/*

  * 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.johnzon.mapper.access;

 import org.apache.johnzon.mapper.JohnzonProperty;

 import org.apache.johnzon.mapper.MapperException;

 import java.lang.annotation.Annotation;

 import java.lang.reflect.Field;

 import java.lang.reflect.Modifier;

 import java.lang.reflect.Type;

 import java.util.HashMap;

 import java.util.Map;

 public class FieldAccessMode implements AccessMode {

     @Override

     public Map<String, Reader> findReaders(final Class<?> clazz) {

         final Map<String, Reader> readers = new HashMap<String, Reader>();

         for (final Map.Entry<String, Field> f : fields(clazz).entrySet()) {

             final String key = f.getKey();

             if (isIgnored(key)) {

                 continue;

             }

             readers.put(extractKey(f.getValue(), key), new FieldReader(f.getValue()));

         }

         return readers;

     }

     @Override

     public Map<String, Writer> findWriters(final Class<?> clazz) {

         final Map<String, Writer> writers = new HashMap<String, Writer>();

         for (final Map.Entry<String, Field> f : fields(clazz).entrySet()) {

             final String key = f.getKey();

             if (isIgnored(key)) {

                 continue;

             }

             writers.put(extractKey(f.getValue(), key), new FieldWriter(f.getValue()));

         }

         return writers;

     }

     private String extractKey(final Field f, final String key) {

         final JohnzonProperty property = f.getAnnotation(JohnzonProperty.class);

         return property != null ? property.value() : key;

     }

     protected boolean isIgnored(final String key) {

         return key.contains("$");

     }

     private Map<String, Field> fields(final Class<?> clazz) {

         final Map<String, Field> fields = new HashMap<String, Field>();

         Class<?> current = clazz;

         while (current != null && current != Object.class) {

             for (final Field f : current.getDeclaredFields()) {

                 final String name = f.getName();

                 final int modifiers = f.getModifiers();

                 if (fields.containsKey(name)

                         || Modifier.isStatic(modifiers)

                         || Modifier.isTransient(modifiers)) {

                     continue;

                 }

                 fields.put(name, f);

             }

             current = current.getSuperclass();

         }

         return fields;

     }

     protected static abstract class FieldDecoratedType implements DecoratedType {

         protected final Field field;

         public FieldDecoratedType(final Field field) {

             this.field = field;

             if (!field.isAccessible()) {

                 this.field.setAccessible(true);

             }

         }

         @Override

         public Type getType() {

             return field.getGenericType();

         }

         @Override

         public <T extends Annotation> T getAnnotation(final Class<T> clazz) {

             return field.getAnnotation(clazz);

         }

     }

     public static class FieldWriter extends FieldDecoratedType implements Writer {

         public FieldWriter(final Field field) {

             super(field);

         }

         @Override

         public void write(final Object instance, final Object value) {

             try {

                 field.set(instance, value);

             } catch (final Exception e) {

                 throw new MapperException(e);

             }

         }

     }

     public static class FieldReader extends FieldDecoratedType  implements Reader {

         public FieldReader(final Field field) {

             super(field);

         }

         @Override

         public Object read(final Object instance) {

             try {

                 return field.get(instance);

             } catch (final Exception e) {

                 throw new MapperException(e);

             }

         }

     }

 }