/*
 * Copyright 2012 - 2014 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.nio.charset.Charset;
import java.net.SocketAddress;
import java.util.Calendar;
import java.util.Date;
import java.util.LinkedList;
import java.util.List;
import java.util.TimeZone;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.channel.Channel;

import org.traccar.BaseProtocolDecoder;
import org.traccar.helper.ChannelBufferTools;
import org.traccar.helper.UnitsConverter;
import org.traccar.model.Event;
import org.traccar.model.Position;

public class MeitrackProtocolDecoder extends BaseProtocolDecoder {

    public MeitrackProtocolDecoder(MeitrackProtocol protocol) {
        super(protocol);
    }

    private static final Pattern pattern = Pattern.compile(
            "\\$\\$." +                         // Flag
            "\\d+," +                           // Length
            "(\\d+)," +                         // IMEI
            "\\p{XDigit}{3}," +                 // Command
            "(?:\\d+,)?" +
            "(\\d+)," +                         // Event
            "(-?\\d+\\.\\d+)," +                // Latitude
            "(-?\\d+\\.\\d+)," +                // Longitude
            "(\\d{2})(\\d{2})(\\d{2})" +        // Date (YYMMDD)
            "(\\d{2})(\\d{2})(\\d{2})," +       // Time (HHMMSS)
            "([AV])," +                         // Validity
            "(\\d+)," +                         // Satellites
            "(\\d+)," +                         // GSM Signal
            "(\\d+\\.?\\d*)," +                 // Speed
            "(\\d+)," +                         // Course
            "(\\d+\\.?\\d*)," +                 // HDOP
            "(-?\\d+)," +                       // Altitude
            "(\\d+)," +                         // Odometer
            "(\\d+)," +                         // Runtime
            "(\\d+\\|\\d+\\|\\p{XDigit}+\\|\\p{XDigit}+)," + // Cell
            "(\\p{XDigit}+)," +                 // State
            "(\\p{XDigit}+)?\\|" +              // ADC1
            "(\\p{XDigit}+)?\\|" +              // ADC2
            "(\\p{XDigit}+)?\\|" +              // ADC3
            "(\\p{XDigit}+)\\|" +               // Battery
            "(\\p{XDigit}+)," +                 // Power
            "(?:([^,]+)?," +                    // Event Specific
            "[^,]*," +                          // Reserved
            "\\d*," +                           // Protocol
            "(\\p{XDigit}{4})?)?" +              // Fuel
            ".*\\*\\p{XDigit}{2}(?:\r\n)?");

    private Position decodeRegularMessage(Channel channel, ChannelBuffer buf) {

        // Parse message
        String sentence = buf.toString(Charset.defaultCharset());
        Matcher parser = pattern.matcher(sentence);
        if (!parser.matches()) {
            return null;
        }

        // Create new position
        Position position = new Position();
        position.setProtocol(getProtocolName());

        Integer index = 1;

        // Identification
        if (!identify(parser.group(index++), channel)) {
            return null;
        }
        position.setDeviceId(getDeviceId());

        // Event
        int event = Integer.parseInt(parser.group(index++));
        position.set(Event.KEY_EVENT, event);

        // Coordinates
        position.setLatitude(Double.valueOf(parser.group(index++)));
        position.setLongitude(Double.valueOf(parser.group(index++)));

        // Time
        Calendar time = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
        time.clear();
        time.set(Calendar.YEAR, 2000 + Integer.parseInt(parser.group(index++)));
        time.set(Calendar.MONTH, Integer.parseInt(parser.group(index++)) - 1);
        time.set(Calendar.DAY_OF_MONTH, Integer.parseInt(parser.group(index++)));
        time.set(Calendar.HOUR_OF_DAY, Integer.parseInt(parser.group(index++)));
        time.set(Calendar.MINUTE, Integer.parseInt(parser.group(index++)));
        time.set(Calendar.SECOND, Integer.parseInt(parser.group(index++)));
        position.setTime(time.getTime());

        // Validity
        position.setValid(parser.group(index++).compareTo("A") == 0);

        // Satellites
        position.set(Event.KEY_SATELLITES, parser.group(index++));

        // GSM Signal
        position.set(Event.KEY_GSM, parser.group(index++));

        // Speed
        position.setSpeed(UnitsConverter.knotsFromKph(Double.valueOf(parser.group(index++))));

        // Course
        position.setCourse(Double.valueOf(parser.group(index++)));

        // HDOP
        position.set(Event.KEY_HDOP, parser.group(index++));

        // Altitude
        position.setAltitude(Double.valueOf(parser.group(index++)));

        // Other
        position.set(Event.KEY_ODOMETER, parser.group(index++));
        position.set("runtime", parser.group(index++));
        position.set(Event.KEY_CELL, parser.group(index++));
        position.set(Event.KEY_STATUS, parser.group(index++));

