////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2018 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 Simon Grätzer
////////////////////////////////////////////////////////////////////////////////

#include "Basics/StaticStrings.h"
#include "Basics/StringUtils.h"
#include "Basics/VelocyPackHelper.h"
#include "Cluster/ServerState.h"
#include "ClusterEngine/ClusterEngine.h"
#include "ClusterEngine/ClusterIndex.h"
#include "ClusterIndexFactory.h"
#include "Indexes/Index.h"
#include "StorageEngine/EngineSelectorFeature.h"
#include "VocBase/LogicalCollection.h"
#include "VocBase/ticks.h"
#include "VocBase/voc-types.h"

#include <velocypack/Builder.h>
#include <velocypack/Iterator.h>
#include <velocypack/Slice.h>
#include <velocypack/velocypack-aliases.h>

namespace {

struct DefaultIndexFactory : public arangodb::IndexTypeFactory {
  std::string const _type;

  explicit DefaultIndexFactory(std::string const& type) : _type(type) {}

  bool equal(arangodb::velocypack::Slice const& lhs,
             arangodb::velocypack::Slice const& rhs) const override {
    auto* clusterEngine =
        static_cast<arangodb::ClusterEngine*>(arangodb::EngineSelectorFeature::ENGINE);

    if (!clusterEngine) {
      THROW_ARANGO_EXCEPTION(arangodb::Result(
          TRI_ERROR_INTERNAL,
          "cannot find cluster engine while normalizing index"));
    }

    auto* engine = clusterEngine->actualEngine();

    if (!engine) {
      THROW_ARANGO_EXCEPTION(arangodb::Result(
          TRI_ERROR_INTERNAL,
          "cannot find storage engine while normalizing index"));
    }

    return engine->indexFactory().factory(_type).equal(lhs, rhs);
  }

  std::shared_ptr<arangodb::Index> instantiate(arangodb::LogicalCollection& collection,
                                               arangodb::velocypack::Slice const& definition, TRI_idx_iid_t id,
                                               bool /* isClusterConstructor */) const override {
    auto* clusterEngine =
        static_cast<arangodb::ClusterEngine*>(arangodb::EngineSelectorFeature::ENGINE);

    if (!clusterEngine) {
      THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL,
          "cannot find cluster engine while creating index");
    }

    auto ct = clusterEngine->engineType();

    return std::make_shared<arangodb::ClusterIndex>(id, collection, ct,
                                                    arangodb::Index::type(_type),
                                                    definition);
  }

  virtual arangodb::Result normalize( // normalize definition
      arangodb::velocypack::Builder& normalized, // normalized definition (out-param)
      arangodb::velocypack::Slice definition, // source definition
      bool isCreation, // definition for index creation
      TRI_vocbase_t const& vocbase // index vocbase
  ) const override {
    auto* clusterEngine =
        static_cast<arangodb::ClusterEngine*>(arangodb::EngineSelectorFeature::ENGINE);

    if (!clusterEngine) {
      return arangodb::Result(
          TRI_ERROR_INTERNAL,
          "cannot find cluster engine while normalizing index");
    }

    auto* engine = clusterEngine->actualEngine();

    if (!engine) {
      return arangodb::Result(
          TRI_ERROR_INTERNAL,
          "cannot find storage engine while normalizing index");
    }

    return engine->indexFactory().factory(_type).normalize( // normalize definition
      normalized, definition, isCreation, vocbase // args
    );
  }
};

struct EdgeIndexFactory : public DefaultIndexFactory {
  explicit EdgeIndexFactory(std::string const& type)
      : DefaultIndexFactory(type) {}

  std::shared_ptr<arangodb::Index> instantiate(arangodb::LogicalCollection& collection,
                                               arangodb::velocypack::Slice const& definition,
                                               TRI_idx_iid_t id, bool isClusterConstructor) const override {
    if (!isClusterConstructor) {
      // this index type cannot be created directly
      THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL, "cannot create edge index");
    }

    auto* clusterEngine =
        static_cast<arangodb::ClusterEngine*>(arangodb::EngineSelectorFeature::ENGINE);

    if (!clusterEngine) {
      THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL,
          "cannot find storage engine while creating index");
    }

    auto ct = clusterEngine->engineType();

