// Copyright (c) 2021 Dominic Msters
// 
// This software is released under the MIT License.
// https://opensource.org/licenses/MIT

#pragma once
#include "../libs.h"
#include "../util/math.h"
#include "matrix.h"

/** The math for the camera is stored here. */
typedef struct {
  /** View Matrix (Where the camera looks) */
  matrix_t view;

  /** Projection Matrix (How the camera looks) */
  matrix_t projection;
} camera_t;

typedef struct {
  float x, y, z, lookX, lookY, lookZ;
} cameralookat_t;

/**
 * Make a camera look at a position in world space while itself being positioned
 * within world space.
 * 
 * @param camera The camera to position.
 * @param x The X position in world space of the camera.
 * @param y The Y position in world space of the camera.
 * @param z The Z position in world space of the camera.
 * @param targetX The Target X position in world space of the camera.
 * @param targetY The Target Y position in world space of the camera.
 * @param targetZ The Target Z position in world space of the camera.
 */
void cameraLookAt(camera_t *camera,
  float x, float y, float z,
  float targetX, float targetY, float targetZ
);

/**
 * Shorthand for look at that uses the look struct.
 * 
 * @param camera Camera to position.
 * @param look Look vectors.
 */
void cameraLookAtStruct(camera_t *camera, cameralookat_t look);

/**
 * Make a camera look in a direction based on a rotation direction.
 * 
 * @param camera The camera to position.
 * @param x The X position in world space of the camera.
 * @param y The Y position in world space of the camera.
 * @param z The Z position in world space of the camera.
 * @param pitch The pitch of the camera.
 * @param yaw The yaw of the camera.
 * @param roll The roll of the camera.
 */
void cameraLook(camera_t *camera,
  float x, float y, float z,
  float pitch, float yaw, float roll
);

/**
 * Make a camera's projection be a 3D Perspective view.
 * 
 * @param camera The camera to project.
 * @param fov The field of view of the camera (in degrees).
 * @param aspect The aspect ratio of the camera (w / h)
 * @param camNear The near plane clip.
 * @param camFar the far plane clip.
 */
void cameraPerspective(camera_t *camera,
  float fov, float aspect, float camNear, float camFar
);

/**
 * Defines an orthorgonal camera matrix.
 * 
 * @param camera Camera to position.
 * @param left The left side of the viewport.
 * @param right The right side of the viewport.
 * @param bottom The bottom side of the viewport.
 * @param camNear The near plane clip.
 * @param camFar the far plane clip.
 */
void cameraOrtho(camera_t *camera,
  float left, float right, float bottom, float top, float camNear, float camFar
);

/**
 * Update a camera to orbit around a point.
 * 
 * @param camera Camera to update
 * @param distance Distance from the point
 * @param yaw Yaw (Y axis) rotation.
 * @param pitch Pitch (X/Z axis) rotation.
 * @param targetX X point to orbit around.
 * @param targetY Y point to orbit around.
 * @param targetZ Z point to orbit around.
 */
void cameraOrbit(camera_t *camera,
  float distance, float yaw, float pitch,
  float targetX, float targetY, float targetZ
);