/static/js/controllers/searchcontroller.js

define([
  'config',
  'config/searchProviders',
  'underscore',
  'backbone',
  'lib/template',
  'lib/routecontroller',

  'models/searchcollections',
  'views/stackheadinglistview',
  'views/postlistview',

  'lib/bridge',
  'views/widgetview',
  'views/searchviews',
  'logger'
], function(
  config,
  searchProviders,
  util,
  Backbone,
  template,
  RouteController,

  searchCollections,
  StackHeadingListView,
  PostListView,

  Bridge,
  WidgetView,
  searchViews,
  logger
) {
  // We need to pass an empty array into empty collections that need options
  // (null gets interpreted as a value and wrapped). It's a bit fussy, but it
  // should be faster to share a single object than create one.
  var emptyArray = [];

  var bridge = new Bridge();

  var onStackVisit = function(view, model, e) {
    e.preventDefault();

    // Make a PUT request to the server to get a new session_id.
    // The model will come back as the first argument of success callback,
    // with a session_id added.
    model.save(null, {
      // Change the URL hit with this call to a PUT against
      // `lattice/:username/stack/search`. Instead of hard-coding, crawl
      // back up to the stack and grab its URL, just in case.
      // SiteModel.PlaceCollection.StackModel.StackCollection.
      url: model.parent().stack().parent().url(),
      success: function (model) {
        var data = util.extend(model.toJSON(), { origin: config.appName });
        bridge.changeStack(data).showViewer();
      },
      error: function(err){
        logger.error("Error encountered when handling stack launch", err);
      }
    });
  };

  var SearchController = RouteController.extend({
    initialize: function (options) {
      // Initialize collections object for storing search collections.
      var collections = this.collections = {};

      // Create an empty `StackSearchCollection` to be shared for
      // the lifetime of this controller. Views are relied on to 
      // adapt to the changing contents of this controller.
      collections.stacks = new searchCollections.Stack(emptyArray, {
        urlTokens: { method: 'search' },
        urlQuery: {
          // Set the `limit` param to 4 -- the maximum number of stacks
          // that can be returned with the search.
          l: 4,
          // `q: query.terms,` should be manually configured in the `enter`
          // method using `terms` method.
          // 
          // We want to use the `v3` version of this API -- it has the
          // `matches` property for searches.
          v: 3,
          // Set the maximum number of places to be returned by this API.
          p: 3
        }
      });

      // > Depending on how many providers we end up with, we may want to
      // > figure out a way to lazily create collections based on what we
      // > actually need. Prototypal objects are fast, though, so it might
      // > not actually matter -GB.
      collections.bings = new searchCollections.Bing(emptyArray, {
        urlTokens: {
          base: config.searchRoot,
          path: 'bing'
        },
        urlQuery: {
          // `q: query.terms,` should be manually configured in the `enter`
          // method using `terms` method.
          format: 'json'
        }
      });

      collections.tweets = new searchCollections.Tweets(emptyArray, {
        urlTokens: {
          base: config.searchRoot,
          path: 'twitter'
        },
        urlQuery: {
          // `q: query.terms,` should be manually configured in the `enter`
          // method using `terms` method.
          format: 'json'
        }        
      });

      this.mainView = new searchViews.SearchTabsView();

      var stackListView = this.stacks(collections.stacks);
      var bingListView = this.bings(collections.bings);
      var tweetListView = this.tweets(collections.tweets);

      this.mainView.widgets({
        '#stack-results': stackListView,
        '#bing-results': bingListView,
        '#twitter-results': tweetListView
      });

      this.mainView.bind('activate', function (view) {
        var activeView = view.widget(view.active);
        var collection = activeView.collection;
        if (collection.state() === 'invalid') {
          activeView.render();
          collection.fetchDebounced();
        }
      });

      this.mainView.activateTab('#bing-results');
    },

    enter: function (query, options) {
      util.extend(this, options || {});

      // Set this view as active in the app.
      this.appView.widget(
        '#main',
        this.mainView
      );
    },

    update: function (query, options) {
      // Update instance from options.
      // 
      // TODO: I'm not wild about the way this works -- it's too brittle -GB
      util.extend(this, options || {});

      var terms = this.parseQuery(query).terms;
      var collections = this.collections;

      var stacks = collections.stacks;

      // Update terms on all collections.
      for(var key in collections) collections[key].terms(terms);

      // Fetch stacks.
      stacks.fetchDebounced();

