#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#include <glsym/glsym.h>

#include "../../libretro.h"

#define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
static struct retro_hw_render_callback hw_render;

#if defined(HAVE_PSGL)
#define RARCH_GL_FRAMEBUFFER GL_FRAMEBUFFER_OES
#define RARCH_GL_FRAMEBUFFER_COMPLETE GL_FRAMEBUFFER_COMPLETE_OES
#define RARCH_GL_COLOR_ATTACHMENT0 GL_COLOR_ATTACHMENT0_EXT
#elif defined(OSX_PPC)
#define RARCH_GL_FRAMEBUFFER GL_FRAMEBUFFER_EXT
#define RARCH_GL_FRAMEBUFFER_COMPLETE GL_FRAMEBUFFER_COMPLETE_EXT
#define RARCH_GL_COLOR_ATTACHMENT0 GL_COLOR_ATTACHMENT0_EXT
#else
#define RARCH_GL_FRAMEBUFFER GL_FRAMEBUFFER
#define RARCH_GL_FRAMEBUFFER_COMPLETE GL_FRAMEBUFFER_COMPLETE
#define RARCH_GL_COLOR_ATTACHMENT0 GL_COLOR_ATTACHMENT0
#endif

#define BASE_WIDTH 320
#define BASE_HEIGHT 240
#ifdef GLES
#define MAX_WIDTH 1024
#define MAX_HEIGHT 1024
#else
#define MAX_WIDTH 2048
#define MAX_HEIGHT 2048
#endif

static unsigned width  = BASE_WIDTH;
static unsigned height = BASE_HEIGHT;

void retro_init(void)
{}

void retro_deinit(void)
{}

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 (FF)";
   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   = BASE_WIDTH,
      .base_height  = BASE_HEIGHT,
      .max_width    = MAX_WIDTH,
      .max_height   = MAX_HEIGHT,
      .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;

   struct retro_variable variables[] = {
      {
         "testgl_resolution",
#ifdef GLES
         "Internal resolution; 320x240|360x480|480x272|512x384|512x512|640x240|640x448|640x480|720x576|800x600|960x720|1024x768",
#else
         "Internal resolution; 320x240|360x480|480x272|512x384|512x512|640x240|640x448|640x480|720x576|800x600|960x720|1024x768|1024x1024|1280x720|1280x960|1600x1200|1920x1080|1920x1440|1920x1600|2048x2048",
#endif
      },
#ifdef CORE
      { "testgl_multisample", "Multisampling; 1x|2x|4x" },
#endif
      { NULL, NULL },
   };

   bool no_rom = true;
   cb(RETRO_ENVIRONMENT_SET_SUPPORT_NO_GAME, &no_rom);
   cb(RETRO_ENVIRONMENT_SET_VARIABLES, variables);
}

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 void update_variables(void)
{
   struct retro_variable var = {
      .key = "testgl_resolution",
   };

   if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value)
   {
      char *pch;
      char str[100];
      snprintf(str, sizeof(str), "%s", var.value);
      
      pch = strtok(str, "x");
      if (pch)
         width = strtoul(pch, NULL, 0);
      pch = strtok(NULL, "x");
      if (pch)
         height = strtoul(pch, NULL, 0);

      fprintf(stderr, "[libretro-test]: Got size: %u x %u.\n", width, height);
   }

#ifdef CORE
   var.key = "testgl_multisample";
   var.value = NULL;

   if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var) && var.value)
   {
      switch (*var.value)
      {
         case '1':
            init_multisample(1);
            break;

         case '2':
            init_multisample(2);
            break;

         case '4':
            init_multisample(4);
            break;
      }
   }
#endif
}

static unsigned frame_count;

void retro_run(void)
{
   bool updated = false;
   if (environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE_UPDATE, &updated) && updated)
      update_variables();

   input_poll_cb();

   if (input_state_cb(0, RETRO_DEVICE_JOYPAD, 0, RETRO_DEVICE_ID_JOYPAD_UP))
   {
   }

   float ratio = width / (float)height;

   glBindFramebuffer(RARCH_GL_FRAMEBUFFER, hw_render.get_current_framebuffer());

   glClearColor(0.3, 0.4, 0.5, 1.0);
   glViewport(0, 0, width, height);
   glClear(GL_COLOR_BUFFER_BIT);

   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   glOrtho(-ratio, ratio, -1.f, 1.f, 1.f, -1.f);
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
   glRotatef((float)frame_count * 2, 0.0f, 0.0f, 0.1f);

   glLoadIdentity();
   glBegin(GL_TRIANGLES);

   glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
   glVertex2f(-0.5f, -0.5f);

   glColor4f(1.0f, 1.0f, 0.0f, 1.0f);
   glVertex2f(0.5f, -0.5f);
   
   glColor4f(0.0f, 1.0f, 1.0f, 1.0f);
   glVertex2f(-0.5f, 0.5f);

   glColor4f(1.0f, 0.0f, 1.0f, 1.0f);
   glVertex2f(0.5f, 0.5f);

   glEnd();

   frame_count++;

   video_cb(RETRO_HW_FRAME_BUFFER_VALID, width, height, 0);
}

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

static void context_destroy(void)
{
   fprintf(stderr, "Context destroy!\n");
}

#ifdef GLES
static bool retro_init_hw_context(void)
{
#if defined(GLES31)
   hw_render.context_type = RETRO_HW_CONTEXT_OPENGLES_VERSION;
   hw_render.version_major = 3;
   hw_render.version_minor = 1;
#elif defined(GLES3)
   hw_render.context_type = RETRO_HW_CONTEXT_OPENGLES3;
#else
   hw_render.context_type = RETRO_HW_CONTEXT_OPENGLES2;
#endif
   hw_render.context_reset = context_reset;
   hw_render.context_destroy = context_destroy;
   hw_render.depth = true;
   hw_render.bottom_left_origin = true;

   if (!environ_cb(RETRO_ENVIRONMENT_SET_HW_RENDER, &hw_render))
      return false;

   return true;
}
#else
static bool retro_init_hw_context(void)
{
   hw_render.context_type = RETRO_HW_CONTEXT_OPENGL;
   hw_render.context_reset = context_reset;
   hw_render.context_destroy = context_destroy;
   hw_render.depth = true;
   hw_render.bottom_left_origin = true;

   if (!environ_cb(RETRO_ENVIRONMENT_SET_HW_RENDER, &hw_render))
      return false;

   return true;
}
#endif

bool retro_load_game(const struct retro_game_info *info)
{
   update_variables();

   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;
   }

   if (!retro_init_hw_context())
   {
      fprintf(stderr, "HW Context could not be initialized, exiting...\n");
      return false;
   }

   fprintf(stderr, "Loaded game!\n");
   (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;
}