(function($) {
  var history;
  Drupal.search_api_ajax = {};

  if (Drupal.settings.search_api_ajax) {
    var blocks = Drupal.settings.search_api_ajax.blocks;
    var content = Drupal.settings.search_api_ajax.content;
    var regions = Drupal.settings.search_api_ajax.regions;
    var spinner = Drupal.settings.search_api_ajax.spinner;
    var target = Drupal.settings.search_api_ajax.scrolltarget;
    var fade = Drupal.settings.search_api_ajax.fade;
    var opacity = Drupal.settings.search_api_ajax.opacity;
    var speed = Drupal.settings.search_api_ajax.scrollspeed;
    // notice the "search_api_ajax_path" instead of
    // "search_api_ajax.path" for magic reasons
    var ajaxPath = Drupal.settings.search_api_ajax_path;
    var qPath = Drupal.settings.search_api_ajax_qpath;
    var isView = Drupal.settings.search_api_ajax.view;

    // initialize listeners
    Drupal.search_api_ajax.initialize = function() {
      if (content) {
        Drupal.search_api_ajax.ajax(content);
      }
      if (blocks) {
        for (var block in blocks) {
          Drupal.search_api_ajax.ajax(blocks[block]);
        }
      }
    };
    // extract url for ajax history
    Drupal.search_api_ajax.url_to_state = function(url) {
      var state = '';
      if (isView) {
        var query = Drupal.search_api_ajax.get_url_state(url)["query"];
      }
      state = url.replace(new RegExp('^.*' + Drupal.settings.basePath + ajaxPath + '/' + '?'), '');
      if (query) {
        state = query + state.replace('?query=' + query, '');
      }
      else {
        state = state.replace('?query=', '');
        state = state.replace('?', '&');
      }
      return state;
    };

    Drupal.search_api_ajax.get_url_state = function(url) {
      var vars = [], hash;
      var hashes = url.slice(url.indexOf('?') + 1).split('&');
      for (var i = 0; i < hashes.length; i++) {
        hash = hashes[i].split('=');
        vars.push(hash[0]);
        vars[hash[0]] = hash[1];
      }
      return vars;
    }
    // prepare and perform ajax search request
    Drupal.search_api_ajax.request_callback = function(state) {
      if (content) {
        if (fade) {
          $(content + ':first').fadeTo('fast', opacity);
        }
        if (spinner) {
          $('#content').append('<div id="search-api-ajax-spinner"><img class="spinner" src="' + Drupal.settings.basePath + spinner + '" /></div>')
        }
      }

      // Scroll back to top, when top is out of view. Inspired by views module.
      if (target) {
        var offset = $(target).offset();
        var scrollTarget = target;
        while ($(scrollTarget).scrollTop() == 0 && $(scrollTarget).parent()) {
          scrollTarget = $(scrollTarget).parent()
        }
        if (offset.top - 10 < $(scrollTarget).scrollTop()) {
          $(scrollTarget).animate({
            scrollTop: (offset.top - 10)
          }, speed);
        }
      }

      // post ajax, read json
      var keysPath = '/' + state;
      if (isView) {
        keysPath = '?query=' + state;
      }

      $.post(Drupal.settings.basePath + 'search_api_ajax/' + ajaxPath + keysPath, {
        js: 1
      }, Drupal.search_api_ajax.response_callback, 'json');
    };
    // update search page with ajax, based on the json we read
    Drupal.search_api_ajax.response_callback = function(data) {
      if (content) {
        if (fade) {
          $(content + ':first').fadeTo('fast', 1);
        }
        if (spinner) {
          $('#search-api-ajax-spinner').remove();
        }
      }

      for (var setting in data.settings) {
        Drupal.settings[setting] = data.settings[setting];
      }

      var list = [];

      // we have to add the new blocks, that have come into existence
      // @see search_api_ajax.pages.inc where we add this blocks variable
      if (data.blocks) {
        for (var new_block in data.blocks) {
          blocks[new_block] = data.blocks[new_block];
        }
      }

