#include "camera_controller.h"
#include "utils/mirror.h"

START_REFLECT(CameraController);
REFLECT_TYPECLASS(CameraController, SceneNodeEntity);
END_REFLECT(CameraController);

impl_Drop_for(CameraController,
    DestroyCameraController
)
impl_SceneNodeEntity_for(CameraController,
    CameraControllerEnterTree,
    CameraControllerExitTree,
    CameraControllerTick
)

SceneNode *CreateCameraController(Transformable target) {
    CameraController *self = new(CameraController);
    *self = (CameraController){
        .transform = tc_null(Transformable),
        .rotation_speed = 5.f,
        .max_speed_time = 4.f,
        .target = target,
        .time_rotated = 0.f
    };
    SceneNode *node = CreateSceneNode(CameraController_as_SceneNodeEntity(self));
    return node;
}

void DestroyCameraController(CameraController *self) {
    free(self);
}

void CameraControllerEnterTree(CameraController *self) {
    self->transform = TC_CAST(self->node->parent->entity, Transformable);
    self->global = self->transform.tc->get_global_transform(self->transform.data);
}

void CameraControllerExitTree(CameraController *self) {}

void CameraControllerTick(CameraController *self, double delta) {
    Transform current = self->transform.tc->get_global_transform(self->transform.data);
    self->target.tc->force_update(self->target.data);
    Transform target = self->target.tc->get_global_transform(self->target.data);
    // calculate time multiplier...
    float const time_mul = fminf(1.f, fmaxf(0.1f, powf(self->time_rotated / self->max_speed_time, 0.5f)));
    // ... angle difference ...
    float const angle = QuaternionAngleDifference(current.rotation, target.rotation);
    // ... and maximum frame step size
    float const step = self->rotation_speed * time_mul * delta;
    if(angle > 0.f)
        target.rotation = QuaternionSlerp(current.rotation, target.rotation, fminf(fminf(step, angle) / angle, 0.99f));
    if(step > angle && self->time_rotated > delta)
        self->time_rotated -= 3.f * delta;
    else if(step > angle)
        self->time_rotated = 0.f;
    self->time_rotated += delta;
    self->transform.tc->set_global_transform(self->transform.data, target);
}