/*
 * ConnectBot: simple, powerful, open-source SSH client for Android
 * Copyright 2007 Kenny Root, Jeffrey Sharkey
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.connectbot.service;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CoderResult;
import java.nio.charset.CodingErrorAction;

import org.apache.harmony.niochar.charset.additional.IBM437;
import org.connectbot.transport.AbsTransport;
import org.connectbot.util.EastAsianWidth;

import android.util.Log;
import de.mud.terminal.vt320;

/**
 * @author Kenny Root
 */
public class Relay implements Runnable {
	private static final String TAG = "CB.Relay";

	private static final int BUFFER_SIZE = 4096;

	private TerminalBridge bridge;

	private Charset currentCharset;
	private CharsetDecoder decoder;

	private AbsTransport transport;

	private vt320 buffer;

	private ByteBuffer byteBuffer;
	private CharBuffer charBuffer;

	private byte[] byteArray;
	private char[] charArray;

	public Relay(TerminalBridge bridge, AbsTransport transport, vt320 buffer, String encoding) {
		setCharset(encoding);
		this.bridge = bridge;
		this.transport = transport;
		this.buffer = buffer;
	}

	public void setCharset(String encoding) {
		Log.d("ConnectBot.Relay", "changing charset to " + encoding);
		Charset charset;
		if (encoding.equals("CP437"))
			charset = new IBM437("IBM437",
					new String[] { "IBM437", "CP437" });
		else
			charset = Charset.forName(encoding);

		if (charset == currentCharset || charset == null)
			return;

		CharsetDecoder newCd = charset.newDecoder();
		newCd.onUnmappableCharacter(CodingErrorAction.REPLACE);
		newCd.onMalformedInput(CodingErrorAction.REPLACE);

		currentCharset = charset;
		synchronized (this) {
			decoder = newCd;
		}
	}

	public Charset getCharset() {
		return currentCharset;
	}

	public void run() {
		byteBuffer = ByteBuffer.allocate(BUFFER_SIZE);
		charBuffer = CharBuffer.allocate(BUFFER_SIZE);

		/* for East Asian character widths */
		byte[] wideAttribute = new byte[BUFFER_SIZE];

		byteArray = byteBuffer.array();
		charArray = charBuffer.array();

		CoderResult result;

		int bytesRead = 0;
		byteBuffer.limit(0);
		int bytesToRead;
		int offset;
		int charWidth;

		EastAsianWidth measurer = EastAsianWidth.getInstance();

		try {
			while (true) {
				charWidth = bridge.charWidth;
				bytesToRead = byteBuffer.capacity() - byteBuffer.limit();
				offset = byteBuffer.arrayOffset() + byteBuffer.limit();
				bytesRead = transport.read(byteArray, offset, bytesToRead);

				if (bytesRead > 0) {
					byteBuffer.limit(byteBuffer.limit() + bytesRead);

					synchronized (this) {
						result = decoder.decode(byteBuffer, charBuffer, false);
					}

					if (result.isUnderflow() &&
							byteBuffer.limit() == byteBuffer.capacity()) {
						byteBuffer.compact();
						byteBuffer.limit(byteBuffer.position());
						byteBuffer.position(0);
					}

					offset = charBuffer.position();

					measurer.measure(charArray, 0, offset, wideAttribute, bridge.defaultPaint, charWidth);
					buffer.putString(charArray, wideAttribute, 0, charBuffer.position());
					bridge.propagateConsoleText(charArray, charBuffer.position());
					charBuffer.clear();
					bridge.redraw();
				}
			}
		} catch (IOException e) {
			Log.e(TAG, "Problem while handling incoming data in relay thread", e);
		}
	}
}