using Misaki.HighPerformance.Mathematics;
using System.Runtime.CompilerServices;
using static Misaki.HighPerformance.Mathematics.math;

namespace Misaki.HighPerformance.Test.Jobs;

public static partial class noise
{
    // Modulo 289 without a division (only multiplications)
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static float mod289(float x)
    {
        return x - floor(x * (1.0f / 289.0f)) * 289.0f;
    }
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static float2 mod289(float2 x)
    {
        return x - floor(x * (1.0f / 289.0f)) * 289.0f;
    }
    public static float3 mod289(float3 x)
    {
        return x - floor(x * (1.0f / 289.0f)) * 289.0f;
    }
    public static float4 mod289(float4 x)
    {
        return x - floor(x * (1.0f / 289.0f)) * 289.0f;
    }

    // Modulo 7 without a division
    public static float3 mod7(float3 x)
    {
        return x - floor(x * (1.0f / 7.0f)) * 7.0f;
    }
    public static float4 mod7(float4 x)
    {
        return x - floor(x * (1.0f / 7.0f)) * 7.0f;
    }

    // Permutation polynomial: (34x^2 + x) math.mod 289
    public static float permute(float x)
    {
        return mod289((34.0f * x + 1.0f) * x);
    }
    public static float3 permute(float3 x)
    {
        return mod289((34.0f * x + 1.0f) * x);
    }
    public static float4 permute(float4 x)
    {
        return mod289((34.0f * x + 1.0f) * x);
    }

    public static float taylorInvSqrt(float r)
    {
        return 1.79284291400159f - 0.85373472095314f * r;
    }
    public static float4 taylorInvSqrt(float4 r)
    {
        return 1.79284291400159f - 0.85373472095314f * r;
    }

    public static float2 fade(float2 t)
    {
        return t * t * t * (t * (t * 6.0f - 15.0f) + 10.0f);
    }
    public static float3 fade(float3 t)
    {
        return t * t * t * (t * (t * 6.0f - 15.0f) + 10.0f);
    }
    public static float4 fade(float4 t)
    {
        return t * t * t * (t * (t * 6.0f - 15.0f) + 10.0f);
    }

    public static float4 grad4(float j, float4 ip)
    {
        var ones = float4(1.0f, 1.0f, 1.0f, -1.0f);
        var pxyz = floor(frac(float3(j) * ip.xyz) * 7.0f) * ip.z - 1.0f;
        var pw = 1.5f - dot(abs(pxyz), ones.xyz);
        var p = float4(pxyz, pw);
        var s = float4(p < 0.0f);
        p.xyz = p.xyz + (s.xyz * 2.0f - 1.0f) * s.www;
        return p;
    }

    // Hashed 2-D gradients with an extra rotation.
    // (The constant 0.0243902439 is 1/41)
    public static float2 rgrad2(float2 p, float rot)
    {
        // For more isotropic gradients, math.sin/math.cos can be used instead.
        var u = permute(permute(p.x) + p.y) * 0.0243902439f + rot; // Rotate by shift
        u = frac(u) * 6.28318530718f; // 2*pi
        return float2(cos(u), sin(u));
    }
}