package org.zeroturnaround.javarebel.integration.generic;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.URL;
import java.net.URLClassLoader;
import org.zeroturnaround.javarebel.ClassResource;
import org.zeroturnaround.javarebel.ClassResourceSource;
import org.zeroturnaround.javarebel.LoggerFactory;
import org.zeroturnaround.javarebel.support.FallbackClassResource;
import org.zeroturnaround.javarebel.support.FileClassResource;
import org.zeroturnaround.javarebel.support.JarClassResource;

public class FindResourceClassResourceSource implements ClassResourceSource {  
  private ClassLoader classloader;
  
  private static Method findResourceMethod;
  
  static {
    try {
      findResourceMethod = ClassLoader.class.getDeclaredMethod("findResource", new Class[] {String.class});
      findResourceMethod.setAccessible(true);
    } 
    catch (NoSuchMethodException e) {
      LoggerFactory.getInstance().errorEcho(e);
    }
  }

  public FindResourceClassResourceSource(ClassLoader classloader) {
    this.classloader = classloader;
  }
  
  public ClassResource getClassResource(String className) {
    // Most containers don't like when JavaRebel instruments their code
    if (className.startsWith("weblogic.")
        || className.startsWith("com.evermind.")
        || className.startsWith("oracle.")
        || className.startsWith("com.bea.")
        || className.startsWith("org.apache.jsp."))
      return null;
    
    URL url;
    if (classloader instanceof URLClassLoader)
      url = ((URLClassLoader) classloader).findResource(className.replace('.', '/') + ".class");
    else {
      try {
        url = (URL) findResourceMethod.invoke(classloader, new Object[] {className.replace('.', '/') + ".class"});
      } catch (IllegalArgumentException e) {
        throw new RuntimeException(e);
      } catch (IllegalAccessException e) {
        throw new RuntimeException(e);
      } catch (InvocationTargetException e) {
        throw new RuntimeException(e.getTargetException());
      }
    }      
    
    if (url == null)
      return null;
    
    LoggerFactory.getInstance().log("Found URL '" + url + "' for class '" + className + "'.");

    if (url.getProtocol().equals("file")) {
      return new FileClassResource(url);
    }
    else if (url.getProtocol().equals("jar") || url.getProtocol().equals("zip") || url.getProtocol().equals("code-source")) {
      return new JarClassResource(url);
    }
    else {
      return new FallbackClassResource(url);
    }
  }

}