//
//  ========================================================================
//  Copyright (c) 1995-2014 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;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/* ======================================================================== */
/** IO Utilities.
 * Provides stream handling utilities in
 * singleton Threadpool implementation accessed by static members.
 */
public class IO 
{
	private static final Logger LOG = LoggerFactory.getLogger(IO.class);
	
	/* ------------------------------------------------------------------- */
	private static int bufferSize = 64*1024;
	
	/* ------------------------------------------------------------------- */
	/** Copy Stream in to Stream out until EOF or exception.
	 */
	public static void copy(InputStream in, OutputStream out)
		 throws IOException
	{
		copy(in,out,-1);
	}
	
	/* ------------------------------------------------------------------- */
	/** Copy Reader to Writer out until EOF or exception.
	 */
	public static void copy(Reader in, Writer out)
		 throws IOException
	{
		copy(in,out,-1);
	}
	
	/* ------------------------------------------------------------------- */
	/** Copy Stream in to Stream for byteCount bytes or until EOF or exception.
	 */
	public static void copy(InputStream in,
							OutputStream out,
							long byteCount)
		 throws IOException
	{     
		byte buffer[] = new byte[bufferSize];
		int len=bufferSize;
		
		if (byteCount>=0)
		{
			while (byteCount>0)
			{
				int max = byteCount<bufferSize?(int)byteCount:bufferSize;
				len=in.read(buffer,0,max);
				
				if (len==-1)
					break;
				
				byteCount -= len;
				out.write(buffer,0,len);
			}
		}
		else
		{
			while (true)
			{
				len=in.read(buffer,0,bufferSize);
				if (len<0 )
					break;
				out.write(buffer,0,len);
			}
		}
	}  
	
	/* ------------------------------------------------------------------- */
	/** Copy Reader to Writer for byteCount bytes or until EOF or exception.
	 */
	public static void copy(Reader in,
							Writer out,
							long byteCount)
		 throws IOException
	{  
		char buffer[] = new char[bufferSize];
		int len=bufferSize;
		
		if (byteCount>=0)
		{
			while (byteCount>0)
			{
				if (byteCount<bufferSize)
					len=in.read(buffer,0,(int)byteCount);
				else
					len=in.read(buffer,0,bufferSize);                   
				
				if (len==-1)
					break;
				
				byteCount -= len;
				out.write(buffer,0,len);
			}
		}
		else if (out instanceof PrintWriter)
		{
			PrintWriter pout=(PrintWriter)out;
			while (!pout.checkError())
			{
				len=in.read(buffer,0,bufferSize);
				if (len==-1)
					break;
				out.write(buffer,0,len);
			}
		}
		else
		{
			while (true)
			{
				len=in.read(buffer,0,bufferSize);
				if (len==-1)
					break;
				out.write(buffer,0,len);
			}
		}
	}

	/* ------------------------------------------------------------ */
	/** Copy files or directories
	 * @param from
	 * @param to
	 * @throws IOException
	 */
	public static void copy(File from,File to) throws IOException
	{
		if (from.isDirectory())
			copyDir(from,to);
		else
			copyFile(from,to);
	}

	/* ------------------------------------------------------------ */
	public static void copyDir(File from,File to) throws IOException
	{
		if (to.exists())
		{
			if (!to.isDirectory())
				throw new IllegalArgumentException(to.toString());
		}
		else
			to.mkdirs();
		
		File[] files = from.listFiles();
		if (files!=null)
		{
			for (int i=0;i<files.length;i++)
			{
				String name = files[i].getName();
				if (".".equals(name) || "..".equals(name))
					continue;
				copy(files[i],new File(to,name));
			}
		}
	}
	
	/* ------------------------------------------------------------ */
	public static void copyFile(File from,File to) throws IOException
	{
		FileInputStream in=new FileInputStream(from);
		FileOutputStream out=new FileOutputStream(to);
		copy(in,out);
		in.close();
		out.close();
	}
	

	/* ------------------------------------------------------------ */
	/**
	 * closes any {@link Closeable}
	 *
	 * @param c the closeable to close
	 */
	public static void close(Closeable c)
	{
		try
		{
			if (c != null)
				c.close();
		}
		catch (IOException e)
		{
			LOG.trace("",e);
		}
	}
	
	/**
	 * closes an input stream, and logs exceptions
	 *
	 * @param is the input stream to close
	 */
	public static void close(InputStream is)
	{
		try
		{
			if (is != null)
				is.close();
		}
		catch (IOException e)
		{
			LOG.trace("",e);
		}
	}

	/**
	 * closes a reader, and logs exceptions
	 * 
	 * @param reader the reader to close
	 */
	public static void close(Reader reader)
	{
		try
		{
			if (reader != null)
				reader.close();
		} catch (IOException e)
		{
			LOG.trace("",e);
		}
	}

	/**
	 * closes a writer, and logs exceptions
	 * 
	 * @param writer the writer to close
	 */
	public static void close(Writer writer)
	{
		try
		{
			if (writer != null)
				writer.close();
		} catch (IOException e)
		{
			LOG.trace("",e);
		}
	}
	
	/* ------------------------------------------------------------ */
	/**
	 * closes an output stream, and logs exceptions
	 *
	 * @param os the output stream to close
	 */
	public static void close(OutputStream os)
	{
		try
		{
			if (os != null)
				os.close();
		}
		catch (IOException e)
		{
			LOG.trace("",e);
		}
	}

	/* ------------------------------------------------------------ */
	/** 
	 * @return An outputstream to nowhere
	 */
	public static InputStream getClosedStream()
	{
		return __closedStream;
	}
	
	/* ------------------------------------------------------------ */
	/* ------------------------------------------------------------ */
	private static class ClosedIS extends InputStream                                    
	{
		@Override
		public int read() throws IOException
		{
			return -1;
		}
	}
	private static ClosedIS __closedStream = new ClosedIS();
}