/*******************************************************************************
 *
 * Copyright (c) 2004-2010, 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:
 *
 *
 *
 *
 *******************************************************************************/ 

package hudson.console;

import hudson.util.ByteArrayOutputStream2;

import java.io.IOException;
import java.io.OutputStream;

/**
 * Filtering {@link OutputStream} that buffers text by line, so that the derived
 * class can perform some manipulation based on the contents of the whole line.
 *
 * TODO: Mac is supposed to be CR-only. This class needs to handle that.
 *
 * @author Kohsuke Kawaguchi
 * @since 1.349
 */
public abstract class LineTransformationOutputStream extends OutputStream {

    private ByteArrayOutputStream2 buf = new ByteArrayOutputStream2();

    /**
     * Called for each end of the line.
     *
     * @param b Contents of the whole line, including the EOL code like CR/LF.
     * @param len Specifies the length of the valid contents in 'b'. The rest is
     * garbage. This is so that the caller doesn't have to allocate an array of
     * the exact size.
     */
    protected abstract void eol(byte[] b, int len) throws IOException;

    public void write(int b) throws IOException {
        buf.write(b);
        if (b == LF) {
            eol();
        }
    }

    private void eol() throws IOException {
        eol(buf.getBuffer(), buf.size());

        // reuse the buffer under normal circumstances, but don't let the line buffer grow unbounded
        if (buf.size() > 4096) {
            buf = new ByteArrayOutputStream2();
        } else {
            buf.reset();
        }
    }

    @Override
    public void write(byte[] b, int off, int len) throws IOException {
        int end = off + len;

        for (int i = off; i < end; i++) {
            write(b[i]);
        }
    }

    @Override
    public void close() throws IOException {
        forceEol();
    }

    /**
     * Forces the EOL behavior.
     *
     * Useful if the caller wants to make sure the buffered content is all
     * processed, but without actually neither flushing nor closing the stream.
     */
    public void forceEol() throws IOException {
        if (buf.size() > 0) {
            /*
             because LargeText cuts output at the line end boundary, this is
             possible only for the very end of the console output, if the output ends without NL.
             */
            eol();
        }
    }

    protected String trimEOL(String line) {
        int slen = line.length();
        while (slen > 0) {
            char ch = line.charAt(slen - 1);
            if (ch == '\r' || ch == '\n') {
                slen--;
                continue;
            }
            break;
        }
        line = line.substring(0, slen);
        return line;
    }
    private static final int LF = 0x0A;
}