/*jshint strict: false */
/*global AQL_EXPLAIN */

////////////////////////////////////////////////////////////////////////////////
/// @brief query explain actions
///
/// @file
///
/// DISCLAIMER
///
/// Copyright 2014 ArangoDB GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
///     http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Jan Steemann
/// @author Copyright 2014, ArangoDB GmbH, Cologne, Germany
/// @author Copyright 2012, triAGENS GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////

var actions = require("@arangodb/actions");
var ERRORS = require("internal").errors;


////////////////////////////////////////////////////////////////////////////////
/// @brief was docuBlock JSF_post_api_explain
////////////////////////////////////////////////////////////////////////////////

function post_api_explain (req, res) {
  if (req.suffix.length !== 0) {
    actions.resultNotFound(req,
                           res,
                           ERRORS.errors.ERROR_HTTP_NOT_FOUND.code,
                           ERRORS.errors.ERROR_HTTP_NOT_FOUND.message);
    return;
  }

  var json = actions.getJsonBody(req, res);

  if (json === undefined) {
    return;
  }

  var result = AQL_EXPLAIN(json.query, json.bindVars, json.options || { });

  if (result instanceof Error) {
    actions.resultException(req, res, result, undefined, false);
    return;
  }

  if (result.hasOwnProperty("plans")) {
    result = { 
      plans: result.plans,
      warnings: result.warnings,
      stats: result.stats
    };
  }
  else {
    result = {
      plan: result.plan,
      warnings: result.warnings,
      stats: result.stats,
      cacheable: result.cacheable
    };
  }
  actions.resultOk(req, res, actions.HTTP_OK, result);
}


////////////////////////////////////////////////////////////////////////////////
/// @brief explain gateway
////////////////////////////////////////////////////////////////////////////////

actions.defineHttp({
  url : "_api/explain",

  callback : function (req, res) {
    try {
      switch (req.requestType) {
        case actions.POST:
          post_api_explain(req, res);
          break;

        default:
          actions.resultUnsupported(req, res);
      }
    }
    catch (err) {
      actions.resultException(req, res, err, undefined, false);
    }
  }
});