using System;
using Microsoft.SPOT;

namespace UTILS
{
    public class Stopwatch
    {
        private long _startTicks;
        private bool _isRunning;

        private const long _ticksPerSecond = System.TimeSpan.TicksPerMillisecond * 1000;

        public Stopwatch()
        {
            _startTicks = 0;
            _isRunning = false;
        }

        public bool IsRunning()
        {
            return _isRunning;
        }

        public void Reset()
        {
            _startTicks = 0;
            _isRunning = false;
        }

        public void Start()
        {
            _startTicks = Microsoft.SPOT.Hardware.Utility.GetMachineTime().Ticks; // start new timer
            _isRunning = true;
        }

        public void Stop()
        {
            _startTicks = 0;
            _isRunning = false;
        }

        public long ElapsedSeconds
        {
            get
            {
                if (_startTicks != 0 && _isRunning)
                    return (Microsoft.SPOT.Hardware.Utility.GetMachineTime().Ticks - _startTicks) / _ticksPerSecond;
                else
                    throw new InvalidOperationException();
            }
        }
    }
}