//////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2017 EMC Corporation
///
/// 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 EMC Corporation
///
/// @author Andrey Abramov
/// @author Vasiliy Nabatchikov
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGODB_IRESEARCH__IRESEARCH_VIEW_META_H
#define ARANGODB_IRESEARCH__IRESEARCH_VIEW_META_H 1

#include <locale>
#include <unordered_set>

#include "IResearchViewSort.h"
#include "VocBase/voc-types.h"
#include "index/index_writer.hpp"
#include "velocypack/Builder.h"

namespace arangodb {
namespace velocypack {

struct ObjectBuilder;  // forward declarations
class Slice;           // forward declarations

}  // namespace velocypack
}  // namespace arangodb

namespace arangodb {
namespace iresearch {

// -----------------------------------------------------------------------------
// --SECTION--                                                      public
// types
// -----------------------------------------------------------------------------

////////////////////////////////////////////////////////////////////////////////
/// @brief metadata describing the IResearch view
////////////////////////////////////////////////////////////////////////////////
struct IResearchViewMeta {
  class ConsolidationPolicy {
   public:
    ConsolidationPolicy() = default;
    ConsolidationPolicy(irs::index_writer::consolidation_policy_t&& policy,
                        arangodb::velocypack::Builder&& properties) noexcept
        : _policy(std::move(policy)), _properties(std::move(properties)) {}

    irs::index_writer::consolidation_policy_t const& policy() const noexcept {
      return _policy;
    }

    arangodb::velocypack::Slice properties() const noexcept {
      return _properties.slice();
    }

   private:
    irs::index_writer::consolidation_policy_t _policy;  // policy instance (false == disable)
    arangodb::velocypack::Builder _properties;  // normalized policy definition
  };

  struct Mask {
    bool _cleanupIntervalStep;
    bool _commitIntervalMsec;
    bool _consolidationIntervalMsec;
    bool _consolidationPolicy;
    bool _locale;
    bool _version;
    bool _writebufferActive;
    bool _writebufferIdle;
    bool _writebufferSizeMax;
    bool _primarySort;
    explicit Mask(bool mask = false) noexcept;
  };

  size_t _cleanupIntervalStep; // issue cleanup after <count> commits (0 == disable)
  size_t _commitIntervalMsec; // issue commit after <interval> milliseconds (0 == disable)
  size_t _consolidationIntervalMsec; // issue consolidation after <interval> milliseconds (0 == disable)
  ConsolidationPolicy _consolidationPolicy; // the consolidation policy to use
  std::locale _locale; // locale used for ordering processed attribute names
  uint32_t _version; // the version of the iresearch interface e.g. which how data is stored in iresearch (default == latest)
  size_t _writebufferActive; // maximum number of concurrent segments before segment aquisition blocks, e.g. max number of concurrent transacitons) (0 == unlimited)
  size_t _writebufferIdle; // maximum number of segments cached in the pool
  size_t _writebufferSizeMax; // maximum memory byte size per segment before a segment flush is triggered (0 == unlimited)
  IResearchViewSort _primarySort;
  // NOTE: if adding fields don't forget to modify the default constructor !!!
  // NOTE: if adding fields don't forget to modify the copy constructor !!!
  // NOTE: if adding fields don't forget to modify the move constructor !!!
  // NOTE: if adding fields don't forget to modify the comparison operator !!!
  // NOTE: if adding fields don't forget to modify IResearchLinkMeta::Mask !!!
  // NOTE: if adding fields don't forget to modify IResearchLinkMeta::Mask
  // constructor !!! NOTE: if adding fields don't forget to modify the init(...)
  // function !!! NOTE: if adding fields don't forget to modify the json(...)
  // function !!! NOTE: if adding fields don't forget to modify the memory()
  // function !!!

  IResearchViewMeta();
  IResearchViewMeta(IResearchViewMeta const& other);
  IResearchViewMeta(IResearchViewMeta&& other) noexcept;

  IResearchViewMeta& operator=(IResearchViewMeta&& other) noexcept;
  IResearchViewMeta& operator=(IResearchViewMeta const& other);

  bool operator==(IResearchViewMeta const& other) const noexcept;
  bool operator!=(IResearchViewMeta const& other) const noexcept;

  ////////////////////////////////////////////////////////////////////////////////
  /// @brief return default IResearchViewMeta values
  ////////////////////////////////////////////////////////////////////////////////
  static const IResearchViewMeta& DEFAULT();

