/*
    * 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.sql.parser.sql.common.segment.dml.pagination.rownum;
  
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.expr.BinaryOperationExpression;
  import org.apache.shardingsphere.sql.parser.sql.common.segment.dml.expr.ExpressionSegment;
  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 java.util.List;
  
  /**
   * Row number value segment for expression.
   */
  public final class ExpressionRowNumberValueSegment extends RowNumberValueSegment {
      
      private final ExpressionSegment expressionSegment;
      
      public ExpressionRowNumberValueSegment(final int startIndex, final int stopIndex, final ExpressionSegment expressionSegment, final boolean boundOpened) {
          super(startIndex, stopIndex, boundOpened);
          this.expressionSegment = expressionSegment;
      }
      
      /**
       * Get value.
       *
       * @param params parameters
       * @return value
       */
      public Long getValue(final List<Object> params) {
          return getValueFromExpression(expressionSegment, params);
      }
      
      private Long getValueFromExpression(final ExpressionSegment expressionSegment, final List<Object> params) {
          if (expressionSegment instanceof ParameterMarkerExpressionSegment) {
              return null == params || params.isEmpty() ? 0L : Long.parseLong(params.get(((ParameterMarkerExpressionSegment) expressionSegment).getParameterMarkerIndex()).toString());
          }
          if (expressionSegment instanceof BinaryOperationExpression) {
              return getValueFromBinaryOperationExpression((BinaryOperationExpression) expressionSegment, params);
          }
          if (expressionSegment instanceof LiteralExpressionSegment) {
              return Long.parseLong(expressionSegment.getText());
          }
          throw new UnsupportedOperationException(String.format("Unsupported expression: %s in page expression", expressionSegment.getClass().getName()));
      }
      
      private Long getValueFromBinaryOperationExpression(final BinaryOperationExpression binaryOperationExpression, final List<Object> params) {
          String operator = binaryOperationExpression.getOperator();
          Long leftValue = getValueFromExpression(binaryOperationExpression.getLeft(), params);
          Long rightValue = getValueFromExpression(binaryOperationExpression.getRight(), params);
          switch (operator) {
              case "+":
                  return leftValue + rightValue;
              case "-":
                  return leftValue - rightValue;
              case "*":
                  return leftValue * rightValue;
              case "/":
                  return leftValue / rightValue;
              default:
                  throw new UnsupportedOperationException(String.format("Unsupported operator: %s in page expression", operator));
          }
      }
  }