//
//  Matrix4.h
//  Kraken Engine / Hydra
//
//  Copyright 2022 Kearwood Gilbert. All rights reserved.
//
//  Redistribution and use in source and binary forms, with or without modification, are
//  permitted provided that the following conditions are met:
//
//  1. Redistributions of source code must retain the above copyright notice, this list of
//  conditions and the following disclaimer.
//
//  2. Redistributions in binary form must reproduce the above copyright notice, this list
//  of conditions and the following disclaimer in the documentation and/or other materials
//  provided with the distribution.
//
//  THIS SOFTWARE IS PROVIDED BY KEARWOOD GILBERT ''AS IS'' AND ANY EXPRESS OR IMPLIED
//  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
//  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KEARWOOD GILBERT OR
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//  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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//  or implied, of Kearwood Gilbert.
//


#include "vector3.h"
#include "vector4.h"

#ifndef KRAKEN_MATRIX4_H
#define KRAKEN_MATRIX4_H

namespace kraken {

enum class AXIS {
  X_AXIS,
  Y_AXIS,
  Z_AXIS
};

class Quaternion;

class Matrix4 {
public:

  union {
    struct {
      Vector4 axis_x, axis_y, axis_z, transform;
    };
    // Matrix components, in column-major order
    float c[16];
  };
    
  // Default initializer - Creates an identity matrix
  void init();
    
  void init(float *pMat);
  void init(const Vector3 &new_axis_x, const Vector3 &new_axis_y, const Vector3 &new_axis_z, const Vector3 &new_transform);
  void init(const Matrix4 &m);

  static Matrix4 Create(float *pMat);
  static Matrix4 Create(const Vector3 &new_axis_x, const Vector3 &new_axis_y, const Vector3 &new_axis_z, const Vector3 &new_transform);
    
  // Overload comparison operator
  bool operator==(const Matrix4 &m) const;
    
  // Overload compound multiply operator
  Matrix4& operator*=(const Matrix4 &m);
    
  float& operator[](unsigned i);
  float operator[](unsigned i) const;
    
  // Overload multiply operator
  //Matrix4& operator*(const Matrix4 &m);
  Matrix4 operator*(const Matrix4 &m) const;
    
  float *getPointer();
    
  void perspective(float fov, float aspect, float nearz, float farz);
  void ortho(float left, float right, float top, float bottom, float nearz, float farz);
  void translate(float x, float y, float z);
  void translate(const Vector3 &v);
  void scale(float x, float y, float z);
  void scale(const Vector3 &v);
  void scale(float s);
  void rotate(float angle, AXIS axis);
  void rotate(const Quaternion &q);
  void bias();
  bool invert();
  void transpose();
    
  static Vector3 DotNoTranslate(const Matrix4 &m, const Vector3 &v); // Dot product without including translation; useful for transforming normals and tangents
  static Matrix4 Invert(const Matrix4 &m);
  static Matrix4 Transpose(const Matrix4 &m);
  static Vector3 Dot(const Matrix4 &m, const Vector3 &v);
  static Vector4 Dot4(const Matrix4 &m, const Vector4 &v);
  static float DotW(const Matrix4 &m, const Vector3 &v);
  static Vector3 DotWDiv(const Matrix4 &m, const Vector3 &v);
    
  static Matrix4 LookAt(const Vector3 &cameraPos, const Vector3 &lookAtPos, const Vector3 &upDirection);
    
  static Matrix4 Translation(const Vector3 &v);
  static Matrix4 Rotation(const Vector3 &v);
  static Matrix4 Scaling(const Vector3 &v);
  static Matrix4 Identity();
};
static_assert(std::is_pod<Matrix4>::value, "kraken::Matrix4 must be a POD type.");

} // namespace kraken

namespace std {
  template<>
  struct hash<kraken::Matrix4> {
  public:
    size_t operator()(const kraken::Matrix4 &s) const
    {
      size_t h1 = hash<kraken::Vector4>()(s.axis_x);
      size_t h2 = hash<kraken::Vector4>()(s.axis_y);
      size_t h3 = hash<kraken::Vector4>()(s.axis_z);
      size_t h4 = hash<kraken::Vector4>()(s.transform);
      return h1 ^ (h2 << 1) ^ (h3 << 2) ^ (h4 << 3);
    }
  };
} // namespace std

#endif // KRAKEN_MATRIX4_H