/*
 * Copyright 2022 Frederico de Oliveira Linhares
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "rotation_3d.hpp"

#include "vector_3d.hpp"

namespace
{
inline float
pitch_limit(float pitch)
{
  if(pitch > M_PI/2) pitch = M_PI/2;
  else if (pitch < -(M_PI/2)) pitch = -(M_PI/2);

  return pitch;
}

}

void
cg_free_rotation_3d(mrb_state *mrb, void* obj)
{
  auto ptr = static_cast<std::shared_ptr<glm::vec3>*>(obj);

  ptr->~shared_ptr();
  mrb_free(mrb, ptr);
}

const struct mrb_data_type cg_rotation_3d_type = {
  "CG_Rotation3D", cg_free_rotation_3d};

static mrb_value
cg_cRotation3D_initialize(mrb_state *mrb, mrb_value self)
{
  mrb_float pitch, yaw, roll;
  std::shared_ptr<glm::vec3> *ptr;

  mrb_get_args(mrb, "fff", &pitch, &yaw, &roll);
  ptr = (std::shared_ptr<glm::vec3>*)DATA_PTR(self);
  if(ptr) mrb_free(mrb, ptr);
  ptr = (std::shared_ptr<glm::vec3>*)mrb_malloc(
    mrb, sizeof(std::shared_ptr<glm::vec3>));

  new(ptr)std::shared_ptr<glm::vec3>(
    std::make_shared<glm::vec3>(pitch_limit(pitch), yaw, roll));

  mrb_data_init(self, ptr, &cg_rotation_3d_type);
  return self;
}

// Rotation when there is a up direction (ex.: Earth).
static mrb_value
cg_cRotation3D_rotate(mrb_state *mrb, mrb_value self)
{
  mrb_float pitch, yaw;
  auto *ptr = (std::shared_ptr<glm::vec3>*)DATA_PTR(self);

  mrb_get_args(mrb, "ff", &pitch, &yaw);

  (*ptr)->x = pitch_limit((*ptr)->x + pitch);
  (*ptr)->y += yaw;

  return self;
}

// Rotation when there is a up direction (ex.: space without gravity).
static mrb_value
cg_cRotation3D_baseless_rotation(mrb_state *mrb, mrb_value self)
{
  mrb_float x, y;

  // TODO

  return self;
}

void
cg_rotation_3d_init(mrb_state *mrb)
{
  struct RClass *cg_m, *cg_cRotation3D;

  cg_m = mrb_module_get(mrb, "CandyGear");
  cg_cRotation3D = mrb_define_class_under(
    mrb, cg_m, "Rotation3D", mrb->object_class);
  MRB_SET_INSTANCE_TT(cg_cRotation3D, MRB_TT_DATA);
  mrb_define_method(
    mrb, cg_cRotation3D, "initialize", cg_cRotation3D_initialize,
    MRB_ARGS_REQ(3));

  mrb_define_method(
    mrb, cg_cRotation3D, "pitch", cg_cVector3D_get_x, MRB_ARGS_NONE());
  mrb_define_method(
    mrb, cg_cRotation3D, "yaw", cg_cVector3D_get_y, MRB_ARGS_NONE());
  mrb_define_method(
    mrb, cg_cRotation3D, "roll", cg_cVector3D_get_z, MRB_ARGS_NONE());

  mrb_define_method(
    mrb, cg_cRotation3D, "rotate", cg_cRotation3D_rotate, MRB_ARGS_REQ(2));
}