/*******************************************************************************
 *
 * Copyright (c) 2004-2009 Oracle Corporation.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * 
 *    Kohsuke Kawaguchi
 *
 *
 *******************************************************************************/ 

package hudson.util;

import java.io.OutputStream;
import java.io.Writer;
import java.io.IOException;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CodingErrorAction;
import java.nio.charset.CoderResult;
import java.nio.charset.Charset;
import java.nio.charset.UnsupportedCharsetException;
import java.nio.*;

/**
 * {@link OutputStream} that writes to {@link Writer} by assuming the platform
 * default encoding.
 *
 * @author Kohsuke Kawaguchi
 * @deprecated since 2008-05-28. Use the one in stapler.
 */
public class WriterOutputStream extends OutputStream {

    private final Writer writer;
    private final CharsetDecoder decoder;
    private java.nio.ByteBuffer buf = java.nio.ByteBuffer.allocate(1024);
    private CharBuffer out = CharBuffer.allocate(1024);

    public WriterOutputStream(Writer out) {
        this.writer = out;
        decoder = DEFAULT_CHARSET.newDecoder();
        decoder.onMalformedInput(CodingErrorAction.REPLACE);
        decoder.onUnmappableCharacter(CodingErrorAction.REPLACE);
    }

    public void write(int b) throws IOException {
        if (buf.remaining() == 0) {
            decode(false);
        }
        buf.put((byte) b);
    }

    public void write(byte b[], int off, int len) throws IOException {
        while (len > 0) {
            if (buf.remaining() == 0) {
                decode(false);
            }
            int sz = Math.min(buf.remaining(), len);
            buf.put(b, off, sz);
            off += sz;
            len -= sz;
        }
    }

    public void flush() throws IOException {
        decode(false);
        flushOutput();
        writer.flush();
    }

    private void flushOutput() throws IOException {
        writer.write(out.array(), 0, out.position());
        out.clear();
    }

    public void close() throws IOException {
        decode(true);
        flushOutput();
        writer.close();

        buf.rewind();
    }

    /**
     * Decodes the contents of {@link #buf} as much as possible to {@link #out}.
     * If necessary {@link #out} is further sent to {@link #writer}.
     *
     * <p> When this method returns, the {@link #buf} is back to the
     * 'accumulation' mode.
     *
     * @param last if true, tell the decoder that all the input bytes are ready.
     */
    private void decode(boolean last) throws IOException {
        buf.flip();
        while (true) {
            CoderResult r = decoder.decode(buf, out, last);
            if (r == CoderResult.OVERFLOW) {
                flushOutput();
                continue;
            }
            if (r == CoderResult.UNDERFLOW) {
                buf.compact();
                return;
            }
            // otherwise treat it as an error
            r.throwException();
        }
    }
    private static final Charset DEFAULT_CHARSET = getDefaultCharset();

    private static Charset getDefaultCharset() {
        try {
            String encoding = System.getProperty("file.encoding");
            return Charset.forName(encoding);
        } catch (UnsupportedCharsetException e) {
            return Charset.forName("UTF-8");
        }
    }
}