        // ADC
        String adc1 = parser.group(index++);
        if (adc1 != null) {
            position.set(Event.PREFIX_ADC + 1, Integer.parseInt(adc1, 16));
        }
        String adc2 = parser.group(index++);
        if (adc2 != null) {
            position.set(Event.PREFIX_ADC + 2, Integer.parseInt(adc2, 16));
        }
        String adc3 = parser.group(index++);
        if (adc3 != null) {
            position.set(Event.PREFIX_ADC + 3, Integer.parseInt(adc3, 16));
        }
        position.set(Event.KEY_BATTERY, Integer.parseInt(parser.group(index++), 16));
        position.set(Event.KEY_POWER, Integer.parseInt(parser.group(index++), 16));

        // Event specific
        String data = parser.group(index++);
        if (data != null && !data.isEmpty()) {
            switch (event) {
                case 37:
                    position.set(Event.KEY_RFID, data);
                    break;
            }
        }

        // Fuel
        String fuel = parser.group(index++);
        if (fuel != null) {
            position.set(Event.KEY_FUEL,
                    Integer.parseInt(fuel.substring(0, 2), 16) + Integer.parseInt(fuel.substring(2), 16) * 0.01);
        }

        return position;
    }

    private List<Position> decodeBinaryMessage(Channel channel, ChannelBuffer buf) {
        List<Position> positions = new LinkedList<>();

        String flag = buf.toString(2, 1, Charset.defaultCharset());
        int index = ChannelBufferTools.find(buf, 0, buf.readableBytes(), ",");

        // Identification
        String imei = buf.toString(index + 1, 15, Charset.defaultCharset());
        if (!identify(imei, channel)) {
            return null;
        }

        buf.skipBytes(index + 1 + 15 + 1 + 3 + 1 + 2 + 2 + 4);

        while (buf.readableBytes() >= 0x34) {

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

            // Event
            position.set(Event.KEY_EVENT, buf.readUnsignedByte());

            // Location
            position.setLatitude(buf.readInt() * 0.000001);
            position.setLongitude(buf.readInt() * 0.000001);

            // Time (946684800 - timestamp for 2000-01-01)
            position.setTime(new Date((946684800 + buf.readUnsignedInt()) * 1000));

            // Validity
            position.setValid(buf.readUnsignedByte() == 1);

            // Satellites
            position.set(Event.KEY_SATELLITES, buf.readUnsignedByte());

            // GSM Signal
            position.set(Event.KEY_GSM, buf.readUnsignedByte());

            // Speed
            position.setSpeed(UnitsConverter.knotsFromKph(buf.readUnsignedShort()));

            // Course
            position.setCourse(buf.readUnsignedShort());

            // HDOP
            position.set(Event.KEY_HDOP, buf.readUnsignedShort() * 0.1);

            // Altitude
            position.setAltitude(buf.readUnsignedShort());

            // Other
            position.set(Event.KEY_ODOMETER, buf.readUnsignedInt());
            position.set("runtime", buf.readUnsignedInt());
            position.set(Event.KEY_CELL,
                    buf.readUnsignedShort() + "|" + buf.readUnsignedShort() + "|" +
                    buf.readUnsignedShort() + "|" + buf.readUnsignedShort());
            position.set(Event.KEY_STATUS, buf.readUnsignedShort());

            // ADC
            position.set(Event.PREFIX_ADC + 1, buf.readUnsignedShort());
            position.set(Event.KEY_BATTERY, buf.readUnsignedShort() * 0.01);
            position.set(Event.KEY_POWER, buf.readUnsignedShort());

            buf.readUnsignedInt(); // geo-fence
            positions.add(position);
        }

        // Delete recorded data
        if (channel != null) {
            StringBuilder command = new StringBuilder("@@");
            command.append(flag).append(27 + positions.size() / 10).append(",");
            command.append(imei).append(",CCC,").append(positions.size()).append("*");
            int checksum = 0;
            for (int i = 0; i < command.length(); i += 1) checksum += command.charAt(i);
            command.append(String.format("%02x\r\n", checksum & 0xff).toUpperCase());
            channel.write(command.toString());
        }

        return positions;
    }

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

        ChannelBuffer buf = (ChannelBuffer) msg;

        // Find type
        Integer index = ChannelBufferTools.find(buf, 0, buf.readableBytes(), ",");
        index = ChannelBufferTools.find(buf, index + 1, buf.readableBytes(), ",");

        String type = buf.toString(index + 1, 3, Charset.defaultCharset());
        if (type.equals("CCC")) {
            return decodeBinaryMessage(channel, buf);
        } else {
            return decodeRegularMessage(channel, buf);
        }
    }

}