/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2010-2014 - Hans-Kristian Arntzen
 *  Copyright (C) 2011-2014 - Daniel De Matteis
 * 
 *  RetroArch is free software: you can redistribute it and/or modify it under the terms
 *  of the GNU General Public License as published by the Free Software Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  RetroArch is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 *  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 *  PURPOSE.  See the GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along with RetroArch.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

#include "../../driver.h"
#include "../../general.h"
#include "../gfx_common.h"
#include "../gl_common.h"

#include <EGL/egl.h>

#include "../../frontend/platform/platform_android.h"
#include "../image/image.h"

#include <stdint.h>

static bool g_use_hw_ctx;
static EGLContext g_egl_hw_ctx;
static EGLContext g_egl_ctx;
static EGLSurface g_egl_surf;
static EGLDisplay g_egl_dpy;
static EGLConfig g_config;
static bool g_es3;

static void gfx_ctx_set_swap_interval(void *data, unsigned interval)
{
   (void)data;
   RARCH_LOG("gfx_ctx_set_swap_interval(%u).\n", interval);
   eglSwapInterval(g_egl_dpy, interval);
}

static void gfx_ctx_destroy(void *data)
{
   (void)data;

   if (g_egl_dpy)
   {
      if (g_egl_ctx)
      {
         eglMakeCurrent(g_egl_dpy, EGL_NO_SURFACE, EGL_NO_SURFACE, EGL_NO_CONTEXT);
         eglDestroyContext(g_egl_dpy, g_egl_ctx);
      }

      if (g_egl_hw_ctx)
         eglDestroyContext(g_egl_dpy, g_egl_hw_ctx);

      if (g_egl_surf)
         eglDestroySurface(g_egl_dpy, g_egl_surf);
      eglTerminate(g_egl_dpy);
   }

   // Be as careful as possible in deinit.

   g_egl_ctx     = NULL;
   g_egl_hw_ctx  = NULL;
   g_egl_surf    = NULL;
   g_egl_dpy     = NULL;
   g_config      = 0;
}

static void gfx_ctx_get_video_size(void *data, unsigned *width, unsigned *height)
{
   (void)data;
   if (g_egl_dpy)
   {
      EGLint gl_width, gl_height;
      eglQuerySurface(g_egl_dpy, g_egl_surf, EGL_WIDTH, &gl_width);
      eglQuerySurface(g_egl_dpy, g_egl_surf, EGL_HEIGHT, &gl_height);
      *width  = gl_width;
      *height = gl_height;
   }
   else
   {
      *width  = 0;
      *height = 0;
   }
}

static bool gfx_ctx_init(void *data)
{
   struct android_app *android_app = (struct android_app*)g_android;
   const EGLint attribs[] = {
      EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT,
      EGL_SURFACE_TYPE, EGL_WINDOW_BIT,
      EGL_BLUE_SIZE, 8,
      EGL_GREEN_SIZE, 8,
      EGL_RED_SIZE, 8,
      EGL_ALPHA_SIZE, 8,
      EGL_NONE
   };
   EGLint num_config;
   EGLint egl_version_major, egl_version_minor;
   EGLint format;

   RARCH_LOG("Android EGL: GLES version = %d.\n", g_es3 ? 3 : 2);
   EGLint context_attributes[] = {
      EGL_CONTEXT_CLIENT_VERSION, g_es3 ? 3 : 2,
      EGL_NONE
   };

   g_egl_dpy = eglGetDisplay(EGL_DEFAULT_DISPLAY);
   if (!g_egl_dpy)
   {
      RARCH_ERR("[Android/EGL]: Couldn't get EGL display.\n");
      goto error;
   }

   if (!eglInitialize(g_egl_dpy, &egl_version_major, &egl_version_minor))
      goto error;

   RARCH_LOG("[ANDROID/EGL]: EGL version: %d.%d\n", egl_version_major, egl_version_minor);

   if (!eglChooseConfig(g_egl_dpy, attribs, &g_config, 1, &num_config))
      goto error;

   int var = eglGetConfigAttrib(g_egl_dpy, g_config, EGL_NATIVE_VISUAL_ID, &format);

   if (!var)
   {
      RARCH_ERR("eglGetConfigAttrib failed: %d.\n", var);
      goto error;
   }

