////////////////////////////////////////////////////////////////////////////////
/// 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 Heiko Kernbach
////////////////////////////////////////////////////////////////////////////////

#include "RowFetcherHelper.h"
#include "gtest/gtest.h"

#include "Aql/AqlItemBlock.h"
#include "Aql/ExecutorInfos.h"
#include "Aql/InputAqlItemRow.h"
#include "Aql/LimitExecutor.h"
#include "Aql/ResourceUsage.h"
#include "Aql/SingleRowFetcher.h"

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

using namespace arangodb;
using namespace arangodb::aql;

namespace arangodb {
namespace tests {
namespace aql {

class LimitExecutorTest : public ::testing::Test {
 protected:
  ExecutionState state;
  ResourceMonitor monitor;
  AqlItemBlockManager itemBlockManager;
  SharedAqlItemBlockPtr block;
  std::shared_ptr<const std::unordered_set<RegisterId>> outputRegisters;
  std::shared_ptr<const std::unordered_set<RegisterId>> registersToKeep;

  // Special parameters:
  // 4th offset
  // 5th limit
  // 6th fullCount
  // 7th queryDepth

  LimitExecutorTest()
      : itemBlockManager(&monitor),
        block(new AqlItemBlock(itemBlockManager, 1000, 1)),
        outputRegisters(std::make_shared<const std::unordered_set<RegisterId>>(
            std::initializer_list<RegisterId>{})),
        registersToKeep(std::make_shared<const std::unordered_set<RegisterId>>(
            std::initializer_list<RegisterId>{0})) {}
};

TEST_F(LimitExecutorTest, no_rows_upstream_the_producer_doesnt_wait) {
  LimitExecutorInfos infos(1, 1, {}, {0}, 0, 1, true);
  VPackBuilder input;

  SingleRowFetcherHelper<false> fetcher(input.steal(), false);
  LimitExecutor testee(fetcher, infos);
  LimitStats stats{};

  OutputAqlItemRow result{std::move(block), outputRegisters, registersToKeep,
                          infos.registersToClear()};
  std::tie(state, stats) = testee.produceRows(result);
  ASSERT_TRUE(state == ExecutionState::DONE);
  ASSERT_TRUE(!result.produced());
  ASSERT_TRUE(stats.getFullCount() == 0);
}

TEST_F(LimitExecutorTest, now_rows_upstream_the_producer_waits) {
  LimitExecutorInfos infos(1, 1, {}, {0}, 0, 1, true);
  VPackBuilder input;

  SingleRowFetcherHelper<false> fetcher(input.steal(), true);
  LimitExecutor testee(fetcher, infos);
  LimitStats stats{};

  OutputAqlItemRow result{std::move(block), outputRegisters, registersToKeep,
                          infos.registersToClear()};
  std::tie(state, stats) = testee.produceRows(result);
  ASSERT_TRUE(state == ExecutionState::WAITING);
  ASSERT_TRUE(!result.produced());
  ASSERT_TRUE(stats.getFullCount() == 0);

  std::tie(state, stats) = testee.produceRows(result);
  ASSERT_TRUE(state == ExecutionState::DONE);
  ASSERT_TRUE(!result.produced());
  ASSERT_TRUE(stats.getFullCount() == 0);
}

TEST_F(LimitExecutorTest, rows_upstream_the_producer_doesnt_wait_limit_1_offset_0_fullcount_false) {
  auto input = VPackParser::fromJson("[ [1], [2], [3], [4] ]");
  LimitExecutorInfos infos(1, 1, {}, {0}, 0, 1, false);
  SingleRowFetcherHelper<false> fetcher(input->steal(), false);
  LimitExecutor testee(fetcher, infos);
  LimitStats stats{};

  OutputAqlItemRow row{std::move(block), outputRegisters, registersToKeep,
                       infos.registersToClear()};

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(row.produced());
  row.advanceRow();

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(state == ExecutionState::DONE);
  ASSERT_TRUE(!row.produced());
}

TEST_F(LimitExecutorTest, rows_upstream_the_producer_doesnt_wait_limit_1_offset_0_fullcount_true) {
  auto input = VPackParser::fromJson("[ [1], [2], [3], [4] ]");
  LimitExecutorInfos infos(1, 1, {}, {0}, 0, 1, true);
  SingleRowFetcherHelper<false> fetcher(input->steal(), false);
  LimitExecutor testee(fetcher, infos);
  LimitStats stats{};