  ////////////////////////////////////////////////////////////////////////////////
  /// @brief initialize IResearchViewMeta with values from a JSON description
  ///        return success or set 'errorField' to specific field with error
  ///        on failure state is undefined
  /// @param mask if set reflects which fields were initialized from JSON
  ////////////////////////////////////////////////////////////////////////////////
  bool init(arangodb::velocypack::Slice const& slice, std::string& errorField,
            IResearchViewMeta const& defaults = DEFAULT(), Mask* mask = nullptr) noexcept;

  ////////////////////////////////////////////////////////////////////////////////
  /// @brief fill and return a JSON description of a IResearchViewMeta object
  ///        do not fill values identical to ones available in 'ignoreEqual'
  ///        or (if 'mask' != nullptr) values in 'mask' that are set to false
  ///        elements are appended to an existing object
  ///        return success or set TRI_set_errno(...) and return false
  ////////////////////////////////////////////////////////////////////////////////
  bool json(arangodb::velocypack::Builder& builder,
            IResearchViewMeta const* ignoreEqual = nullptr, Mask const* mask = nullptr) const;

  ////////////////////////////////////////////////////////////////////////////////
  /// @brief amount of memory in bytes occupied by this iResearch Link meta
  ////////////////////////////////////////////////////////////////////////////////
  size_t memory() const;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief internal configuration state of an IResearch view instance
///        not directly modifiable by user
////////////////////////////////////////////////////////////////////////////////
struct IResearchViewMetaState {
  struct Mask {
    bool _collections;
    explicit Mask(bool mask = false) noexcept;
  };

  std::unordered_set<TRI_voc_cid_t> _collections;  // collection links added to this view via IResearchLink
                                                   // creation (may contain no-longer valid cids)
  // NOTE: if adding fields don't forget to modify the default constructor !!!
  // NOTE: if adding fields don't forget to modify the copy constructor !!!
  // NOTE: if adding fields don't forget to modify the move constructor !!!
  // NOTE: if adding fields don't forget to modify the comparison operator !!!
  // NOTE: if adding fields don't forget to modify IResearchLinkMetaState::Mask
  // !!! NOTE: if adding fields don't forget to modify
  // IResearchLinkMetaState::Mask constructor !!! NOTE: if adding fields don't
  // forget to modify the init(...) function !!! NOTE: if adding fields don't
  // forget to modify the json(...) function !!! NOTE: if adding fields don't
  // forget to modify the memory() function !!!

  IResearchViewMetaState();
  IResearchViewMetaState(IResearchViewMetaState const& other);
  IResearchViewMetaState(IResearchViewMetaState&& other) noexcept;

  IResearchViewMetaState& operator=(IResearchViewMetaState&& other) noexcept;
  IResearchViewMetaState& operator=(IResearchViewMetaState const& other);

  bool operator==(IResearchViewMetaState const& other) const noexcept;
  bool operator!=(IResearchViewMetaState const& other) const noexcept;

  ////////////////////////////////////////////////////////////////////////////////
  /// @brief return default IResearchViewMeta values
  ////////////////////////////////////////////////////////////////////////////////
  static const IResearchViewMetaState& DEFAULT();

  ////////////////////////////////////////////////////////////////////////////////
  /// @brief initialize IResearchViewMeta with values from a JSON description
  ///        return success or set 'errorField' to specific field with error
  ///        on failure state is undefined
  /// @param mask if set reflects which fields were initialized from JSON
  ////////////////////////////////////////////////////////////////////////////////
  bool init(arangodb::velocypack::Slice const& slice, std::string& errorField,
            IResearchViewMetaState const& defaults = DEFAULT(), Mask* mask = nullptr);

  ////////////////////////////////////////////////////////////////////////////////
  /// @brief fill and return a JSON description of a IResearchViewMeta object
  ///        do not fill values identical to ones available in 'ignoreEqual'
  ///        or (if 'mask' != nullptr) values in 'mask' that are set to false
  ///        elements are appended to an existing object
  ///        return success or set TRI_set_errno(...) and return false
  ////////////////////////////////////////////////////////////////////////////////
  bool json(arangodb::velocypack::Builder& builder,
            IResearchViewMetaState const* ignoreEqual = nullptr,
            Mask const* mask = nullptr) const;

  ////////////////////////////////////////////////////////////////////////////////
  /// @brief amount of memory in bytes occupied by this iResearch Link meta
  ////////////////////////////////////////////////////////////////////////////////
  size_t memory() const;
};

}  // namespace iresearch
}  // namespace arangodb

#endif