    return std::make_shared<arangodb::ClusterIndex>(id, collection, ct,
                                                    arangodb::Index::TRI_IDX_TYPE_EDGE_INDEX,
                                                    definition);
  }
};

struct PrimaryIndexFactory : public DefaultIndexFactory {
  explicit PrimaryIndexFactory(std::string const& type)
      : DefaultIndexFactory(type) {}

  std::shared_ptr<arangodb::Index> instantiate(arangodb::LogicalCollection& collection,
                                               arangodb::velocypack::Slice const& definition,
                                               TRI_idx_iid_t id, bool isClusterConstructor) const override {
    if (!isClusterConstructor) {
      // this index type cannot be created directly
      THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL, "cannot create primary index");
    }

    auto* clusterEngine =
        static_cast<arangodb::ClusterEngine*>(arangodb::EngineSelectorFeature::ENGINE);

    if (!clusterEngine) {
      THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL,
          "cannot find storage engine while creating index");
    }

    auto ct = clusterEngine->engineType();

    return std::make_shared<arangodb::ClusterIndex>(0, collection, ct,
                                                    arangodb::Index::TRI_IDX_TYPE_PRIMARY_INDEX,
                                                    definition);
  }
};

}  // namespace

namespace arangodb {

ClusterIndexFactory::ClusterIndexFactory() {
  static const EdgeIndexFactory edgeIndexFactory("edge");
  static const DefaultIndexFactory fulltextIndexFactory("fulltext");
  static const DefaultIndexFactory geoIndexFactory("geo");
  static const DefaultIndexFactory geo1IndexFactory("geo1");
  static const DefaultIndexFactory geo2IndexFactory("geo2");
  static const DefaultIndexFactory hashIndexFactory("hash");
  static const DefaultIndexFactory persistentIndexFactory("persistent");
  static const PrimaryIndexFactory primaryIndexFactory("primary");
  static const DefaultIndexFactory skiplistIndexFactory("skiplist");
  static const DefaultIndexFactory ttlIndexFactory("ttl");

  emplace(edgeIndexFactory._type, edgeIndexFactory);
  emplace(fulltextIndexFactory._type, fulltextIndexFactory);
  emplace(geoIndexFactory._type, geoIndexFactory);
  emplace(geo1IndexFactory._type, geo1IndexFactory);
  emplace(geo2IndexFactory._type, geo2IndexFactory);
  emplace(hashIndexFactory._type, hashIndexFactory);
  emplace(persistentIndexFactory._type, persistentIndexFactory);
  emplace(primaryIndexFactory._type, primaryIndexFactory);
  emplace(skiplistIndexFactory._type, skiplistIndexFactory);
  emplace(ttlIndexFactory._type, ttlIndexFactory);
}

/// @brief index name aliases (e.g. "persistent" => "hash", "skiplist" =>
/// "hash") used to display storage engine capabilities
std::unordered_map<std::string, std::string> ClusterIndexFactory::indexAliases() const {
  auto* ce = static_cast<ClusterEngine*>(EngineSelectorFeature::ENGINE);
  auto* ae = ce->actualEngine();
  if (!ae) {
    THROW_ARANGO_EXCEPTION_MESSAGE(
        TRI_ERROR_INTERNAL, "no actual storage engine for ClusterIndexFactory");
  }
  return ae->indexFactory().indexAliases();
}

Result ClusterIndexFactory::enhanceIndexDefinition( // normalize definition
    velocypack::Slice const definition, // source definition
    velocypack::Builder& normalized, // normalized definition (out-param)
    bool isCreation, // definition for index creation
    TRI_vocbase_t const& vocbase // index vocbase
) const {
  auto* ce = static_cast<ClusterEngine*>(EngineSelectorFeature::ENGINE);

  if (!ce) {
    return TRI_ERROR_INTERNAL;
  }

  auto* ae = ce->actualEngine();

  if (!ae) {
    return TRI_ERROR_INTERNAL;
  }

  return ae->indexFactory().enhanceIndexDefinition( // normalize definition
    definition, normalized, isCreation, vocbase // args
  );
}

void ClusterIndexFactory::fillSystemIndexes(arangodb::LogicalCollection& col,
                                            std::vector<std::shared_ptr<arangodb::Index>>& systemIndexes) const {
  // create primary index
  VPackBuilder input;
  input.openObject();
  input.add(StaticStrings::IndexType, VPackValue("primary"));
  input.add(StaticStrings::IndexId, VPackValue("0"));
  input.add(StaticStrings::IndexName, VPackValue(StaticStrings::IndexNamePrimary));
  input.add(StaticStrings::IndexFields, VPackValue(VPackValueType::Array));
  input.add(VPackValue(StaticStrings::KeyString));
  input.close();
  input.add(StaticStrings::IndexUnique, VPackValue(true));
  input.add(StaticStrings::IndexSparse, VPackValue(false));
  input.close();

