using System;
using System.Collections.Generic;
using System.Text;

namespace SalsaModel
{
    public class Timing : SalsaModel.ITiming
    {
        //public double BeatLength = 300;
        //public double BeatLength = 1000;

        const bool c_onOne = false;

      double _beatLength = 300;
      public double BeatLength {
        get { return _beatLength; }
        set {
          double beatsSoFar = ((double)Tick) / _beatLength;
          _beatLength = value;
          initialCount = System.Environment.TickCount - (int)(beatsSoFar * _beatLength);
        }
      }

        public int initialCount = 0;
        bool paused;
        public int Tick
        {
            get
            {
                if (initialCount == 0)
                {
                    initialCount = System.Environment.TickCount;
                }
                if (paused)
                {
                    return pauseTime - initialCount;
                }
                else
                {
                    return System.Environment.TickCount - initialCount;
                }
            }
        }
        /// <summary>
        /// The current beat, from 1 to 8.  NOTE: not 0-7!
        /// </summary>
        /// <returns></returns>
        public int Beat()
        {
            return ((int)(Tick / BeatLength) % 8) + 1;
        }
        public int GlobalBeat()
        {
            return (int)(Tick / BeatLength) + 1;
        }
        public double Percent()
        {
            return (Tick % BeatLength) / BeatLength;
        }

        /// <summary>
        /// Returns the current step number, 0-5.  For on-1, step 0 is beat 1; 
        /// for on-2, the steps are not aligned directly with the bars.  The
        /// beats 4 and 8 where "nothing happens" are returned as -1.
        /// </summary>
        public int StepNumber()
        {
            int beat = Beat();

            if (c_onOne)
            {
                switch (beat)
                {
                    case 1:
                    case 2:
                    case 3:
                        return beat - 1;
                    case 5:
                    case 6:
                    case 7:
                        return beat - 2;
                    case 4:
                    case 8:
                        return -1;
                    default:
                        throw new InvalidOperationException("bad beat");
                }
            }
            else
            {
                switch (beat)
                {
                    // case 5: return 0;
                    case 6: return 0;
                    case 7: return 1;
                    case 1: return 2;
                    case 2: return 3;
                    case 3: return 4;
                    case 5: return 5;

                    case 8:
                    case 4:
                        return -1;

                    default: throw new InvalidOperationException("bad beat");
                }

            }
        }


        int pauseTime;
        public void Pause()
        {
            pauseTime = System.Environment.TickCount;
            paused = true;
        }
        public void Unpause() {
            initialCount += System.Environment.TickCount - pauseTime;
            paused = false;
        }
    }
}