/*
    * Copyright 2002-2014 the original author or authors.
    *
    * Licensed 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.springframework.expression.spel.ast;
  
  import java.math.BigDecimal;
  import java.math.BigInteger;
  
  import org.springframework.asm.MethodVisitor;
  import org.springframework.expression.EvaluationException;
  import org.springframework.expression.spel.CodeFlow;
  import org.springframework.expression.spel.ExpressionState;
  import org.springframework.expression.spel.support.BooleanTypedValue;
  import org.springframework.util.NumberUtils;
  
  /**
   * Implements the less-than operator.
   *
   * @author Andy Clement
   * @author Juergen Hoeller
   * @author Giovanni Dall'Oglio Risso
   * @since 3.0
   */
  public class OpLT extends Operator {
  
  	public OpLT(int pos, SpelNodeImpl... operands) {
  		super("<", pos, operands);
  		this.exitTypeDescriptor = "Z";
  	}
  
  
  	@Override
  	public BooleanTypedValue getValueInternal(ExpressionState state) throws EvaluationException {
  		Object left = getLeftOperand().getValueInternal(state).getValue();
  		Object right = getRightOperand().getValueInternal(state).getValue();
  
  		this.leftActualDescriptor = CodeFlow.toDescriptorFromObject(left);
  		this.rightActualDescriptor = CodeFlow.toDescriptorFromObject(right);
  
  		if (left instanceof Number && right instanceof Number) {
  			Number leftNumber = (Number) left;
  			Number rightNumber = (Number) right;
  
  			if (leftNumber instanceof BigDecimal || rightNumber instanceof BigDecimal) {
  				BigDecimal leftBigDecimal = NumberUtils.convertNumberToTargetClass(leftNumber, BigDecimal.class);
  				BigDecimal rightBigDecimal = NumberUtils.convertNumberToTargetClass(rightNumber, BigDecimal.class);
  				return BooleanTypedValue.forValue(leftBigDecimal.compareTo(rightBigDecimal) < 0);
  			}
  			else if (leftNumber instanceof Double || rightNumber instanceof Double) {
  				return BooleanTypedValue.forValue(leftNumber.doubleValue() < rightNumber.doubleValue());
  			}
  			else if (leftNumber instanceof Float || rightNumber instanceof Float) {
  				return BooleanTypedValue.forValue(leftNumber.floatValue() < rightNumber.floatValue());
  			}
  			else if (leftNumber instanceof BigInteger || rightNumber instanceof BigInteger) {
  				BigInteger leftBigInteger = NumberUtils.convertNumberToTargetClass(leftNumber, BigInteger.class);
  				BigInteger rightBigInteger = NumberUtils.convertNumberToTargetClass(rightNumber, BigInteger.class);
  				return BooleanTypedValue.forValue(leftBigInteger.compareTo(rightBigInteger) < 0);
  			}
  			else if (leftNumber instanceof Long || rightNumber instanceof Long) {
  				return BooleanTypedValue.forValue(leftNumber.longValue() < rightNumber.longValue());
  			}
  			else if (leftNumber instanceof Integer || rightNumber instanceof Integer) {
  				return BooleanTypedValue.forValue(leftNumber.intValue() < rightNumber.intValue());
  			}
  			else if (leftNumber instanceof Short || rightNumber instanceof Short) {
  				return BooleanTypedValue.forValue(leftNumber.shortValue() < rightNumber.shortValue());
  			}
  			else if (leftNumber instanceof Byte || rightNumber instanceof Byte) {
  				return BooleanTypedValue.forValue(leftNumber.byteValue() < rightNumber.byteValue());
  			}
  			else {
  				// Unknown Number subtypes -> best guess is double comparison
  				return BooleanTypedValue.forValue(leftNumber.doubleValue() < rightNumber.doubleValue());
  			}
  		}
  
  		if (left instanceof CharSequence && right instanceof CharSequence) {
  			left = left.toString();
  			right = right.toString();
  		}
  
  		return BooleanTypedValue.forValue(state.getTypeComparator().compare(left, right) < 0);
  	}
  	
  	@Override
 	public boolean isCompilable() {
 		return isCompilableOperatorUsingNumerics();
 	}
 	
 	@Override
 	public void generateCode(MethodVisitor mv, CodeFlow cf) {
 		generateComparisonCode(mv, cf, IFGE, IF_ICMPGE);
 	}
 
 }