/***
    * Copyright (C) 2006 Philipp Mpalampanis
    *
    * License: MPL 1.1/GPL 2.0/LGPL 2.1
    *
    * The contents of this file are subject to the Mozilla Public License Version
    * 1.1 (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.mozilla.org/MPL/
   *
   * Software distributed under the License is distributed on an "AS IS" basis,
   * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
   * for the specific language governing rights and limitations under the
   * License.
   *
   * Alternatively, the contents of this file may be used under the terms of
   * either the GNU General Public License Version 2 or later (the "GPL"), or
   * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
   * in which case the provisions of the GPL or the LGPL are applicable instead
   * of those above. If you wish to allow use of your version of this file only
   * under the terms of either the GPL or the LGPL, and not to allow others to
   * use your version of this file under the terms of the MPL, indicate your
   * decision by deleting the provisions above and replace them with the notice
   * and other provisions required by the GPL or the LGPL. If you do not delete
   * the provisions above, a recipient may use your version of this file under
   * the terms of any one of the MPL, the GPL or the LGPL.
   */
  
  package net.sf.echobinding.binding;
  
  import java.beans.PropertyChangeListener;
  import java.beans.PropertyChangeSupport;
  import java.io.Serializable;
  import java.lang.reflect.Method;
  import java.util.HashMap;
  import java.util.Map.Entry;
  
  import net.sf.echobinding.model.PresentationModel;
  import net.sf.echobinding.validation.ValidationHandler;
  import net.sf.echobinding.validation.ValidationReport;
  import ognl.Ognl;
  import ognl.OgnlContext;
  
  import org.apache.log4j.Logger;
  
  /***
   * 
   */
  public class OgnlBindingContext extends AbstractBindingContext {
  
  	private static final long serialVersionUID = -3799783525654201978L;
  
  	/***
  	 * The OGNL namespace/prefix used to access the presentation model. 
  	 */
  	public static final String OGNL_NAMESPACE_PMOD = "pm";
  
  	@SuppressWarnings("unused")
  	private final Logger _logger = Logger.getLogger(OgnlBindingContext.class);
  	
  	private Object _model;
  
  	private OgnlContext _ognlContext = new OgnlContext();
  
  	private HashMap<String, Object> _contextMap = new HashMap<String, Object>();
  
  	private ValidationHandler _validationHandler;
  
  	
  	/***
  	 * Creates a new OgnlBindingContext.
  	 * 
  	 * @param bean The bean
  	 *
  	 */
  	public OgnlBindingContext(Object bean) {
  		this();
  		setModel(bean);
  	}
  
  	/***
  	 * Creates a new OgnlBindingContext.
  	 *
  	 */
  	public OgnlBindingContext() {
  		super();
  	}
  
  	public BindingContext add(String id, PropertyAdapter adapter) {
  
  		if (!(adapter instanceof OgnlPropertyAdapter))
  			throw new ClassCastException("Adapter has to be of type OgnlPropertyAdapter!");
  
  		super.add(id, adapter);
  
  		return this;
  	}
  
  
 	public Object getValue(String id) throws BindingException {
 		OgnlPropertyAdapter adapter = getAdapter(id);
 
 		Object value = (_ognlContext == null) ? adapter.getValue(_model)
 				: adapter.getValue(_ognlContext, _model);
 		
 		return value;
 	}
 
 	
 	
 	/*
 	 * (non-Javadoc)
 	 * 
 	 * @see echobinding.BindingContext#setValue(java.lang.String,
 	 *      java.lang.Object)
 	 */
 	public void setValue(String id, Object value) throws BindingException {
 
 		OgnlPropertyAdapter adapter = getAdapter(id);
 
 		Object oldValue = this.getValue(id);
 		
 		if (_ognlContext == null)
 			adapter.setValue( _model, value );
 		else
 			adapter.setValue( _ognlContext, _model, value );
 			
 		firePropertyChange(id, oldValue, value);
 	}
 
 	/*
 	 * (non-Javadoc)
 	 * 
 	 * @see echobinding.BindingContext#isValid(java.lang.String,
 	 *      java.lang.Object)
 	 */
 	@SuppressWarnings("unchecked")
 	public ValidationReport validate(String id, Object value) {
 		Object bean = getModel();
 		OgnlPropertyAdapter adapter = getAdapter(id);
 		String ognlNameSpace = adapter.getOgnlContextName();
 		if(ognlNameSpace != null && getOgnlContext() != null) {
 			bean = getOgnlContext().get( ognlNameSpace );
 		}
 		
 		return adapter.validate(bean, value);
 	}
 	
 	
 	/*
 	 * (non-Javadoc)
 	 * 
 	 * @see echobinding.BindingContext#getModel()
 	 */
 	public Object getModel() {
 		return _model;
 	}
 
 	/*
 	 * (non-Javadoc)
 	 * 
 	 * @see echobinding.BindingContext#setModel(java.lang.Object)
 	 */
 	public OgnlBindingContext setModel(Object bean) {
 		_model = bean;
 		
 		registerSource( bean );
 		
 		return this;
 	}
 	
 	
 
