#include "shader.h"
#include "SDL3/SDL_iostream.h"
#include "SDL3/SDL_log.h"
#include "arena_allocator.h"
#include <GLES2/gl2.h>

wn_shader *wn_shader_init(Arena *arena,
                          wn_shader_code_location shader_code_location) {

  wn_shader *shader = arena_alloc(arena, sizeof(wn_shader));
  *shader = (wn_shader){.shaderProgram = 0, .success = false};

  const char *vertexShaderSource =
      SDL_LoadFile(shader_code_location.vertex_shader_source_path, NULL);
  const char *fragmentShaderSource =
      SDL_LoadFile(shader_code_location.fragment_shader_source_path, NULL);

  // vertex shader
  unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
  glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
  glCompileShader(vertexShader);
  // check for shader compile errors
  int success;
  char infoLog[512];
  glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
  if (!success) {
    glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                 "Failed to compile vertex shader: %s", infoLog);
    return shader;
  }

  // fragment shader
  unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
  glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
  glCompileShader(fragmentShader);
  // check for shader compile errors
  glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
  if (!success) {
    glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                 "Failed to compile fragment shader: %s", infoLog);
    return shader;
  }

  // Free source code memory
  SDL_free((void *)vertexShaderSource);
  SDL_free((void *)fragmentShaderSource);

  // link shaders
  unsigned int shaderProgram = glCreateProgram();
  glAttachShader(shaderProgram, vertexShader);
  glAttachShader(shaderProgram, fragmentShader);
  glLinkProgram(shaderProgram);

  // check for linking errors
  glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
  if (!success) {
    glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
    SDL_LogError(SDL_LOG_CATEGORY_APPLICATION,
                 "Failed to link shader program: %s", infoLog);
    return shader;
  }
  glDeleteShader(vertexShader);
  glDeleteShader(fragmentShader);

  shader->shaderProgram = shaderProgram;
  shader->success = true;

  arena_deinit_task_push(arena, (ArenaDeinitTask){.func_ptr = *wn_shader_deinit,
                                                  .func_param = shader,
                                                  .next = NULL});
  return shader;
}

void wn_shader_deinit(void *shader) {
  wn_shader *cast_shader = (wn_shader *)shader;
  glDeleteProgram(cast_shader->shaderProgram);
}