////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS 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 Max Neunhoeffer
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGOD_AQL_REST_AQL_HANDLER_H
#define ARANGOD_AQL_REST_AQL_HANDLER_H 1

#include "Basics/Common.h"
#include "Basics/JsonHelper.h"
#include "Aql/QueryRegistry.h"
#include "Aql/types.h"
#include "RestHandler/RestVocbaseBaseHandler.h"
#include "RestServer/VocbaseContext.h"
#include "V8Server/ApplicationV8.h"

struct TRI_vocbase_t;

namespace arangodb {
namespace aql {

////////////////////////////////////////////////////////////////////////////////
/// @brief shard control request handler
////////////////////////////////////////////////////////////////////////////////

class RestAqlHandler : public RestVocbaseBaseHandler {
 public:
  RestAqlHandler(HttpRequest* request,
                 std::pair<ApplicationV8*, QueryRegistry*>* pair);

 public:
  bool isDirect() const override;

  size_t queue() const override;

  //////////////////////////////////////////////////////////////////////////////
  /// @brief executes the handler
  //////////////////////////////////////////////////////////////////////////////

  status_t execute() override;

  //////////////////////////////////////////////////////////////////////////////
  /// @brief POST method for /_api/aql/instantiate
  /// The body is a VelocyPack with attributes "plan" for the execution plan and
  /// "options" for the options, all exactly as in AQL_EXECUTEJSON.
  //////////////////////////////////////////////////////////////////////////////

  void createQueryFromVelocyPack();

  //////////////////////////////////////////////////////////////////////////////
  /// @brief POST method for /_api/aql/parse
  /// The body is a Json with attributes "query" for the query string,
  /// "parameters" for the query parameters and "options" for the options.
  /// This does the same as AQL_PARSE with exactly these parameters and
  /// does not keep the query hanging around.
  //////////////////////////////////////////////////////////////////////////////

  void parseQuery();

  //////////////////////////////////////////////////////////////////////////////
  /// @brief POST method for /_api/aql/explain
  /// The body is a Json with attributes "query" for the query string,
  /// "parameters" for the query parameters and "options" for the options.
  /// This does the same as AQL_EXPLAIN with exactly these parameters and
  /// does not keep the query hanging around.
  //////////////////////////////////////////////////////////////////////////////

  void explainQuery();

  //////////////////////////////////////////////////////////////////////////////
  /// @brief POST method for /_api/aql/query
  /// The body is a Json with attributes "query" for the query string,
  /// "parameters" for the query parameters and "options" for the options.
  /// This sets up the query as as AQL_EXECUTE would, but does not use
  /// the cursor API yet. Rather, the query is stored in the query registry
  /// for later use by PUT requests.
  //////////////////////////////////////////////////////////////////////////////

  void createQueryFromString();

  //////////////////////////////////////////////////////////////////////////////
  /// @brief PUT method for /_api/aql/<operation>/<queryId>, this is using
  /// the part of the cursor API with side effects.
  /// <operation>: can be "getSome" or "skip".
  /// The body must be a Json with the following attributes:
  /// For the "getSome" operation one has to give:
  ///   "atLeast":
  ///   "atMost": both must be positive integers, the cursor returns never
  ///             more than "atMost" items and tries to return at least
  ///             "atLeast". Note that it is possible to return fewer than
  ///             "atLeast", for example if there are only fewer items
  ///             left. However, the implementation may return fewer items
  ///             than "atLeast" for internal reasons, for example to avoid
  ///             excessive copying. The result is the JSON representation of an
  ///             AqlItemBlock.
  /// For the "skip" operation one has to give:
  ///   "number": must be a positive integer, the cursor skips as many items,
  ///             possibly exhausting the cursor.
  ///             The result is a JSON with the attributes "error" (boolean),
  ///             "errorMessage" (if applicable) and "exhausted" (boolean)
  ///             to indicate whether or not the cursor is exhausted.
  //////////////////////////////////////////////////////////////////////////////

  void useQuery(std::string const& operation, std::string const& idString);

  //////////////////////////////////////////////////////////////////////////////
  /// @brief GET method for /_api/aql/<queryId>
  //////////////////////////////////////////////////////////////////////////////

  void getInfoQuery(std::string const& operation, std::string const& idString);

 private:

  //////////////////////////////////////////////////////////////////////////////
  /// @brief Send slice as result with the given response type.
  //////////////////////////////////////////////////////////////////////////////

  void sendResponse(GeneralResponse::ResponseCode,
                    arangodb::velocypack::Slice const,
                    TransactionContext*);

  //////////////////////////////////////////////////////////////////////////////
  /// @brief handle for useQuery
  //////////////////////////////////////////////////////////////////////////////

  void handleUseQuery(std::string const&, Query*,
                      arangodb::velocypack::Slice const);

  //////////////////////////////////////////////////////////////////////////////
  /// @brief parseVelocyPackBody, returns a nullptr and produces an error response if
  /// parse was not successful.
  //////////////////////////////////////////////////////////////////////////////

  std::shared_ptr<arangodb::velocypack::Builder> parseVelocyPackBody();

 private:
  //////////////////////////////////////////////////////////////////////////////
  /// @brief dig out vocbase from context and query from ID, handle errors
  //////////////////////////////////////////////////////////////////////////////

  bool findQuery(std::string const& idString, Query*& query);

  //////////////////////////////////////////////////////////////////////////////
  /// @brief name of the queue
  //////////////////////////////////////////////////////////////////////////////

  static std::string const QUEUE_NAME;

  //////////////////////////////////////////////////////////////////////////////
  /// @brief _applicationV8
  //////////////////////////////////////////////////////////////////////////////

  ApplicationV8* _applicationV8;

  //////////////////////////////////////////////////////////////////////////////
  /// @brief request context
  //////////////////////////////////////////////////////////////////////////////

  VocbaseContext* _context;

  //////////////////////////////////////////////////////////////////////////////
  /// @brief the vocbase
  //////////////////////////////////////////////////////////////////////////////

  TRI_vocbase_t* _vocbase;

  //////////////////////////////////////////////////////////////////////////////
  /// @brief our query registry
  //////////////////////////////////////////////////////////////////////////////

  QueryRegistry* _queryRegistry;

  //////////////////////////////////////////////////////////////////////////////
  /// @brief id of current query
  //////////////////////////////////////////////////////////////////////////////

  QueryId _qId;
};
}
}

#endif