using System;
using System.Collections.Generic;
using GrimoireEngine.Framework.Logic;
using GrimoireEngine.Framework.Maths;
using OpenTK;

namespace GrimoireEngine.Framework.Utilities
{
    public sealed class GrimoireRandom
    {
        private int _seed;
        private int _inext;
        private int _inextp;
        private int[] _seedArray = new int[56];

        /// <summary>
        /// The current seed of this instance.
        /// </summary>
        public int Seed
        {
            get
            {
                return _seed;
            }
            set
            {
                _seed = value;
                int subtraction = (_seed == Int32.MinValue) ? Int32.MaxValue : Math.Abs(_seed);
                int mj = 0x9a4ec86 - subtraction;
                _seedArray[0x37] = mj;
                int mk = 1;
                for (int i = 1; i < 0x37; i++)
                {
                    int ii = (0x15 * i) % 0x37;
                    _seedArray[ii] = mk;
                    mk = mj - mk;
                    if (mk < 0x0)
                    {
                        mk += Int32.MaxValue;
                    }
                    mj = _seedArray[ii];
                }
                for (int k = 1; k < 0x5; k++)
                {
                    for (int i = 1; i < 0x38; i++)
                    {
                        _seedArray[i] -= _seedArray[1 + (i + 0x1e) % 0x37];
                        if (_seedArray[i] < 0)
                        {
                            _seedArray[i] += Int32.MaxValue;
                        }
                    }
                }
                _inext = 0;
                _inextp = 21;
            }
        }

        public GrimoireRandom()
            // Used to generate a varying seed, regardless of close-frequency allocation
            : this(Guid.NewGuid().GetHashCode())
        { }

        public GrimoireRandom(string seed)
            : this(seed.GetHashCode())
        { }

        public GrimoireRandom(int[] saveState)
        {
            LoadState(saveState);
        }

        public GrimoireRandom(int seed)
        {
            Seed = seed;
        }

        /// <summary>
        /// Resets this instance using it's current seed.
        /// This means that the RNG will start over again,
        /// repeating the same values that it originally had.
        /// </summary>
        public void Reset()
        {
            Reseed(this.Seed);
        }

        /// <summary>
        /// Reseeds this instance using a new GUID Hashcode
        /// </summary>
        public void Reseed()
        {
            Reseed(Guid.NewGuid().GetHashCode());
        }

        /// <summary>
        /// Reseeds this instance using the hashcode of a given string.
        /// </summary>
        /// <param name="seed"></param>
        public void Reseed(string seed)
        {
            Reseed(seed.GetHashCode());
        }

        /// <summary>
        /// Reseeds this instance using a given integer seed.
        /// </summary>
        /// <param name="seed"></param>
        public void Reseed(int seed)
        {
            this.Seed = seed;
        }

        public int NextInteger()
        {
            return NextSample();
        }

        public void NextIntegers(int[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextInteger();
            }
        }

        public int[] NextIntegers(int quantity)
        {
            int[] buffer = new int[quantity];
            NextIntegers(buffer);
            return buffer;
        }


        public int NextInteger(int minValue, int maxValue)
        {
            return (int)(this.NextSample() * (1.0D / Int32.MaxValue) * (maxValue - minValue)) + minValue;
        }


        public void NextIntegers(int minValue, int maxValue, int[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextInteger(minValue, maxValue);
            }
        }


        public int[] NextIntegers(int minValue, int maxValue, int quantity)
        {
            int[] buffer = new int[quantity];
            NextIntegers(minValue, maxValue, buffer);
            return buffer;
        }

        public int NextInteger(int maxValue)
        {
            return NextInteger(0, maxValue);
        }

        public void NextIntegers(int maxValue, int[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextInteger(maxValue);
            }
        }

        public int[] NextIntegers(int maxValue, int quantity)
        {
            int[] buffer = new int[quantity];
            NextIntegers(maxValue, buffer);
            return buffer;
        }

        public double NextDouble()
        {
            return NextSample() * (1.0D / Int32.MaxValue);
        }

        public void NextDoubles(double[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextDouble();
            }
        }

        public double[] NextDoubles(int quantity)
        {
            double[] buffer = new double[quantity];
            NextDoubles(buffer);
            return buffer;
        }

        public double NextDouble(double minValue, double maxValue)
        {
            return NextDouble() * (maxValue - minValue) + minValue;
        }

        public void NextDoubles(double minValue, double maxValue, double[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextDouble(minValue, maxValue);
            }
        }

