/**
    * 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.xbean.spring.context.impl;
  
  import org.springframework.beans.BeansException;
  import org.springframework.beans.FatalBeanException;
  import org.springframework.beans.MutablePropertyValues;
  import org.springframework.beans.PropertyValue;
  import org.springframework.beans.factory.FactoryBean;
  import org.springframework.beans.factory.config.BeanDefinitionHolder;
  import org.springframework.beans.factory.config.ConstructorArgumentValues;
  import org.springframework.beans.factory.support.AbstractBeanDefinition;
  
  import java.lang.reflect.Constructor;
  import java.lang.reflect.Method;
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  
  /**
   * NamedConstructorArgs is a BeanFactoryPostProcessor that converts property declarations into indexed constructor args
   * based on the the constructor parameter names annotation.  This process first selects a constructor and then fills in
   * the constructor arguments from the properties defined in the bean definition.  If a property is not defined in the
   * bean definition, first the defaultValues map is checked for a value and if a value is not present a Java default
   * value is provided for the constructor argument (e.g. numbers are assigned 0 and objects are assigned null).
   *
   * @author Dain Sundstrom
   * @version $Id$
   * @since 2.0
   */
  public class NamedConstructorArgs {
      private Map defaultValues = new HashMap();
  
      /**
       * Gets the default values that are assigned to constructor arguments without a defined value.
       * @return the default values that are assigned to constructor arguments without a defined value
       */
      public List getDefaultValues() {
          List values = new LinkedList();
          for (Iterator iterator = defaultValues.entrySet().iterator(); iterator.hasNext();) {
              Map.Entry entry = (Map.Entry) iterator.next();
              PropertyKey key = (PropertyKey) entry.getKey();
              Object value = entry.getValue();
              values.add(new DefaultProperty(key.name, key.type, value));
          }
          return values;
      }
  
      /**
       * Sets the default values that are assigned to constructor arguments without a defined value.
       * @param defaultValues the values that are assigned to constructor arguments without a defined value
       */
      public void setDefaultValues(List defaultValues) {
          this.defaultValues.clear();
          for (Iterator iterator = defaultValues.iterator(); iterator.hasNext();) {
              addDefaultValue((DefaultProperty) iterator.next());
          }
      }
  
      /**
       * Adds a default value for a property with the specified name and type.
       * @param name the name of the property
       * @param type the type of the property
       * @param value the default value for a property with the specified name and type
       */
      public void addDefaultValue(String name, Class type, Object value) {
          defaultValues.put(new PropertyKey(name, type), value);
      }
  
      /**
       * Adds a defautl value for a property.
       * @param defaultProperty the default property information
       */
      private void addDefaultValue(DefaultProperty defaultProperty) {
          defaultValues.put(new PropertyKey(defaultProperty.getName(), defaultProperty.getType()), defaultProperty.getValue());
      }
  
     public void processParameters(BeanDefinitionHolder definitionHolder, MappingMetaData metadata) throws BeansException {
         // this only works if we have an abstsract bean definition
         if (!(definitionHolder.getBeanDefinition() instanceof AbstractBeanDefinition)) {
             return;
         }
 
         AbstractBeanDefinition beanDefinition = (AbstractBeanDefinition) definitionHolder.getBeanDefinition();
         ConstructorArgumentValues constructorArgumentValues = beanDefinition.getConstructorArgumentValues();
 
         // if this bean already has constructor arguments defined, don't mess with them
         if (constructorArgumentValues.getArgumentCount() > 0) {
             return;
         }
 
         // try to get a list of constructor arg names to use
         ConstructionInfo constructionInfo = selectConstructionMethod(beanDefinition, metadata);
         if (constructionInfo == null) {
             return;
         }
 
         // remove each named property and add an indexed constructor arg
         MutablePropertyValues propertyValues = beanDefinition.getPropertyValues();
         String[] parameterNames = constructionInfo.parameterNames;
         Class[] parameterTypes = constructionInfo.parameterTypes;
         for (int i = 0; i < parameterNames.length; i++) {
             String parameterName = parameterNames[i];
             Class parameterType = parameterTypes[i];
 
