using System;

namespace Fusion.Addons.SimpleKCC
{
    internal abstract class SmoothValue<T>
    {
        private SmoothItem<T>[] _items;

        private int _index;

        public SmoothItem<T>[] Items => _items;

        public SmoothValue(int capacity)
        {
            _items = new SmoothItem<T>[capacity];
            for (int i = 0; i < capacity; i++)
            {
                _items[i] = new SmoothItem<T>();
            }
        }

        public void AddValue(int frame, double size, T value)
        {
            if (size <= 0.0)
            {
                throw new ArgumentException("size");
            }

            SmoothItem<T> smoothItem = _items[_index];
            if (smoothItem.Frame == frame)
            {
                smoothItem.Size = size;
                smoothItem.Value = value;
                return;
            }

            _index = (_index + 1) % _items.Length;
            smoothItem = _items[_index];
            smoothItem.Frame = frame;
            smoothItem.Size = size;
            smoothItem.Value = value;
        }

        public void ClearValues()
        {
            int i = 0;
            for (int num = _items.Length; i < num; i++)
            {
                SmoothItem<T> obj = _items[i];
                obj.Frame = 0;
                obj.Size = 0.0;
                obj.Value = GetDefaultValue();
            }

            _index = 0;
        }

        public T CalculateSmoothValue(double window, double size)
        {
            int frames;
            return CalculateSmoothValue(window, size, out frames);
        }

        public T CalculateSmoothValue(double window, double size, out int frames)
        {
            frames = 0;
            if (window <= 0.0)
            {
                SmoothItem<T> smoothItem = _items[_index];
                if (smoothItem.Frame == 0)
                {
                    return default(T);
                }

                frames = 1;
                return smoothItem.Value;
            }

            double num = window;
            T accumulatedValue = GetDefaultValue();
            for (int num2 = _index; num2 >= 0; num2--)
            {
                SmoothItem<T> smoothItem = _items[num2];
                if (smoothItem.Frame != 0)
                {
                    if (num <= smoothItem.Size)
                    {
                        double scale = num / smoothItem.Size;
                        accumulatedValue = AccumulateValue(accumulatedValue, smoothItem.Value, scale);
                        frames++;
                        return GetSmoothValue(accumulatedValue, size / window);
                    }

                    num -= smoothItem.Size;
                    accumulatedValue = AccumulateValue(accumulatedValue, smoothItem.Value, 1.0);
                    frames++;
                }
            }

            for (int num3 = _items.Length - 1; num3 > _index; num3--)
            {
                SmoothItem<T> smoothItem = _items[num3];
                if (smoothItem.Frame != 0)
                {
                    if (num < smoothItem.Size)
                    {
                        double scale2 = num / smoothItem.Size;
                        accumulatedValue = AccumulateValue(accumulatedValue, smoothItem.Value, scale2);
                        frames++;
                        return GetSmoothValue(accumulatedValue, size / window);
                    }

                    num -= smoothItem.Size;
                    accumulatedValue = AccumulateValue(accumulatedValue, smoothItem.Value, 1.0);
                    frames++;
                }
            }

            if (num >= window)
            {
                return default(T);
            }

            double num4 = window - num;
            return GetSmoothValue(accumulatedValue, size / num4);
        }

        protected abstract T GetDefaultValue();

        protected abstract T AccumulateValue(T accumulatedValue, T value, double scale);

        protected abstract T GetSmoothValue(T accumulatedValue, double scale);
    }
}