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

namespace CountdownTimer
{
    class TimerSource : INotifyPropertyChanged
    {
        int _secs = 900;
        Timer _timer;

        public event PropertyChangedEventHandler PropertyChanged;
        void Notify(string propName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propName));
        }

        public delegate void TimedOutHandler();
        public event TimedOutHandler TimedOut;

        public string Time
        {
            get
            {
                int mins, secs;
                mins = Math.DivRem(_secs, 60, out secs);
                return String.Format("{0}:{1:D2}", mins, secs);
            }
            set 
            { 
                // XXX handle string form mm:ss
                _secs = Int32.Parse(value); 
            }
        }

        public void Start()
        {
            _timer = new Timer(this.tick, null, 0, 1000);
        }

        private void tick(object unused)
        {
            _secs--;
            Notify("Time");
            if (_secs == 0)
            {
                _timer.Dispose();
                _timer = null;

                if (TimedOut != null)
                    TimedOut();
            }
        }

        internal void SetTime(int secs)
        {
            _secs = secs;
        }
    }
}