/*
 * Copyright 2011 JBoss, by Red Hat, Inc
 *
 * 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.jboss.errai.codegen;

import org.jboss.errai.codegen.exception.InvalidExpressionException;
import org.jboss.errai.codegen.meta.MetaClass;
import org.jboss.errai.codegen.meta.MetaClassFactory;

/**
 * @author Mike Brock <cbrock@redhat.com>
 * @author Christian Sadilek <csadilek@redhat.com>
 */
public class OperatorImpl implements Operator {

  private final String canonicalString;
  private final int operatorPrecedence;
  private final MetaClass[] constraints;

  OperatorImpl(String canonicalString, int operatorPrecedence, Class<?>... constraints) {
    this.canonicalString = canonicalString;
    this.operatorPrecedence = operatorPrecedence;
    this.constraints = MetaClassFactory.fromClassArray(constraints);
  }

  @Override
  public String getCanonicalString() {
    return canonicalString;
  }

  @Override
  public int getOperatorPrecedence() {
    return operatorPrecedence;
  }

  @Override
  public boolean isHigherPrecedenceThan(Operator operator) {
    return operator.getOperatorPrecedence() < getOperatorPrecedence();
  }

  @Override
  public boolean isEqualOrHigherPrecedenceThan(Operator operator) {
    return operator.getOperatorPrecedence() <= getOperatorPrecedence();
  }

  @Override
  public void assertCanBeApplied(MetaClass clazz) {
    if (!canBeApplied(clazz)) {
      throw new InvalidExpressionException("Not a valid type for operator '" +
          canonicalString + "': " + clazz.getFullyQualifiedName());
    }
  }

  @Override
  public boolean canBeApplied(MetaClass clazz) {
    if (constraints.length == 0) return true;

    for (MetaClass mc : constraints) {
      if (mc.asBoxed().isAssignableFrom(clazz.asBoxed())) return true;
    }

    return false;
  }
}