/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 **/

#ifndef QUICKSTEP_RELATIONAL_OPERATORS_SELECT_OPERATOR_HPP_
#define QUICKSTEP_RELATIONAL_OPERATORS_SELECT_OPERATOR_HPP_

#include <memory>
#include <string>
#include <utility>
#include <vector>

#include "catalog/CatalogRelation.hpp"
#include "catalog/CatalogTypedefs.hpp"

#ifdef QUICKSTEP_HAVE_LIBNUMA
#include "catalog/NUMAPlacementScheme.hpp"
#endif

#include "catalog/PartitionSchemeHeader.hpp"
#include "query_execution/QueryContext.hpp"
#include "relational_operators/RelationalOperator.hpp"
#include "relational_operators/WorkOrder.hpp"
#include "storage/StorageBlockInfo.hpp"
#include "utility/Macros.hpp"

#include "glog/logging.h"

#include "tmb/id_typedefs.h"

namespace tmb { class MessageBus; }

namespace quickstep {

class CatalogRelationSchema;
class InsertDestination;
class Predicate;
class Scalar;
class StorageManager;
class WorkOrderProtosContainer;
class WorkOrdersContainer;

namespace serialization { class WorkOrder; }

/** \addtogroup RelationalOperators
 *  @{
 */

/**
 * @brief An operator which performs simple selection over a relation.
 **/
class SelectOperator : public RelationalOperator {
 public:
  /**
   * @brief Constructor for selection with arbitrary expressions in projection
   *        list.
   *
   * @param query_id The ID of the query to which this operator belongs.
   * @param input_relation The relation to perform selection over.
   * @param output_relation The output relation.
   * @param output_destination_index The index of the InsertDestination in the
   *        QueryContext to insert the selection results.
   * @param predicate_index The index of selection predicate in QueryContext.
   *        All tuples matching pred will be selected (or kInvalidPredicateId to
   *        select all tuples).
   * @param selection_index The group index of Scalars in QueryContext, which
   *        will be evaluated to project input tuples.
   * @param input_relation_is_stored If input_relation is a stored relation and
   *        is fully available to the operator before it can start generating
   *        workorders.
   **/
  SelectOperator(
      const std::size_t query_id,
      const CatalogRelation &input_relation,
      const CatalogRelation &output_relation,
      const QueryContext::insert_destination_id output_destination_index,
      const QueryContext::predicate_id predicate_index,
      const QueryContext::scalar_group_id selection_index,
      const bool input_relation_is_stored)
      : RelationalOperator(query_id),
        input_relation_(input_relation),
        output_relation_(output_relation),
        output_destination_index_(output_destination_index),
        predicate_index_(predicate_index),
        selection_index_(selection_index),
        input_relation_block_ids_(input_relation_is_stored
                                      ? input_relation.getBlocksSnapshot()
                                      : std::vector<block_id>()),
        num_workorders_generated_(0),
        simple_projection_(false),
        input_relation_is_stored_(input_relation_is_stored),
        started_(false) {
#ifdef QUICKSTEP_HAVE_LIBNUMA
    placement_scheme_ = input_relation.getNUMAPlacementSchemePtr();
#endif
    if (input_relation.hasPartitionScheme()) {
      const PartitionScheme &part_scheme = input_relation.getPartitionScheme();
      const PartitionSchemeHeader &part_scheme_header = part_scheme.getPartitionSchemeHeader();
      const std::size_t num_partitions = part_scheme_header.getNumPartitions();
      input_relation_block_ids_in_partition_.resize(num_partitions);
      num_workorders_generated_in_partition_.resize(num_partitions);
      num_workorders_generated_in_partition_.assign(num_partitions, 0);
      for (std::size_t part_id = 0; part_id < num_partitions; ++part_id) {
        if (input_relation_is_stored) {
          input_relation_block_ids_in_partition_[part_id] =
              part_scheme.getBlocksInPartition(part_id);
        } else {
          input_relation_block_ids_in_partition_[part_id] =
              std::vector<block_id>();
        }
      }
    }
  }

