using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SipComponent.Simoco
{
    static class SP6
    {
        // Short data (Over-the-Air) PDU
        // byte 0           - Rezerved (Header) 0
        // byte 1           - Type (Header)     0 (Management)
        // byte 2...end     - Management payload

        // Management payload
        // byte 2           - Protocol Control  0
        // byte 3           - Type              0 - GPS, 1 - Device Status, 255 - Ping
        // byte 4           - Command           depends on Tpe
        // byte 5...end     - Parameters


        private static void AddManagementShortData(byte[] data, byte type, byte command)
        {
            data[3] = type;
            data[4] = command;
        }

        public static byte GetType(byte[] managementShortData)
        {
            return managementShortData[3];
        }

        public static byte GetCommand(byte[] managementShortData)
        {
            return managementShortData[4];
        }

        public static AlarmType GetAlarmType(byte[] deviceStatusReport)
        {
            // bytes   5..6  User Status
            // bytes   7..10  Alarm Conditions Flags
            // bytes   11..14 GPS Latitude
            // bytes   15..18 GPS Longitude             
            return (AlarmType)BitConverter.ToUInt32(deviceStatusReport, 7);
        }

        public static void GetGPSFromStatusReport(byte[] deviceStatusReport, out double latitude, out double longitude)
        {
            byte[] latitudeBytes = new byte[4];
            byte[] longitudeBytes = new byte[4];
            Array.Copy(deviceStatusReport, 11, latitudeBytes, 0, 4);
            Array.Reverse(latitudeBytes);
            Array.Copy(deviceStatusReport, 15, longitudeBytes, 0, 4);
            Array.Reverse(longitudeBytes);
            latitude = BitConverter.ToInt32(latitudeBytes, 0) / 10000000.0;
            longitude = BitConverter.ToInt32(longitudeBytes, 0) / 10000000.0;
        }

        public static byte[] PingCommand(params byte[] arbitraryData)
        {
            // lungimea in oceti = 5 + arbitrary data
            int n = 5 + arbitraryData.Length;
            byte[] ping = new byte[n];

            AddManagementShortData(ping, 0xFF, 0);
            Array.Copy(arbitraryData, 0, ping, 5, arbitraryData.Length);

            return ping;
        }

        public static byte[] GPSRequestCommand()
        {
            byte[] GPSRequest = new byte[5];
            AddManagementShortData(GPSRequest, 0, 1);
            return GPSRequest;
        }

        public static byte[] StatusRequestCommand()
        {
            byte[] StatusRequest = new byte[5];
            AddManagementShortData(StatusRequest, 1, 0);
            return StatusRequest;
        }

        public static byte[] CapabilityRequestCommand()
        {
            byte[] deviceCapabilityRequest = new byte[5];
            AddManagementShortData(deviceCapabilityRequest, 1, 3);
            return deviceCapabilityRequest;
        }
    }

    /// <summary>
    /// Contains a list of Alarm types
    /// </summary>
    public enum AlarmType : uint
    {
        /// <summary>
        /// Alarm generated by pressing a button
        /// </summary>
        USER_GENERATED = 0x01000000,
        /// <summary>
        /// MAN DOWN
        /// </summary>
        MAN_DOWN = 0x02000000,
        /// <summary>
        /// LONE WORKER
        /// </summary>
        LONE_WORKER = 0x04000000,
        /// <summary>
        /// NO ALARM
        /// </summary>
        NO_ALARM = 0x00000000
    }
}