namespace Encompass
{
    internal class TimeManager
    {
        private TimeDilationData timeDilationData = new TimeDilationData { factor = 1 };
        private bool newTimeDilationData = false;
        private TimeDilationData nextFrameTimeDilationData = new TimeDilationData { factor = 1 };

        private double Linear(double t, double b, double c, double d)
        {
            return c * t / d + b;
        }
        private int minPriority = int.MaxValue;

        public double TimeDilationFactor
        {
            get
            {
                return timeDilationData.Factor;
            }
        }

        public bool TimeDilationActive
        {
            get => TimeDilationFactor != 1;
        }

        public void Update(double dt)
        {
            if (newTimeDilationData)
            {
                timeDilationData = nextFrameTimeDilationData;
            }

            timeDilationData.elapsedTime += dt;
            newTimeDilationData = false;
            minPriority = int.MaxValue;
        }

        public void ActivateTimeDilation(double factor, double easeInTime, double activeTime, double easeOutTime, int priority)
        {
            ActivateTimeDilation(factor, easeInTime, Linear, activeTime, easeOutTime, Linear, priority);
        }

        public void ActivateTimeDilation(double factor, double easeInTime, System.Func<double, double, double, double, double> easeInFunction, double activeTime, double easeOutTime, int priority)
        {
            ActivateTimeDilation(factor, easeInTime, easeInFunction, activeTime, easeOutTime, Linear, priority);
        }

        public void ActivateTimeDilation(double factor, double easeInTime, double activeTime, double easeOutTime, System.Func<double, double, double, double, double> easeOutFunction, int priority)
        {
            ActivateTimeDilation(factor, easeInTime, Linear, activeTime, easeOutTime, easeOutFunction, priority);
        }

        public void ActivateTimeDilation(double factor, double easeInTime, System.Func<double, double, double, double, double> easeInFunction, double activeTime, double easeOutTime, System.Func<double, double, double, double, double> easeOutFunction, int priority)
        {
            if (priority <= minPriority)
            {
                newTimeDilationData = true;
                nextFrameTimeDilationData = new TimeDilationData
                {
                    elapsedTime = 0,
                    easeInTime = easeInTime,
                    easeInFunction = easeInFunction,
                    activeTime = activeTime,
                    easeOutTime = easeOutTime,
                    easeOutFunction = easeOutFunction,
                    factor = factor
                };
            }
        }
    }
}