#pragma once

#include "math.h"
#include "matrices.h"

inline static struct mat4x4 translation(float x, float y, float z)
{
  return mat4x4(1.0f, 0.0f, 0.0f, x,
                0.0f, 1.0f, 0.0f, y,
                0.0f, 0.0f, 1.0f, z,
                0.0f, 0.0f, 0.0f, 1.0f);
}

inline static struct mat4x4 scaling(float x, float y, float z)
{
  return mat4x4(x,    0.0f, 0.0f, 0.0f,
                0.0f, y,    0.0f, 0.0f,
                0.0f, 0.0f, z,    0.0f,
                0.0f, 0.0f, 0.0f, 1.0f);
}

inline static struct mat4x4 rotation_x(float r)
{
  return mat4x4(1.0f, 0.0f,     0.0f,    0.0f,
                0.0f, cosf(r), -sinf(r), 0.0f,
                0.0f, sinf(r),  cosf(r), 0.0f,
                0.0f, 0.0f,     0.0f,    1.0f);
}

inline static struct mat4x4 rotation_y(float r)
{
  return mat4x4( cosf(r), 0.0f, sinf(r), 0.0f,
                 0.0f,    1.0f, 0.0f,    0.0f,
                -sinf(r), 0.0f, cosf(r), 0.0f,
                 0.0f,    0.0f, 0.0f,    1.0f);
}

inline static struct mat4x4 rotation_z(float r)
{
  return mat4x4( cosf(r), -sinf(r), 0.0f, 0.0f,
                 sinf(r),  cosf(r), 0.0f, 0.0f,
                 0.0f,     0.0f,    1.0f, 0.0f,
                 0.0f,     0.0f,    0.0f, 1.0f);
}

inline static struct mat4x4 shearing(float xy,
                                     float xz,
                                     float yx,
                                     float yz,
                                     float zx,
                                     float zy)
{
  return mat4x4(1.0f, xy,   xz,   0.0f,
                yx,   1.0f, yz,   0.0f,
                zx,   zy,   1.0f, 0.0f,
                0.0f, 0.0f, 0.0f, 1.0f);
}

inline static struct mat4x4 view_transform(struct tuple from,
                                           struct tuple to,
                                           struct tuple up)
{
  struct tuple forward = tuple_normalize(tuple_sub(to, from));
  struct tuple left = tuple_cross(forward, tuple_normalize(up));
  struct tuple true_up = tuple_cross(left, forward);

  struct mat4x4 orientation = mat4x4(left.x,      left.y,     left.z,    0.0f,
                                     true_up.x,   true_up.y,  true_up.z, 0.0f,
                                     -forward.x, -forward.y, -forward.z, 0.0f,
                                     0.0f,        0.0f,       0.0f,      1.0f);

  struct mat4x4 translate = translation(-from.x, -from.y, -from.z);
  return mat4x4_mul_m(orientation, translate);
}