//
//  ========================================================================
//  Copyright (c) 1995-2017 Mort Bay Consulting Pty. Ltd.
//  ------------------------------------------------------------------------
//  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.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.channels.FileChannel;
import java.nio.channels.ReadableByteChannel;
import java.nio.file.DirectoryIteratorException;
import java.nio.file.DirectoryStream;
import java.nio.file.Files;
import java.nio.file.InvalidPathException;
import java.nio.file.LinkOption;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import java.nio.file.StandardOpenOption;
import java.nio.file.attribute.FileTime;
import java.util.ArrayList;
import java.util.List;

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

/**
 * Java NIO Path equivalent of FileResource.
 */
public class PathResource extends Resource
{
    private static final Logger LOG = Log.getLogger(PathResource.class);

    private final Path path;
    private final URI uri;
    private LinkOption linkOptions[] = new LinkOption[] { LinkOption.NOFOLLOW_LINKS };

    public PathResource(File file)
    {
        this(file.toPath());
    }

    public PathResource(Path path)
    {
        this.path = path;
        assertValidPath(path);
        this.uri = this.path.toUri();
    }

    public PathResource(URI uri) throws IOException
    {
        if (!uri.isAbsolute())
        {
            throw new IllegalArgumentException("not an absolute uri");
        }

        if (!uri.getScheme().equalsIgnoreCase("file"))
        {
            throw new IllegalArgumentException("not file: scheme");
        }

        Path path;
        try
        {
            path = new File(uri).toPath();
        }
        catch (InvalidPathException e)
        {
            throw e;
        }
        catch (IllegalArgumentException e)
        {
            throw e;
        }
        catch (Exception e)
        {
            LOG.ignore(e);
            throw new IOException("Unable to build Path from: " + uri,e);
        }

        this.path = path;
        this.uri = path.toUri();
    }

    public PathResource(URL url) throws IOException, URISyntaxException
    {
        this(url.toURI());
    }

    @Override
    public Resource addPath(String apath) throws IOException, MalformedURLException
    {
        return new PathResource(this.path.getFileSystem().getPath(path.toString(), apath));
    }

    private void assertValidPath(Path path)
    {
        String str = path.toString();
        int idx = StringUtil.indexOfControlChars(str);
        if(idx >= 0)
        {
            throw new InvalidPathException(str, "Invalid Character at index " + idx);
        }
    }

    @Override
    public void close()
    {
        // not applicable for FileSytem / Path
    }

    @Override
    public boolean delete() throws SecurityException
    {
        try
        {
            return Files.deleteIfExists(path);
        }
        catch (IOException e)
        {
            LOG.ignore(e);
            return false;
        }
    }

    @Override
    public boolean equals(Object obj)
    {
        if (this == obj)
        {
            return true;
        }
        if (obj == null)
        {
            return false;
        }
        if (getClass() != obj.getClass())
        {
            return false;
        }
        PathResource other = (PathResource)obj;
        if (path == null)
        {
            if (other.path != null)
            {
                return false;
            }
        }
        else if (!path.equals(other.path))
        {
            return false;
        }
        return true;
    }

    @Override
    public boolean exists()
    {
        return Files.exists(path,linkOptions);
    }

    @Override
    public File getFile() throws IOException
    {
        return path.toFile();
    }

    public boolean getFollowLinks()
    {
        return (linkOptions != null) && (linkOptions.length > 0) && (linkOptions[0] == LinkOption.NOFOLLOW_LINKS);
    }

    @Override
    public InputStream getInputStream() throws IOException
    {
        return Files.newInputStream(path,StandardOpenOption.READ);
    }

    @Override
    public String getName()
    {
        return path.toAbsolutePath().toString();
    }

    @Override
    public String toString() {
        return path.toString();
    }

    @Override
    public ReadableByteChannel getReadableByteChannel() throws IOException
    {
        return FileChannel.open(path,StandardOpenOption.READ);
    }

    @Override
    public URI getURI()
    {
        return this.uri;
    }

    @Override
    public URL getURL()
    {
        try
        {
            return path.toUri().toURL();
        }
        catch (MalformedURLException e)
        {
            return null;
        }
    }

    @Override
    public int hashCode()
    {
        final int prime = 31;
        int result = 1;
        result = (prime * result) + ((path == null)?0:path.hashCode());
        return result;
    }

    @Override
    public boolean isContainedIn(Resource r) throws MalformedURLException
    {
        // not applicable for FileSystem / path
        return false;
    }

    @Override
    public boolean isDirectory()
    {
        return Files.isDirectory(path,linkOptions);
    }

    @Override
    public long lastModified()
    {
        try
        {
            FileTime ft = Files.getLastModifiedTime(path,linkOptions);
            return ft.toMillis();
        }
        catch (IOException e)
        {
            LOG.ignore(e);
            return 0;
        }
    }

    @Override
    public long length()
    {
        try
        {
            return Files.size(path);
        }
        catch (IOException e)
        {
            // in case of error, use File.length logic of 0L
            return 0L;
        }
    }

    @Override
    public URI getAlias()
    {
        if (Files.isSymbolicLink(path))
        {
            try
            {
                return path.toRealPath().toUri();
            }
            catch (IOException e)
            {
                LOG.debug(e);
                return null;
            }
        }
        else
        {
            return null;
        }
    }

    @Override
    public String[] list()
    {
        try (DirectoryStream<Path> dir = Files.newDirectoryStream(path))
        {
            List<String> entries = new ArrayList<>();
            for (Path entry : dir)
            {
                String name = entry.getFileName().toString();

                if (Files.isDirectory(entry))
                {
                    name += "/";
                }

                entries.add(name);
            }
            int size = entries.size();
            return entries.toArray(new String[size]);
        }
        catch (DirectoryIteratorException e)
        {
            LOG.debug(e);
        }
        catch (IOException e)
        {
            LOG.debug(e);
        }
        return null;
    }

    @Override
    public boolean renameTo(Resource dest) throws SecurityException
    {
        if (dest instanceof PathResource)
        {
            PathResource destRes = (PathResource)dest;
            try
            {
                Path result = Files.move(path,destRes.path,StandardCopyOption.ATOMIC_MOVE);
                return Files.exists(result,linkOptions);
            }
            catch (IOException e)
            {
                LOG.ignore(e);
                return false;
            }
        }
        else
        {
            return false;
        }
    }

    public void setFollowLinks(boolean followLinks)
    {
        if (followLinks)
        {
            linkOptions = new LinkOption[0];
        }
        else
        {
            linkOptions = new LinkOption[] { LinkOption.NOFOLLOW_LINKS };
        }
    }
}
