/*
    * 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.
   */
  
  package org.apache.shardingsphere.proxy.backend.response.header.update;
  
  import lombok.AccessLevel;
  import lombok.Getter;
  import org.apache.shardingsphere.infra.executor.sql.execute.result.update.UpdateResult;
  import org.apache.shardingsphere.proxy.backend.response.header.ResponseHeader;
  import org.apache.shardingsphere.sql.parser.sql.common.statement.SQLStatement;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.LinkedList;
  import java.util.List;
  
  /**
   * Update response header.
   */
  @Getter
  public final class UpdateResponseHeader implements ResponseHeader {
      
      private final SQLStatement sqlStatement;
      
      private final long lastInsertId;
      
      @Getter(AccessLevel.NONE)
      private final Collection<Integer> updateCounts = new LinkedList<>();
      
      private long updateCount;
      
      public UpdateResponseHeader(final SQLStatement sqlStatement) {
          this(sqlStatement, Collections.emptyList(), Collections.emptyList());
      }
      
      public UpdateResponseHeader(final SQLStatement sqlStatement, final Collection<UpdateResult> updateResults) {
          this(sqlStatement, updateResults, Collections.emptyList());
      }
      
      public UpdateResponseHeader(final SQLStatement sqlStatement, final Collection<UpdateResult> updateResults, final Collection<Comparable<?>> autoIncrementGeneratedValues) {
          this.sqlStatement = sqlStatement;
          lastInsertId = getLastInsertId(updateResults, autoIncrementGeneratedValues);
          updateCount = updateResults.iterator().hasNext() ? updateResults.iterator().next().getUpdateCount() : 0;
          for (UpdateResult each : updateResults) {
              updateCounts.add(each.getUpdateCount());
          }
      }
      
      private long getLastInsertId(final Collection<UpdateResult> updateResults, final Collection<Comparable<?>> autoIncrementGeneratedValues) {
          List<Long> lastInsertIds = new ArrayList<>(updateResults.size() + autoIncrementGeneratedValues.size());
          for (UpdateResult each : updateResults) {
              if (each.getLastInsertId() > 0L) {
                  lastInsertIds.add(each.getLastInsertId());
              }
          }
          for (Comparable<?> each : autoIncrementGeneratedValues) {
              if (each instanceof Number) {
                  lastInsertIds.add(((Number) each).longValue());
              }
          }
          return lastInsertIds.isEmpty() ? 0L : getMinLastInsertId(lastInsertIds);
      }
      
      private long getMinLastInsertId(final List<Long> lastInsertIds) {
          Collections.sort(lastInsertIds);
          return lastInsertIds.iterator().next();
      }
      
      /**
       * Merge updated counts.
       */
      public void mergeUpdateCount() {
          updateCount = 0L;
          for (int each : updateCounts) {
              updateCount += each;
          }
      }
  }