/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and
 * limitations under the License.
 *
 * The Original Code is the Places Tagging Service.
 *
 * The Initial Developer of the Original Code is
 * Mozilla Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2007
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Asaf Romano <mano@mozilla.com> (Original Author)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

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

Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");

const NH_CONTRACTID = "@mozilla.org/browser/nav-history-service;1";
const BMS_CONTRACTID = "@mozilla.org/browser/nav-bookmarks-service;1";
const IO_CONTRACTID = "@mozilla.org/network/io-service;1";
const ANNO_CONTRACTID = "@mozilla.org/browser/annotation-service;1";
const FAV_CONTRACTID = "@mozilla.org/browser/favicon-service;1";
const OBSS_CONTRACTID = "@mozilla.org/observer-service;1";

const TAG_CONTAINER_ICON_URI = "chrome://mozapps/skin/places/tagContainerIcon.png"

var gIoService = Cc[IO_CONTRACTID].getService(Ci.nsIIOService);

/**
 * The Places Tagging Service
 */
function TaggingService() {
}

TaggingService.prototype = {
  get _bms() {
    if (!this.__bms)
      this.__bms = Cc[BMS_CONTRACTID].getService(Ci.nsINavBookmarksService);
    return this.__bms;
  },

  get _history() {
    if (!this.__history)
      this.__history = Cc[NH_CONTRACTID].getService(Ci.nsINavHistoryService);
    return this.__history;
  },

  get _annos() {
    if (!this.__annos)
      this.__annos =  Cc[ANNO_CONTRACTID].getService(Ci.nsIAnnotationService);
    return this.__annos;
  },

  get _tagsResult() {
    if (!this.__tagsResult) {
      var options = this._history.getNewQueryOptions();
      var query = this._history.getNewQuery();
      query.setFolders([this._bms.tagRoot], 1);
      this.__tagsResult = this._history.executeQuery(query, options);
      this.__tagsResult.root.containerOpen = true;

      // we need to null out the result on shutdown
      var observerSvc = Cc[OBSS_CONTRACTID].getService(Ci.nsIObserverService);
      observerSvc.addObserver(this, "xpcom-shutdown", false);
    }
    return this.__tagsResult;
  },

  // Feed XPCOMUtils
  classDescription: "Places Tagging Service",
  contractID: "@mozilla.org/browser/tagging-service;1",
  classID: Components.ID("{bbc23860-2553-479d-8b78-94d9038334f7}"),

  // nsISupports
  QueryInterface: XPCOMUtils.generateQI([Ci.nsITaggingService,
                                         Ci.nsIObserver]),

  /**
   * If there's no tag with the given name, null is returned;
   */
  _getTagNode: function TS__getTagIndex(aName) {
    var root = this._tagsResult.root;
    var cc = root.childCount;
    for (var i=0; i < cc; i++) {
      var child = root.getChild(i);
      if (child.title == aName)
        return child;
    }

    return null;
  },

  get _tagContainerIcon() {
    if (!this.__tagContainerIcon) {
      this.__tagContainerIcon =
        gIoService.newURI(TAG_CONTAINER_ICON_URI, null, null);
    }

    return this.__tagContainerIcon;
  },

  /**
   * Creates a tag container under the tags-root with the given name.
   *
   * @param aName
   *        the name for the new container.
   * @returns the id of the new container.
   */
  _createTag: function TS__createTag(aName) {
    var id = this._bms.createFolder(this._bms.tagRoot, aName,
                                    this._bms.DEFAULT_INDEX);

    // Set the favicon
    var faviconService = Cc[FAV_CONTRACTID].getService(Ci.nsIFaviconService);
    var uri = this._bms.getFolderURI(id);
    faviconService.setFaviconUrlForPage(uri, this._tagContainerIcon);

    return id;
  },

  /**
   * Checks whether the given uri is tagged with the given tag.
   *
   * @param [in] aURI
   *        url to check for
   * @param [in] aTagId
   *        id of the folder representing the tag to check
   * @param [out] aItemId
   *        the id of the item found under the tag container
   * @returns true if the given uri is tagged with the given tag, false
   *          otherwise.
   */
  _isURITaggedInternal: function TS__uriTagged(aURI, aTagId, aItemId) {
    var options = this._history.getNewQueryOptions();
    options.queryType = Ci.nsINavHistoryQueryOptions.QUERY_TYPE_BOOKMARKS;
    var query = this._history.getNewQuery();
    query.setFolders([aTagId], 1);
    query.uri = aURI;
    var result = this._history.executeQuery(query, options);
    var rootNode = result.root;
    rootNode.containerOpen = true;
    if (rootNode.childCount != 0) {
      aItemId.value = rootNode.getChild(0).itemId;
      return true;
    }
    return false;
  },

