/*
 * Copyright (C) 2011 Red Hat, Inc. and/or its affiliates.
 *
 * 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.databinding.rebind;

import java.util.List;

import org.jboss.errai.codegen.meta.MetaClass;
import org.jboss.errai.databinding.client.api.Bindable;

/**
 * Validation utilities for data binding.
 *
 * @author Christian Sadilek <csadilek@redhat.com>
 * @author Jonathan Fuerth <jfuerth@redhat.com>
 */
public class DataBindingValidator {

  private DataBindingValidator() {}

  /**
   * Returns true if and only if the given property chain is a valid property expression rooted in the given bindable
   * type.
   *
   * @param bindableType
   *          The root type the given property chain is resolved against. Not null.
   * @param propertyChain
   *          The data binding property chain to validate. Not null.
   * @return True if the given property chain is resolvable from the given bindable type.
   */
  public static boolean isValidPropertyChain(final MetaClass bindableType, final String propertyChain) {
    if (!bindableType.isAnnotationPresent(Bindable.class) &&
        !DataBindingUtil.getConfiguredBindableTypes().contains(bindableType) &&
        !bindableType.getFullyQualifiedName().equals(List.class.getName())) {
      return false;
    }

    if ("this".equals(propertyChain)) {
      return true;
    }

    int dotPos = propertyChain.indexOf(".");
    if (dotPos <= 0) {
      return bindableType.getBeanDescriptor().getProperties().contains(propertyChain);
    }
    else {
      String thisProperty = propertyChain.substring(0, dotPos);
      String moreProperties = propertyChain.substring(dotPos + 1);
      if (!bindableType.getBeanDescriptor().getProperties().contains(thisProperty)) {
        return false;
      }
      MetaClass propertyType = bindableType.getBeanDescriptor().getPropertyType(thisProperty);
      return  isValidPropertyChain(propertyType, moreProperties);
    }
  }

  /**
   * @param bindableType
   *          The root type the given property chain is resolved against. Not null.
   * @param propertyChain
   *          The data binding property chain to validate. Not null.
   * @return The type of the given property within the given bindable type.
   */
  public static MetaClass getPropertyType(final MetaClass bindableType, final String propertyChain) {
    if ("this".equals(propertyChain)) {
      return bindableType;
    }

    final int dotPos = propertyChain.indexOf('.');
    if (dotPos >= 0) {
      final String firstProp = propertyChain.substring(0, dotPos);
      final String subChain = propertyChain.substring(dotPos+1);

      return getPropertyType(bindableType.getBeanDescriptor().getPropertyType(firstProp), subChain);
    }
    else {
      return bindableType.getBeanDescriptor().getPropertyType(propertyChain);
    }
  }
}