using System;
using System.Collections.Generic;
using System.Linq;
using UnityEngine;
using Valve.VR.InteractionSystem;

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

    public abstract class RestrictionSuggestor : IRestrectionSuggestor
    {
        protected readonly float threshold;
        protected readonly float minRestriction;
        protected readonly float maxRestriction;
        protected readonly float maxValue;

        protected RestrictionSuggestor(float threshold, float minRestriction, float maxRestriction,
            float maxValue)
        {
            this.threshold = threshold;
            this.minRestriction = minRestriction;
            this.maxRestriction = maxRestriction;
            this.maxValue = maxValue;
        }

        protected float LerpedSuggestion(float value) => Mathf.Lerp(minRestriction, maxRestriction,
            (value - threshold) / (maxValue - threshold));

        public abstract float Suggestion { get; }
    }

    public class ValueBasedRestrictionSuggestor : RestrictionSuggestor
    {
        public override float Suggestion
        {
            get
            {
                var abs = Mathf.Abs(Value);
                return abs < threshold
                    ? 0f
                    : LerpedSuggestion(abs);
            }
        }

        public float Value { set; get; } = 0f;


        public ValueBasedRestrictionSuggestor(float threshold, float minRestriction, float maxRestriction,
            float maxValue) : base(threshold, minRestriction, maxRestriction, maxValue)
        {
        }
    }

    public class ValueAndTimeBasedRestrictionSuggestor : RestrictionSuggestor
    {
        private readonly float tolerance;
        private readonly float timespan;
        private readonly Dictionary<float, float> values = new Dictionary<float, float>();
        private float value;

        public ValueAndTimeBasedRestrictionSuggestor(float threshold, float minRestriction, float maxRestriction, float maxValue, float tolerance, float timespan) : base(threshold, minRestriction, maxRestriction, maxValue)
        {
            this.tolerance = tolerance;
            this.timespan = timespan;
        }

        public override float Suggestion
        {
            get
            {
                var abs = Mathf.Abs(value);
                var stable = !values.Values.Any(v => Mathf.Abs(v - value) > tolerance);

                return abs < threshold || stable
                    ? 0f
                    : LerpedSuggestion(abs);
            }
        }

        public void UpdateValue(float v)
        {
            value = v;
            var t = Time.time;
            values[t] = v;
            var keys = values.Keys.Where(k => t - k > timespan).ToList();
            keys.ForEach(k => values.Remove(k));
        }
    }

    public abstract class QueueBasedRestrictionSuggestor<T> : RestrictionSuggestor
    {
        protected Queue<Tuple<float, T>> values;
        protected int bufferSize;

        public QueueBasedRestrictionSuggestor(float threshold, float minRestriction, float maxRestriction,
            float maxValue, int bufferSize = 10) : base(threshold, minRestriction, maxRestriction, maxValue)
        {
            this.bufferSize = bufferSize;
            values = new Queue<Tuple<float, T>>(bufferSize);
        }

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

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

    public class QueueBasedRestrictionSuggestorFloat : QueueBasedRestrictionSuggestor<float>
    {
        public QueueBasedRestrictionSuggestorFloat(float threshold, float minRestriction, float maxRestriction,
            float maxValue, int bufferSize = 10) : base(threshold, minRestriction, maxRestriction, maxValue, bufferSize)
        {
        }

        public override 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
                    var timeDif = value.Item1 - previousValue.Item1;
                    perSecond[index] = timeDif == 0
                        ? 0f
                        : Mathf.Abs(value.Item2 - previousValue.Item2) /
                          timeDif;
                    previousValue = value;
                    index++;
                }

                var avg = perSecond.Length == 0 ? 0f : perSecond.Average();
                return avg < threshold
                    ? 0f
                    : LerpedSuggestion(avg);
            }
        }
    }

    public class QueueBasedRestrictionSuggestorVector3 : QueueBasedRestrictionSuggestor<Vector3>
    {
        public QueueBasedRestrictionSuggestorVector3(float threshold, float minRestriction, float maxRestriction,
            float maxValue, int bufferSize = 10) : base(threshold, minRestriction, maxRestriction, maxValue, bufferSize)
        {
        }

        public override float Suggestion
        {
            get
            {
                var perSecond = new Vector3[values.Count];
                var index = 0;
                var previousValue = values.FirstOrDefault();
                foreach (var value in values)
                {
                    // ReSharper disable once PossibleNullReferenceException
                    var timeDif = value.Item1 - previousValue.Item1;
                    perSecond[index] = timeDif == 0
                        ? Vector3.zero
                        : Helpers.Vector3Abs(value.Item2 - previousValue.Item2) /
                          timeDif;
                    previousValue = value;
                    index++;
                }

                var avg = perSecond.Aggregate(Vector3.zero, (agg, v) => agg + v) / perSecond.Length;
                var max = Helpers.GetMaxComponent(avg);
                return max < threshold
                    ? 0f
                    : LerpedSuggestion(max);
            }
        }
    }
}