/*
 * Copyright 2015 Anton Tananaev (anton.tananaev@gmail.com)
 *
 * 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.traccar.protocol;

import java.net.SocketAddress;
import java.nio.ByteOrder;
import java.nio.charset.Charset;
import java.util.Date;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.Channel;
import org.traccar.BaseProtocolDecoder;
import org.traccar.helper.BitUtil;
import org.traccar.helper.ChannelBufferTools;
import org.traccar.helper.UnitsConverter;
import org.traccar.model.Event;
import org.traccar.model.Position;

public class TytanProtocolDecoder extends BaseProtocolDecoder {

    public TytanProtocolDecoder(TytanProtocol protocol) {
        super(protocol);
    }

    private static float readSwappedFloat(ChannelBuffer buf) {
        byte[] bytes = new byte[4];
        buf.readBytes(bytes);
        return ChannelBuffers.wrappedBuffer(ByteOrder.LITTLE_ENDIAN, bytes).readFloat();
    }

    @Override
    protected Object decode(
            Channel channel, SocketAddress remoteAddress, Object msg)
            throws Exception {

        ChannelBuffer buf = (ChannelBuffer) msg;

        buf.readUnsignedByte(); // protocol
        buf.readUnsignedShort(); // length
        int index = buf.readUnsignedByte() >> 3;

        if (channel != null) {
            ChannelBuffer response = ChannelBuffers.copiedBuffer(
                    "^" + index, Charset.defaultCharset());
            channel.write(response, remoteAddress);
        }

        String id = String.valueOf(buf.readUnsignedInt());
        if (!identify(id, channel, remoteAddress)) {
            return null;
        }

        List<Position> positions = new LinkedList<>();

        while (buf.readableBytes() > 2) {

            Position position = new Position();
            position.setProtocol(getProtocolName());
            position.setDeviceId(getDeviceId());

            int end = buf.readerIndex() + buf.readUnsignedByte();

            position.setTime(new Date(buf.readUnsignedInt() * 1000));

            int flags = buf.readUnsignedByte();
            position.set(Event.KEY_SATELLITES, BitUtil.range(flags, 2));
            position.setValid(BitUtil.range(flags, 0, 2) > 0);

            // Latitude
            double lat = buf.readUnsignedMedium();
            lat = lat * -180 / 16777216 + 90;
            position.setLatitude(lat);

            // Longitude
            double lon = buf.readUnsignedMedium();
            lon = lon * 360 / 16777216 - 180;
            position.setLongitude(lon);

            // Status
            flags = buf.readUnsignedByte();
            position.set(Event.KEY_IGNITION, BitUtil.check(flags, 0));
            position.set(Event.KEY_GSM, BitUtil.range(flags, 2, 3));
            position.setCourse((BitUtil.range(flags, 5) * 45 + 180) % 360);

            // Speed
            int speed = buf.readUnsignedByte();
            if (speed < 250) {
                position.setSpeed(UnitsConverter.knotsFromKph(speed));
            }

            while (buf.readerIndex() < end) {

                int type = buf.readUnsignedByte();
                int length = buf.readUnsignedByte();
                if (length == 255) {
                    length += buf.readUnsignedByte();
                }

                switch (type) {
                    case 2:
                        position.set(Event.KEY_ODOMETER, buf.readUnsignedMedium() * 5);
                        break;
                    case 5:
                        position.set(Event.KEY_INPUT, buf.readUnsignedByte());
                        break;
                    case 6:
                        {
                            int n = buf.readUnsignedByte() >> 4;
                            if (n < 2) {
                                position.set(Event.PREFIX_ADC + n, readSwappedFloat(buf));
                            } else {
                                position.set("di" + (n - 2), readSwappedFloat(buf));
                            }
                        }
                        break;
                    case 7:
                        {
                            int alarm = buf.readUnsignedByte();
                            buf.readUnsignedByte();
                            if (BitUtil.check(alarm, 5)) {
                                position.set(Event.KEY_ALARM, BitUtil.range(alarm, 0, 4));
                            }
                        }
                        break;
                    case 8:
                        position.set("antihijack", buf.readUnsignedByte());
                        break;
                    case 9:
                        position.set("authorized", ChannelBufferTools.readHexString(buf, 16));
                        break;
                    case 10:
                        position.set("unauthorized", ChannelBufferTools.readHexString(buf, 16));
                        break;
                    case 24:
                        {
                            Set<Integer> temps = new LinkedHashSet<>();
                            int temp = buf.readUnsignedByte();
                            for (int i = 3; i >= 0; i--) {
                                int n = (temp >> (2 * i)) & 0x03;
                                if (!temps.contains(n)) {
                                    temps.add(n);
                                }
                            }
                            for (int n : temps) {
                                position.set(Event.PREFIX_TEMP + n, buf.readUnsignedByte());
                            }
                        }
                        break;
                    case 28:
                        position.set("weight", buf.readUnsignedShort());
                        buf.readUnsignedByte();
                        break;
                    case 90:
                        position.set(Event.KEY_POWER, readSwappedFloat(buf));
                        break;
                    case 101:
                        position.set(Event.KEY_OBD_SPEED, buf.readUnsignedByte());
                        break;
                    case 102:
                        position.set(Event.KEY_RPM, buf.readUnsignedByte() * 50);
                        break;
                    case 107:
                        {
                            int fuel = buf.readUnsignedShort();
                            switch (fuel >> 16) {
                                case 1:
                                    position.set(Event.KEY_FUEL, (buf.readUnsignedShort() & 0x3fff) * 0.4 + "%");
                                    break;
                                case 2:
                                    position.set(Event.KEY_FUEL, (buf.readUnsignedShort() & 0x3fff) * 0.5 + "l");
                                    break;
                                case 3:
                                    position.set(Event.KEY_FUEL, (buf.readUnsignedShort() & 0x3fff) * -0.5 + "l");
                                    break;
                            }
                        }
                        break;
                    case 108:
                        position.set(Event.KEY_OBD_ODOMETER, buf.readUnsignedInt() * 5);
                        break;
                    case 150:
                        position.set("door", buf.readUnsignedByte());
                        break;
                    default:
                        buf.skipBytes(length);
                        break;
                }
            }

            positions.add(position);
        }

        return positions;
    }

}

@@ -4079,20 +4079,16 @@
 Medium()
- * 5
 );%0A     
@@ -7052,17 +7052,17 @@
 uel %3E%3E 1
-6
+4
 ) %7B%0A    
@@ -7163,39 +7163,20 @@
 _FUEL, (
-buf.readUnsignedShort()
+fuel
  & 0x3ff
@@ -7341,39 +7341,20 @@
 _FUEL, (
-buf.readUnsignedShort()
+fuel
  & 0x3ff
@@ -7361,24 +7361,25 @@
 f) * 0.5 + %22
+ 
 l%22);%0A       
@@ -7520,39 +7520,20 @@
 _FUEL, (
-buf.readUnsignedShort()
+fuel
  & 0x3ff
@@ -7545,16 +7545,17 @@
 -0.5 + %22
+ 
 l%22);%0A   

Fix minor issues in Tytan decoder