// $Id$

/**
 * The Manager acts as the controller in a Model-View-Controller framework. All
 * public calls should be performed on the manager object.
 *
 * @param properties A map of fields to set. Refer to the list of public fields.
 * @class AbstractManager
 */
AjaxSolr.AbstractManager = AjaxSolr.Class.extend(
  /** @lends AjaxSolr.AbstractManager.prototype */
  {
  /**
   * The fully-qualified URL of the Solr application. You must include the
   * trailing slash. Do not include the path to any Solr servlet.
   *
   * @field
   * @public
   * @type String
   * @default "http://localhost:8983/solr/"
   */
  solrUrl: 'http://localhost:8983/solr/',

  /**
   * If we want to proxy queries through a script, rather than send queries
   * to Solr directly, set this field to the fully-qualified URL of the script.
   *
   * @field
   * @public
   * @type String
   */
  proxyUrl: null,

  /**
   * The default Solr servlet. You may prepend the servlet with a core if using
   * multiple cores.
   *
   * @field
   * @public
   * @type String
   * @default "select"
   */
  servlet: 'select',

  /**
   * The most recent response from Solr.
   *
   * @field
   * @private
   * @type Object
   * @default {}
   */
  response: {},

  /** 
   * A collection of all registered widgets. For internal use only.
   *
   * @field
   * @private
   * @type Object
   * @default {}
   */
  widgets: {},

  /**
   * The parameter store for the manager and its widgets. For internal use only.
   *
   * @field
   * @private
   * @type Object
   */
  store: null,

  /**
   * Whether <tt>init()</tt> has been called yet. For internal use only.
   *
   * @field
   * @private
   * @type Boolean
   * @default false
   */
  initialized: false,

  /**
   * An abstract hook for child implementations.
   *
   * <p>This method should be called after the store and the widgets have been
   * added. It should initialize the widgets and the store, and do any other
   * one-time initializations, e.g., perform the first request to Solr.</p>
   *
   * <p>If no store has been set, it sets the store to the basic <tt>
   * AjaxSolr.ParameterStore</tt>.</p>
   */
  init: function () {
    this.initialized = true;
    if (this.store === null) {
      this.setStore(new AjaxSolr.ParameterStore());
    }
    this.store.load(false);
    for (var widgetId in this.widgets) {
      this.widgets[widgetId].init();
    }
    this.store.init();
  },

  /**
   * Set the manager's parameter store.
   *
   * @param {AjaxSolr.ParameterStore} store
   */
  setStore: function (store) { 
    store.manager = this;
    this.store = store;
  },

  /** 
   * Adds a widget to the manager.
   *
   * @param {AjaxSolr.AbstractWidget} widget
   */
  addWidget: function (widget) { 
    widget.manager = this;
    this.widgets[widget.id] = widget;
  },

  /** 
   * Stores the Solr parameters to be sent to Solr and sends a request to Solr.
   *
   * @param {Boolean} [start] The Solr start offset parameter.
   * @param {String} [servlet] The Solr servlet to send the request to.
   */
  doRequest: function (start, servlet) {
    if (this.initialized === false) {
      this.init();
    }
    // Allow non-pagination widgets to reset the offset parameter.
    if (start !== undefined) {
      this.store.get('start').val(start);
    }
    if (servlet === undefined) {
      servlet = this.servlet;
    }

    this.store.save();

    for (var widgetId in this.widgets) {
      this.widgets[widgetId].beforeRequest();
    }

    this.executeRequest(servlet);
  },

  /**
   * An abstract hook for child implementations.
   *
   * <p>Sends the request to Solr, i.e. to <code>this.solrUrl</code> or <code>
   * this.proxyUrl</code>, and receives Solr's response. It should send <code>
   * this.store.string()</code> as the Solr query, and it should pass Solr's
   * response to <code>handleResponse()</code> for handling.</p>
   *
   * <p>See <tt>managers/Manager.jquery.js</tt> for a jQuery implementation.</p>
   *
   * @param {String} servlet The Solr servlet to send the request to.
   * @throws If not defined in child implementation.
   */
  executeRequest: function (servlet) {
    throw 'Abstract method executeRequest must be overridden in a subclass.';
  },

  /**
   * This method is executed after the Solr response data arrives. Allows each
   * widget to handle Solr's response separately.
   *
   * @param {Object} data The Solr response.
   */
  handleResponse: function (data) {
    this.response = data;

    for (var widgetId in this.widgets) {
      this.widgets[widgetId].afterRequest();
    }
  }
});