/*
 * Copyright 2012 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.util.Calendar;
import java.util.TimeZone;
import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBuffers;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.traccar.GenericProtocolDecoder;
import org.traccar.helper.Log;
import org.traccar.model.DataManager;
import org.traccar.model.Position;

/**
 * Progress tracker protocol decoder
 */
public class ProgressProtocolDecoder extends GenericProtocolDecoder {

    /**
     * Device ID
     */
    private long deviceId;

    /**
     * Initialize
     */
    public ProgressProtocolDecoder(DataManager dataManager) {
        super(dataManager);
    }

    /*
     * Message types
     */
    private static final int MSG_NULL = 0;
    private static final int MSG_IDENT = 1;
    private static final int MSG_IDENT_FULL = 2;
    private static final int MSG_POINT = 10;
    private static final int MSG_LOG_SYNC = 100;
    private static final int MSG_LOGMSG = 101;
    private static final int MSG_TEXT = 102;
    private static final int MSG_ALARM = 200;
    private static final int MSG_ALARM_RECIEVED = 201;
    
    private static final String HEX_CHARS = "0123456789ABCDEF";

    /**
     * Decode message
     */
    @Override
    protected Object decode(
            ChannelHandlerContext ctx, Channel channel, Object msg)
            throws Exception {

        ChannelBuffer buf = (ChannelBuffer) msg;
        int type = buf.readUnsignedShort();
        int length = buf.readUnsignedShort();

        // Authentication
        if (type == MSG_IDENT || type == MSG_IDENT_FULL) {
            long id = buf.readUnsignedInt();
            length = buf.readUnsignedShort();
            buf.skipBytes(length);
            length = buf.readUnsignedShort();
            buf.skipBytes(length);
            length = buf.readUnsignedShort();
            String imei = buf.readBytes(length).toString(Charset.defaultCharset());
            try {
                deviceId = getDataManager().getDeviceByImei(imei).getId();
            } catch(Exception error) {
                Log.warning("Unknown device - " + imei + " (id - " + id + ")");
            }
        }

        // Position
        else if (deviceId != 0 && (type == MSG_POINT || type == MSG_ALARM)) {
            Position position = new Position();
            StringBuilder extendedInfo = new StringBuilder("<protocol>progress</protocol>");
            position.setDeviceId(deviceId);

            // Message index
            position.setId(buf.readUnsignedInt());

            // Time
            Calendar time = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
            time.clear();
            time.setTimeInMillis(buf.readUnsignedInt() * 1000);
            position.setTime(time.getTime());

            // Latitude
            position.setLatitude(((double) buf.readInt()) / 0x7FFFFFFF * 180.0);

            // Longitude
            position.setLongitude(((double) buf.readInt()) / 0x7FFFFFFF * 180.0);

            // Speed
            position.setSpeed(((double) buf.readUnsignedInt()) / 100);

            // Course
            position.setCourse(((double) buf.readUnsignedShort()) / 100);

            // Altitude
            position.setAltitude(((double) buf.readUnsignedShort()) / 100);

            // Satellites
            int satellitesNumber = buf.readUnsignedByte();
            extendedInfo.append("<satellites>");
            extendedInfo.append(satellitesNumber);
            extendedInfo.append("</satellites>");

            // Validity
            position.setValid(satellitesNumber >= 3); // TODO: probably wrong

            // Cell signal
            extendedInfo.append("<gsm>");
            extendedInfo.append(buf.readUnsignedByte());
            extendedInfo.append("</gsm>");

            // Milage
            extendedInfo.append("<milage>");
            extendedInfo.append(buf.readUnsignedInt());
            extendedInfo.append("</milage>");
            
            long extraFlags = buf.readLong();

            // Analog inputs
            if ((extraFlags & 0x1) == 0x1) {
                int count = buf.readUnsignedShort();
                for (int i = 1; i <= count; i++) {
                    extendedInfo.append("<adc").append(i).append(">");
                    extendedInfo.append(buf.readUnsignedShort());
                    extendedInfo.append("</adc").append(i).append(">");
                }
                
            }

            // CAN adapter
            if ((extraFlags & 0x2) == 0x2) {
                int size = buf.readUnsignedShort();
                extendedInfo.append("<can>");
                extendedInfo.append(buf.toString(buf.readerIndex(), size, Charset.defaultCharset()));
                extendedInfo.append("</can>");
                buf.skipBytes(size);
            }
            
            // Passenger sensor
            if ((extraFlags & 0x4) == 0x4) {
                int size = buf.readUnsignedShort();
                
                // Convert binary data to hex
                StringBuilder hex = new StringBuilder();
                for (int i = buf.readerIndex(); i < buf.readerIndex() + size; i++) {
                    byte b = buf.getByte(i);
                    hex.append(HEX_CHARS.charAt((b & 0xf0) >> 4));
                    hex.append(HEX_CHARS.charAt((b & 0x0F)));
                }

                extendedInfo.append("<passenger>");
                extendedInfo.append(hex);
                extendedInfo.append("</passenger>");
                
                buf.skipBytes(size);
            }

            // Send response for alarm message
            if (type == MSG_ALARM) {
                byte[] response = {(byte)0xC9,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
                channel.write(ChannelBuffers.wrappedBuffer(response));

                extendedInfo.append("<alarm>true</alarm>");
            }

            // Extended info
            position.setExtendedInfo(extendedInfo.toString());

            return position;
        }

        return null;
    }

}