      // schedule items for removal to reduce page jumpiness.
      if (blocks) {
        for (var block in blocks) {
          list.push($(blocks[block]));
        }
        for (var i = 0, l = list.length; i < l; i++) {
          list[i].remove();
        }
      }
      for (var region in data.regions) {
        if (region == 'search_api_ajax') {
          if (content) {
            $(content + ':first').html(data.regions[region]);
          }
        }
        else {
          for (var block in data.regions[region]) {
            if (regions[region] && blocks[block]) {
              $(regions[region]).append(data.regions[region][block]);
            }
          }
        }
      }

      // re-attach Drupal behaviors for whole document
      Drupal.attachBehaviors('body');
    };

    Drupal.search_api_ajax.navigate = function(url) {
      if (url !== undefined) {
        YUI().use('history', function(Y) {
          history.add({
            q: Drupal.search_api_ajax.url_to_state(url)
          });
        });
      }
      return false;
    };

    Drupal.search_api_ajax.ajax = function(selector) {
      // observe regular facet and sorts links ^ starts with * contains
      // check two paths: ^basePath/ajaxPath OR ^search_api_ajax/basePath/ajaxPath
      // @see http://api.jquery.com/category/selectors/attribute-selectors/
      // Create an array of selectors for readability.
      var selectors = [selector + ' a[href^="' + Drupal.settings.basePath + ajaxPath + '"]', selector + ' a[href^="' + Drupal.settings.basePath + 'search_api_ajax/' + ajaxPath + '"]'];
      $(selectors.join(', ')).livequery('click', function() {
        return Drupal.search_api_ajax.navigate($(this).attr('href'));
      });
      // Add support for facetapi checkboxes widget.
      // Unbind facetapi click event.
      $(selector + ' .facetapi-checkbox').unbind('click');
      $(selector + ' .facetapi-checkbox').livequery('click', function() {
        return Drupal.search_api_ajax.navigate($(this).next('a').attr('href'));
      })
      // observe search keys forms (or views input forms, must be custom set)

      $(selector + ' form[action^="' + Drupal.settings.basePath + ajaxPath + '"], ' + selector + ' form[action^="' + Drupal.settings.basePath + 'search_api_ajax/' + ajaxPath + '"]').livequery('submit', function() {
        return Drupal.search_api_ajax.navigate($(this).find('input[name*="keys"]').val());
      });

      // observe facet range sliders
      $(selector + ' .search-api-ranges-widget form[action^="' + Drupal.settings.basePath + ajaxPath + '"], ' + selector + ' .search-api-ranges-widget form[action^="' + Drupal.settings.basePath + 'search_api_ajax/' + ajaxPath + '"]').livequery('submit', function() {
        var separator = '?';
        if ($(this).find('input[name="range-ajax-target"]').val().indexOf("?") !== -1) {
          separator = '&';
        }

        // add a filter in the form of &f[n]=field_name:[A B]
        // instead of actually knowing what "n" is, we just f[]
        // @todo Facet API can have different 'f', how to know which?
        var addFilter = 'f[]=' + $(this).find('input[name="range-field"]').val() + ':' + '[' + $(this).find('input[name="range-from"]').val() + ' TO ' + $(this).find('input[name="range-to"]').val() + ']';

        return Drupal.search_api_ajax.navigate($(this).find('input[name="range-ajax-target"]').val() + separator + addFilter);
      });
    };
  }

  // we initiate YUI3's History extension
  YUI().use('history', function(Y) {

    // initialize
    history = new Y.HistoryHash();
    if (history.get('q')) {
      Drupal.search_api_ajax.request_callback(history.get('q'));
    }

    // listen to changes
    // @todo when going from /page#q= to /page it should also trigger
    Y.on('history:change', function(e) {
      var changed = e.changed;
      if (changed.q) {
        Drupal.search_api_ajax.request_callback(history.get('q'));
      }
    });
  });

  Drupal.behaviors.search_api_ajax = {
    attach: function(context, settings) {

      // initialize livequery() event only if there is an active search
      // only needed for search api pages, not for views paths
      if (Drupal.search_api_ajax.url_to_state(window.location.href) != '' || isView === 1) {
        Drupal.search_api_ajax.initialize();
      }
    }
  };
})(jQuery);