             PropertyValue propertyValue = propertyValues.getPropertyValue(parameterName);
             if (propertyValue != null) {
                 propertyValues.removePropertyValue(parameterName);
                 constructorArgumentValues.addIndexedArgumentValue(i, propertyValue.getValue(), parameterType.getName());
             } else {
                 Object defaultValue = defaultValues.get(new PropertyKey(parameterName, parameterType));
                 if (defaultValue == null) {
                     defaultValue = DEFAULT_VALUE.get(parameterType);
                 }
                 if (defaultValue instanceof FactoryBean) {
                     try {
                         defaultValue = ((FactoryBean)defaultValue).getObject();
                     } catch (Exception e) {
                         throw new FatalBeanException("Unable to get object value from bean factory", e);
                     }
                 }
                 constructorArgumentValues.addIndexedArgumentValue(i, defaultValue, parameterType.getName());
             }
         }
 
         // todo set any usable default values on the bean definition
     }
 
     private ConstructionInfo selectConstructionMethod(AbstractBeanDefinition beanDefinition, MappingMetaData metadata) {
         Class beanClass = beanDefinition.getBeanClass();
 
         // get a set containing the names of the defined properties
         Set definedProperties = new HashSet();
         PropertyValue[] values = beanDefinition.getPropertyValues().getPropertyValues();
         for (int i = 0; i < values.length; i++) {
             definedProperties.add(values[i].getName());
         }
 
         // first check for a factory method
         if (beanDefinition.getFactoryMethodName() != null) {
             return selectFactory(beanClass, beanDefinition, metadata, definedProperties);
         } else {
             return selectConstructor(beanClass, metadata, definedProperties);
         }
     }
 
     private ConstructionInfo selectFactory(Class beanClass, AbstractBeanDefinition beanDefinition, MappingMetaData metadata, Set definedProperties) {
         String factoryMethodName = beanDefinition.getFactoryMethodName();
 
         // get the factory methods sorted by longest arg length first
         Method[] methods = beanClass.getMethods();
         List factoryMethods = new ArrayList(methods.length);
         for (int i = 0; i < methods.length; i++) {
             Method method = methods[i];
             if (method.getName().equals(factoryMethodName)) {
                 factoryMethods.add(method);
             }
         }
 
         Collections.sort(factoryMethods, new ArgLengthComparator());
 
         // if a factory method has been annotated as the default constructor we always use that constructor
         for (Iterator iterator = factoryMethods.iterator(); iterator.hasNext();) {
             Method factoryMethod = (Method) iterator.next();
 
             if (metadata.isDefaultFactoryMethod(beanClass, factoryMethod)) {
                 return new ConstructionInfo(beanClass, factoryMethod, metadata);
             }
         }
 
         // try to find a constructor for which we have all of the properties defined
         for (Iterator iterator = factoryMethods.iterator(); iterator.hasNext();) {
             Method factoryMethod = (Method) iterator.next();
             ConstructionInfo constructionInfo = new ConstructionInfo(beanClass, factoryMethod, metadata);
             if (isUsableConstructor(constructionInfo, definedProperties)) {
                 return constructionInfo;
             }
         }
         return null;
     }
 
     private ConstructionInfo selectConstructor(Class beanClass, MappingMetaData metadata, Set definedProperties) {
         // get the constructors sorted by longest arg length first
         List constructors = new ArrayList(Arrays.asList(beanClass.getConstructors()));
         Collections.sort(constructors, new ArgLengthComparator());
 
         // if a constructor has been annotated as the default constructor we always use that constructor
         for (Iterator iterator = constructors.iterator(); iterator.hasNext();) {
             Constructor constructor = (Constructor) iterator.next();
 
             if (metadata.isDefaultConstructor(constructor)) {
                 return new ConstructionInfo(constructor, metadata);
             }
         }
 
