#include <celeritas.h>
#include "glfw3.h"

camera cam;
pipeline_handle draw_pipeline;
buf_handle cube_vbuf;
buf_handle transform_buf;
tex_handle texture;

// transformation data
typedef struct MVPData {
  mat4 model;
  mat4 view;
  mat4 projection;
} MVPData;

// draw calls for a single frame
void draw() {
  // prepare model data
  f32 angle_degrees = glfwGetTime() * 45.0;
  f32 angle = angle_degrees * PI / 180.0;

  // Move origin to cube center
  vec3 center_offset = vec3(0.5, 0.5, 0.5);
  mat4 to_center = mat4_translation(vec3_negate(center_offset));
  mat4 from_center = mat4_translation(center_offset);

  // Create rotation around Y axis
  mat4 rotation = mat4_rotation(quat_from_axis_angle(VEC3_Y, angle, true));

  // Print debug info for one frame
  static bool printed = false;
  if (!printed) {
    printf("\nTo Center:\n");
    for (int i = 0; i < 16; i += 4) {
      printf("%f %f %f %f\n", to_center.data[i], to_center.data[i + 1], to_center.data[i + 2], to_center.data[i + 3]);
    }
    printed = true;
  }

  // Order: first move to center, then rotate, then move back
  mat4 cube_transform = mat4_mult(from_center, mat4_mult(rotation, to_center));

  mat4 move = mat4_translation(vec3(-0.5, -0.5, 0));
  cube_transform = mat4_mult(move, cube_transform);

  // prepare camera data
  mat4 view, proj;
  camera_view_proj(cam, 800, 600, &view, &proj);

  render_pass_desc d = {};
  gpu_encoder* enc = ral_render_encoder(d);
  ral_encode_bind_pipeline(enc, draw_pipeline);
  ral_set_default_settings(enc);

  MVPData mvp = { .model = cube_transform, .view = view, .projection = proj };

  ral_buffer_upload_data(transform_buf, sizeof(MVPData), &mvp);
  ral_bind_buffer(enc, transform_buf, 1);  // bind the transform data buffer to binding 1
  ral_encode_set_vertex_buf(enc, cube_vbuf);
  ral_encode_set_texture(enc, texture, 0);
  ral_encode_draw_tris(enc, 0, 36);
  ral_encoder_finish_and_submit(enc);
}

void test_matrix_mult() {
  // Create a simple translation matrix (1 unit in x)
  mat4 trans1 = mat4_translation(vec3(1, 0, 0));
  // Create another translation matrix (1 unit in y)
  mat4 trans2 = mat4_translation(vec3(0, 1, 0));

  printf("Matrix 1 (translate x+1):\n");
  for (int i = 0; i < 16; i += 4) {
    printf("%f %f %f %f\n", trans1.data[i], trans1.data[i + 1], trans1.data[i + 2], trans1.data[i + 3]);
  }

  printf("\nMatrix 2 (translate y+1):\n");
  for (int i = 0; i < 16; i += 4) {
    printf("%f %f %f %f\n", trans2.data[i], trans2.data[i + 1], trans2.data[i + 2], trans2.data[i + 3]);
  }

  mat4 result = mat4_mult(trans1, trans2);

  printf("\nResult matrix:\n");
  for (int i = 0; i < 16; i += 4) {
    printf("%f %f %f %f\n", result.data[i], result.data[i + 1], result.data[i + 2], result.data[i + 3]);
  }
}

int main() {
  test_matrix_mult();
  // exit(1);

  core_bringup("Celeritas Example: Triangle", NULL);

  // create rendering pipeline
  gfx_pipeline_desc pipeline_desc = {
    .label = "Textured cube pipeline",
    .vertex_desc = static_3d_vertex_format(),
    .vertex = {
      .source = NULL,
      .is_spirv = false,
      .entry_point = "cubeVertexShader",
      .stage = STAGE_VERTEX,
    },
    .fragment = {
      .source = NULL,
      .is_spirv = false,
      .entry_point = "fragmentShader",
      .stage = STAGE_FRAGMENT,
    },
  };

  draw_pipeline = ral_gfx_pipeline_create(pipeline_desc);

  // load texture from file
  texture = ral_texture_load_from_file("assets/textures/mc_grass.jpeg");

  cam = (camera){ .position = vec3(0, 3, 5), .forwards = vec3(0, -3, -5), .fov = 45.0, .up = VEC3_Y };

  // create the cube geometry
  geometry cube = geo_cuboid(1.0, 1.0, 1.0);

  // (debug) print out each vertex
  size_t vertex_stride = cube.data_length / cube.n_vertices;
  printf("Vertex stride %ld\n", vertex_stride);
  for (int i = 0; i < cube.n_vertices; i++) {
    static_3d_vert* vertex = (static_3d_vert*)(cube.vertex_data + vertex_stride * i);
    print_static_3d_vert(vertex);
  }

  // upload vertex data to the gpu
  cube_vbuf = ral_buffer_create(64 * 36, cube.vertex_data);

  // create a buffer to hold the MVP transforms
  MVPData d = {};
  transform_buf = ral_buffer_create(sizeof(MVPData), &d);

  while (!app_should_exit()) {
    glfwPollEvents();

    ral_frame_start();
    ral_frame_draw(&draw);
    ral_frame_end();
  }

  return 0;
}