  // nsITaggingService
  tagURI: function TS_tagURI(aURI, aTags) {
    if (!aURI || !aTags)
      throw Cr.NS_ERROR_INVALID_ARG;

    for (var i=0; i < aTags.length; i++) {
      if (aTags[i].length == 0)
        throw Cr.NS_ERROR_INVALID_ARG;

      var tagNode = this._getTagNode(aTags[i]);
      if (!tagNode) {
        var tagId = this._createTag(aTags[i]);
        this._bms.insertBookmark(tagId, aURI, this._bms.DEFAULT_INDEX, null);
      }
      else {
        var tagId = tagNode.itemId;
        if (!this._isURITaggedInternal(aURI, tagNode.itemId, {}))
          this._bms.insertBookmark(tagId, aURI, this._bms.DEFAULT_INDEX, null);
      }
    }
  },

  /**
   * Removes the tag container from the tags-root if the given tag is empty.
   *
   * @param aTagId
   *        the item-id of the tag element under the tags root
   */
  _removeTagIfEmpty: function TS__removeTagIfEmpty(aTagId) {
    var options = this._history.getNewQueryOptions();
    var query = this._history.getNewQuery();
    query.setFolders([aTagId], 1);
    var result = this._history.executeQuery(query, options);
    var rootNode = result.root;
    rootNode.containerOpen = true;
    if (rootNode.childCount == 0)
      this._bms.removeFolder(aTagId);
  },

  // nsITaggingService
  untagURI: function TS_untagURI(aURI, aTags) {
    if (!aURI)
      throw Cr.NS_ERROR_INVALID_ARG;

    if (!aTags) {
      // see IDL.
      // XXXmano: write a perf-sensitive version of this code path...
      aTags = this.getTagsForURI(aURI);
    }

    for (var i=0; i < aTags.length; i++) {
      if (aTags[i].length == 0)
        throw Cr.NS_ERROR_INVALID_ARG;

      var tagNode = this._getTagNode(aTags[i]);
      if (tagNode) {
        var itemId = { };
        if (this._isURITaggedInternal(aURI, tagNode.itemId, itemId)) {
          this._bms.removeItem(itemId.value);
          this._removeTagIfEmpty(tagNode.itemId);
        }
      }
    }
  },

  // nsITaggingService
  getURIsForTag: function TS_getURIsForTag(aTag) {
    if (aTag.length == 0)
      throw Cr.NS_ERROR_INVALID_ARG;

    var uris = [];
    var tagNode = this._getTagNode(aTag);
    if (tagNode) {
      tagNode.QueryInterface(Ci.nsINavHistoryContainerResultNode);
      tagNode.containerOpen = true;
      var cc = tagNode.childCount;
      for (var i=0; i < cc; i++)
        uris.push(gIoService.newURI(tagNode.getChild(i).uri, null, null));
      tagNode.containerOpen = false;
    }
    return uris;
  },

  // nsITaggingService
  getTagsForURI: function TS_getTagsForURI(aURI) {
    if (!aURI)
      throw Cr.NS_ERROR_INVALID_ARG;

    var tags = [];
    var bookmarkIds = this._bms.getBookmarkIdsForURI(aURI, {});
    var root = this._tagsResult.root;
    var cc = root.childCount;
    for (var i=0; i < bookmarkIds.length; i++) {
      var parent = this._bms.getFolderIdForItem(bookmarkIds[i]);
      for (var j=0; j < cc; j++) {
        var child = root.getChild(j);
        if (child.itemId == parent)
          tags.push(child.title);
      }
    }

    // sort the tag list
    tags.sort();
    return tags;
  },

  // nsITaggingService
  get allTags() {
    var tags = [];
    var root = this._tagsResult.root;
    var cc = root.childCount;
    for (var j=0; j < cc; j++) {
      var child = root.getChild(j);
      tags.push(child.title);
    }

    // sort the tag list
    tags.sort();
    return tags;
  },
  
  // nsITaggingService
  get tagContainerIconSpec() {
    return TAG_CONTAINER_ICON_URI;
  },

  // nsIObserver
  observe: function TS_observe(subject, topic, data) {
    if (topic == "xpcom-shutdown") {
      this.__tagsResult.root.containerOpen = false;
      this.__tagsResult = null;
      var observerSvc = Cc[OBSS_CONTRACTID].getService(Ci.nsIObserverService);
      observerSvc.removeObserver(this, "xpcom-shutdown");
    }
  }
};

function NSGetModule(compMgr, fileSpec) {
  return XPCOMUtils.generateModule([TaggingService]);
}
