////////////////////////////////////////////////////////////////////////////////
/// 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 Jan Steemann
////////////////////////////////////////////////////////////////////////////////

#include "MMFilesTransactionManager.h"
#include "Basics/ReadLocker.h"
#include "Basics/WriteLocker.h"

using namespace arangodb;

// register a list of failed transactions
void MMFilesTransactionManager::registerFailedTransactions(
    std::unordered_set<TRI_voc_tid_t> const& failedTransactions) {
  READ_LOCKER(allTransactionsLocker, _allTransactionsLock);

  for (auto const& it : failedTransactions) {
    size_t bucket = getBucket(it);

    WRITE_LOCKER(locker, _transactions[bucket]._lock);

    _transactions[bucket]._failedTransactions.emplace(it);
  }
}

// unregister a list of failed transactions
void MMFilesTransactionManager::unregisterFailedTransactions(
    std::unordered_set<TRI_voc_tid_t> const& failedTransactions) {
  READ_LOCKER(allTransactionsLocker, _allTransactionsLock);

  for (size_t bucket = 0; bucket < numBuckets; ++bucket) {
    WRITE_LOCKER(locker, _transactions[bucket]._lock);

    std::for_each(failedTransactions.begin(), failedTransactions.end(), [&](TRI_voc_tid_t id) {
      _transactions[bucket]._failedTransactions.erase(id);
    });
  }
}

void MMFilesTransactionManager::registerTransaction(TRI_voc_tid_t transactionId,
                                                    std::unique_ptr<TransactionData> data) {
  TRI_ASSERT(data != nullptr);

  size_t bucket = getBucket(transactionId);
  READ_LOCKER(allTransactionsLocker, _allTransactionsLock);

  WRITE_LOCKER(writeLocker, _transactions[bucket]._lock);

  // insert into currently running list of transactions
  _transactions[bucket]._activeTransactions.emplace(transactionId, std::move(data));
}

// unregisters a transaction
void MMFilesTransactionManager::unregisterTransaction(TRI_voc_tid_t transactionId,
                                                      bool markAsFailed) {
  size_t bucket = getBucket(transactionId);
  READ_LOCKER(allTransactionsLocker, _allTransactionsLock);

  WRITE_LOCKER(writeLocker, _transactions[bucket]._lock);

  _transactions[bucket]._activeTransactions.erase(transactionId);

  if (markAsFailed) {
    _transactions[bucket]._failedTransactions.emplace(transactionId);
  }
}

// return the set of failed transactions
std::unordered_set<TRI_voc_tid_t> MMFilesTransactionManager::getFailedTransactions() {
  std::unordered_set<TRI_voc_tid_t> failedTransactions;

  {
    WRITE_LOCKER(allTransactionsLocker, _allTransactionsLock);

    for (size_t bucket = 0; bucket < numBuckets; ++bucket) {
      READ_LOCKER(locker, _transactions[bucket]._lock);

      for (auto const& it : _transactions[bucket]._failedTransactions) {
        failedTransactions.emplace(it);
      }
    }
  }

  return failedTransactions;
}

void MMFilesTransactionManager::iterateActiveTransactions(
    std::function<void(TRI_voc_tid_t, TransactionData const*)> const& callback) {
  WRITE_LOCKER(allTransactionsLocker, _allTransactionsLock);

  // iterate over all active transactions
  for (size_t bucket = 0; bucket < numBuckets; ++bucket) {
    READ_LOCKER(locker, _transactions[bucket]._lock);

    for (auto const& it : _transactions[bucket]._activeTransactions) {
      callback(it.first, it.second.get());
    }
  }
}

uint64_t MMFilesTransactionManager::getActiveTransactionCount() {
  WRITE_LOCKER(allTransactionsLocker, _allTransactionsLock);

  uint64_t count = 0;
  // iterate over all active transactions
  for (size_t bucket = 0; bucket < numBuckets; ++bucket) {
    READ_LOCKER(locker, _transactions[bucket]._lock);
    count += _transactions[bucket]._activeTransactions.size();
  }
  return count;
}