      // Fetch active search collection.
      this.mainView.widget(this.mainView.active).collection.fetchDebounced();
    },

    exit: function () {
      // Empty collections on exit.
      var collections = this.collections;
      for (var key in collections) collections[key].reset();

      // These memoized collections are available as properties on the
      // bings collection.
      this.collections.bings.images().reset();
      this.collections.bings.suggestions().reset();
    },

    // Centralizing the scratch logic it takes to create and configure a
    // stackListView for the search controller.
    stacks: function (collection) {
      var stackListView = new StackHeadingListView({
        className: 'headinglist headinglist--with-divider',
        collection: collection
      });

      stackListView.bind('visit', onStackVisit);

      return stackListView;
    },

    // Factory function for creating tweet result view with configured
    // click handlers. This is all a little bit obtuse, and could probably
    // be cleaner, but I want to avoid binding handlers in the view constructor.
    tweets: function (collection) {
      var searchTweetsView = new searchViews.SearchTweetsView({
        collection: collection
      });

      searchTweetsView.bind('visit', function (placeView, siteModel, e) {
        e.preventDefault();

        var terms = siteModel.collection.terms();

        var msg = util.extend(siteModel.toJSON(), {
          search_terms: terms,

          // TODO: GB: hard-coded. This should be pulled from a list of registered
          // search providers -- probably from an API somewhere. The client should
          // be dumb.
          search_provider: 'twitter',

          // TODO: GB: hard-coded. This should be pulled from a list of registered
          // search providers -- probably from an API somewhere. The client should
          // be dumb.
          search_url: template(config.searchResults)({
            query: terms,
            provider: 'twitter'
          }),
          origin: config.appName
        });

        // Clear search field. Reset to home.
        var appModel = this.appView.model;
        setTimeout(util.bind(appModel.set, appModel, { search: '' }), 1000);

        // Send message up.
        bridge.createStack(msg);        
      }, this);

      return searchTweetsView;
    },

    // Factory function for creating bing result view with configured
    // click handlers. This is all a little bit obtuse, and could probably
    // be cleaner, but I want to avoid binding handlers in the view constructor.
    bings: function (collection) {
      var bingView = new searchViews.SearchBingView({
        collection: collection
      });

      // Define a handler for `visit` events on the `view`.
      bingView.bind('visit', function (placeView, siteModel, e) {
        e.preventDefault();

        // Capture search terms by calling the custom `terms` method on the
        // this collection.
        // Capture terms from collection via closure, at event-time.
        var terms = collection.terms();

        var msg = util.extend(siteModel.toJSON(), {
          search_terms: terms,
          // TODO: GB: hard-coded. This should be pulled from a list of registered
          // search providers -- probably from an API somewhere. The client should
          // be dumb.
          search_provider: 'bing',
          
          search_url: template(config.searchResults)({
            query: terms,
            provider: 'bing'
          }),
          origin: config.appName
        });

        // We have to access this property at runtime, rather than via closure
        // because `bings` is called at initialization, but `this.appView` isn't
        // part of the object until it is mixed in via `enter` method.
        // 
        // TODO: this is confusing and brittle. We should handle requirements
        // during construction.
        var appModel = this.appView.model;

        // Clear search field. Reset to home.
        setTimeout(util.bind(appModel.set, appModel, { search: '' }), 1000);

        // Send message up.
        bridge.createStack(msg);
      }, this)
      .bind('suggest', function (view, model, e) {
        e.preventDefault();

        // We have to access this property at runtime, rather than via closure
        // because `bings` is called at initialization, but `this.appView` isn't
        // part of the object until it is mixed in via `enter` method.
        // 
        // TODO: this is confusing and brittle. We should handle requirements
        // during construction.
        var appModel = this.appView.model;

        appModel.set({ search: model.get('place_title') });
      }, this);

      return bingView;
    },

    parseQuery: function (query) {
      var // parse out the query - it can be something like twitter/term1/term2
          // or just 'term'
          terms = query.split('/'),
          // a master list of search providers we support, with name: prefix.
          // define in config maybe?
          providers = searchProviders;

      var parsed = {};

      // We consider the first term to be a provider if it matches one of the
      // providers in our list.
      if(terms.length > 1 && providers[terms[0]]) {
        parsed.provider = terms.shift();
      }

      parsed.terms = terms.join(' ');
      return parsed;
    }
  });

  return new SearchController();
});