#include "../libretro.h"
#include <stdint.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <stdio.h>
#include <GL/gl.h>
#include <GL/glext.h>

static uint16_t *frame_buf;

void retro_init(void)
{
   frame_buf = calloc(320 * 240, sizeof(uint16_t));
}

void retro_deinit(void)
{
   free(frame_buf);
   frame_buf = NULL;
}

unsigned retro_api_version(void)
{
   return RETRO_API_VERSION;
}

void retro_set_controller_port_device(unsigned port, unsigned device)
{
   (void)port;
   (void)device;
}

void retro_get_system_info(struct retro_system_info *info)
{
   memset(info, 0, sizeof(*info));
   info->library_name     = "TestCore GL";
   info->library_version  = "v1";
   info->need_fullpath    = false;
   info->valid_extensions = NULL; // Anything is fine, we don't care.
}

void retro_get_system_av_info(struct retro_system_av_info *info)
{
   info->timing = (struct retro_system_timing) {
      .fps = 60.0,
      .sample_rate = 30000.0,
   };

   info->geometry = (struct retro_game_geometry) {
      .base_width   = 320,
      .base_height  = 240,
      .max_width    = 320,
      .max_height   = 240,
      .aspect_ratio = 4.0 / 3.0,
   };
}

static retro_video_refresh_t video_cb;
static retro_audio_sample_t audio_cb;
static retro_audio_sample_batch_t audio_batch_cb;
static retro_environment_t environ_cb;
static retro_input_poll_t input_poll_cb;
static retro_input_state_t input_state_cb;

void retro_set_environment(retro_environment_t cb)
{
   environ_cb = cb;
}

void retro_set_audio_sample(retro_audio_sample_t cb)
{
   audio_cb = cb;
}

void retro_set_audio_sample_batch(retro_audio_sample_batch_t cb)
{
   audio_batch_cb = cb;
}

void retro_set_input_poll(retro_input_poll_t cb)
{
   input_poll_cb = cb;
}

void retro_set_input_state(retro_input_state_t cb)
{
   input_state_cb = cb;
}

void retro_set_video_refresh(retro_video_refresh_t cb)
{
   video_cb = cb;
}

static struct retro_hw_render_callback hw_render;

void retro_run(void)
{
   input_poll_cb();
   static unsigned frame_count = 0;
   frame_count = (frame_count + 1) % 60;
   glBindFramebuffer(GL_FRAMEBUFFER, hw_render.get_current_framebuffer());
   glViewport(0, 0, 320, 240);
   glClearColor(frame_count / 120.0, frame_count / 60.0, frame_count / 60.0, 1.0);
   glClear(GL_COLOR_BUFFER_BIT);
   video_cb(RETRO_HW_FRAME_BUFFER_VALID, 320, 240, 0);
}


static void context_reset(void)
{
   fprintf(stderr, "Context reset!\n");
}

bool retro_load_game(const struct retro_game_info *info)
{
   enum retro_pixel_format fmt = RETRO_PIXEL_FORMAT_XRGB8888;
   if (!environ_cb(RETRO_ENVIRONMENT_SET_PIXEL_FORMAT, &fmt))
   {
      fprintf(stderr, "XRGB8888 is not supported.\n");
      return false;
   }

   hw_render.context_type = RETRO_HW_CONTEXT_OPENGL;
   hw_render.context_reset = context_reset;
   if (!environ_cb(RETRO_ENVIRONMENT_SET_HW_RENDER, &hw_render))
      return false;

   (void)info;
   return true;
}

void retro_unload_game(void)
{}

unsigned retro_get_region(void)
{
   return RETRO_REGION_NTSC;
}

bool retro_load_game_special(unsigned type, const struct retro_game_info *info, size_t num)
{
   (void)type;
   (void)info;
   (void)num;
   return false;
}

size_t retro_serialize_size(void)
{
   return 0;
}

bool retro_serialize(void *data, size_t size)
{
   (void)data;
   (void)size;
   return false;
}

bool retro_unserialize(const void *data, size_t size)
{
   (void)data;
   (void)size;
   return false;
}

void *retro_get_memory_data(unsigned id)
{
   (void)id;
   return NULL;
}

size_t retro_get_memory_size(unsigned id)
{
   (void)id;
   return 0;
}

void retro_reset(void)
{}

void retro_cheat_reset(void)
{}

void retro_cheat_set(unsigned index, bool enabled, const char *code)
{
   (void)index;
   (void)enabled;
   (void)code;
}