#ifndef _ktransform_SYSTEM_H_
#define _ktransform_SYSTEM_H_

#include "systems/kmatrix_system.h"
#include <math/math_types.h>

struct frame_data;

typedef struct ktransform_system_config {
	// The initial number of slots to allocate for ktransforms on startup.
	u32 initial_slot_count;
} ktransform_system_config;

struct ktransform_system_state;

#define KRENDERBUFFER_NAME_MATRIX_GLOBAL "Kohi.StorageBuffer.MatrixGlobal"

b8 ktransform_system_initialize (u64 *memory_requirement, void *state, void *config);

void ktransform_system_shutdown (void *state);

b8 ktransform_system_update (struct ktransform_system_state *state, struct frame_data *p_frame_data);

/**
 * @brief Creates and returns a new ktransform, using a zero
 * vector for position, identity quaternion for rotation, and
 * a one vector for scale. Not marked dirty by default.
 *
 * @param user User data, typically a handle or pointer to something for reverse lookups.
 * @return A handle to the new ktransform.
 */
KAPI ktransform ktransform_create (u64 user);

/**
 * @brief Creates and returns a new ktransform, using the position,
 * rotation and scale of the provided original transform.
 * Not marked dirty by default.
 *
 * @param original The transform to be cloned.
 * @param user User data, typically a handle or pointer to something for reverse lookups.
 * @return A handle to the new ktransform.
 */
KAPI ktransform ktransform_clone (ktransform original, u64 user);

/**
 * Forces the transform to be dirty, thus forcing a recalculation on the next update.
 *
 * @param transform The transform to flag as dirty.
 */
KAPI void ktransform_mark_dirty (ktransform transform);

/**
 * @brief Creates a ktransform from the given position.
 * Uses a zero rotation and a one scale.
 *
 * @param position The position to be used.
 * @param user User data, typically a handle or pointer to something for reverse lookups.
 * @return A handle to the new ktransform.
 */
KAPI ktransform ktransform_from_position (vec3 position, u64 user);

/**
 * @brief Creates a ktransform from the given rotation.
 * Uses a zero position and a one scale.
 *
 * @param rotation The rotation to be used.
 * @param user User data, typically a handle or pointer to something for reverse lookups.
 * @return A handle to the new ktransform.
 */
KAPI ktransform ktransform_from_rotation (quat rotation, u64 user);

/**
 * @brief Creates a ktransform from the given position and rotation.
 * Uses a one scale.
 *
 * @param position The position to be used.
 * @param rotation The rotation to be used.
 * @param user User data, typically a handle or pointer to something for reverse lookups.
 * @return A handle to the new ktransform.
 */
KAPI ktransform ktransform_from_position_rotation (vec3 position, quat rotation, u64 user);

/**
 * @brief Creates a ktransform from the given position, rotation and scale.
 *
 * @param position The position to be used.
 * @param rotation The rotation to be used.
 * @param scale The scale to be used.
 * @param user User data, typically a handle or pointer to something for reverse lookups.
 * @return A handle to the new ktransform.
 */
KAPI ktransform ktransform_from_position_rotation_scale (vec3 position, quat rotation, vec3 scale, u64 user);

/**
 * @brief Creates a ktransform from the provided matrix.
 *
 * @param m The matrix to decompose and extract a transform from.
 * @param user User data, typically a handle or pointer to something for reverse lookups.
 * @return A handle to the new ktransform.
 */
KAPI ktransform ktransform_from_matrix (mat4 m, u64 user);

/**
 * @brief Destroys the ktransform with the given handle, and frees the handle.
 * @param t A pointer to a handle to the transform to be destroyed. The handle itself is also invalidated.
 */
KAPI void ktransform_destroy (ktransform *t);

/**
 * @brief Returns the kmatrix_id for the given transform.
 *
 * @param t The transform to get the kmatrix_id for.
 * @return The kmatrix_id of the transform, or KMATRIX_INVALID if it does not exist.
 */
KAPI kmatrix_id ktransform_kmatrixid_get (ktransform t);

/**
 * @brief Indicates if the provided transform is an identity transform (i.e. zero position, identity rotation, one-scale).
 * @param t A handle to the transform to be analyzed.
 *
 * @return True if the transform is identity; otherwise false.
 */
KAPI b8 ktransform_is_identity (ktransform t);

KAPI b8 ktransform_parent_set (ktransform t, ktransform parent);
KAPI ktransform ktransform_parent_get (ktransform t);

/**
 * @brief Returns the local position of the given ktransform.
 *
 * @param t A handle whose position to get.
 * @return A copy of the position.
 */
KAPI vec3 ktransform_position_get (ktransform t);

/**
 * @brief Returns the world position of the given ktransform.
 *
 * @param t A handle whose position to get.
 * @return A copy of the position.
 */
KAPI vec3 ktransform_world_position_get (ktransform t);