  /**
   * @brief Constructor for selection with simple projection of attributes.
   *
   * @note selection_index_ is invalid, and will not be used for projection.
   *
   * @param query_id The ID of the query to which this operator belongs.
   * @param input_relation The relation to perform selection over.
   * @param output_relation The output relation.
   * @param output_destination_index The index of the InsertDestination in the
   *        QueryContext to insert the selection results.
   * @param selection A projection list of attribute IDs. The operator takes
   *        ownership of selection.
   * @param predicate_index The index of selection predicate in QueryContext.
   *        All tuples matching pred will be selected (or kInvalidPredicateId to
   *        select all tuples).
   * @param input_relation_is_stored If input_relation is a stored relation and
   *        is fully available to the operator before it can start generating
   *        workorders.
   **/
  SelectOperator(
      const std::size_t query_id,
      const CatalogRelation &input_relation,
      const CatalogRelation &output_relation,
      const QueryContext::insert_destination_id output_destination_index,
      const QueryContext::predicate_id predicate_index,
      std::vector<attribute_id> &&selection,
      const bool input_relation_is_stored)
      : RelationalOperator(query_id),
        input_relation_(input_relation),
        output_relation_(output_relation),
        output_destination_index_(output_destination_index),
        predicate_index_(predicate_index),
        selection_index_(QueryContext::kInvalidScalarGroupId),
        simple_selection_(std::move(selection)),
        input_relation_block_ids_(input_relation_is_stored
                                      ? input_relation.getBlocksSnapshot()
                                      : std::vector<block_id>()),
        num_workorders_generated_(0),
        simple_projection_(true),
        input_relation_is_stored_(input_relation_is_stored),
        started_(false) {
#ifdef QUICKSTEP_HAVE_LIBNUMA
    placement_scheme_ = input_relation.getNUMAPlacementSchemePtr();
#endif
    if (input_relation.hasPartitionScheme()) {
      const PartitionScheme &part_scheme = input_relation.getPartitionScheme();
      const PartitionSchemeHeader &part_scheme_header = part_scheme.getPartitionSchemeHeader();
      const std::size_t num_partitions = part_scheme_header.getNumPartitions();
      input_relation_block_ids_in_partition_.resize(num_partitions);
      num_workorders_generated_in_partition_.resize(num_partitions);
      num_workorders_generated_in_partition_.assign(num_partitions, 0);
      for (std::size_t part_id = 0; part_id < num_partitions; ++part_id) {
        if (input_relation_is_stored) {
          input_relation_block_ids_in_partition_[part_id] =
              part_scheme.getBlocksInPartition(part_id);
        } else {
          input_relation_block_ids_in_partition_[part_id] =
              std::vector<block_id>();
        }
      }
    }
  }

  ~SelectOperator() override {}

  std::string getName() const override {
    return "SelectOperator";
  }

  const CatalogRelation& input_relation() const {
    return input_relation_;
  }

  bool getAllWorkOrders(WorkOrdersContainer *container,
                        QueryContext *query_context,
                        StorageManager *storage_manager,
                        const tmb::client_id scheduler_client_id,
                        tmb::MessageBus *bus) override;

  bool getAllWorkOrderProtos(WorkOrderProtosContainer *container) override;

  void feedInputBlock(const block_id input_block_id, const relation_id input_relation_id) override {
    if (input_relation_.hasPartitionScheme()) {
      const partition_id part_id =
          input_relation_.getPartitionScheme().getPartitionForBlock(input_block_id);
      input_relation_block_ids_in_partition_[part_id].push_back(input_block_id);
    } else {
      input_relation_block_ids_.push_back(input_block_id);
    }
  }

  // TODO(gerald): Each call to getPartitionForBlock() involves grabbing shared
  // locks on each partition's mutex, checking if the block belongs to the
  // partition. Instead, we can provide a method getPartitionsForBlocks() which
  // accepts a list of blocks and returns corresponding list of their partition IDs.
  // Therefore, once we grab a lock for a partition, we search for all the blocks
  // and then release the lock.
  void feedInputBlocks(const relation_id rel_id, std::vector<block_id> *partially_filled_blocks) override {
    if (input_relation_.hasPartitionScheme()) {
      for (auto it = partially_filled_blocks->begin(); it != partially_filled_blocks->end(); ++it) {
        const partition_id part_id = input_relation_.getPartitionScheme().getPartitionForBlock((*it));
        input_relation_block_ids_in_partition_[part_id].insert(input_relation_block_ids_in_partition_[part_id].end(),
                                                               *it);
      }
    } else {
      input_relation_block_ids_.insert(input_relation_block_ids_.end(),
                                       partially_filled_blocks->begin(),
                                       partially_filled_blocks->end());
    }
  }

  QueryContext::insert_destination_id getInsertDestinationID() const override {
    return output_destination_index_;
  }

  const relation_id getOutputRelationID() const override {
    return output_relation_.getID();
  }

  void addWorkOrders(WorkOrdersContainer *container,
                     StorageManager *storage_manager,
                     const Predicate *predicate,
                     const std::vector<std::unique_ptr<const Scalar>> *selection,
                     InsertDestination *output_destination);

  void addPartitionAwareWorkOrders(WorkOrdersContainer *container,
                                   StorageManager *storage_manager,
                                   const Predicate *predicate,
                                   const std::vector<std::unique_ptr<const Scalar>> *selection,
                                   InsertDestination *output_destination);

 private:
  /**
   * @brief Create Work Order proto.
   *
   * @param block The block id used in the Work Order.
   **/
  serialization::WorkOrder* createWorkOrderProto(const block_id block);

  const CatalogRelation &input_relation_;
  const CatalogRelation &output_relation_;
  const QueryContext::insert_destination_id output_destination_index_;
  const QueryContext::predicate_id predicate_index_;

  const QueryContext::scalar_group_id selection_index_;
  const std::vector<attribute_id> simple_selection_;

  std::vector<block_id> input_relation_block_ids_;
  // A vector of vectors V where V[i] indicates the list of block IDs of the
  // input relation that belong to the partition i.
  std::vector<std::vector<block_id>> input_relation_block_ids_in_partition_;

