/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.logging.filter.jboss5;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.log4j.spi.Filter;
import org.apache.log4j.spi.LoggingEvent;

import org.jboss.classloader.spi.base.BaseClassLoader;
import org.jboss.classloading.spi.dependency.ClassLoading;
import org.jboss.classloading.spi.dependency.Module;
import org.jboss.classloading.spi.visitor.ResourceContext;
import org.jboss.classloading.spi.visitor.ResourceFilter;
import org.jboss.classloading.spi.visitor.ResourceVisitor;

import org.jboss.util.collection.WeakSet;

/**
 * TCLFilter based on new CL architecute implementation 
 * of JBoss5
 * 
 * @author <a href="vicky.kak@gmail.com">Vicky Kak</a>
 * 
 */
public class TCLFilter extends Filter {
	/** The set of TCLs seen to match DeployURL */
	private WeakSet matchSet = new WeakSet();
	/** The set of TCLs seen to not match DeployURL */
	private WeakSet missSet = new WeakSet();
	/** The deployment URL string fragment to match against */
	private String deployURL;
	/** Whether a match should return ACCEPT or DENY */
	private boolean acceptOnMatch = true;
	
	private Pattern pattern;

	public boolean isAcceptOnMatch() {
		return acceptOnMatch;
	}

	public void setAcceptOnMatch(boolean acceptOnMatch) {
		this.acceptOnMatch = acceptOnMatch;
	}

	public String getDeployURL() {
		return deployURL;
	}

	public void setDeployURL(String deployURL) {
		this.deployURL = deployURL;
		this.pattern = Pattern.compile("^.*" + deployURL + ".*");
	}

	public int decide(LoggingEvent event) {
		int ok = Filter.NEUTRAL;
		if (acceptOnMatch == true) {
			if (isMatchingTCL())
				ok = Filter.ACCEPT;
		} else {
			if (isMatchingTCL())
				ok = Filter.DENY;
		}
		return ok;
	}

	/**
	 * Start with the current thread context class loader
	 *
	 * @return true if the caller tcl has a url matching our deployURL
	 */
	private boolean isMatchingTCL(){

	      ClassLoader tcl = Thread.currentThread().getContextClassLoader();
	      if( matchSet.contains(tcl) )
		 return true;
	      if( missSet.contains(tcl) )
		 return false;

	      // Search the class loader URLs for a match
	      ClassLoader cl = tcl;
	      while( cl != null )
	      {
		 if (matchClassLoader(cl))
		    break;

		 cl = cl.getParent();
	      }

	      if( cl != null )
		 matchSet.add(tcl);
	      else
		 missSet.add(tcl);

	      return (cl != null);
	   }

	   private boolean matchClassLoader(ClassLoader cl){

	      Module module = ClassLoading.getModuleForClassLoader(cl);
	      if (module == null)
		 return false;
	      
	      MatchFragment mf = new MatchFragment();
	      module.visit(mf, null, mf);
	      return mf.isFound();
	   }

	   private class MatchFragment implements ResourceVisitor, ResourceFilter{

	      private boolean found;
	      private boolean visited;

	      public ResourceFilter getFilter()
	      {
		 return null;
	      }

	      public boolean accepts(ResourceContext rc)
	      {
		 if (visited)
		 {
		    visited = false; // reset recursion filter
		    return false;
		 }
		 return true;
	      }

	      public void visit(ResourceContext rc)
	      {
		 visited = true;
		 
		 if (found)
		    return;
		     
		 String rcString = rc.getUrl().toExternalForm();
		 Matcher m = pattern.matcher(rcString);
		 if (m.matches()) {
		 	found = true;
		 	//return;
		 }		 
		 //found = rcString.contains(deployURL);
	      }

	      public boolean isFound()
	      {
		 return found;
	      }
	   }
}