   ANativeWindow_setBuffersGeometry(android_app->window, 0, 0, format);

   g_egl_ctx = eglCreateContext(g_egl_dpy, g_config, EGL_NO_CONTEXT, context_attributes);

   if (g_egl_ctx == EGL_NO_CONTEXT)
      goto error;

   if (g_use_hw_ctx)
   {
      g_egl_hw_ctx = eglCreateContext(g_egl_dpy, g_config, g_egl_ctx,
            context_attributes);
      RARCH_LOG("[Android/EGL]: Created shared context: %p.\n", (void*)g_egl_hw_ctx);

      if (g_egl_hw_ctx == EGL_NO_CONTEXT)
         goto error;
   }

   g_egl_surf = eglCreateWindowSurface(g_egl_dpy, g_config, android_app->window, 0);
   if (!g_egl_surf)
      goto error;

   if (!eglMakeCurrent(g_egl_dpy, g_egl_surf, g_egl_surf, g_egl_ctx))
      goto error;

   return true;

error:
   gfx_ctx_destroy(data);
   return false;
}

static void gfx_ctx_swap_buffers(void *data)
{
   (void)data;
   eglSwapBuffers(g_egl_dpy, g_egl_surf);
}

static void gfx_ctx_check_window(void *data, bool *quit,
      bool *resize, unsigned *width, unsigned *height, unsigned frame_count)
{
   (void)frame_count;

   *quit = false;

   unsigned new_width, new_height;
   gfx_ctx_get_video_size(data, &new_width, &new_height);
   if (new_width != *width || new_height != *height)
   {
      *width  = new_width;
      *height = new_height;
      *resize = true;
   }

   // Check if we are exiting.
   if (g_extern.system.shutdown)
      *quit = true;
}

static void gfx_ctx_set_resize(void *data, unsigned width, unsigned height)
{
   (void)data;
   (void)width;
   (void)height;
}

static void gfx_ctx_update_window_title(void *data)
{
   (void)data;
   char buf[128], buf_fps[128];
   bool fps_draw = g_settings.fps_show;
   gfx_get_fps(buf, sizeof(buf), fps_draw ? buf_fps : NULL, sizeof(buf_fps));

   if (fps_draw)
      msg_queue_push(g_extern.msg_queue, buf_fps, 1, 1);
}

static bool gfx_ctx_set_video_mode(void *data,
      unsigned width, unsigned height,
      bool fullscreen)
{
   (void)data;
   (void)width;
   (void)height;
   (void)fullscreen;
   return true;
}

static void gfx_ctx_input_driver(void *data, const input_driver_t **input, void **input_data)
{
   (void)data;
   void *androidinput = input_android.init();
   *input = androidinput ? &input_android : NULL;
   *input_data = androidinput;
}

static gfx_ctx_proc_t gfx_ctx_get_proc_address(const char *symbol)
{
   rarch_assert(sizeof(void*) == sizeof(void (*)(void)));
   gfx_ctx_proc_t ret;

   void *sym__ = eglGetProcAddress(symbol);
   memcpy(&ret, &sym__, sizeof(void*));

   return ret;
}

static bool gfx_ctx_bind_api(void *data, enum gfx_ctx_api api, unsigned major, unsigned minor)
{
   (void)data;

   unsigned version = major * 100 + minor;
   if (version > 300)
      return false;
#ifdef HAVE_OPENGLES3
   if (version < 300)
      g_es3 = false;
   else if (version == 300)
      g_es3 = true;
#endif
   return api == GFX_CTX_OPENGL_ES_API;
}

static bool gfx_ctx_has_focus(void *data)
{
   (void)data;
   return true;
}

static bool gfx_ctx_has_windowed(void *data)
{
   (void)data;
   return false;
}

static void android_gfx_ctx_bind_hw_render(void *data, bool enable)
{
   (void)data;
   g_use_hw_ctx = enable;
   if (g_egl_dpy && g_egl_surf)
      eglMakeCurrent(g_egl_dpy, g_egl_surf, g_egl_surf,
            enable ? g_egl_hw_ctx : g_egl_ctx);
}

const gfx_ctx_driver_t gfx_ctx_android = {
   gfx_ctx_init,
   gfx_ctx_destroy,
   gfx_ctx_bind_api,
   gfx_ctx_set_swap_interval,
   gfx_ctx_set_video_mode,
   gfx_ctx_get_video_size,
   NULL,
   gfx_ctx_update_window_title,
   gfx_ctx_check_window,
   gfx_ctx_set_resize,
   gfx_ctx_has_focus,
   gfx_ctx_has_windowed,
   gfx_ctx_swap_buffers,
   gfx_ctx_input_driver,
   gfx_ctx_get_proc_address,
#ifdef HAVE_EGL
   NULL,
   NULL,
#endif
   NULL,
   "android",
   android_gfx_ctx_bind_hw_render,
};