  // A single workorder is generated for each block of input relation.
  std::vector<block_id>::size_type num_workorders_generated_;
  // A single workorder is generated for each block in each partition of input relation.
  std::vector<std::size_t> num_workorders_generated_in_partition_;

  const bool simple_projection_;
  const bool input_relation_is_stored_;
#ifdef QUICKSTEP_HAVE_LIBNUMA
  const NUMAPlacementScheme *placement_scheme_;
#endif
  bool started_;

  DISALLOW_COPY_AND_ASSIGN(SelectOperator);
};

/**
 * @brief A WorkOrder produced by SelectOperator.
 **/
class SelectWorkOrder : public WorkOrder {
 public:
  /**
   * @brief Constructor.
   *
   * @note Reference parameter selection is NOT owned by this class and must
   *       remain valid until after execute() is called.
   *
   * @param query_id The ID of the query to which this WorkOrder belongs.
   * @param input_relation The relation to perform selection over.
   * @param input_block_id The block id.
   * @param predicate All tuples matching \c predicate will be selected (or NULL
   *        to select all tuples).
   * @param simple_projection Whether the Select is simple.
   * @param simple_selection The list of attribute ids, used if \c
   *        simple_projection is true.
   * @param selection A list of Scalars which will be evaluated to project
   *        input tuples, used if \c simple_projection is false.
   * @param output_destination The InsertDestination to insert the selection
   *        results.
   * @param storage_manager The StorageManager to use.
   **/
  SelectWorkOrder(const std::size_t query_id,
                  const CatalogRelationSchema &input_relation,
                  const block_id input_block_id,
                  const Predicate *predicate,
                  const bool simple_projection,
                  const std::vector<attribute_id> &simple_selection,
                  const std::vector<std::unique_ptr<const Scalar>> *selection,
                  InsertDestination *output_destination,
                  StorageManager *storage_manager,
                  const numa_node_id numa_node = 0)
      : WorkOrder(query_id),
        input_relation_(input_relation),
        input_block_id_(input_block_id),
        predicate_(predicate),
        simple_projection_(simple_projection),
        simple_selection_(simple_selection),
        selection_(selection),
        output_destination_(DCHECK_NOTNULL(output_destination)),
        storage_manager_(DCHECK_NOTNULL(storage_manager)) {
    preferred_numa_nodes_.push_back(numa_node);
  }

  /**
   * @brief Constructor for the distributed version.
   *
   * @note Reference parameter selection is NOT owned by this class and must
   *       remain valid until after execute() is called.
   *
   * @param query_id The ID of the query to which this WorkOrder belongs.
   * @param input_relation The relation to perform selection over.
   * @param input_block_id The block id.
   * @param predicate All tuples matching \c predicate will be selected (or NULL
   *        to select all tuples).
   * @param simple_projection Whether the Select is simple.
   * @param simple_selection The list of attribute ids, used if \c
   *        simple_projection is true.
   * @param selection A list of Scalars which will be evaluated to project
   *        input tuples, used if \c simple_projection is false.
   * @param output_destination The InsertDestination to insert the selection
   *        results.
   * @param storage_manager The StorageManager to use.
   **/
  SelectWorkOrder(const std::size_t query_id,
                  const CatalogRelationSchema &input_relation,
                  const block_id input_block_id,
                  const Predicate *predicate,
                  const bool simple_projection,
                  std::vector<attribute_id> &&simple_selection,
                  const std::vector<std::unique_ptr<const Scalar>> *selection,
                  InsertDestination *output_destination,
                  StorageManager *storage_manager,
                  const numa_node_id numa_node = 0)
      : WorkOrder(query_id),
        input_relation_(input_relation),
        input_block_id_(input_block_id),
        predicate_(predicate),
        simple_projection_(simple_projection),
        simple_selection_(std::move(simple_selection)),
        selection_(selection),
        output_destination_(DCHECK_NOTNULL(output_destination)),
        storage_manager_(DCHECK_NOTNULL(storage_manager)) {
    preferred_numa_nodes_.push_back(numa_node);
  }

  ~SelectWorkOrder() override {}

  /**
   * @exception TupleTooLargeForBlock A tuple produced by this selection was
   *            too large to insert into an empty block provided by
   *            output_destination_index_ in query_context. Select may be
   *            partially complete (with some tuples inserted into the
   *            destination) when this exception is thrown, causing potential
   *            inconsistency.
   **/
  void execute() override;

 private:
  const CatalogRelationSchema &input_relation_;
  const block_id input_block_id_;
  const Predicate *predicate_;

  const bool simple_projection_;
  const std::vector<attribute_id> simple_selection_;
  const std::vector<std::unique_ptr<const Scalar>> *selection_;

  InsertDestination *output_destination_;
  StorageManager *storage_manager_;

  DISALLOW_COPY_AND_ASSIGN(SelectWorkOrder);
};

/** @} */

}  // namespace quickstep

#endif  // QUICKSTEP_RELATIONAL_OPERATORS_SELECT_OPERATOR_HPP_