/**
 * @brief Sets the position of the given ktransform.
 *
 * @param t A handle to the ktransform to be updated.
 * @param position The position to be set.
 */
KAPI void ktransform_position_set (ktransform t, vec3 position);

/**
 * @brief Applies a translation to the given ktransform. Not the
 * same as setting.
 *
 * @param t A handle to the ktransform to be updated.
 * @param translation The translation to be applied.
 */
KAPI void ktransform_translate (ktransform t, vec3 translation);

/**
 * @brief Returns the rotation of the given ktransform.
 *
 * @param t A handle whose rotation to get.
 * @return A copy of the rotation.
 */
KAPI quat ktransform_rotation_get (ktransform t);

/**
 * @brief Returns the world rotation of the given ktransform.
 *
 * @param t A handle whose world rotation to get.
 * @return A copy of the world rotation.
 */
KAPI quat ktransform_world_rotation_get (ktransform t);

/**
 * @brief Sets the rotation of the given ktransform.
 *
 * @param t A handle to the ktransform to be updated.
 * @param rotation The rotation to be set.
 */
KAPI void ktransform_rotation_set (ktransform t, quat rotation);

/**
 * @brief Applies a rotation to the given ktransform. Not the
 * same as setting.
 *
 * @param t A handle to the ktransform to be updated.
 * @param rotation The rotation to be applied.
 */
KAPI void ktransform_rotate (ktransform t, quat rotation);

/**
 * @brief Returns the scale of the given ktransform.
 *
 * @param t A handle whose scale to get.
 * @return A copy of the scale.
 */
KAPI vec3 ktransform_scale_get (ktransform t);

/**
 * @brief Returns the world scale of the given ktransform.
 *
 * @param t A handle whose scale to get.
 * @return A copy of the scale.
 */
KAPI vec3 ktransform_world_scale_get (ktransform t);

/**
 * @brief Sets the scale of the given ktransform.
 *
 * @param t A handle to the ktransform to be updated.
 * @param scale The scale to be set.
 */
KAPI void ktransform_scale_set (ktransform t, vec3 scale);

/**
 * @brief Applies a scale to the given ktransform. Not the
 * same as setting.
 *
 * @param t A handle to the ktransform to be updated.
 * @param scale The scale to be applied.
 */
KAPI void ktransform_scale (ktransform t, vec3 scale);

/**
 * @brief Sets the position and rotation of the given ktransform.
 *
 * @param t A handle to the ktransform to be updated.
 * @param position The position to be set.
 * @param rotation The rotation to be set.
 */
KAPI void ktransform_position_rotation_set (ktransform t, vec3 position, quat rotation);

/**
 * @brief Sets the position, rotation and scale of the given ktransform.
 *
 * @param t A handle to the ktransform to be updated.
 * @param position The position to be set.
 * @param rotation The rotation to be set.
 * @param scale The scale to be set.
 */
KAPI void ktransform_position_rotation_scale_set (ktransform t, vec3 position, quat rotation, vec3 scale);

/**
 * @brief Applies translation and rotation to the given ktransform.
 *
 * @param t A handle to the ktransform to be updated.
 * @param translation The translation to be applied.
 * @param rotation The rotation to be applied.
 * @return KAPI
 */
KAPI void ktransform_translate_rotate (ktransform t, vec3 translation, quat rotation);

/**
 * Recalculates the local matrix for the transform with the given handle.
 */
KAPI void ktransform_calculate_local (ktransform t);

/**
 * @brief Retrieves the local ktransformation matrix from the provided ktransform.
 * Automatically recalculates the matrix if it is dirty. Otherwise, the already
 * calculated one is returned.
 *
 * @param t A handle to the ktransform whose matrix to retrieve.
 * @return A copy of the local ktransformation matrix.
 */
KAPI mat4 ktransform_local_get (ktransform t);

/**
 * @brief Obtains the world matrix of the given ktransform.
 *
 * @param t A handle to the ktransform whose world matrix to retrieve.
 * @return A copy of the world matrix.
 */
KAPI mat4 ktransform_world_get (ktransform t);

KAPI u64 ktransform_user_get (ktransform t);
KAPI void ktransform_user_set (ktransform t, u64 user);

/**
 * @brief Returns a string representation of the ktransform pointed to by the given handle.
 *
 * @param t A handle to the ktransform to retrieve as a string.
 * @return The ktransform in string format.
 */
KAPI const char *ktransform_to_string (ktransform t);

/**
 * @brief Creates an ktransform from the given string.
 *
 * @param str The string from which to create the ktransform. Should be either 'x y z qx qy qz qw sx sy sz' (quaternion rotation) OR 'x y z ex ey ez sx sy sz' (euler rotation)
 * @param user User data, typically a handle or pointer to something for reverse lookups.
 * @param out_ktransform A pointer to hold the handle to the newly created ktransform.
 * @returns True on success; otherwise false.
 */
KAPI b8 ktransform_from_string (const char *str, u64 user, ktransform *out_ktransform);

#endif