// This file is part of the 64k demo project.
// It tests the 3D system components (Camera, Object, Scene).

#include "3d/camera.h"
#include "3d/object.h"
#include "3d/scene.h"
#include <cassert>
#include <cmath>
#include <iostream>

bool near(float a, float b, float e = 0.001f) {
  return std::abs(a - b) < e;
}

void test_camera() {
  std::cout << "Testing Camera..." << std::endl;
  Camera cam;
  cam.position = vec3(0, 0, 10);
  cam.target = vec3(0, 0, 0);

  mat4 view = cam.get_view_matrix();
  // Camera at (0,0,10) looking at (0,0,0). World (0,0,0) -> View (0,0,-10)
  assert(near(view.m[14], -10.0f));

  mat4 proj = cam.get_projection_matrix();
  // Check aspect ratio influence (m[0] = 1/(tan(fov/2)*asp))
  // fov ~0.785 (45deg), tan(22.5) ~0.414. asp=1.777.
  // m[0] should be around 1.35
  assert(proj.m[0] > 1.0f);
}

void test_object_transform() {
  std::cout << "Testing Object Transform..." << std::endl;
  Object3D obj;
  obj.position = vec3(10, 0, 0);
  
  // Model matrix should translate by (10,0,0)
  mat4 m = obj.get_model_matrix();
  assert(near(m.m[12], 10.0f)); // Col 3, Row 0 is x translation in Col-Major? 
  // Wait, my mat4 struct:
  // r.m[12] = t.x; // Index 12 is translation X
  assert(near(m.m[12], 10.0f));

  // Rotate 90 deg Y
  obj.rotation = quat::from_axis(vec3(0, 1, 0), 1.570796f);
  m = obj.get_model_matrix();
  
  // Transform point (1,0,0) -> Rot(0,0,-1) -> Trans(10,0,-1)
  vec4 p(1, 0, 0, 1);
  vec4 res = m * p;
  assert(near(res.x, 10.0f)); // Rotated vector is (0,0,-1). + (10,0,0) translation -> (10,0,-1)
  assert(near(res.z, -1.0f));
}

void test_scene() {
  std::cout << "Testing Scene..." << std::endl;
  Scene scene;
  scene.add_object(Object3D());
  assert(scene.objects.size() == 1);
  scene.clear();
  assert(scene.objects.empty());
}

int main() {
  test_camera();
  test_object_transform();
  test_scene();
  std::cout << "--- 3D SYSTEM TESTS PASSED ---" << std::endl;
  return 0;
}