/*
    *  Copyright 2001-2013 Stephen Colebourne
    *
    *  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.joda.beans.impl.reflection;
  
  import java.lang.reflect.Field;
  import java.lang.reflect.Modifier;
  import java.util.Collections;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.NoSuchElementException;
  
  import org.joda.beans.Bean;
  import org.joda.beans.BeanBuilder;
  import org.joda.beans.MetaBean;
  import org.joda.beans.MetaProperty;
  import org.joda.beans.PropertyMap;
  import org.joda.beans.impl.BasicBeanBuilder;
  import org.joda.beans.impl.BasicPropertyMap;
  
  /**
   * A standard meta-bean implementation.
   * <p>
   * This is the standard implementation of a meta-bean.
   * It requires that the bean implements {@code Bean} and has a no-arguments constructor.
   * 
   * @author Stephen Colebourne
   */
  public final class ReflectiveMetaBean implements MetaBean {
  
      /** The bean type. */
      private final Class<? extends Bean> beanType;
      /** The meta-property instances of the bean. */
      private final Map<String, MetaProperty<?>> metaPropertyMap;
  
      /**
       * Factory to create a meta-bean avoiding duplicate generics.
       * 
       * @param <B>  the type of the bean
       * @param beanClass  the bean class, not null
       * @return the meta-bean, not null
       */
      public static <B extends Bean> ReflectiveMetaBean of(Class<B> beanClass) {
          return new ReflectiveMetaBean(beanClass);
      }
  
      /**
       * Constructor.
       * 
       * @param beanType  the bean type, not null
       */
      @SuppressWarnings("unchecked")
      private ReflectiveMetaBean(Class<? extends Bean> beanType) {
          if (beanType == null) {
              throw new NullPointerException("Bean class must not be null");
          }
          this.beanType = beanType;
          Map<String, MetaProperty<?>> map = new HashMap<String, MetaProperty<?>>();
          Field[] fields = beanType.getDeclaredFields();
          for (Field field : fields) {
              if (MetaProperty.class.isAssignableFrom(field.getType()) && Modifier.isStatic(field.getModifiers())) {
                  field.setAccessible(true);
                  MetaProperty<Object> mp;
                  try {
                      mp = (MetaProperty<Object>) field.get(null);
                      if (mp instanceof ReflectiveMetaProperty) {
                          ((ReflectiveMetaProperty<Object>) mp).setMetaBean(this);
                      }
                  } catch (IllegalArgumentException ex) {
                      throw new UnsupportedOperationException("MetaProperty cannot be created: " + field.getName(), ex);
                  } catch (IllegalAccessException ex) {
                      throw new UnsupportedOperationException("MetaProperty cannot be created: " + field.getName(), ex);
                  }
                  if (mp == null) {
                      throw new UnsupportedOperationException("MetaProperty cannot be created: " + field.getName() + ": Value must not be null");
                  }
                  map.put(mp.name(), mp);
              }
          }
          
          this.metaPropertyMap = Collections.unmodifiableMap(map);
      }
  
      //-----------------------------------------------------------------------
      @Override
      public BeanBuilder<Bean> builder() {
          try {
             Bean bean = beanType.newInstance();
             return new BasicBeanBuilder<Bean>(bean);
         } catch (InstantiationException ex) {
             throw new UnsupportedOperationException("Bean cannot be created: " + beanName(), ex);
         } catch (IllegalAccessException ex) {
             throw new UnsupportedOperationException("Bean cannot be created: " + beanName(), ex);
         }
     }
 
     @Override
     public PropertyMap createPropertyMap(Bean bean) {
         return BasicPropertyMap.of(bean);
     }
 
     //-----------------------------------------------------------------------
     @Override
     public String beanName() {
         return beanType.getName();
     }
 
     @Override
     public Class<? extends Bean> beanType() {
         return beanType;
     }
 
     //-----------------------------------------------------------------------
     @Override
     public int metaPropertyCount() {
         return metaPropertyMap.size();
     }
 
     @Override
     public boolean metaPropertyExists(String propertyName) {
         return metaPropertyMap.containsKey(propertyName);
     }
 
     @SuppressWarnings("unchecked")
     @Override
     public <R> MetaProperty<R> metaProperty(String propertyName) {
         MetaProperty<?> metaProperty = metaPropertyMap.get(propertyName);
         if (metaProperty == null) {
             throw new NoSuchElementException("Property not found: " + propertyName);
         }
         return (MetaProperty<R>) metaProperty;
     }
 
     @Override
     public Iterable<MetaProperty<?>> metaPropertyIterable() {
         return metaPropertyMap.values();
     }
 
     @Override
     public Map<String, MetaProperty<?>> metaPropertyMap() {
         return metaPropertyMap;
     }
 
     //-----------------------------------------------------------------------
     @Override
     public boolean equals(Object obj) {
         if (obj instanceof ReflectiveMetaBean) {
             ReflectiveMetaBean other = (ReflectiveMetaBean) obj;
             return this.beanType.equals(other.beanType);
         }
         return false;
     }
 
     @Override
     public int hashCode() {
         return beanType.hashCode() + 3;
     }
 
     /**
      * Returns a string that summarises the meta-bean.
      * 
      * @return a summary string, not null
      */
     @Override
     public String toString() {
         return "MetaBean:" + beanName();
     }
 
 }