/*
 * 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 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.Checksum;
import org.traccar.helper.DateBuilder;
import org.traccar.helper.UnitsConverter;
import org.traccar.model.Event;
import org.traccar.model.Position;

import java.net.SocketAddress;
import java.nio.charset.Charset;
import java.util.TimeZone;

public class HuabaoProtocolDecoder extends BaseProtocolDecoder {

    public HuabaoProtocolDecoder(HuabaoProtocol protocol) {
        super(protocol);
    }

    public static final int MSG_GENERAL_RESPONSE = 0x8001;
    public static final int MSG_TERMINAL_REGISTER = 0x0100;
    public static final int MSG_TERMINAL_REGISTER_RESPONSE = 0x8100;
    public static final int MSG_TERMINAL_AUTH = 0x0102;
    public static final int MSG_LOCATION_REPORT = 0x0200;

    public static final int RESULT_SUCCESS = 0;

    private void sendResponse(
            Channel channel, SocketAddress remoteAddress, int type, ChannelBuffer id, ChannelBuffer data) {
        ChannelBuffer response = ChannelBuffers.dynamicBuffer();
        response.writeByte(0x7e);
        response.writeShort(type);
        response.writeShort(data.readableBytes());
        response.writeBytes(id);
        response.writeShort(1); // index
        response.writeBytes(data);
        response.writeByte(Checksum.xor(response.toByteBuffer(1, response.readableBytes() - 1)));
        response.writeByte(0x7e);
        if (channel != null) {
            channel.write(response, remoteAddress);
        }
    }

    private void sendGeneralResponse(
            Channel channel, SocketAddress remoteAddress, ChannelBuffer id, int type, int index) {
        ChannelBuffer response = ChannelBuffers.dynamicBuffer();
        response.writeShort(index);
        response.writeShort(type);
        response.writeByte(RESULT_SUCCESS);
        sendResponse(channel, remoteAddress, MSG_GENERAL_RESPONSE, id, response);
    }

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

        ChannelBuffer buf = (ChannelBuffer) msg;

        buf.readUnsignedByte(); // start marker
        int type = buf.readUnsignedShort();
        buf.readUnsignedShort(); // body length
        ChannelBuffer id = buf.readBytes(6); // phone number
        int index = buf.readUnsignedShort();

        if (!identify(id.toString(Charset.defaultCharset()), channel, remoteAddress)) {
            return null;
        }

        if (type == MSG_TERMINAL_REGISTER) {

            ChannelBuffer response = ChannelBuffers.dynamicBuffer();
            response.writeShort(index);
            response.writeByte(RESULT_SUCCESS);
            response.writeBytes("authentication".getBytes(Charset.defaultCharset()));
            sendResponse(channel, remoteAddress, MSG_TERMINAL_REGISTER_RESPONSE, id, response);

        } else if (type == MSG_TERMINAL_AUTH) {

            sendGeneralResponse(channel, remoteAddress, id, type, index);

        } else if (type == MSG_LOCATION_REPORT) {

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

            position.set(Event.KEY_ALARM, buf.readUnsignedInt());

            int flags = buf.readInt();

            position.set(Event.KEY_IGNITION, BitUtil.check(flags, 0));

            position.setValid(BitUtil.check(flags, 1));

            double lat = buf.readUnsignedInt() * 0.000001;
            double lon = buf.readUnsignedInt() * 0.000001;

            if (BitUtil.check(flags, 2)) {
                position.setLatitude(-lat);
            } else {
                position.setLatitude(lat);
            }

            if (BitUtil.check(flags, 3)) {
                position.setLongitude(-lon);
            } else {
                position.setLongitude(lon);
            }

            position.setAltitude(buf.readShort());
            position.setSpeed(UnitsConverter.knotsFromKph(buf.readUnsignedShort() * 0.1));
            position.setCourse(buf.readUnsignedShort());

            DateBuilder dateBuilder = new DateBuilder(TimeZone.getTimeZone("GMT+8"))
                    .setYear(ChannelBufferTools.readHexInteger(buf, 2))
                    .setMonth(ChannelBufferTools.readHexInteger(buf, 2))
                    .setDay(ChannelBufferTools.readHexInteger(buf, 2))
                    .setHour(ChannelBufferTools.readHexInteger(buf, 2))
                    .setMinute(ChannelBufferTools.readHexInteger(buf, 2))
                    .setSecond(ChannelBufferTools.readHexInteger(buf, 2));
            position.setTime(dateBuilder.getDate());

            // additional information

            return position;

        }

        return null;
    }

}