this.recline = this.recline || {};
this.recline.Backend = this.recline.Backend || {};
this.recline.Backend.ElasticSearch = this.recline.Backend.ElasticSearch || {};

(function($, my) {
  // ## ElasticSearch Wrapper
  //
  // Connecting to [ElasticSearch](http://www.elasticsearch.org/) endpoints.
  // @param {String} endpoint: url for ElasticSearch type/table, e.g. for ES running
  // on localhost:9200 with index // twitter and type tweet it would be:
  // 
  // <pre>http://localhost:9200/twitter/tweet</pre>
  // @param {Object} options: set of options such as:
  //
  // * headers - {dict of headers to add to each request}
  my.Wrapper = function(endpoint, options) { 
    var self = this;
    this.endpoint = endpoint;
    this.options = _.extend({
        dataType: 'json'
      },
      options);

    this.mapping = function() {
      var schemaUrl = self.endpoint + '/_mapping';
      var jqxhr = recline.Backend.makeRequest({
        url: schemaUrl,
        dataType: this.options.dataType
      });
      return jqxhr;
    };

    this.get = function(id, error, success) {
      var base = this.endpoint + '/' + id;
      return recline.Backend.makeRequest({
        url: base,
        dataType: 'json',
        error: error,
        success: success
      });
    }

    // ### upsert
    //
    // create / update a document to ElasticSearch backend
    //
    // @param {Object} doc an object to insert to the index.
    // @param {string} url (optional) url for ElasticSearch endpoint (if not
    // defined called this._getESUrl()
    this.upsert = function(doc, error, success) {
      var data = JSON.stringify(doc);
      url = this.endpoint;
      if (doc.id) {
        url += '/' + doc.id;
      }
      return recline.Backend.makeRequest({
        url: url,
        type: 'POST',
        data: data,
        dataType: 'json',
        error: error,
        success: success
      });
    };

    // ### delete
    //
    // Delete a document from the ElasticSearch backend.
    //
    // @param {Object} id id of object to delete
    // @param {string} url (optional) url for ElasticSearch endpoint (if not
    // provided called this._getESUrl()
    this.delete = function(id, error, success) {
      url = this.endpoint;
      url += '/' + id;
      return recline.Backend.makeRequest({
        url: url,
        type: 'DELETE',
        dataType: 'json'
      });
    };

    this._normalizeQuery = function(queryObj) {
      var out = queryObj && queryObj.toJSON ? queryObj.toJSON() : _.extend({}, queryObj);
      if (out.q !== undefined && out.q.trim() === '') {
        delete out.q;
      }
      if (!out.q) {
        out.query = {
          match_all: {}
        };
      } else {
        out.query = {
          query_string: {
            query: out.q
          }
        };
        delete out.q;
      }
      // now do filters (note the *plural*)
      if (out.filters && out.filters.length) {
        if (!out.filter) {
          out.filter = {};
        }
        if (!out.filter.and) {
          out.filter.and = [];
        }
        out.filter.and = out.filter.and.concat(out.filters);
      }
      if (out.filters !== undefined) {
        delete out.filters;
      }
      return out;
    };

    this.query = function(queryObj) {
      var queryNormalized = this._normalizeQuery(queryObj);
      var data = {source: JSON.stringify(queryNormalized)};
      var url = this.endpoint + '/_search';
      var jqxhr = recline.Backend.makeRequest({
        url: url,
        data: data,
        dataType: this.options.dataType
      });
      return jqxhr;
    }
  };

  // ## ElasticSearch Backbone Backend
  //
  // Backbone connector for an ES backend.
  //
  // Usage:
  //
  // var backend = new recline.Backend.ElasticSearch(options);
  //
  // `options` are passed through to Wrapper
  my.Backbone = function(options) {
    var self = this;
    var esOptions = options;
    this.__type__ = 'elasticsearch';

    // ### sync
    //
    // Backbone sync implementation for this backend.
    //
    // URL of ElasticSearch endpoint to use must be specified on the
    // dataset (and on a Document by the document having a dataset
    // attribute) by the dataset having one of the following data
    // attributes (see also `_getESUrl` function):
    //
    // <pre>
    // elasticsearch_url
    // webstore_url
    // url
    // </pre>
    this.sync = function(method, model, options) {
      if (model.__type__ == 'Dataset') {
        var endpoint = self._getESUrl(model);
      } else {
        var endpoint = self._getESUrl(model.dataset);
      }
      var es = new my.Wrapper(endpoint, esOptions);
      if (method === "read") {
        if (model.__type__ == 'Dataset') {
          var dfd = $.Deferred();
          es.mapping().done(function(schema) {
            // only one top level key in ES = the type so we can ignore it
            var key = _.keys(schema)[0];
            var fieldData = _.map(schema[key].properties, function(dict, fieldName) {
              dict.id = fieldName;
              return dict;
            });
            model.fields.reset(fieldData);
            dfd.resolve(model);
          })
          .fail(function(arguments) {
            dfd.reject(arguments);
          });
          return dfd.promise();
        } else if (model.__type__ == 'Document') {
          return es.get(model.dataset.id);
        }
      } else if (method === 'update') {
        if (model.__type__ == 'Document') {
          return es.upsert(model.toJSON());
        }
      } else if (method === 'delete') {
        if (model.__type__ == 'Document') {
          return es.delete(model.id);
        }
      }
    };

    // ### _getESUrl
    //
    // get url to ElasticSearch endpoint (see above)
    this._getESUrl = function(dataset) {
      if (dataset) {
        var out = dataset.get('elasticsearch_url');
        if (out) return out;
        out = dataset.get('webstore_url');
        if (out) return out;
        out = dataset.get('url');
        return out;
      }
      return this.get('url');
    };

    this.query = function(model, queryObj) {
      var dfd = $.Deferred();
      var url = this._getESUrl(model);
      var es = new my.Wrapper(url, esOptions);
      var jqxhr = es.query(queryObj);
      // TODO: fail case
      jqxhr.done(function(results) {
        _.each(results.hits.hits, function(hit) {
          if (!('id' in hit._source) && hit._id) {
            hit._source.id = hit._id;
          }
        });
        if (results.facets) {
          results.hits.facets = results.facets;
        }
        dfd.resolve(results.hits);
      });
      return dfd.promise();
    };
  };

}(jQuery, this.recline.Backend.ElasticSearch));