear, for various items
Sanitizer.TIMESPAN_EVERYTHING = 0;
Sanitizer.TIMESPAN_HOUR       = 1;
Sanitizer.TIMESPAN_2HOURS     = 2;
Sanitizer.TIMESPAN_4HOURS     = 3;
Sanitizer.TIMESPAN_TODAY      = 4;

Sanitizer.IS_SHUTDOWN         = true;

// Return a 2 element array representing the start and end times,
// in the uSec-since-epoch format that PRTime likes.  If we should
// clear everything, return null.  Use ts if it is defined; otherwise
// use the timeSpan pref.
Sanitizer.getClearRange = function(ts) {
  if (ts === undefined) {
    ts = Sanitizer.prefs.getIntPref("timeSpan");
  }
  if (ts === Sanitizer.TIMESPAN_EVERYTHING) {
    return null;
  }
  
  // PRTime is microseconds while JS time is milliseconds
  var endDate = Date.now() * 1000;
  switch (ts) {
    case Sanitizer.TIMESPAN_HOUR :
      var startDate = endDate - 3600000000; // 1*60*60*1000000
      break;
    case Sanitizer.TIMESPAN_2HOURS :
      startDate = endDate - 7200000000; // 2*60*60*1000000
      break;
    case Sanitizer.TIMESPAN_4HOURS :
      startDate = endDate - 14400000000; // 4*60*60*1000000
      break;
    case Sanitizer.TIMESPAN_TODAY :
      var d = new Date();  // Start with today
      d.setHours(0);      // zero us back to midnight...
      d.setMinutes(0);
      d.setSeconds(0);
      startDate = d.valueOf() * 1000; // convert to epoch usec
      break;
    default:
      throw "Invalid time span for clear private data: " + ts;
  }
  return [startDate, endDate];
};

Sanitizer._prefs = null;
Sanitizer.__defineGetter__("prefs", function() {
  return Sanitizer._prefs ?
         Sanitizer._prefs :
         Sanitizer._prefs = Components.classes["@mozilla.org/preferences-service;1"]
                                      .getService(Components.interfaces.nsIPrefService)
                                      .getBranch(Sanitizer.prefDomain);
});

// Shows sanitization UI
Sanitizer.showUI = function(aParentWindow) {
  var ww = Components.classes["@mozilla.org/embedcomp/window-watcher;1"]
                     .getService(Components.interfaces.nsIWindowWatcher);
  ww.openWindow(aParentWindow,
                "chrome://browser/content/sanitize.xul",
                "Sanitize",
                "chrome,titlebar,dialog,centerscreen,modal",
                null);
};

/** 
 * Deletes privacy sensitive data in a batch, optionally showing the 
 * sanitize UI, according to user preferences
 */
Sanitizer.sanitize = function(aParentWindow) {
  Sanitizer.showUI(aParentWindow);
};

Sanitizer.onStartup = function() {
  // we check for unclean exit with pending sanitization
  Sanitizer._checkAndSanitize();
};

Sanitizer.onShutdown = function() {
  // we check if sanitization is needed and perform it
  Sanitizer._checkAndSanitize(Sanitizer.IS_SHUTDOWN);
};

// this is called on startup and shutdown, to perform pending sanitizations
Sanitizer._checkAndSanitize = function(isShutDown) {
  const prefs = Sanitizer.prefs;
  if (prefs.getBoolPref(Sanitizer.prefShutdown) && 
      !prefs.prefHasUserValue(Sanitizer.prefDidShutdown)) {
    // this is a shutdown or a startup after an unclean exit
    var s = new Sanitizer();
    s.prefDomain = "privacy.clearOnShutdown.";
    s.isShutDown = isShutDown;
    s.sanitize().then(function() {
      prefs.setBoolPref(Sanitizer.prefDidShutdown, true);
    });
  }
};