  // get the storage engine type
  ClusterEngine* ce = static_cast<ClusterEngine*>(EngineSelectorFeature::ENGINE);
  ClusterEngineType ct = ce->engineType();

  systemIndexes.emplace_back(
      std::make_shared<arangodb::ClusterIndex>(0, col, ct, Index::TRI_IDX_TYPE_PRIMARY_INDEX,
                                               input.slice()));

  // create edges indexes
  if (col.type() == TRI_COL_TYPE_EDGE) {
    // first edge index
    input.clear();
    input.openObject();
    input.add(StaticStrings::IndexType,
              VPackValue(Index::oldtypeName(Index::TRI_IDX_TYPE_EDGE_INDEX)));
    input.add(StaticStrings::IndexId, VPackValue("1"));

    input.add(StaticStrings::IndexFields, VPackValue(VPackValueType::Array));
    input.add(VPackValue(StaticStrings::FromString));
    if (ct == ClusterEngineType::MMFilesEngine) {
      input.add(VPackValue(StaticStrings::ToString));
    }
    input.close();

    if (ct == ClusterEngineType::MMFilesEngine) {
      input.add(StaticStrings::IndexName, VPackValue(StaticStrings::IndexNameEdge));
    } else if (ct == ClusterEngineType::RocksDBEngine) {
      input.add(StaticStrings::IndexName, VPackValue(StaticStrings::IndexNameEdgeFrom));
    }

    input.add(StaticStrings::IndexUnique, VPackValue(false));
    input.add(StaticStrings::IndexSparse, VPackValue(false));
    input.close();
    systemIndexes.emplace_back(
        std::make_shared<arangodb::ClusterIndex>(1, col, ct, Index::TRI_IDX_TYPE_EDGE_INDEX,
                                                 input.slice()));

    // second edge index
    if (ct == ClusterEngineType::RocksDBEngine) {
      input.clear();
      input.openObject();
      input.add(StaticStrings::IndexType,
                VPackValue(Index::oldtypeName(Index::TRI_IDX_TYPE_EDGE_INDEX)));
      input.add(StaticStrings::IndexId, VPackValue("2"));
      input.add(StaticStrings::IndexName, VPackValue(StaticStrings::IndexNameEdgeTo));
      input.add(StaticStrings::IndexFields, VPackValue(VPackValueType::Array));
      input.add(VPackValue(StaticStrings::ToString));
      input.close();
      input.add(StaticStrings::IndexUnique, VPackValue(false));
      input.add(StaticStrings::IndexSparse, VPackValue(false));
      input.close();
      systemIndexes.emplace_back(std::make_shared<arangodb::ClusterIndex>(
          2, col, ct, Index::TRI_IDX_TYPE_EDGE_INDEX, input.slice()));
    }
  }
}

void ClusterIndexFactory::prepareIndexes(
    LogicalCollection& col, arangodb::velocypack::Slice const& indexesSlice,
    std::vector<std::shared_ptr<arangodb::Index>>& indexes) const {
  TRI_ASSERT(indexesSlice.isArray());

  for (auto const& v : VPackArrayIterator(indexesSlice)) {
    if (!validateFieldsDefinition(v, 0, SIZE_MAX).ok()) {
      // We have an error here. Do not add.
      continue;
    }

    if (basics::VelocyPackHelper::getBooleanValue(v, StaticStrings::IndexIsBuilding, false)) {
      // This index is still being built. Do not add.
      continue;
    }

    try {
      auto idx = prepareIndexFromSlice(v, false, col, true);
      TRI_ASSERT(idx != nullptr);
      indexes.emplace_back(std::move(idx));
    } catch (std::exception const& ex) {
      LOG_TOPIC("7ed52", ERR, arangodb::Logger::ENGINES)
          << "error creating index from definition '" << v.toString() << "': " << ex.what();

    }
  }
}

}  // namespace arangodb