package org.jboss.seam.deployment;

import groovy.lang.GroovyRuntimeException;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.HashSet;
import java.util.Set;

import org.codehaus.groovy.control.CompilationFailedException;
import org.jboss.seam.annotations.Install;
import org.jboss.seam.annotations.Name;
import org.jboss.seam.log.LogProvider;
import org.jboss.seam.log.Logging;

/**
 * A deployment handler for (uncompiled) Groovy Seam components
 * 
 * @author Pete Muir
 *
 */
public class GroovyDeploymentHandler extends AbstractDeploymentHandler
{
   
   private class GroovyDeploymentHandlerMetadata implements DeploymentMetadata
   {
      
      private String groovyExtension;

      public GroovyDeploymentHandlerMetadata(String groovyExtension)
      {
         this.groovyExtension = groovyExtension;
      }

      public String getFileNameSuffix()
      {
         return groovyExtension;
      }
      
   }
   
   private DeploymentMetadata metadata;
   
   private static final LogProvider log = Logging.getLogProvider(GroovyDeploymentHandler.class);
   
   public static final String NAME = "org.jboss.seam.deployment.GroovyDeploymentHandler";
   
   private final String groovyFileExtension;
   
   private Set<ClassDescriptor> classes;
   
   /**
    * 
    * @param groovyFileExtension The extension to use for the groovy file
    */
   public GroovyDeploymentHandler(String groovyFileExtension)
   {
      this.groovyFileExtension = groovyFileExtension;
      this.classes = new HashSet<ClassDescriptor>();
      this.metadata = new GroovyDeploymentHandlerMetadata(groovyFileExtension);
   }
   
   /**
    * Get all the Groovy Seam Components this handler has handled 
    */
   public Set<ClassDescriptor> getClasses()
   {
      return classes;
   }
   
   @Override
   public void postProcess(ClassLoader classLoader)
   {
      for (FileDescriptor fileDescriptor : getResources())
      {
         log.debug("Found a groovy file: " + fileDescriptor.getName());
         String classname = filenameToGroovyname(fileDescriptor.getName());
         String filename = groovyComponentFilename(fileDescriptor.getName());
         BufferedReader buffReader = null;
         try
         {
            InputStream stream = classLoader.getResourceAsStream(fileDescriptor.getName());
            //TODO is BufferedInputStream necessary?
            buffReader = new BufferedReader(new InputStreamReader(stream));
            String line = buffReader.readLine();
            while (line != null)
            {
               if (line.indexOf("@Name") != -1 || line.indexOf("@" + Name.class.getName()) != -1)
               {
                  //possibly a Seam component
                  log.debug("Groovy file possibly a Seam component: " + fileDescriptor.getName());
                  Class<Object> groovyClass = (Class<Object>) classLoader.loadClass(classname);
                  Install install = groovyClass.getAnnotation(Install.class);
                  boolean installable = ( install == null || install.value() )
                        && ( groovyClass.isAnnotationPresent(Name.class)
                           || classLoader.getResources(filename).hasMoreElements() );
                  if (installable)
                  {
                     log.debug("found groovy component class: " + fileDescriptor.getName());
                     classes.add(new ClassDescriptor(fileDescriptor.getName(), fileDescriptor.getUrl(), groovyClass));
                  }
                  break;
               }
               line = buffReader.readLine();
            }
         }
         catch (ClassNotFoundException cnfe)
         {
            log.debug("could not load groovy class: " + classname, cnfe);

         }
         catch (LinkageError ncdfe)
         {
            log.debug("could not load groovy class (missing dependency): " + classname, ncdfe);

         }
         catch (IOException ioe)
         {
            log.debug("could not load groovy file: " + classname, ioe);
         }
         catch( CompilationFailedException e) {
            log.debug("Compilation error in Groovy file:" + classname, e);
         }
         catch(GroovyRuntimeException e) {
            log.debug("Unknown error reading Groovy file:" + classname, e);
         }
         finally
         {
            if (buffReader != null) {
               try
               {
                  buffReader.close();
               }
               catch (IOException e)
               {
                  log.trace("Could not close stream");
               }
            }
         }
      }
   }
   

   
   private String filenameToGroovyname(String filename)
   {
      return filename.substring(0, filename.lastIndexOf(groovyFileExtension))
            .replace('/', '.').replace('\\', '.');
   }

   private String groovyComponentFilename(String name)
   {
      return name.substring(0, name.lastIndexOf(groovyFileExtension)) + ".component.xml";
   }
   
   public String getName()
   {
      return NAME;
   }

   public DeploymentMetadata getMetadata()
   {
      return metadata;
   }
   
}
