(function($, exports) {
  "use strict";
  
  /**
   * Base LocalStorage cache
   *
   * @param options {object}
   *    - key (required) identifier of the collection
   *    - serverId (recommended) identifier of the Piwigo instance
   *    - serverKey (required) state of collection server-side
   *    - lifetime (optional) cache lifetime in seconds
   *    - loader (required) function called to fetch data, takes a callback as first argument
   *        which must be called with the loaded date
   */
  var LocalStorageCache = function(options) {
    this._init(options);
  };

  /*
   * Constructor (deported for easy inheritance)
   */
  LocalStorageCache.prototype._init = function(options) {
    this.key = options.key + '_' + options.serverId;
    this.serverKey = options.serverKey;
    this.lifetime = options.lifetime ? options.lifetime*1000 : 3600*1000;
    this.loader = options.loader;
    
    this.storage = window.localStorage;
    this.ready = !!this.storage;
  };

  /*
   * Get the cache content
   * @param callback {function} called with the data as first parameter
   */
  LocalStorageCache.prototype.get = function(callback) {
    var now = new Date().getTime(),
        that = this;
    
    if (this.ready && this.storage[this.key] != undefined) {
      var cache = JSON.parse(this.storage[this.key]);
      
      if (now - cache.timestamp <= this.lifetime && cache.key == this.serverKey) {
        callback(cache.data);
        return;
      }
    }
    
    this.loader(function(data) {
      that.set.call(that, data);
      callback(data);
    });
  };

  /*
   * Manually set the cache content
   * @param data {mixed}
   */
  LocalStorageCache.prototype.set = function(data) {
    if (this.ready) {
      this.storage[this.key] = JSON.stringify({
        timestamp: new Date().getTime(),
        key: this.serverKey,
        data: data
      });
    }
  };

  /*
   * Manually clear the cache
   */
  LocalStorageCache.prototype.clear = function() {
    if (this.ready) {
      this.storage.removeItem(this.key);
    }
  };

  
  /**
   * Abstract class containing common initialization code for selectize
   */
  var AbstractSelectizer = function(){};
  AbstractSelectizer.prototype = new LocalStorageCache({});

  /*
   * Load Selectize with cache content
   * @param $target {jQuery} may have some data attributes (create, default, value)
   * @param options {object}
   *    - value (optional) list of preselected items (ids, or objects with "id" attribute")
   *    - default (optional) default value which will be forced if the select is emptyed
   *    - create (optional) allow item user creation
   *    - filter (optional) function called for each select before applying the data
   *      takes two parameters: cache data, options
   *      must return new data
   */
  AbstractSelectizer.prototype._selectize = function($target, globalOptions) {
    this.get(function(data) {
      $target.each(function() {
        var filtered, value, defaultValue,
            options = $.extend({}, globalOptions);
        
        // apply filter function
        if (options.filter != undefined) {
          filtered = options.filter.call(this, data, options);
        }
        else {
          filtered = data;
        }
        
        // active creation mode
        if (this.hasAttribute('data-create')) {
          options.create = true;
        }
        this.selectize.settings.create = !!options.create;

        // load options
        this.selectize.load(function(callback) {
          if ($.isEmptyObject(this.options)) {
            callback(filtered);
          }
        });

        // load items
        if ((value = $(this).data('value'))) {
          options.value = value;
        }
        if (options.value != undefined) {
          $.each(value, $.proxy(function(i, cat) {
            if ($.isNumeric(cat))
              this.selectize.addItem(cat);
            else
              this.selectize.addItem(cat.id);
          }, this));
        }
        
        // set default
        if ((defaultValue = $(this).data('default'))) {
          options.default = defaultValue;
        }
        if (options.default == 'first') {
          options.default = filtered[0] ? filtered[0].id : undefined;
        }
        
        if (options.default != undefined) {
          // add default item
          if (this.selectize.getValue() == '') {
            this.selectize.addItem(options.default);
          }

          // if multiple: prevent item deletion
          if (this.multiple) {
            this.selectize.getItem(options.default).find('.remove').hide();
            
            this.selectize.on('item_remove', function(id) {
              if (id == options.default) {
                this.addItem(id);
                this.getItem(id).find('.remove').hide();
              }
            });
          }
          // if single: restore default on blur
          else {
            this.selectize.on('dropdown_close', function() {
              if (this.getValue() == '') {
                this.addItem(options.default);
              }
            });
          }
        }
      });
    });
  };
  
  // redefine Selectize templates without escape
  AbstractSelectizer.getRender = function(field_label, lang) {
    lang = lang || { 'Add': 'Add' };

  	return {
      'option': function(data, escape) {
        return '<div class="option">' + data[field_label] + '</div>';
      },
      'item': function(data, escape) {
        return '<div class="item">' + data[field_label] + '</div>';
      },
      'option_create': function(data, escape) {
        return '<div class="create">' + lang['Add'] + ' <strong>' + data.input + '</strong>&hellip;</div>';
      }
    };
  };


