/*
 * Copyright 2013 - 2017 Anton Tananaev (anton@traccar.org)
 *
 * 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 org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.Channel;
import org.traccar.BaseProtocolDecoder;
import org.traccar.DeviceSession;
import org.traccar.model.Position;

import java.net.SocketAddress;
import java.nio.ByteOrder;
import java.nio.charset.StandardCharsets;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class GalileoProtocolDecoder extends BaseProtocolDecoder {

    public GalileoProtocolDecoder(GalileoProtocol protocol) {
        super(protocol);
    }

    private static final Map<Integer, Integer> TAG_LENGTH_MAP = new HashMap<>();

    static {
        int[] l1 = {
            0x01, 0x02, 0x35, 0x43, 0xc4, 0xc5, 0xc6, 0xc7,
            0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
            0xd0, 0xd1, 0xd2, 0xd5, 0x88, 0x8a, 0x8b, 0x8c,
            0xa0, 0xaf, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6,
            0xa7, 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae
        };
        int[] l2 = {
            0x04, 0x10, 0x34, 0x40, 0x41, 0x42, 0x45, 0x46,
            0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x60, 0x61,
            0x62, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76,
            0x77, 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
            0xb7, 0xb8, 0xb9, 0xd6, 0xd7, 0xd8, 0xd9, 0xda
        };
        int[] l3 = {
            0x63, 0x64, 0x6f, 0x5d, 0x65, 0x66, 0x67, 0x68,
            0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e
        };
        int[] l4 = {
            0x20, 0x33, 0x44, 0x90, 0xc0, 0xc2, 0xc3, 0xd3,
            0xd4, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, 0xf0, 0xf9,
            0x5a, 0x47, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6,
            0xf7, 0xf8, 0xe2, 0xe9
        };
        for (int i : l1) {
            TAG_LENGTH_MAP.put(i, 1);
        }
        for (int i : l2) {
            TAG_LENGTH_MAP.put(i, 2);
        }
        for (int i : l3) {
            TAG_LENGTH_MAP.put(i, 3);
        }
        for (int i : l4) {
            TAG_LENGTH_MAP.put(i, 4);
        }
        TAG_LENGTH_MAP.put(0x5b, 7); // variable length
        TAG_LENGTH_MAP.put(0x5c, 68);
    }

    private static int getTagLength(int tag) {
        Integer length = TAG_LENGTH_MAP.get(tag);
        if (length == null) {
            throw new IllegalArgumentException("Unknown tag: " + tag);
        }
        return length;
    }

    private void sendReply(Channel channel, int checksum) {
        ChannelBuffer reply = ChannelBuffers.directBuffer(ByteOrder.LITTLE_ENDIAN, 3);
        reply.writeByte(0x02);
        reply.writeShort((short) checksum);
        if (channel != null) {
            channel.write(reply);
        }
    }

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

        ChannelBuffer buf = (ChannelBuffer) msg;

        buf.readUnsignedByte(); // header
        int length = (buf.readUnsignedShort() & 0x7fff) + 3;

        List<Position> positions = new LinkedList<>();
        Set<Integer> tags = new HashSet<>();
        boolean hasLocation = false;

        Position position = new Position();

        while (buf.readerIndex() < length) {

            // Check if new message started
            int tag = buf.readUnsignedByte();
            if (tags.contains(tag)) {
                if (hasLocation && position.getFixTime() != null) {
                    positions.add(position);
                }
                tags.clear();
                hasLocation = false;
                position = new Position();
            }
            tags.add(tag);

            switch (tag) {
                case 0x01:
                    position.set(Position.KEY_VERSION_HW, buf.readUnsignedByte());
                    break;
                case 0x02:
                    position.set(Position.KEY_VERSION_FW, buf.readUnsignedByte());
                    break;
                case 0x03:
                    getDeviceSession(channel, remoteAddress, buf.readBytes(15).toString(StandardCharsets.US_ASCII));
                    break;
                case 0x04:
                    position.set("deviceId", buf.readUnsignedShort());
                    break;
                case 0x10:
                    position.set(Position.KEY_INDEX, buf.readUnsignedShort());
                    break;
                case 0x20:
                    position.setTime(new Date(buf.readUnsignedInt() * 1000));
                    break;
                case 0x30:
                    hasLocation = true;
                    position.setValid((buf.readUnsignedByte() & 0xf0) == 0x00);
                    position.setLatitude(buf.readInt() / 1000000.0);
                    position.setLongitude(buf.readInt() / 1000000.0);
                    break;
                case 0x33:
                    position.setSpeed(buf.readUnsignedShort() * 0.0539957);
                    position.setCourse(buf.readUnsignedShort() * 0.1);
                    break;
                case 0x34:
                    position.setAltitude(buf.readShort());
                    break;
                case 0x40:
                    position.set(Position.KEY_STATUS, buf.readUnsignedShort());
                    break;
                case 0x41:
                    position.set(Position.KEY_POWER, buf.readUnsignedShort());
                    break;
                case 0x42:
                    position.set(Position.KEY_BATTERY, buf.readUnsignedShort());
                    break;
                case 0x43:
                    position.set(Position.KEY_DEVICE_TEMP, buf.readByte());
                    break;
                case 0x44:
                    position.set(Position.KEY_ACCELERATION, buf.readUnsignedInt());
                    break;
                case 0x45:
                    position.set(Position.KEY_OUTPUT, buf.readUnsignedShort());
                    break;
                case 0x46:
                    position.set(Position.KEY_INPUT, buf.readUnsignedShort());
                    break;
                case 0xd4:
                    position.set(Position.KEY_ODOMETER, buf.readUnsignedInt());
                    break;
                case 0xc1:
                    position.set(Position.KEY_FUEL, buf.readUnsignedByte() * 0.4);
                    position.set(Position.PREFIX_TEMP + 1, buf.readUnsignedByte() - 40);
                    position.set(Position.KEY_RPM, buf.readUnsignedShort() * 0.125);
                    break;
                case 0x50:
                    position.set(Position.PREFIX_ADC + 0, buf.readUnsignedShort());
                    break;
                case 0x51:
                    position.set(Position.PREFIX_ADC + 1, buf.readUnsignedShort());
                    break;
                case 0x52:
                    position.set(Position.PREFIX_ADC + 2, buf.readUnsignedShort());
                    break;
                case 0x53:
                    position.set(Position.PREFIX_ADC + 3, buf.readUnsignedShort());
                    break;
                case 0xe2:
                    position.set("userData", buf.readUnsignedInt());
                    break;
                case 0xea:
                    position.set("userDataArray", ChannelBuffers.hexDump(buf.readBytes(buf.readUnsignedByte())));
                    break;
                default:
                    buf.skipBytes(getTagLength(tag));
                    break;
            }
        }
        if (hasLocation && position.getFixTime() != null) {
            positions.add(position);
        }

        DeviceSession deviceSession = getDeviceSession(channel, remoteAddress);
        if (deviceSession == null) {
            return null;
        }

        sendReply(channel, buf.readUnsignedShort());

        for (Position p : positions) {
            p.setProtocol(getProtocolName());
            p.setDeviceId(deviceSession.getDeviceId());
        }

        if (positions.isEmpty()) {
            return null;
        }
        return positions;
    }

}