/*
 * 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 com.five_ten_sg.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 com.five_ten_sg.connectbot.transport.AbsTransport;
import android.graphics.Paint;
import android.text.AndroidCharacter;
import android.util.Log;
import de.mud.terminal.vt320;

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

    private void eastAsianWidthMeasure(char[] charArray, int start, int end,
                                       byte[] wideAttribute, Paint paint, int charWidth) {
        AndroidCharacter.getEastAsianWidths(charArray, start, end - start, wideAttribute);
    }

    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;

        try {
            while (true) {
                charWidth = bridge.charWidth;
                bytesToRead = byteBuffer.capacity() - byteBuffer.limit();
                offset = byteBuffer.arrayOffset() + byteBuffer.limit();

                if (transport.willBlock()) buffer.testChanged();

                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();
                    eastAsianWidthMeasure(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);
        }
    }
}