//////////////////////////////////////////////////////////////////////////////
/// 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 Lars Maier
////////////////////////////////////////////////////////////////////////////////

#include "IResearchCommon.h"
#include "IResearchDocument.h"
#include "IResearchFeature.h"
#include "IResearchFilterFactory.h"
#include "IResearchLink.h"
#include "IResearchLinkHelper.h"

#include <velocypack/Iterator.h>

#include "Logger/LogMacros.h"
#include "RestServer/DatabaseFeature.h"
#include "RestServer/DatabasePathFeature.h"
#include "RestServer/FlushFeature.h"
#include "StorageEngine/StorageEngine.h"
#include "StorageEngine/TransactionState.h"
#include "Transaction/Methods.h"
#include "Transaction/StandaloneContext.h"
#include "Utils/ExecContext.h"
#include "VocBase/LogicalCollection.h"
#include "VocBase/LogicalView.h"
#include "VocBase/vocbase.h"

#include "IResearchView.h"
#include "IResearchViewSingleServer.h"

namespace arangodb {
namespace iresearch {

/*static*/ std::shared_ptr<LogicalView> IResearchViewSingleServer::make(
    TRI_vocbase_t& vocbase, arangodb::velocypack::Slice const& info, bool isNew,
    uint64_t planVersion, LogicalView::PreCommitCallback const& preCommit /*= {}*/
) {
  auto& properties = info.isObject() ? info : emptyObjectSlice();  // if no 'info' then assume defaults
  std::string error;

  bool hasLinks = properties.hasKey(StaticStrings::LinksField);

  if (hasLinks && isNew) {
    arangodb::velocypack::ObjectIterator iterator{info.get(StaticStrings::LinksField)};

    for (auto itr : iterator) {
      if (!itr.key.isString()) {
        continue;  // not a resolvable collection (invalid jSON)
      }

      auto colname = itr.key.copyString();

      // check if the collection exists
      auto collection = vocbase.lookupCollection(colname);
      if (!collection) {
        LOG_TOPIC("af7b2", WARN, arangodb::iresearch::TOPIC)
            << "Could not create view: "
            << "Collection not found: " << colname;
        TRI_set_errno(TRI_ERROR_ARANGO_DATA_SOURCE_NOT_FOUND);
        return nullptr;
      }

      // check if the collection can be used
      if (arangodb::ExecContext::CURRENT &&
          !arangodb::ExecContext::CURRENT->canUseCollection(vocbase.name(),
                                                            collection->name(),
                                                            arangodb::auth::Level::RO)) {
        return nullptr;
      }
    }
  }

  auto view = IResearchView::make(vocbase, info, isNew, planVersion, preCommit);

  // create links - "on a best-effort basis"
  if (properties.hasKey("links") && isNew) {
    std::unordered_set<TRI_voc_cid_t> collections;
    auto result = IResearchLinkHelper::updateLinks(collections, vocbase, *view.get(),
                                                   properties.get("links"));

    if (result.fail()) {
      TRI_set_errno(result.errorNumber());
      LOG_TOPIC("73836", ERR, arangodb::iresearch::TOPIC)
          << "Failure to construct links on new view in database '"
          << vocbase.id() << "', error: " << error;
    }
  }

  return view;
}

}  // namespace iresearch
}  // namespace arangodb