////////////////////////////////////////////////////////////////////////////////
/// 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 Michael Hackstein
////////////////////////////////////////////////////////////////////////////////

#include "MMFilesIndexFactory.h"
#include "Basics/Exceptions.h"
#include "Basics/StaticStrings.h"
#include "Basics/StringRef.h"
#include "Basics/StringUtils.h"
#include "Basics/VelocyPackHelper.h"
#include "Cluster/ServerState.h"
#include "Indexes/Index.h"
#include "MMFiles/MMFilesEdgeIndex.h"
#include "MMFiles/MMFilesFulltextIndex.h"
#include "MMFiles/MMFilesGeoIndex.h"
#include "MMFiles/MMFilesHashIndex.h"
#include "MMFiles/MMFilesPersistentIndex.h"
#include "MMFiles/MMFilesPrimaryIndex.h"
#include "MMFiles/MMFilesSkiplistIndex.h"
#include "MMFiles/mmfiles-fulltext-index.h"
#include "VocBase/LogicalCollection.h"
#include "VocBase/voc-types.h"

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

using namespace arangodb;

////////////////////////////////////////////////////////////////////////////////
/// @brief process the fields list and add them to the json
////////////////////////////////////////////////////////////////////////////////

static int ProcessIndexFields(VPackSlice const definition, VPackBuilder& builder,
                              int numFields, bool create) {
  TRI_ASSERT(builder.isOpenObject());
  std::unordered_set<StringRef> fields;

  try {
    VPackSlice fieldsSlice = definition.get("fields");
    builder.add(VPackValue("fields"));
    builder.openArray();
    if (fieldsSlice.isArray()) {
      // "fields" is a list of fields
      for (auto const& it : VPackArrayIterator(fieldsSlice)) {
        if (!it.isString()) {
          return TRI_ERROR_BAD_PARAMETER;
        }

        StringRef f(it);

        if (f.empty() || (create && f == StaticStrings::IdString)) {
          // accessing internal attributes is disallowed
          return TRI_ERROR_BAD_PARAMETER;
        }

        if (fields.find(f) != fields.end()) {
          // duplicate attribute name
          return TRI_ERROR_BAD_PARAMETER;
        }

        fields.insert(f);
        builder.add(it);
      }
    }

    if (fields.empty() || (numFields > 0 && (int)fields.size() != numFields)) {
      return TRI_ERROR_BAD_PARAMETER;
    }

    builder.close();
  } catch (std::bad_alloc const&) {
    return TRI_ERROR_OUT_OF_MEMORY;
  } catch (...) {
    return TRI_ERROR_INTERNAL;
  }
  return TRI_ERROR_NO_ERROR;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief process the unique flag and add it to the json
////////////////////////////////////////////////////////////////////////////////

static void ProcessIndexUniqueFlag(VPackSlice const definition, VPackBuilder& builder) {
  bool unique = basics::VelocyPackHelper::getBooleanValue(definition, "unique", false);
  builder.add("unique", VPackValue(unique));
}

////////////////////////////////////////////////////////////////////////////////
/// @brief process the sparse flag and add it to the json
////////////////////////////////////////////////////////////////////////////////

static void ProcessIndexSparseFlag(VPackSlice const definition,
                                   VPackBuilder& builder, bool create) {
  if (definition.hasKey("sparse")) {
    bool sparseBool =
        basics::VelocyPackHelper::getBooleanValue(definition, "sparse", false);
    builder.add("sparse", VPackValue(sparseBool));
  } else if (create) {
    // not set. now add a default value
    builder.add("sparse", VPackValue(false));
  }
}

////////////////////////////////////////////////////////////////////////////////
/// @brief process the deduplicate flag and add it to the json
////////////////////////////////////////////////////////////////////////////////

static void ProcessIndexDeduplicateFlag(VPackSlice const definition, VPackBuilder& builder) {
  bool dup = true;
  if (definition.hasKey("deduplicate")) {
    dup = basics::VelocyPackHelper::getBooleanValue(definition, "deduplicate", true);
  }
  builder.add("deduplicate", VPackValue(dup));
}

////////////////////////////////////////////////////////////////////////////////
/// @brief enhances the json of a hash index
////////////////////////////////////////////////////////////////////////////////

static int EnhanceJsonIndexHash(VPackSlice const definition,
                                VPackBuilder& builder, bool create) {
  int res = ProcessIndexFields(definition, builder, 0, create);
  if (res == TRI_ERROR_NO_ERROR) {
    ProcessIndexSparseFlag(definition, builder, create);
    ProcessIndexUniqueFlag(definition, builder);
    ProcessIndexDeduplicateFlag(definition, builder);
  }
  return res;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief enhances the json of a skiplist index
////////////////////////////////////////////////////////////////////////////////

