/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.property.access.internal;

import java.io.Serializable;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
import java.util.Map;

import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.engine.spi.SharedSessionContractImplementor;
import org.hibernate.property.access.spi.Getter;
import org.hibernate.property.access.spi.PropertyAccess;
import org.hibernate.property.access.spi.PropertyAccessStrategy;
import org.hibernate.property.access.spi.Setter;

/**
 * @author Gavin King
 * @author Steve Ebersole
 */
public class PropertyAccessStrategyBackRefImpl implements PropertyAccessStrategy {
	/**
	 * A placeholder for a property value, indicating that
	 * we don't know the value of the back reference
	 */
	public static final Serializable UNKNOWN = new Serializable() {
		@Override
		public String toString() {
			return "<unknown>";
		}

		public Object readResolve() {
			return UNKNOWN;
		}
	};

	private final String entityName;
	private final String propertyName;

	public PropertyAccessStrategyBackRefImpl(String collectionRole, String entityName) {
		this.entityName = entityName;
		this.propertyName = collectionRole.substring( entityName.length() + 1 );
	}

	@Override
	public PropertyAccess buildPropertyAccess(Class containerJavaType, String propertyName) {
		return new PropertyAccessBackRefImpl( this );
	}

	private static class PropertyAccessBackRefImpl implements PropertyAccess {
		private PropertyAccessStrategyBackRefImpl strategy;

		private final GetterImpl getter;

		public PropertyAccessBackRefImpl(PropertyAccessStrategyBackRefImpl strategy) {
			this.strategy = strategy;
			this.getter = new GetterImpl( strategy.entityName, strategy.propertyName );
		}

		@Override
		public PropertyAccessStrategy getPropertyAccessStrategy() {
			return strategy;
		}

		@Override
		public Getter getGetter() {
			return getter;
		}

		@Override
		public Setter getSetter() {
			return SetterImpl.INSTANCE;
		}
	}

	private static class GetterImpl implements Getter {
		private final String entityName;
		private final String propertyName;

		public GetterImpl(String entityName, String propertyName) {
			this.entityName = entityName;
			this.propertyName = propertyName;
		}

		@Override
		public Object get(Object owner) {
			return UNKNOWN;
		}

		@Override
		public Object getForInsert(Object owner, Map mergeMap, SharedSessionContractImplementor session) {
			if ( session == null ) {
				return UNKNOWN;
			}
			else {
				return session.getPersistenceContext().getOwnerId( entityName, propertyName, owner, mergeMap );
			}
		}

		@Override
		public Class getReturnType() {
			return Object.class;
		}

		@Override
		public Member getMember() {
			return null;
		}

		@Override
		public String getMethodName() {
			return null;
		}

		@Override
		public Method getMethod() {
			return null;
		}
	}

	private static class SetterImpl implements Setter {
		/**
		 * Singleton access
		 */
		public static final SetterImpl INSTANCE = new SetterImpl();

		@Override
		public void set(Object target, Object value, SessionFactoryImplementor factory) {
			// this page intentionally left blank :)
		}

		@Override
		public String getMethodName() {
			return null;
		}

		@Override
		public Method getMethod() {
			return null;
		}
	}
}