/*
    * 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.infra.binder.context.segment.insert.values;
  
  import com.google.common.base.Preconditions;
  import lombok.Getter;
  import lombok.ToString;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.assignment.ColumnAssignmentSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.column.ColumnSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.expr.ExpressionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.expr.FunctionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.expr.simple.LiteralExpressionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.expr.simple.ParameterMarkerExpressionSegment;
  import org.apache.shardingsphere.sql.parser.sql.common.util.ExpressionExtractUtils;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.List;
  import java.util.stream.Collectors;
  
  @Getter
  @ToString
  public final class OnDuplicateUpdateContext {
      
      private final int parameterCount;
      
      private final List<ExpressionSegment> valueExpressions;
      
      private final List<ParameterMarkerExpressionSegment> parameterMarkerExpressions;
      
      private final List<Object> parameters;
      
      private final List<ColumnSegment> columns;
      
      public OnDuplicateUpdateContext(final Collection<ColumnAssignmentSegment> assignments, final List<Object> params, final int parametersOffset) {
          List<ExpressionSegment> expressionSegments = assignments.stream().map(ColumnAssignmentSegment::getValue).collect(Collectors.toList());
          valueExpressions = getValueExpressions(expressionSegments);
          parameterMarkerExpressions = ExpressionExtractUtils.getParameterMarkerExpressions(expressionSegments);
          parameterCount = parameterMarkerExpressions.size();
          parameters = getParameters(params, parametersOffset);
          columns = assignments.stream().map(each -> each.getColumns().get(0)).collect(Collectors.toList());
      }
      
      private List<ExpressionSegment> getValueExpressions(final Collection<ExpressionSegment> assignments) {
          List<ExpressionSegment> result = new ArrayList<>(assignments.size());
          result.addAll(assignments);
          return result;
      }
      
      private List<Object> getParameters(final List<Object> params, final int paramsOffset) {
          if (params.isEmpty() || 0 == parameterCount) {
              return Collections.emptyList();
          }
          List<Object> result = new ArrayList<>(parameterCount);
          result.addAll(params.subList(paramsOffset, paramsOffset + parameterCount));
          return result;
      }
      
      /**
       * Get value.
       *
       * @param index index
       * @return value
       */
      public Object getValue(final int index) {
          ExpressionSegment valueExpression = valueExpressions.get(index);
          if (valueExpression instanceof ParameterMarkerExpressionSegment) {
              return parameters.get(getParameterIndex((ParameterMarkerExpressionSegment) valueExpression));
          }
          if (valueExpression instanceof FunctionSegment) {
              return valueExpression;
          }
          return ((LiteralExpressionSegment) valueExpression).getLiterals();
      }
      
      private int getParameterIndex(final ParameterMarkerExpressionSegment paramMarkerExpression) {
          int result = parameterMarkerExpressions.indexOf(paramMarkerExpression);
          Preconditions.checkArgument(result >= 0, "Can not get parameter index.");
          return result;
      }
      
      /**
       * Get on duplicate key update column by index of this clause.
      *
      * @param index index
      * @return columnSegment
      */
     public ColumnSegment getColumn(final int index) {
         return columns.get(index);
     }
 }