         // try to find a constructor for which we have all of the properties defined
         for (Iterator iterator = constructors.iterator(); iterator.hasNext();) {
             Constructor constructor = (Constructor) iterator.next();
             ConstructionInfo constructionInfo = new ConstructionInfo(constructor, metadata);
             if (isUsableConstructor(constructionInfo, definedProperties)) {
                 return constructionInfo;
             }
         }
         return null;
     }
 
     private boolean isUsableConstructor(ConstructionInfo constructionInfo, Set definedProperties) {
         // if we don't have parameter names this is not the constructor we are looking for
         String[] parameterNames = constructionInfo.parameterNames;
         if (parameterNames == null) {
             return false;
         }
 
         Class[] parameterTypes = constructionInfo.parameterTypes;
         for (int i = 0; i < parameterNames.length; i++) {
             String parameterName = parameterNames[i];
             Class parameterType = parameterTypes[i];
 
             // can we satify this property using a defined property or default property
             if (!definedProperties.contains(parameterName) && !defaultValues.containsKey(new PropertyKey(parameterName, parameterType))) {
                 return false;
             }
         }
 
         return true;
     }
 
     private class ConstructionInfo {
         private final Class[] parameterTypes;
         private final String[] parameterNames;
 
         public ConstructionInfo(Constructor constructor, MappingMetaData metadata) {
             this.parameterTypes = constructor.getParameterTypes();
             String[] names = metadata.getParameterNames(constructor);
 
             // verify that we have enough parameter names
             int expectedParameterCount = parameterTypes.length;
             if (names != null && names.length != expectedParameterCount) {
                 throw new FatalBeanException("Excpected " + expectedParameterCount + " parameter names for constructor but only got " +
                         names.length + ": " + constructor.toString());
             }
             if (expectedParameterCount == 0) {
                 names = new String[0];
             }
 
             this.parameterNames = names;
         }
 
         public ConstructionInfo(Class beanClass, Method factoryMethod, MappingMetaData metadata) {
             this.parameterTypes = factoryMethod.getParameterTypes();
 
             String[] names = metadata.getParameterNames(beanClass, factoryMethod);
 
             // verify that we have enough parameter names
             int expectedParameterCount = parameterTypes.length;
             if (names != null && names.length != expectedParameterCount) {
                 throw new FatalBeanException("Excpected " + expectedParameterCount + " parameter names for factory method but only got " +
                         names.length + ": " + factoryMethod.toString());
             }
             if (expectedParameterCount == 0) {
                 names = new String[0];
             }
 
             this.parameterNames = names;
         }
     }
 
     private static class ArgLengthComparator implements Comparator {
         public int compare(Object o1, Object o2) {
             return getArgLength(o2) - getArgLength(o1);
         }
 
         private int getArgLength(Object object) {
             if (object instanceof Method) {
                 return ((Method) object).getParameterTypes().length;
             } else {
                 return ((Constructor) object).getParameterTypes().length;
             }
         }
     }
 
     private static class PropertyKey {
         private final String name;
         private final Class type;
 
         public PropertyKey(String name, Class type) {
             this.name = name;
             this.type = type;
         }
 
         public boolean equals(Object object) {
             if (!(object instanceof PropertyKey)) {
                 return false;
             }
 
             PropertyKey defaultProperty = (PropertyKey) object;
             return name.equals(defaultProperty.name) && type.equals(type);
         }
 
         public int hashCode() {
             int result = 17;
             result = 37 * result + name.hashCode();
             result = 37 * result + type.hashCode();
             return result;
         }
 
         public String toString() {
             return "[" + name + " " + type + "]";
         }
     }
 
     private static final Map DEFAULT_VALUE;
     static {
         Map temp = new HashMap();
         temp.put(Boolean.TYPE, Boolean.FALSE);
         temp.put(Byte.TYPE, new Byte((byte) 0));
         temp.put(Character.TYPE, new Character((char) 0));
         temp.put(Short.TYPE, new Short((short) 0));
         temp.put(Integer.TYPE, new Integer(0));
         temp.put(Long.TYPE, new Long(0));
         temp.put(Float.TYPE, new Float(0));
         temp.put(Double.TYPE, new Double(0));
 
         DEFAULT_VALUE = Collections.unmodifiableMap(temp);
     }
 }