/**
    * Copyright 2010 The Kuali Foundation Licensed under the
    * Educational Community 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.osedu.org/licenses/ECL-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.kuali.student.common.util;
  
  import java.util.HashSet;
  import java.util.Properties;
  
  import org.springframework.beans.BeansException;
  import org.springframework.beans.factory.BeanDefinitionStoreException;
  import org.springframework.beans.factory.BeanFactory;
  import org.springframework.beans.factory.InitializingBean;
  import org.springframework.beans.factory.config.BeanDefinition;
  import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
  import org.springframework.beans.factory.config.PropertyPlaceholderConfigurer;
  import org.springframework.core.io.DefaultResourceLoader;
  import org.springframework.core.io.Resource;
  import org.springframework.util.StringValueResolver;
  
  public class ModPropertyPlaceholderConfigurer extends
  		PropertyPlaceholderConfigurer implements InitializingBean  {
  	
  	private String customConfigSystemProperty;
  	private String customConfigFileLocation;
  	private Resource[] locations;	
  	
  	private String beanName;
  	private BeanFactory beanFactory;
  	private String nullValue;
  	
  	
  	public String getCustomConfigSystemProperty() {
  		return customConfigSystemProperty;
  	}
  
  	public void setCustomConfigSystemProperty(String customConfigSystemProperty) {
  		this.customConfigSystemProperty = customConfigSystemProperty;
  	}
  
  	@Override
  	public void setLocations(Resource[] locations) {
  		this.locations=locations;
  		super.setLocations(locations);
  		
  	}
  
  	@Override
  	public void afterPropertiesSet() throws Exception {
  		if(customConfigSystemProperty!=null){
  			String customConfigLocation = System.getProperty(customConfigSystemProperty);
  			try{
  				customConfigLocation = this.parseStringValue(customConfigLocation, System.getProperties(), new HashSet<String>());
  
  				Resource customConfigResource = new DefaultResourceLoader().getResource(customConfigLocation);
  				if(customConfigResource.exists()){
  					Resource[] finalLocations = new Resource[locations.length+1];
  					int i=0;
  					for(Resource resource:locations){
  						finalLocations[i]=resource;
  						i++;
  					}
  					finalLocations[i]=customConfigResource;
  					
  					super.setLocations(finalLocations);
  				}else{
  					logger.warn("File does not exist:"+customConfigLocation);
  				}
  			}catch(Exception e){
  				logger.warn("Could not load custom properties from property:"+customConfigSystemProperty+" location:"+customConfigLocation);
  			}
  		}
  		if(customConfigFileLocation!=null){
  			String location = this.parseStringValue(customConfigFileLocation, System.getProperties(), new HashSet<String>());
  			try{
  				Resource customConfigResource = new DefaultResourceLoader().getResource(location);
  		
  				if(customConfigResource.exists()){
  					Resource[] finalLocations = new Resource[locations.length+1];
  					int i=0;
  					for(Resource resource:locations){
  						finalLocations[i] = resource;
  						i++;
  					}
  					finalLocations[i] = customConfigResource;
  					
  					super.setLocations(finalLocations);
  				}else{
 					logger.warn("File does not exist:"+location);
 				}
 			}catch(Exception e){
 				logger.warn("Could not load custom properties from file:"+location);
 			}
 		}
 	}
 
 	@Override
 	public void setBeanName(String beanName) {
 		this.beanName = beanName;
 		super.setBeanName(beanName);
 	}
 
 	@Override
 	public void setBeanFactory(BeanFactory beanFactory) {
 		this.beanFactory = beanFactory;
 		super.setBeanFactory(beanFactory);
 	}
 	
 	@Override
 	public void setNullValue(String nullValue) {
 		this.nullValue = nullValue;
 		super.setNullValue(nullValue);
 	}
 	
 	@Override
 	protected void processProperties(ConfigurableListableBeanFactory beanFactoryToProcess, Properties props)
 			throws BeansException {
 
 		StringValueResolver valueResolver = new PlaceholderResolvingStringValueResolver(props);
 		ModBeanDefinitionVisitor visitor = new ModBeanDefinitionVisitor(valueResolver);
 		
 		String[] beanNames = beanFactoryToProcess.getBeanDefinitionNames();
 		for (int i = 0; i < beanNames.length; i++) {
 			// Check that we're not parsing our own bean definition,
 			// to avoid failing on unresolvable placeholders in properties file locations.
 			if (!(beanNames[i].equals(this.beanName) && beanFactoryToProcess.equals(this.beanFactory))) {
 				BeanDefinition bd = beanFactoryToProcess.getBeanDefinition(beanNames[i]);
 				try {
 					visitor.visitBeanDefinition(bd);
 				}
 				catch (BeanDefinitionStoreException ex) {
 					throw new BeanDefinitionStoreException(bd.getResourceDescription(), beanNames[i], ex.getMessage());
 				}
 			}
 		}
 		
 		// New in Spring 2.5: resolve placeholders in alias target names and aliases as well.
 		beanFactoryToProcess.resolveAliases(valueResolver);
 	}
 	
 	/**
 	 * BeanDefinitionVisitor that resolves placeholders in String values,
 	 * delegating to the <code>parseStringValue</code> method of the
 	 * containing class.
 	 */
 	public class PlaceholderResolvingStringValueResolver implements StringValueResolver {
 
 		private final Properties props;
 
 		public PlaceholderResolvingStringValueResolver(Properties props) {
 			this.props = props;
 		}
 
 		public String resolveStringValue(String strVal) throws BeansException {
 			String value = parseStringValue(strVal, this.props, new HashSet<String>());
 			return (value.equals(nullValue) ? null : value);
 		}
 		
 		public Properties resolvePropertyValue(String strVal){
 			Properties prefixedProps = new Properties();
 			
 			for(Object key:props.keySet()){
 				String keyStr = (String)key; 
 				if(keyStr.startsWith(strVal)){
 					String newKeyStr = keyStr.substring(strVal.length()+1);
 					prefixedProps.put(newKeyStr, resolveStringValue((String)props.get(key)));
 				}
 			}
 			
 			return prefixedProps;
 		}
 		
 	}
 
 	public String getCustomConfigFileLocation() {
 		return customConfigFileLocation;
 	}
 
 	public void setCustomConfigFileLocation(String customConfigFileLocation) {
 		this.customConfigFileLocation = customConfigFileLocation;
 	}
 }