static int EnhanceJsonIndexSkiplist(VPackSlice const definition,
                                    VPackBuilder& builder, bool create) {
  int res = ProcessIndexFields(definition, builder, 0, create);
  if (res == TRI_ERROR_NO_ERROR) {
    ProcessIndexSparseFlag(definition, builder, create);
    ProcessIndexUniqueFlag(definition, builder);
    ProcessIndexDeduplicateFlag(definition, builder);
  }
  return res;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief enhances the json of a Persistent index
////////////////////////////////////////////////////////////////////////////////

static int EnhanceJsonIndexPersistent(VPackSlice const definition,
                                      VPackBuilder& builder, bool create) {
  int res = ProcessIndexFields(definition, builder, 0, create);
  if (res == TRI_ERROR_NO_ERROR) {
    ProcessIndexSparseFlag(definition, builder, create);
    ProcessIndexUniqueFlag(definition, builder);
    ProcessIndexDeduplicateFlag(definition, builder);
  }
  return res;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief process the geojson flag and add it to the json
////////////////////////////////////////////////////////////////////////////////

static void ProcessIndexGeoJsonFlag(VPackSlice const definition, VPackBuilder& builder) {
  VPackSlice fieldsSlice = definition.get("fields");
  if (fieldsSlice.isArray() && fieldsSlice.length() == 1) {
    // only add geoJson for indexes with a single field (with needs to be an array)
    bool geoJson =
        basics::VelocyPackHelper::getBooleanValue(definition, "geoJson", false);
    builder.add("geoJson", VPackValue(geoJson));
  }
}

////////////////////////////////////////////////////////////////////////////////
/// @brief enhances the json of a geo1 index
////////////////////////////////////////////////////////////////////////////////

static int EnhanceJsonIndexGeo1(VPackSlice const definition,
                                VPackBuilder& builder, bool create) {
  int res = ProcessIndexFields(definition, builder, 1, create);
  if (res == TRI_ERROR_NO_ERROR) {
    if (ServerState::instance()->isCoordinator()) {
      builder.add("ignoreNull", VPackValue(true));
      builder.add("constraint", VPackValue(false));
    }
    builder.add("sparse", VPackValue(true));
    builder.add("unique", VPackValue(false));
    ProcessIndexGeoJsonFlag(definition, builder);
  }
  return res;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief enhances the json of a geo2 index
////////////////////////////////////////////////////////////////////////////////

static int EnhanceJsonIndexGeo2(VPackSlice const definition,
                                VPackBuilder& builder, bool create) {
  int res = ProcessIndexFields(definition, builder, 2, create);
  if (res == TRI_ERROR_NO_ERROR) {
    if (ServerState::instance()->isCoordinator()) {
      builder.add("ignoreNull", VPackValue(true));
      builder.add("constraint", VPackValue(false));
    }
    builder.add("sparse", VPackValue(true));
    builder.add("unique", VPackValue(false));
    ProcessIndexGeoJsonFlag(definition, builder);
  }
  return res;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief enhances the json of a fulltext index
////////////////////////////////////////////////////////////////////////////////

static int EnhanceJsonIndexFulltext(VPackSlice const definition,
                                    VPackBuilder& builder, bool create) {
  int res = ProcessIndexFields(definition, builder, 1, create);
  if (res == TRI_ERROR_NO_ERROR) {
    // hard-coded defaults
    builder.add("sparse", VPackValue(true));
    builder.add("unique", VPackValue(false));

    // handle "minLength" attribute
    int minWordLength = TRI_FULLTEXT_MIN_WORD_LENGTH_DEFAULT;
    VPackSlice minLength = definition.get("minLength");
    if (minLength.isNumber()) {
      minWordLength = minLength.getNumericValue<int>();
    } else if (!minLength.isNull() && !minLength.isNone()) {
      return TRI_ERROR_BAD_PARAMETER;
    }
    builder.add("minLength", VPackValue(minWordLength));
  }
  return res;
}

////////////////////////////////////////////////////////////////////////////////
/// @brief enhances the json of an index
////////////////////////////////////////////////////////////////////////////////

int MMFilesIndexFactory::enhanceIndexDefinition(VPackSlice const definition,
                                                VPackBuilder& enhanced, bool create,
                                                bool isCoordinator) const {
  // extract index type
  Index::IndexType type = Index::TRI_IDX_TYPE_UNKNOWN;
  VPackSlice current = definition.get("type");
  if (current.isString()) {
    std::string t = current.copyString();

    // rewrite type "geo" into either "geo1" or "geo2", depending on the number
    // of fields
    if (t == "geo") {
      t = "geo1";
      current = definition.get("fields");
      if (current.isArray() && current.length() == 2) {
        t = "geo2";
      }
    }
    type = Index::type(t);
  }

  if (type == Index::TRI_IDX_TYPE_UNKNOWN) {
    return TRI_ERROR_BAD_PARAMETER;
  }

  if (create) {
    if (type == Index::TRI_IDX_TYPE_PRIMARY_INDEX || type == Index::TRI_IDX_TYPE_EDGE_INDEX) {
      // creating these indexes yourself is forbidden
      return TRI_ERROR_FORBIDDEN;
    }
  }