 	@Override
 	public void setPresentationModel(PresentationModel presentationModel) {
 		super.setPresentationModel( presentationModel );
 		addModel( OGNL_NAMESPACE_PMOD, presentationModel );
 	}
 
 	/***
 	 * Tries to add this BindingContext as a property change listener to the
 	 * source bean.
 	 * 
 	 * @param contextRoot
 	 */
 	private void registerSource(Object contextRoot) {
 		if(contextRoot==null)
 			return;
 		
 		if ( contextRoot instanceof PropertyChangeSupport ) {
 			PropertyChangeSupport propertyChangeSupport = (PropertyChangeSupport) contextRoot;
 			propertyChangeSupport.addPropertyChangeListener(this);
 		} 
 		else {
 			// check if class provides the addPropertyListener method
 			Class contextClass = contextRoot.getClass();
 			Class[] parameterTypes = new Class[] {PropertyChangeListener.class};
 			Object[] arguments = new Object[] {this};
 			Method addPropertyChangeListenerMethod;
 			try {
 				addPropertyChangeListenerMethod = contextClass.getMethod("addPropertyChangeListener", parameterTypes);
 				addPropertyChangeListenerMethod.invoke(contextRoot, arguments);
 			} catch (Exception e) {
 				// ignore
 			}
 		}
 	}
 
 	/***
 	 * Adds a bean to the OgnlContext. Additional beans can be referenced with
 	 * "#contextName.property" in an OGNL expression.
 	 * 
 	 * @param contextName
 	 * @param bean
 	 * @return
 	 */
 	public OgnlBindingContext addModel(String contextName, Object bean) {
 
 		if (_ognlContext == null)
 			_ognlContext = (OgnlContext) Ognl
 					.createDefaultContext( _model );
 
 		_ognlContext.put(contextName, bean);
 
 		_contextMap.put(contextName, bean);
 
 		return this;
 	}
 
 	
 	public BindingContext createChild() {
 
 		OgnlBindingContext childContext = new OgnlBindingContext();
 
 		for (Entry<String, PropertyAdapter> entry : _adapters.entrySet()) {
 			PropertyAdapter clonedAdapter = entry.getValue().newInstance();
 			childContext.add(entry.getKey(), clonedAdapter);
 		}
 
 		childContext.setContextMap(getContextMap());
 		childContext.setParent(this);
 		
 		if(getPresentationModel()!=null)
 			childContext.setPresentationModel(getPresentationModel().cloneInstance());
 
 		addChild(childContext);
 		
 		childContext.setModel(getModel());
 
 		return childContext;
 	}
 
 	/***
 	 * Returns the context map. 
 	 * 
 	 * @return
 	 */
 	public HashMap<String, Object> getContextMap() {
 		return _contextMap;
 	}
 
 	protected OgnlContext getOgnlContext() {
 		return _ognlContext;
 	}
 
 	/***
 	 * Sets the context map. The context map is a list of additional source
 	 * objects which are used for binding. 
 	 * 
 	 * @param contextMap
 	 */
 	public void setContextMap(HashMap<String, Object> contextMap) {
 		_contextMap = contextMap;
 		if (contextMap != null) {
 			for (Entry<String, Object> entry : contextMap.entrySet()) {
 				_ognlContext.put(entry.getKey(), entry.getValue());
 			}
 		}
 	}
 
 	
 	/* (non-Javadoc)
 	 * @see echobinding.binding.BindingContext#getValidationhandler(java.lang.String)
 	 */
 	public ValidationHandler getValidationHandler(String id) {
 		ValidationHandler handler = getAdapter(id).getValidationHandler();
 		return (handler==null) ? getValidationHandler() : handler;
 	}
 
 	/* (non-Javadoc)
 	 * @see echobinding.binding.BindingContext#setValidationHandler(echobinding.validation.ValidationHandler)
 	 */
 	public BindingContext setValidationHandler(ValidationHandler handler) {
 		_validationHandler = handler;
 		return this;
 	}
 
 	/* (non-Javadoc)
 	 * @see echobinding.binding.BindingContext#getValidationHandler()
 	 */
 	public ValidationHandler getValidationHandler() {
 		return _validationHandler;
 	}
 
 	
 	/* (non-Javadoc)
 	 * @see echobinding.binding.BindingContext#isDirty(java.lang.String, java.lang.Object)
 	 */
 	public boolean isDirty(String id, Object value) throws BindingException {
 		Object oldValue = getValue( id );
 		if(oldValue==null) {
 			if(value==null)
 				return false;
 			return true;
 		}
 		return ! oldValue.equals(value);
 	}
 
 
 	/***
 	 * Returns the <code>PropertyAdapter</code> for the given id. If no adapter for
 	 * this id exists, a new adapter will be lazely generated using the id as
 	 * binding expression. The newly generated adapter will added to he list of
 	 * adapters.
 	 * 
 	 * @param id
 	 * @return
 	 */
 	public OgnlPropertyAdapter getAdapter(String id) {
 		OgnlPropertyAdapter adapter = (OgnlPropertyAdapter) _adapters.get(id);
 		if (adapter == null) {
 			// create a new adapter
 			adapter = new OgnlPropertyAdapter(id);
 			this.add(id, adapter);
 		}
 		return adapter;
 	}
 	
 
 }