        public double[] NextDoubles(double minValue, double maxValue, int quantity)
        {
            double[] buffer = new double[quantity];
            NextDoubles(minValue, maxValue, buffer);
            return buffer;
        }

        public float NextFloat()
        {
            return (float)(NextSample() * (1.0D / Int32.MaxValue));
        }

        public void NextFloats(float[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextFloat();
            }
        }

        public float[] NextFloats(int quantity)
        {
            float[] buffer = new float[quantity];
            NextFloats(buffer);
            return buffer;
        }

        public float NextFloat(float minValue, float maxValue)
        {
            return NextFloat() * (maxValue - minValue) + minValue;
        }

        public void NextFloats(float minValue, float maxValue, float[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextFloat(minValue, maxValue);
            }
        }

        public float[] NextFloats(float minValue, float maxValue, int quantity)
        {
            float[] buffer = new float[quantity];
            NextFloats(minValue, maxValue, buffer);
            return buffer;
        }

        public int NextRange(Range range)
        {
            return NextInteger(range.Minimum, range.Maximum + 1);
        }

        public void NextRanges(Range range, int[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextRange(range);
            }
        }

        public int[] NextRanges(Range range, int quantity)
        {
            int[] buffer = new int[quantity];
            NextRanges(range, buffer);
            return buffer;
        }

        public int NextRange(int minValue, int maxValue)
        {
            return NextInteger(minValue, maxValue + 1);
        }

        public void NextRanges(int minValue, int maxValue, int[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextRange(minValue, maxValue);
            }
        }

        public int[] NextRanges(int minValue, int maxValue, int quantity)
        {
            int[] buffer = new int[quantity];
            NextRanges(minValue, maxValue, buffer);
            return buffer;
        }

        public byte NextByte()
        {
            return (byte)NextInteger(0, 256);
        }

        public void NextBytes(byte[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextByte();
            }
        }

        public byte[] NextBytes(int quantity)
        {
            byte[] buffer = new byte[quantity];
            NextBytes(buffer);
            return buffer;
        }

        public byte NextByte(byte minValue, byte maxValue)
        {
            return (byte)NextInteger(minValue, maxValue);
        }

        public void NextBytes(byte minValue, byte maxValue, byte[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextByte(minValue, maxValue);
            }
        }

        public byte[] NextBytes(byte minValue, byte maxValue, int quantity)
        {
            byte[] buffer = new byte[quantity];
            NextBytes(minValue, maxValue, buffer);
            return buffer;
        }

        public byte NextByte(byte maxValue)
        {
            return (byte)NextInteger(0, maxValue);
        }

        public void NextBytes(byte maxValue, byte[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextByte(maxValue);
            }
        }

        public byte[] NextBytes(byte maxValue, int quantity)
        {
            byte[] buffer = new byte[quantity];
            NextBytes(maxValue, buffer);
            return buffer;
        }

        public bool NextBool()
        {
            return NextInteger(0, 2) == 1;
        }

        public void NextBools(bool[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextBool();
            }
        }

        public bool[] NextBools(int quantity)
        {
            bool[] buffer = new bool[quantity];
            NextBools(buffer);
            return buffer;
        }

        public string NextString(char[] possibleCharacters, int length)
        {
            char[] buffer = new char[length];
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = possibleCharacters[NextInteger(0, possibleCharacters.Length)];
            }
            return new string(buffer);
        }

        public void NextStrings(char[] possibleCharacters, int length, string[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextString(possibleCharacters, length);
            }
        }

        public string[] NextStrings(char[] possibleCharacters, int length, int quantity)
        {
            string[] buffer = new string[quantity];
            NextStrings(possibleCharacters, length, buffer);
            return buffer;
        }

        public void Shuffle<T>(List<T> list)
        {
            int n = list.Count;
            while (n > 1)
            {
                n--;
                int k = NextInteger(0, n + 1);
                T value = list[k];
                list[k] = list[n];
                list[n] = value;
            }
        }

        public void Shuffle<T>(T[] list)
        {
            int n = list.Length;
            while (n > 1)
            {
                n--;
                int k = NextInteger(0, n + 1);
                T value = list[k];
                list[k] = list[n];
                list[n] = value;
            }
        }

        public int NextIndex<T>(T[] array)
        {
            return NextInteger(array.Length);
        }

        public int NextIndex<T>(List<T> list)
        {
            return NextInteger(list.Count);
        }

