package org.jruby.util;

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

import jnr.posix.FileStat;
import jnr.posix.POSIX;

import org.jruby.util.io.ChannelDescriptor;
import org.jruby.util.io.ModeFlags;

public class ClasspathResource implements FileResource {

    public static final String CLASSPATH = "classpath:/";

    private final String uri;
    
    private final JarFileStat fileStat;

    private boolean isFile;

    ClasspathResource(String uri, URL url)
    {
        this.uri = uri;
        this.fileStat = new JarFileStat(this);
        this.isFile = url != null;
    }

    public static URL getResourceURL(String pathname) {
        String path = pathname.substring(CLASSPATH.length() );
        // this is the J2EE case
        URL url = Thread.currentThread().getContextClassLoader().getResource(path);
        if ( url != null ) {
            return url;
        }
        else if (ClasspathResource.class.getClassLoader() != null) {
            // this is OSGi case
            return ClasspathResource.class.getClassLoader().getResource(path);
        }
        return null;
    }
    
    public static FileResource create(String pathname) {
        if (!pathname.startsWith("classpath:")) {
            return null;
        }
        if (pathname.equals("classpath:")) {
            return new ClasspathResource(pathname, null);
        }
        
        URL url = getResourceURL(pathname);
        return new ClasspathResource(pathname, url);
    }

    @Override
    public String absolutePath()
    {
        return uri;
    }

    @Override
    public String canonicalPath() {
        return uri;
    }

    @Override
    public boolean exists()
    {
        return isFile;
    }

    @Override
    public boolean isDirectory()
    {
        return false;
    }

    @Override
    public boolean isFile()
    {
        return isFile;
    }

    @Override
    public long lastModified()
    {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public long length()
    {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public boolean canRead()
    {
        return true;
    }

    @Override
    public boolean canWrite()
    {
        return false;
    }

    @Override
    public String[] list()
    {
        return null;
    }

    @Override
    public boolean isSymLink()
    {
        return false;
    }

    @Override
    public FileStat stat() {
        return fileStat;
    }

    @Override
    public FileStat lstat() {
      return stat(); // we don't have symbolic links here, so lstat == stat
    }

    @Override
    public JRubyFile hackyGetJRubyFile() {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public InputStream openInputStream() {
        try {
            return getResourceURL(uri).openStream();
        } catch (IOException ioE) {
            return null;
        }
    }

    @Override
    public ChannelDescriptor openDescriptor(ModeFlags flags, int perm) throws ResourceException {
        return null;
    }
    
}
