/* Math functions are default 32 bit (f32, i32, etc) unless specified */

#define Pi              ((f32)3.14159265358979323846)
#define Tau             ((f32)6.28318530717958647693)
#define GoldenRatio     ((f32)1.61803398874989484820)

////////////////////////////////
//~ Vector types

#define VEC2(x, y) (Vec2) { (x), (y) }
#define VEC3(x, y, z) (Vec3) { (x), (y), (z) }
#define VEC4(x, y, z, w) (Vec4) { (x), (y), (z), (w) }

#define VEC2I32(x, y) (Vec2I32) { (x), (y) }
#define VEC3I32(x, y, z) (Vec3I32) { (x), (y), (z) }
#define VEC4I32(x, y, z, w) (Vec4I32) { (x), (y), (z), (w) }

#define VEC2U32(x, y) (Vec2U32) { (x), (y) }
#define VEC3U32(x, y, z) (Vec3U32) { (x), (y), (z) }
#define VEC4U32(x, y, z, w) (Vec4U32) { (x), (y), (z), (w) }

Struct(Vec2) { f32 x, y; };
Struct(Vec3) { f32 x, y, z; };
Struct(Vec4) { f32 x, y, z, w; };

Struct(Vec2I32) { i32 x, y; };
Struct(Vec3I32) { i32 x, y, z; };
Struct(Vec4I32) { i32 x, y, z, w; };

Struct(Vec2U32) { u32 x, y; };
Struct(Vec3U32) { u32 x, y, z; };
Struct(Vec4U32) { u32 x, y, z, w; };

Struct(Vec2Array)
{
    Vec2 *points;
    u64 count;
};

Struct(Vec3Array)
{
    Vec3 *points;
    u64 count;
};

Struct(Vec4Array)
{
    Vec4 *points;
    u64 count;
};

////////////////////////////////
//~ Xform types

Struct(Xform)
{
    Vec2 bx;  /* X basis vector (x axis) */
    Vec2 by;  /* Y basis vector (y axis)*/
    Vec2 og;  /* Translation vector (origin) */
};

/* (T)ranslation, (R)otation, (S)cale */
Struct(Trs)
{
    Vec2 t;
    Vec2 s;
    f32 r;
};

////////////////////////////////
//~ Rect types

Struct(Rect) {
    union
    {
        struct { f32 x, y, width, height; };
        struct { Vec2 pos, size; };
    };
};


/* Values expected to be normalized 0.0 -> 1.0 */
Struct(ClipRect)
{
    Vec2 p0, p1;
};

////////////////////////////////
//~ Axis aligned bounding box types

Struct(Aabb) {
    Vec2 p0, p1;
};

////////////////////////////////
//~ Quad types

Struct(Quad) {
    union
    {
        struct { Vec2 p0, p1, p2, p3; };
        struct { Vec2 e[4]; };
    };
};

////////////////////////////////
//~ Spring types

Struct(SoftSpring)
{
    f32 bias_rate;
    f32 mass_scale;
    f32 impulse_scale;
};

////////////////////////////////
//~ Mat4x4 types

Struct(Mat4x4)
{
    union
    {
        struct { Vec4 bx, by, bz, bw; };
        f32 e[4][4];
    };
};

////////////////////////////////
//~ Min / max

//- Min
u8 MinU8(u8 a, u8 b);
i8 MinI8(i8 a, i8 b);
u32 MinU32(u32 a, u32 b);
i32 MinI32(i32 a, i32 b);
f32 MinF32(f32 a, f32 b);
u64 MinU64(u64 a, u64 b);
i64 MinI64(i64 a, i64 b);
f64 MinF64(f64 a, f64 b);

//- Max
u8 MaxU8(u8 a, u8 b);
i8 MaxI8(i8 a, i8 b);
u32 MaxU32(u32 a, u32 b);
i32 MaxI32(i32 a, i32 b);
f32 MaxF32(f32 a, f32 b);
u64 MaxU64(u64 a, u64 b);
i64 MaxI64(i64 a, i64 b);
f64 MaxF64(f64 a, f64 b);

//- Clamp
u32 ClampU32(u32 v, u32 min, u32 max);
i32 ClampI32(i32 v, i32 min, i32 max);
f32 ClampF32(f32 v, f32 min, f32 max);
u64 ClampU64(u64 v, u64 min, u64 max);
i64 ClampI64(i64 v, i64 min, i64 max);
f64 ClampF64(f64 v, f64 min, f64 max);

////////////////////////////////
//~ Rounding ops

//- Round
f32 RoundF32(f32 f);
f64 RoundF64(f64 f);
i32 RoundF32ToI32(f32 f);
i64 RoundF64ToI64(f64 f);

