#include <GL/glew.h>

#include "SDL3/SDL_surface.h"
#include "SDL3_image/SDL_image.h"
#include "arena_allocator.h"
#include "mesh.h"

wn_mesh *wn_mesh_init(Arena *arena, wn_shader *shader) {
  // set up vertex data (and buffer(s)) and configure vertex attributes
  wn_mesh *mesh = (wn_mesh *)arena_init(arena, sizeof(wn_mesh));
  arena_deinit_task_push(arena, (ArenaDeinitTask){.func_ptr = *wn_mesh_deinit,
                                                  .func_param = mesh,
                                                  .next = NULL});
  mesh->shader = shader;
  float vertices[] = {
      0.5f,  0.5f,  0.0f, 1.0f, 1.0f, // top right
      0.5f,  -0.5f, 0.0f, 1.0f, 0.0f, // bottom right
      -0.5f, -0.5f, 0.0f, 0.0f, 0.0f, // bottom left
      -0.5f, 0.5f,  0.0f, 0.0f, 1.0f  // top left
  };
  unsigned int indices[] = {
      0, 1, 3, // first Triangle
      1, 2, 3  // second Triangle
  };

  glGenVertexArrays(1, &mesh->VAO);
  glGenBuffers(1, &mesh->VBO);
  glGenBuffers(1, &mesh->EBO);
  // bind the Vertex Array Object first, then bind and set vertex buffer(s), and
  // then configure vertex attributes(s).
  glBindVertexArray(mesh->VAO);

  glBindBuffer(GL_ARRAY_BUFFER, mesh->VBO);
  glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, mesh->EBO);
  glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices,
               GL_STATIC_DRAW);

  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void *)0);
  glEnableVertexAttribArray(0);
  glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float),
                        (void *)(3 * sizeof(float)));
  glEnableVertexAttribArray(1);

  // note that this is allowed, the call to glVertexAttribPointer registered VBO
  // as the vertex attribute's bound vertex buffer object so afterwards we can
  // safely unbind
  // glBindBuffer(GL_ARRAY_BUFFER, 0);

  // remember: do NOT unbind the EBO while a VAO is active as the bound element
  // buffer object IS stored in the VAO; keep the EBO bound.
  // glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

  // You can unbind the VAO afterwards so other VAO calls won't accidentally
  // modify this VAO, but this rarely happens. Modifying other VAOs requires a
  // call to glBindVertexArray anyways so we generally don't unbind VAOs (nor
  // VBOs) when it's not directly necessary.
  // glBindVertexArray(0);

  // Texture Load
  SDL_Surface *image = IMG_Load("./data/testxure.png");
  if (image == NULL) {
    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't load texture");
    return NULL;
  }
  SDL_FlipSurface(image, SDL_FLIP_VERTICAL);

  GLuint texture;
  glActiveTexture(GL_TEXTURE0);
  glGenTextures(1, &texture);

  // Handle different SDL Surface data types
  // int mode = GL_RGB;
  //  if (image->format->BytesPerPixel == 4) {
  int mode = GL_RGBA;
  //    mode = GL_RGBA;
  //  }

  glBindTexture(GL_TEXTURE_2D, texture);
  // set the texture wrapping parameters
  glTexParameteri(
      GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,
      GL_REPEAT); // set texture wrapping to GL_REPEAT (default wrapping method)
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
  // set texture filtering parameters
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

  glTexImage2D(GL_TEXTURE_2D, 0, mode, image->w, image->h, 0, mode,
               GL_UNSIGNED_BYTE, image->pixels);

  glGenerateMipmap(GL_TEXTURE_2D);
  SDL_DestroySurface(image);

  return mesh;
}

void wn_mesh_draw(wn_mesh *mesh) {
  // draw our first triangle
  glUseProgram(mesh->shader->shaderProgram);

  // seeing as we only have a single VAO there's no need to bind it
  // every time, but we'll do so to keep things a bit more organized
  glBindVertexArray(mesh->VAO);

  // glDrawArrays(GL_TRIANGLES, 0, 6);
  glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
  // glBindVertexArray(0); // no need to unbind it every time
}

void wn_mesh_deinit(void *mesh) {
  wn_mesh *cast_mesh = (wn_mesh *)mesh;
  glDeleteVertexArrays(1, &cast_mesh->VAO);
  glDeleteBuffers(1, &cast_mesh->VBO);
  glDeleteBuffers(1, &cast_mesh->EBO);
}