  OutputAqlItemRow row{std::move(block), outputRegisters, registersToKeep,
                       infos.registersToClear()};

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(state == ExecutionState::HASMORE);
  ASSERT_TRUE(row.produced());

  row.advanceRow();

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(!row.produced());
  ASSERT_TRUE(state == ExecutionState::DONE);
  ASSERT_TRUE(stats.getFullCount() == 3);

  auto block = row.stealBlock();
  AqlValue value = block->getValue(0, 0);
  ASSERT_TRUE(value.isNumber());
  ASSERT_TRUE(value.toInt64() == 1);
}

TEST_F(LimitExecutorTest, rows_upstream_the_producer_doesnt_wait_limit_1_offset_1_fullcount_true) {
  auto input = VPackParser::fromJson("[ [1], [2], [3], [4] ]");
  LimitExecutorInfos infos(1, 1, {}, {0}, 1, 1, true);
  SingleRowFetcherHelper<false> fetcher(input->steal(), false);
  LimitExecutor testee(fetcher, infos);
  LimitStats stats{};

  OutputAqlItemRow row{std::move(block), outputRegisters, registersToKeep,
                       infos.registersToClear()};

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(state == ExecutionState::HASMORE);
  ASSERT_TRUE(row.produced());

  row.advanceRow();

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(!row.produced());
  ASSERT_TRUE(state == ExecutionState::DONE);
  ASSERT_TRUE(stats.getFullCount() == 2);

  auto block = row.stealBlock();
  AqlValue value = block->getValue(0, 0);
  ASSERT_TRUE(value.isNumber());
  ASSERT_TRUE(value.toInt64() == 2);
}

TEST_F(LimitExecutorTest, rows_upstream_the_producer_waits_limit_1_offset_0_fullcount_false) {
  auto input = VPackParser::fromJson("[ [1], [2], [3], [4] ]");
  LimitExecutorInfos infos(1, 1, {}, {0}, 0, 1, false);
  SingleRowFetcherHelper<false> fetcher(input->steal(), true);
  LimitExecutor testee(fetcher, infos);
  LimitStats stats{};

  OutputAqlItemRow row{std::move(block), outputRegisters, registersToKeep,
                       infos.registersToClear()};

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(state == ExecutionState::WAITING);
  ASSERT_TRUE(!row.produced());

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(state == ExecutionState::DONE);
  ASSERT_TRUE(row.produced());

  row.advanceRow();

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(state == ExecutionState::DONE);
  ASSERT_TRUE(!row.produced());

  auto block = row.stealBlock();
  AqlValue value = block->getValue(0, 0);
  ASSERT_TRUE(value.isNumber());
  ASSERT_TRUE(value.toInt64() == 1);
}

TEST_F(LimitExecutorTest, rows_upstream_the_producer_waits_limit_1_offset_0_fullcount_true) {
  auto input = VPackParser::fromJson("[ [1], [2], [3], [4] ]");
  LimitExecutorInfos infos(1, 1, {}, {0}, 0, 1, true);
  SingleRowFetcherHelper<false> fetcher(input->steal(), true);
  LimitExecutor testee(fetcher, infos);
  LimitStats stats{};

  OutputAqlItemRow row{std::move(block), outputRegisters, registersToKeep,
                       infos.registersToClear()};

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(state == ExecutionState::WAITING);
  ASSERT_TRUE(!row.produced());

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(state == ExecutionState::HASMORE);
  ASSERT_TRUE(row.produced());

  row.advanceRow();

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(state == ExecutionState::WAITING);
  ASSERT_TRUE(!row.produced());

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(state == ExecutionState::WAITING);
  ASSERT_TRUE(!row.produced());

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(state == ExecutionState::WAITING);
  ASSERT_TRUE(!row.produced());

  std::tie(state, stats) = testee.produceRows(row);
  ASSERT_TRUE(state == ExecutionState::DONE);
  ASSERT_TRUE(stats.getFullCount() == 1);
  ASSERT_TRUE(!row.produced());

  auto block = row.stealBlock();
  AqlValue value = block->getValue(0, 0);
  ASSERT_TRUE(value.isNumber());
  ASSERT_TRUE(value.toInt64() == 1);
}

}  // namespace aql
}  // namespace tests
}  // namespace arangodb