//- Floor
f32 FloorF32(f32 f);
f64 FloorF64(f64 f);
i32 FloorF32ToI32(f32 f);
i64 FloorF64ToI64(f64 f);

//- Ceil
f32 CeilF32(f32 f);
f64 CeilF64(f64 f);
i32 CeilF32ToI32(f32 f);
i64 CeilF64ToI64(f64 f);

//- Trunc
f32 TruncF32(f32 f);
f64 TruncF64(f64 f);

////////////////////////////////
//~ Fmod

f32 ModF32(f32 x, f32 m);
f64 ModF64(f64 x, f64 m);

////////////////////////////////
//~ Abs

f32 AbsF32(f32 f);
f64 AbsF64(f64 f);
u32 AbsI32(i32 v);
u64 AbsI64(i64 v);
i32 SignF32(f32 f);
i64 SignF64(f64 f);

////////////////////////////////
//~ Exponential ops

u64 PowU64(u64 base, u8 exp);
u64 AlignU64Pow2(u64 x);
f32 LnF32(f32 x);
f32 ExpF32(f32 x);
f32 PowF32(f32 a, f32 b);
f32 SqrtF32(f32 x);
f64 SqrtF64(f64 x);
f32 RSqrtF32(f32 x);

////////////////////////////////
//~ Trig

f32 ReduceToPio4(f32 x, i32 *octant_out);
f32 SinApproxF32(f32 x);
f32 CosApproxF32(f32 x);
f32 SinF32(f32 x);
f32 CosF32(f32 x);
f32 ArcTanF32(f32 x);
f32 ArcTan2F32(f32 y, f32 x);
f32 ArcSinF32(f32 x);
f32 ArcCosF32(f32 x);

////////////////////////////////
//~ Angle unwind

/* Returns angle in range [-Pi, Pi] */
f32 UnwindAngleF32(f32 a);

////////////////////////////////
//~ Float lerp

f32 LerpF32(f32 val0, f32 val1, f32 t);
f64 LerpF64(f64 val0, f64 val1, f64 t);
f32 LerpAngleF32(f32 a, f32 b, f32 t);

////////////////////////////////
//~ Int lerp

i32 LerpI32(i32 val0, i32 val1, f32 t);
i64 LerpI64(i64 val0, i64 val1, f64 t);

////////////////////////////////
//~ Vec2 operations

#define Vec2FromVec2I32(v) VEC2((v).x, (v).y)

b32 IsVec2Zero(Vec2 a);
b32 EqVec2(Vec2 a, Vec2 b);

//- Mul
Vec2 MulVec2(Vec2 a, f32 s);
Vec2 MulVec2Vec2(Vec2 a, Vec2 b);
Vec2 NegVec2(Vec2 a);

//- Div
Vec2 DivVec2(Vec2 a, f32 s);
Vec2 DivVec2Vec2(Vec2 a, Vec2 b);

//- Add
Vec2 AddVec2(Vec2 a, Vec2 b);
Vec2 SubVec2(Vec2 a, Vec2 b);

//- Len
f32 Vec2Len(Vec2 a);
f32 Vec2LenSq(Vec2 a);
Vec2 Vec2WithLen(Vec2 a, f32 len);
Vec2 ClampVec2Len(Vec2 a, f32 max);
f32 Vec2Distance(Vec2 a, Vec2 b);
Vec2 NormVec2(Vec2 a);

//- Dot
f32 DotVec2(Vec2 a, Vec2 b);
f32 WedgeVec2(Vec2 a, Vec2 b);
Vec2 PerpVec2(Vec2 a);
Vec2 MulPerpVec2(Vec2 a, f32 s);
Vec2 PerpVec2TowardsDir(Vec2 v, Vec2 dir);

//- Round / floor / ceil
Vec2 RoundVec2(Vec2 a);
Vec2I32 RoundVec2ToVec2I32(Vec2 a);
Vec2 FloorVec2(Vec2 a);
Vec2 CeilVec2(Vec2 a);

//- Angle
i32 WindingFromVec2(Vec2 a, Vec2 b);
Vec2 RotateVec2(Vec2 v, f32 a);
Vec2 Vec2FromAngle(f32 a);
f32 AngleFromVec2(Vec2 v);
f32 AngleFromVec2Dirs(Vec2 dir1, Vec2 dir2);
f32 AngleFromVec2Points(Vec2 pt1, Vec2 pt2);

//- Closest point
Vec2 ClosestPointFromRay(Vec2 ray_pos, Vec2 ray_dir_norm, Vec2 p);

