using System;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;

namespace SicknessReduction.Visual.Vignetting
{
    public interface RestrictionSuggestor
    {
        float Suggestion { get; }
    }

    public class QueueBasedRestrictionSuggestor : RestrictionSuggestor
    {
        private Queue<Tuple<float, float>> values;
        private int bufferSize;
        private float threshold;

        public float Suggestion
        {
            get
            {
                var perSecond = new float[values.Count];
                var index = 0;
                var previousValue = values.FirstOrDefault();
                foreach (var value in values)
                {
                    // ReSharper disable once PossibleNullReferenceException
                    perSecond[index] = Mathf.Abs(value.Item2 - previousValue.Item2) /
                                       (value.Item1 - previousValue.Item1);
                    index++;
                }

                var avg = perSecond.Average();
                if (avg >= threshold)
                {
                    return .5f; //TODO: something better than a magic number
                }

                return 0f;
            }
        }

        public QueueBasedRestrictionSuggestor(float threshold, int bufferSize = 10)
        {
            this.bufferSize = bufferSize;
            this.threshold = threshold;
            values = new Queue<Tuple<float, float>>(bufferSize);
        }

        public void AddValue(float value)
        {
            if (values.Count >= bufferSize)
            {
                values.Dequeue();
            }

            values.Enqueue(new Tuple<float, float>(Time.time, value));
        }
    }
}