  TRI_ASSERT(enhanced.isEmpty());
  int res = TRI_ERROR_INTERNAL;

  try {
    VPackObjectBuilder b(&enhanced);
    current = definition.get("id");
    uint64_t id = 0;
    if (current.isNumber()) {
      id = current.getNumericValue<uint64_t>();
    } else if (current.isString()) {
      id = basics::StringUtils::uint64(current.copyString());
    }
    if (id > 0) {
      enhanced.add("id", VPackValue(std::to_string(id)));
    }

    enhanced.add("type", VPackValue(Index::oldtypeName(type)));

    switch (type) {
      case Index::TRI_IDX_TYPE_PRIMARY_INDEX:
      case Index::TRI_IDX_TYPE_EDGE_INDEX: {
        break;
      }

      case Index::TRI_IDX_TYPE_GEO1_INDEX:
        res = EnhanceJsonIndexGeo1(definition, enhanced, create);
        break;

      case Index::TRI_IDX_TYPE_GEO2_INDEX:
        res = EnhanceJsonIndexGeo2(definition, enhanced, create);
        break;

      case Index::TRI_IDX_TYPE_HASH_INDEX:
        res = EnhanceJsonIndexHash(definition, enhanced, create);
        break;

      case Index::TRI_IDX_TYPE_SKIPLIST_INDEX:
        res = EnhanceJsonIndexSkiplist(definition, enhanced, create);
        break;

      case Index::TRI_IDX_TYPE_PERSISTENT_INDEX:
        res = EnhanceJsonIndexPersistent(definition, enhanced, create);
        break;

      case Index::TRI_IDX_TYPE_FULLTEXT_INDEX:
        res = EnhanceJsonIndexFulltext(definition, enhanced, create);
        break;

      case Index::TRI_IDX_TYPE_UNKNOWN:
      default: {
        res = TRI_ERROR_BAD_PARAMETER;
        break;
      }
    }
  } catch (basics::Exception const& ex) {
    return ex.code();
  } catch (std::exception const&) {
    return TRI_ERROR_OUT_OF_MEMORY;
  } catch (...) {
    return TRI_ERROR_INTERNAL;
  }

  return res;
}

// Creates an index object.
// It does not modify anything and does not insert things into
// the index. It's also safe to use in cluster case.
std::shared_ptr<Index> MMFilesIndexFactory::prepareIndexFromSlice(
    VPackSlice info, bool generateKey, LogicalCollection* col, bool isClusterConstructor) const {
  TRI_idx_iid_t iid = IndexFactory::validateSlice(info, generateKey, isClusterConstructor);

  // extract type
  VPackSlice value = info.get("type");

  if (!value.isString()) {
    THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_BAD_PARAMETER,
                                   "invalid index type definition");
  }

  std::string const typeString = value.copyString();
  if (typeString == "primary") {
    if (!isClusterConstructor) {
      // this indexes cannot be created directly
      THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL,
                                     "cannot create primary index");
    }
    return std::make_shared<MMFilesPrimaryIndex>(col);
  }
  if (typeString == "edge") {
    if (!isClusterConstructor) {
      // this indexes cannot be created directly
      THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL,
                                     "cannot create edge index");
    }
    return std::make_shared<MMFilesEdgeIndex>(iid, col);
  }
  if (typeString == "geo1" || typeString == "geo2" || typeString == "geo") {
    return std::make_shared<MMFilesGeoIndex>(iid, col, info);
  }
  if (typeString == "hash") {
    return std::make_shared<MMFilesHashIndex>(iid, col, info);
  }
  if (typeString == "skiplist") {
    return std::make_shared<MMFilesSkiplistIndex>(iid, col, info);
  }
  if (typeString == "persistent") {
    return std::make_shared<MMFilesPersistentIndex>(iid, col, info);
  }
  if (typeString == "fulltext") {
    return std::make_shared<MMFilesFulltextIndex>(iid, col, info);
  }

  THROW_ARANGO_EXCEPTION_MESSAGE(
      TRI_ERROR_NOT_IMPLEMENTED,
      std::string("invalid or unsupported index type '") + typeString + "'");
}

void MMFilesIndexFactory::fillSystemIndexes(arangodb::LogicalCollection* col,
                                            std::vector<std::shared_ptr<arangodb::Index>>& systemIndexes) const {
  // create primary index
  systemIndexes.emplace_back(std::make_shared<arangodb::MMFilesPrimaryIndex>(col));

  // create edges index
  if (col->type() == TRI_COL_TYPE_EDGE) {
    systemIndexes.emplace_back(std::make_shared<arangodb::MMFilesEdgeIndex>(1, col));
  }
}

std::vector<std::string> MMFilesIndexFactory::supportedIndexes() const {
  return std::vector<std::string>{"primary",    "edge", "hash",    "skiplist",
                                  "persistent", "geo",  "fulltext"};
}