//- Lerp
Vec2 LerpVec2(Vec2 val0, Vec2 val1, f32 t);
Vec2 SlerpVec2(Vec2 val0, Vec2 val1, f32 t);

////////////////////////////////
//~ Vec2I32 Operations

b32 EqVec2I32(Vec2I32 a, Vec2I32 b);
Vec2I32 NegVec2I32(Vec2I32 a);
Vec2I32 AddVec2I32(Vec2I32 a, Vec2I32 b);
Vec2I32 SubVec2I32(Vec2I32 a, Vec2I32 b);

////////////////////////////////
//~ Xform operations

b32 EqXform(Xform xf1, Xform xf2);

//- Initialization
#define XformIdentity (Xform) { .bx = VEC2(1, 0), .by = VEC2(0, 1) }
#define XformIdentityNoCast { .bx = VEC2(1, 0), .by = VEC2(0, 1) }
Xform XformFromPos(Vec2 v);
Xform XformFromRot(f32 r);
Xform XformFromScale(Vec2 scale);
Xform XformFromTrs(Trs trs);
Xform XformFromRect(Rect rect);

//- Translation
Xform TranslateXform(Xform xf, Vec2 v);
Xform WorldTranslateXform(Xform xf, Vec2 v);

//- Rotation
Xform RotateXform(Xform xf, f32 r);
Xform WorldRotateXform(Xform xf, f32 r);
Xform WorldRotateXformBasis(Xform xf, f32 r);
Xform XformWIthWorldRotation(Xform xf, f32 r);

//- Scale
Xform ScaleXform(Xform xf, Vec2 scale);
Xform WorldScaleXform(Xform xf, Vec2 scale);

//- Lerp
Xform LerpXform(Xform a, Xform b, f32 t);

//- Invert
Xform InvertXform(Xform xf);

//- Mul
Vec2 MulXformV2(Xform xf, Vec2 v);
Xform MulXform(Xform a, Xform b);
Quad MulXformQuad(Xform xf, Quad quad);
Vec2 MulXformBasisV2(Xform xf, Vec2 v);
Vec2 InvertXformMulV2(Xform xf, Vec2 v);
Vec2 InvertXformBasisMulV2(Xform xf, Vec2 v);

//- Helpers
Xform BasisFromXform(Xform xf);
f32 DeterminantFromXform(Xform xf);
Vec2 RightFromXform(Xform xf);
Vec2 LeftFromXform(Xform xf);
Vec2 UpFromXform(Xform xf);
Vec2 DownFromXform(Xform xf);
f32 RotationFromXform(Xform xf);
Vec2 ScaleFromXform(Xform xf);

//- Trs
#define TRS(...) ((Trs) { .t = VEC2(0,0), .s = VEC2(1, 1), .r = 0, __VA_ARGS__ })

////////////////////////////////
//~ Rect operations

#define RectFromScalar(_x, _y, _width, _height) (Rect) { .x = (_x), .y = (_y), .width = (_width), .height = (_height) }
#define RectFromVec2(_pos, _size) (Rect) { .pos = (_pos), .size = (_size) }
#define AllClipped ((ClipRect) { { 0.0f, 0.0f }, { 1.0f, 1.0f } })

////////////////////////////////
//~ Quad operations

#define UnitSquareQuad (Quad) { .p0 = VEC2(0, 0), .p1 = VEC2(0, 1), .p2 = VEC2(1, 1), .p3 = VEC2(1, 0) }
#define CenteredUnitSquareQuad (Quad) { .p0 = VEC2(-0.5f, -0.5f), .p1 = VEC2(0.5f, -0.5f), .p2 = VEC2(0.5f, 0.5f), .p3 = VEC2(-0.5f, 0.5f) }

Quad QuadFromRect(Rect rect);
Quad QuadFromAabb(Aabb aabb);
Quad QuadFromLine(Vec2 start, Vec2 end, f32 thickness);
Quad QuadFromRay(Vec2 pos, Vec2 rel, f32 thickness);
Quad ScaleQuad(Quad q, f32 s);
Quad RoundQuad(Quad quad);
Quad FloorQuad(Quad quad);

////////////////////////////////
//~ Spring operations

SoftSpring MakeSpring(f32 hertz, f32 damping_ratio, f32 dt);

////////////////////////////////
//~ Mat4x4 operations

Mat4x4 Mat4x4FromXform(Xform xf);
Mat4x4 Mat4x4FromOrtho(f32 left, f32 right, f32 bottom, f32 top, f32 near_z, f32 far_z);
Mat4x4 MulMat4x4(Mat4x4 m1, Mat4x4 m2);
Mat4x4 ProjectMat4x4View(Xform view, f32 viewport_width, f32 viewport_height);