        public T Choose<T>(T[] items)
        {
            return items[NextInteger(items.Length)];
        }

        public void Choose<T>(T[] items, T[] resultBuffer)
        {
            for (int i = 0; i < resultBuffer.Length; i++)
            {
                resultBuffer[i] = Choose(items);
            }
        }

        public T[] Choose<T>(T[] items, int quantity)
        {
            T[] buffer = new T[quantity];
            Choose(items, buffer);
            return buffer;
        }

        public T Choose<T>(List<T> items)
        {
            return items[NextInteger(0, items.Count)];
        }

        public List<T> Choose<T>(List<T> items, int quantity)
        {
            List<T> buffer = new List<T>(quantity);
            for (int i = 0; i < quantity; i++)
            {
                buffer.Add(Choose(items));
            }
            return buffer;
        }

        public bool NextProbability(float percent)
        {
            if (percent >= 1.0f) return true;
            if (percent <= 0.0f) return false;
            return NextDouble() <= percent;
        }

        public void NextProbability(float percent, bool[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextProbability(percent);
            }
        }

        public bool[] NextProbabilities(float percent, int quantity)
        {
            bool[] buffer = new bool[quantity];
            NextProbability(percent, buffer);
            return buffer;
        }

        public bool NextProbability(int percent)
        {
            if (percent >= 100) return true;
            if (percent <= 0) return false;
            return NextInteger(101) <= percent;
        }

        public void NextProbabilities(int percent, bool[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextProbability(percent);
            }
        }

        public bool[] NextProbabilities(int percent, int quantity)
        {
            bool[] buffer = new bool[quantity];
            NextProbabilities(percent, buffer);
            return buffer;
        }

        public bool NextOdds(int a, int b)
        {
            return NextProbability(((float)a / b));
        }

        public void NextOdds(int a, int b, bool[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextOdds(a, b);
            }
        }

        public bool[] NextOdds(int a, int b, int quantity)
        {
            bool[] buffer = new bool[quantity];
            NextOdds(a, b, buffer);
            return buffer;
        }
        public int NextDiceRoll(DiceType d)
        {
            return NextInteger(1, (int)d + 1);
        }

        public void NextDiceRolls(DiceType d, int[] buffer)
        {
            for (int i = 0; i < buffer.Length; i++)
            {
                buffer[i] = NextDiceRoll(d);
            }
        }

        public int[] NextDiceRolls(DiceType d, int quantity)
        {
            int[] buffer = new int[quantity];
            NextDiceRolls(d, buffer);
            return buffer;
        }

        public Vector3 NextVector3(float xMin, float xMax, float yMin, float yMax, float zMin, float zMax)
        {
            return new Vector3(NextFloat(xMin, xMax), NextFloat(yMin, yMax), NextFloat(zMin, zMax));
        }

        public Vector3 NextVector3(Vector3 min, Vector3 max)
        {
            return NextVector3(min.X, max.X, min.Y, max.Y, min.Z, max.Z);
        }

        public Vector3 NextVector3(float min, float max)
        {
            return NextVector3(min, max, min, max, min, max);
        }

        private int NextSample()
        {
            int locINext = _inext;
            int locINextp = _inextp;
            if (++locINext >= 56)
            {
                locINext = 1;
            }
            if (++locINextp >= 56)
            {
                locINextp = 1;
            }
            int retVal = _seedArray[locINext] - _seedArray[locINextp];
            if (retVal == Int32.MaxValue)
            {
                retVal--;
            }
            if (retVal < 0)
            {
                retVal += Int32.MaxValue;
            }
            _seedArray[locINext] = retVal;
            _inext = locINext;
            _inextp = locINextp;
            return retVal;
        }

        public int[] GetState()
        {
            int[] state = new int[59];
            state[0] = _seed;
            state[1] = _inext;
            state[2] = _inextp;
            for (int i = 3; i < this._seedArray.Length; i++)
            {
                state[i] = _seedArray[i - 3];
            }
            return state;
        }

        public void LoadState(int[] saveState)
        {
            if (saveState.Length != 59)
            {
                throw new Exception("GrimoireRandom state was corrupted!");
            }
            _seed = saveState[0];
            _inext = saveState[1];
            _inextp = saveState[2];
            _seedArray = new int[59];
            for (int i = 3; i < this._seedArray.Length; i++)
            {
                _seedArray[i - 3] = saveState[i];
            }
        }
    }
}