/**
 * 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_DELETE_OPERATOR_HPP_
#define QUICKSTEP_RELATIONAL_OPERATORS_DELETE_OPERATOR_HPP_

#include <cstddef>
#include <string>
#include <vector>

#include "catalog/CatalogRelation.hpp"
#include "catalog/CatalogTypedefs.hpp"
#include "catalog/PartitionScheme.hpp"
#include "query_execution/QueryContext.hpp"
#include "query_execution/QueryExecutionTypedefs.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 Predicate;
class StorageManager;
class WorkOrderProtosContainer;
class WorkOrdersContainer;

namespace serialization { class WorkOrder; }

/** \addtogroup RelationalOperators
 *  @{
 */

/**
 * @brief An operator which deletes some tuples.
 **/
class DeleteOperator : public RelationalOperator {
 public:
  /**
   * @brief Constructor.
   *
   * @param query_id The ID of the query to which this operator belongs.
   * @param relation The relation to perform the DELETE over.
   * @param predicate_index The index of Predicate in QueryContext. All tuples
   *        matching pred will be deleted (If kInvalidPredicateId, then all
   *        tuples will be deleted).
   * @param relation_is_stored If relation is a stored relation and is fully
   *        available to the operator before it can start generating workorders.
   **/
  DeleteOperator(const std::size_t query_id,
                 const CatalogRelation &relation,
                 const QueryContext::predicate_id predicate_index,
                 const bool relation_is_stored)
      : RelationalOperator(query_id, relation.getNumPartitions(), false /* has_repartition */,
                           relation.getNumPartitions()),
        relation_(relation),
        predicate_index_(predicate_index),
        relation_is_stored_(relation_is_stored),
        started_(false),
        relation_block_ids_(num_partitions_),
        num_workorders_generated_(num_partitions_) {
    if (relation_is_stored) {
      if (relation.hasPartitionScheme()) {
        const PartitionScheme &part_scheme = *relation.getPartitionScheme();

        for (partition_id part_id = 0; part_id < num_partitions_; ++part_id) {
          relation_block_ids_[part_id] = part_scheme.getBlocksInPartition(part_id);
        }
      } else {
        DCHECK_EQ(1u, num_partitions_);
        relation_block_ids_[0] = relation.getBlocksSnapshot();
      }
    }
  }

  ~DeleteOperator() override {}

  OperatorType getOperatorType() const override {
    return kDelete;
  }

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

  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;

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

  void feedInputBlock(const block_id input_block_id, const relation_id input_relation_id,
                      const partition_id part_id) override {
    DCHECK(!relation_is_stored_);
    relation_block_ids_[part_id].push_back(input_block_id);
  }

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

  const CatalogRelation &relation_;
  const QueryContext::predicate_id predicate_index_;

  const bool relation_is_stored_;

  bool started_;

  std::vector<std::vector<block_id>> relation_block_ids_;
  std::vector<std::size_t> num_workorders_generated_;

  DISALLOW_COPY_AND_ASSIGN(DeleteOperator);
};

/**
 * @brief A WorkOrder produced by DeleteOperator.
 **/
class DeleteWorkOrder : public WorkOrder {
 public:
  /**
   * @brief Constructor.
   *
   * @param query_id The ID of the query to which this workorder belongs.
   * @param input_relation The relation to perform the DELETE over.
   * @param part_id The partition id.
   * @param input_block_id The block Id.
   * @param predicate All tuples matching \c predicate will be deleted (If
   *        NULL, then all tuples will be deleted).
   * @param storage_manager The StorageManager to use.
   * @param delete_operator_index The index of the Delete Operator in the query
   *        plan DAG.
   * @param scheduler_client_id The TMB client ID of the scheduler thread.
   * @param bus A pointer to the TMB.
   **/
  DeleteWorkOrder(const std::size_t query_id,
                  const CatalogRelationSchema &input_relation,
                  const partition_id part_id,
                  const block_id input_block_id,
                  const Predicate *predicate,
                  StorageManager *storage_manager,
                  const std::size_t delete_operator_index,
                  const tmb::client_id scheduler_client_id,
                  MessageBus *bus)
      : WorkOrder(query_id, part_id),
        input_relation_(input_relation),
        input_block_id_(input_block_id),
        predicate_(predicate),
        storage_manager_(DCHECK_NOTNULL(storage_manager)),
        delete_operator_index_(delete_operator_index),
        scheduler_client_id_(scheduler_client_id),
        bus_(DCHECK_NOTNULL(bus)) {}

  ~DeleteWorkOrder() override {}

  void execute() override;

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

  StorageManager *storage_manager_;

  const std::size_t delete_operator_index_;

  const tmb::client_id scheduler_client_id_;
  MessageBus *bus_;

  DISALLOW_COPY_AND_ASSIGN(DeleteWorkOrder);
};

/** @} */

}  // namespace quickstep

#endif  // QUICKSTEP_RELATIONAL_OPERATORS_DELETE_OPERATOR_HPP_