  /**
   * Special LocalStorage for admin categories list
   *
   * @param options {object}
   *    - serverId (recommended) identifier of the Piwigo instance
   *    - serverKey (required) state of collection server-side
   *    - rootUrl (required) used for WS call
   */
  var CategoriesCache = function(options) {
    options.key = 'categoriesAdminList';
    
    options.loader = function(callback) {
      $.getJSON(options.rootUrl + 'ws.php?format=json&method=pwg.categories.getAdminList', function(data) {
        callback(data.result.categories);
      });
    };
    
    this._init(options);
  };

  CategoriesCache.prototype = new AbstractSelectizer();

  /*
   * Init Selectize with cache content
   * @see AbstractSelectizer._selectize
   */
  CategoriesCache.prototype.selectize = function($target, options) {
    options = options || {};

    $target.selectize({
      valueField: 'id',
      labelField: 'fullname',
      sortField: 'global_rank',
      searchField: ['fullname'],
      plugins: ['remove_button'],
      render: AbstractSelectizer.getRender('fullname', options.lang)
    });
    
    this._selectize($target, options);
  };


  /**
   * Special LocalStorage for admin tags list
   *
   * @param options {object}
   *    - serverId (recommended) identifier of the Piwigo instance
   *    - serverKey (required) state of collection server-side
   *    - rootUrl (required) used for WS call
   */
  var TagsCache = function(options) {
    options.key = 'tagsAdminList';
    
    options.loader = function(callback) {
      $.getJSON(options.rootUrl + 'ws.php?format=json&method=pwg.tags.getAdminList', function(data) {
        var tags = data.result.tags;
        
        for (var i=0, l=tags.length; i<l; i++) {
          tags[i].id = '~~' + tags[i].id + '~~';
        }
        
        callback(tags);
      });
    };
    
    this._init(options);
  };

  TagsCache.prototype = new AbstractSelectizer();

  /*
   * Init Selectize with cache content
   * @see AbstractSelectizer._selectize
   */
  TagsCache.prototype.selectize = function($target, options) {
    options = options || {};

    $target.selectize({
      valueField: 'id',
      labelField: 'name',
      sortField: 'name',
      searchField: ['name'],
      plugins: ['remove_button'],
      render: AbstractSelectizer.getRender('name', options.lang)
    });
    
    this._selectize($target, options);
  };
  
  
  /**
   * Special LocalStorage for admin groups list
   *
   * @param options {object}
   *    - serverId (recommended) identifier of the Piwigo instance
   *    - serverKey (required) state of collection server-side
   *    - rootUrl (required) used for WS call
   */
  var GroupsCache = function(options) {
    options.key = 'groupsAdminList';
    
    options.loader = function(callback) {
      $.getJSON(options.rootUrl + 'ws.php?format=json&method=pwg.groups.getList&per_page=9999', function(data) {
        callback(data.result.groups);
      });
    };
    
    this._init(options);
  };

  GroupsCache.prototype = new AbstractSelectizer();

  /*
   * Init Selectize with cache content
   * @see AbstractSelectizer._selectize
   */
  GroupsCache.prototype.selectize = function($target, options) {
    options = options || {};

    $target.selectize({
      valueField: 'id',
      labelField: 'name',
      sortField: 'name',
      searchField: ['name'],
      plugins: ['remove_button'],
      render: AbstractSelectizer.getRender('name', options.lang)
    });
    
    this._selectize($target, options);
  };
  
  
  /**
   * Special LocalStorage for admin users list
   *
   * @param options {object}
   *    - serverId (recommended) identifier of the Piwigo instance
   *    - serverKey (required) state of collection server-side
   *    - rootUrl (required) used for WS call
   */
  var UsersCache = function(options) {
    options.key = 'usersAdminList';
    
    options.loader = function(callback) {
      var users = [];
      
      // recursive loader
      (function load(page){
        jQuery.getJSON(options.rootUrl + 'ws.php?format=json&method=pwg.users.getList&display=username&per_page=9999&page='+ page, function(data) {
          users = users.concat(data.result.users);
          
          if (data.result.paging.count == data.result.paging.per_page) {
            load(++page);
          }
          else {
            callback(users);
          }
        });
      }(0));
    };
    
    this._init(options);
  };

  UsersCache.prototype = new AbstractSelectizer();

  /*
   * Init Selectize with cache content
   * @see AbstractSelectizer._selectize
   */
  UsersCache.prototype.selectize = function($target, options) {
    options = options || {};

    $target.selectize({
      valueField: 'id',
      labelField: 'username',
      sortField: 'username',
      searchField: ['username'],
      plugins: ['remove_button'],
      render: AbstractSelectizer.getRender('username', options.lang)
    });
    
    this._selectize($target, options);
  };
  
  
  /**
   * Expose classes in global scope
   */
  exports.LocalStorageCache = LocalStorageCache;
  exports.CategoriesCache = CategoriesCache;
  exports.TagsCache = TagsCache;
  exports.GroupsCache = GroupsCache;
  exports.UsersCache = UsersCache;
  
}(jQuery, window));