package org.jboss.seam.debug.jsf;

import java.io.IOException;
import java.net.URL;

import javax.faces.context.FacesContext;
import org.jboss.seam.core.Init;

import com.sun.facelets.impl.ResourceResolver;
import com.sun.facelets.impl.DefaultResourceResolver;

/**
 * Intercepts any request for a path like /debug.xxx and renders
 * the Seam debug page using facelets.
 *
 * @author Mark Collette
 */
public class SeamDebugResourceResolver implements ResourceResolver
{
   private final static String PARAM_RESOURCE_RESOLVER = "seam.RESOURCE_RESOLVER";

   private ResourceResolver delegate;

   public SeamDebugResourceResolver()
   {
	   delegate = buildDelegateResourceResolver();
   }

   public URL resolveUrl(String path)
   {
      System.out.println("SeamDebugResourceResolver.resolveUrl()  path: " + path);
      if ( path!=null && path.startsWith("/debug.") && Init.instance().isDebug() )
      {
         URL url = SeamDebugResourceResolver.class.getClassLoader().getResource("META-INF/debug.xhtml");
         System.out.println("SeamDebugResourceResolver.resolveUrl()  url: " + url);
         return url;
	  }
	  return delegate.resolveUrl(path);
   }

   private ResourceResolver buildDelegateResourceResolver()
   {
      FacesContext ctx = FacesContext.getCurrentInstance();

      ResourceResolver resourceResolver = null;
      String paramResourceResolver = ctx.getExternalContext().getInitParameter(PARAM_RESOURCE_RESOLVER );
      if( paramResourceResolver != null && paramResourceResolver.length() > 0 )
      {
         try
         {
            Class resourceResolverClass = Class.forName(
               paramResourceResolver,
               true,
               Thread.currentThread().getContextClassLoader());
            resourceResolver = (ResourceResolver) resourceResolverClass.newInstance();
         }
         catch(Exception e)
         {
            throw new RuntimeException("Problem initializing Seam delegate ResourceResolver: " + paramResourceResolver, e);
         }
      }
      if( resourceResolver == null )
         resourceResolver = new DefaultResourceResolver();
      return resourceResolver;
   }
}