//
//  ========================================================================
//  Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package org.eclipse.jetty.util.resource;

import java.io.File;
import java.io.FileOutputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.jar.JarEntry;
import java.util.jar.JarInputStream;
import java.util.jar.Manifest;

import org.eclipse.jetty.util.IO;
import org.eclipse.jetty.util.StringUtil;
import org.eclipse.jetty.util.URIUtil;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;

public class JarResource extends URLResource
{
    private static final Logger LOG = Log.getLogger(JarResource.class);
    protected JarURLConnection _jarConnection;

    protected JarResource(URL url)
    {
        super(url, null);
    }

    protected JarResource(URL url, boolean useCaches)
    {
        super(url, null, useCaches);
    }

    @Override
    public synchronized void close()
    {
        _jarConnection = null;
        super.close();
    }

    @Override
    protected synchronized boolean checkConnection()
    {
        super.checkConnection();
        try
        {
            if (_jarConnection != _connection)
                newConnection();
        }
        catch (IOException e)
        {
            LOG.ignore(e);
            _jarConnection = null;
        }

        return _jarConnection != null;
    }

    /**
     * @throws IOException Sub-classes of <code>JarResource</code> may throw an IOException (or subclass)
     */
    protected void newConnection() throws IOException
    {
        _jarConnection = (JarURLConnection)_connection;
    }

    /**
     * Returns true if the represented resource exists.
     */
    @Override
    public boolean exists()
    {
        if (_urlString.endsWith("!/"))
            return checkConnection();
        else
            return super.exists();
    }

    @Override
    public File getFile()
        throws IOException
    {
        return null;
    }

    @Override
    public InputStream getInputStream()
        throws java.io.IOException
    {
        checkConnection();
        if (!_urlString.endsWith("!/"))
            return new FilterInputStream(getInputStream(false))
            {
                @Override
                public void close()
                {
                    this.in = IO.getClosedStream();
                }
            };

        URL url = new URL(_urlString.substring(4, _urlString.length() - 2));
        InputStream is = url.openStream();
        return is;
    }

    @Override
    public void copyTo(File directory)
        throws IOException
    {
        if (!exists())
            return;

        if (LOG.isDebugEnabled())
            LOG.debug("Extract " + this + " to " + directory);

        String urlString = this.getURL().toExternalForm().trim();
        int endOfJarUrl = urlString.indexOf("!/");
        int startOfJarUrl = (endOfJarUrl >= 0 ? 4 : 0);

        if (endOfJarUrl < 0)
            throw new IOException("Not a valid jar url: " + urlString);

        URL jarFileURL = new URL(urlString.substring(startOfJarUrl, endOfJarUrl));
        String subEntryName = (endOfJarUrl + 2 < urlString.length() ? urlString.substring(endOfJarUrl + 2) : null);
        boolean subEntryIsDir = (subEntryName != null && subEntryName.endsWith("/"));

        if (LOG.isDebugEnabled())
            LOG.debug("Extracting entry = " + subEntryName + " from jar " + jarFileURL);
        URLConnection c = jarFileURL.openConnection();
        c.setUseCaches(false);
        try (InputStream is = c.getInputStream();
             JarInputStream jin = new JarInputStream(is))
        {
            JarEntry entry;
            boolean shouldExtract;
            while ((entry = jin.getNextJarEntry()) != null)
            {
                String entryName = entry.getName();
                if ((subEntryName != null) && (entryName.startsWith(subEntryName)))
                {
                    // is the subentry really a dir?
                    if (!subEntryIsDir && subEntryName.length() + 1 == entryName.length() && entryName.endsWith("/"))
                        subEntryIsDir = true;

                    //if there is a particular subEntry that we are looking for, only
                    //extract it.
                    if (subEntryIsDir)
                    {
                        //if it is a subdirectory we are looking for, then we
                        //are looking to extract its contents into the target
                        //directory. Remove the name of the subdirectory so
                        //that we don't wind up creating it too.
                        entryName = entryName.substring(subEntryName.length());
                        //the entry is
                        shouldExtract = !entryName.equals("");
                    }
                    else
                        shouldExtract = true;
                }
                else
                    shouldExtract = (subEntryName == null) || (entryName.startsWith(subEntryName));

                if (!shouldExtract)
                {
                    if (LOG.isDebugEnabled())
                        LOG.debug("Skipping entry: " + entryName);
                    continue;
                }

                String dotCheck = StringUtil.replace(entryName, '\\', '/');
                dotCheck = URIUtil.canonicalPath(dotCheck);
                if (dotCheck == null)
                {
                    if (LOG.isDebugEnabled())
                        LOG.debug("Invalid entry: " + entryName);
                    continue;
                }

                File file = new File(directory, entryName);

                if (entry.isDirectory())
                {
                    // Make directory
                    if (!file.exists())
                        file.mkdirs();
                }
                else
                {
                    // make directory (some jars don't list dirs)
                    File dir = new File(file.getParent());
                    if (!dir.exists())
                        dir.mkdirs();

                    // Make file
                    try (OutputStream fout = new FileOutputStream(file))
                    {
                        IO.copy(jin, fout);
                    }

                    // touch the file.
                    if (entry.getTime() >= 0)
                        file.setLastModified(entry.getTime());
                }
            }

            if ((subEntryName == null) || (subEntryName != null && subEntryName.equalsIgnoreCase("META-INF/MANIFEST.MF")))
            {
                Manifest manifest = jin.getManifest();
                if (manifest != null)
                {
                    File metaInf = new File(directory, "META-INF");
                    metaInf.mkdir();
                    File f = new File(metaInf, "MANIFEST.MF");
                    try (OutputStream fout = new FileOutputStream(f))
                    {
                        manifest.write(fout);
                    }
                }
            }
        }
    }

    public static Resource newJarResource(Resource resource) throws IOException
    {
        if (resource instanceof JarResource)
            return resource;
        return Resource.newResource("jar:" + resource + "!/");
    }
}
