/* CRT SwitchRes Core 
 * Copyright (C) 2018 Alphanu / Ben Templeman.
 *
 * RetroArch - A frontend for libretro.
 *  Copyright (C) 2010-2014 - Hans-Kristian Arntzen
 *  Copyright (C) 2011-2017 - 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 <stddef.h>
#include <string.h>
#include <stdlib.h>

#if defined(_WIN32)
#include <windows.h>
#include "common/win32_common.h"
#endif

#include "video_driver.h"
#include "video_crt_switch.h"

static int ra_core_width     = 0;
static int ra_core_height    = 0;
static int ra_tmp_width      = 0;
static int ra_tmp_height     = 0;
static int ra_set_core_hz    = 0;
static int orig_width        = 0;
static int orig_height       = 0;
static int first_run         = 0;

static float ra_tmp_core_hz  = 0.0f;
static float fly_aspect      = 0.0f;
static float ra_core_hz      = 0.0f;

static void crt_check_first_run(void)
{		
   if (first_run != 1)
   {
      /* Run of first boot to get current display resolution */
#if defined(_WIN32)
      orig_height = GetSystemMetrics(SM_CYSCREEN);
      orig_width  = GetSystemMetrics(SM_CXSCREEN);
#endif
   }

   first_run = 1;
}

static void crt_switch_res(int width, int height,
      int f_restore,int  ra_hz)
{
   /* Windows function to switch resolutions */

#if defined(_WIN32)
   LONG res;
   DEVMODE curDevmode;
   DEVMODE devmode;

   int iModeNum;
   int freq    = 0;
   DWORD flags = 0;
   int depth   = 0;

   if (f_restore == 0)
      freq = ra_hz;

   EnumDisplaySettings(NULL, ENUM_CURRENT_SETTINGS, &curDevmode);

   /* used to stop superresolution bug */
   if (width == curDevmode.dmPelsWidth)
      width  = 0;							
   if (width == 0) 
      width = curDevmode.dmPelsWidth;
   if (height == 0) 
      height = curDevmode.dmPelsHeight;
   if (depth == 0) 
      depth = curDevmode.dmBitsPerPel;
   if (freq == 0) 
      freq = curDevmode.dmDisplayFrequency;

   for (iModeNum = 0; ; iModeNum++) 
   {
      if (!EnumDisplaySettings(NULL, iModeNum, &devmode)) 
         break;

      if (devmode.dmPelsWidth != width) 
         continue;

      if (devmode.dmPelsHeight != height) 
         continue;

      if (devmode.dmBitsPerPel != depth) 
         continue;

      if (devmode.dmDisplayFrequency != freq) 
         continue;

      devmode.dmFields |= 
         DM_PELSWIDTH | DM_PELSHEIGHT | DM_BITSPERPEL | DM_DISPLAYFREQUENCY;
      res               = 
         win32_change_display_settings(NULL, &devmode, CDS_TEST);

      switch (res) 
      {
         case DISP_CHANGE_SUCCESSFUL:
            res = win32_change_display_settings(NULL, &devmode, flags);
            switch (res) 
            {
               case DISP_CHANGE_SUCCESSFUL:
                  return;
               case DISP_CHANGE_NOTUPDATED:
                  return;
               default:
                  break;
            }
            break;
         case DISP_CHANGE_RESTART:
            break;
         default:
            break;
      }
   }
#elif defined(linux)

#endif   
}

static void switch_crt_hz(void)
{
   if (ra_core_hz == ra_tmp_core_hz)
      return;

   /* set hz float an int for windows switching */
   if (ra_core_hz < 53)
      ra_set_core_hz = 50;	
   if (ra_core_hz >= 53  &&  ra_core_hz < 57)
      ra_set_core_hz = 55;	
   if (ra_core_hz >= 57)
      ra_set_core_hz = 60;	
   video_monitor_set_refresh_rate(ra_set_core_hz);
   ra_tmp_core_hz = ra_core_hz;
}

static void crt_aspect_ratio_switch(int width, int height)
{
   /* send aspect float to videeo_driver */
   fly_aspect = (float)width / height;
   video_driver_set_aspect_ratio_value((float)fly_aspect);
}

static void switch_res_crt(int width, int height)
{
   if (height > 100)
   {
      crt_switch_res(width, height,0,ra_set_core_hz);
      video_driver_apply_state_changes();
   }
}

/* Create correct aspect to fit video if resolution does not exist */
static void crt_screen_setup_aspect(int width, int height)
{
   switch_crt_hz();

   /* get original resolution of core */	
   if (height == 4)
   {
      /* detect menu only */	
      if (width < 1920)
         width = 640;
      height = 480;
      crt_aspect_ratio_switch(width,height);
   }

   if (height < 191 && height != 144)
   {				
      crt_aspect_ratio_switch(width,height);
      height = 200;
   }	

   if (height > 191)
      crt_aspect_ratio_switch(width,height);

   if (height == 144 && ra_set_core_hz == 50)
   {				
      height = 288;
      crt_aspect_ratio_switch(width,height);
   }

   if (height > 200 && height < 224)
   {				
      crt_aspect_ratio_switch(width,height);
      height = 224;
   }

   if (height > 224 && height < 240)
   {				
      crt_aspect_ratio_switch(width,height);
      height = 240;
   }

   if (height > 240 && height < 255)
   {								
      crt_aspect_ratio_switch(width,height);
      height = 254;
   }

   if (height == 528 && ra_set_core_hz == 60)
   {								
      crt_aspect_ratio_switch(width,height);
      height = 480;
   }

   if (height >= 240 && height < 255 && ra_set_core_hz == 55)
   {
      crt_aspect_ratio_switch(width,height);
      height = 254;
   }

   switch_res_crt(width, height);
}


void crt_switch_res_core(int width, int height, float hz)
{
   /* ra_core_hz float passed from within 
    * void video_driver_monitor_adjust_system_rates(void) */
   ra_core_width  = width;		
   ra_core_height = height;
   ra_core_hz     = hz;

   crt_check_first_run();

   /* Detect resolution change and switch */
   if (
         (ra_tmp_height != ra_core_height) || 
         (ra_core_width != ra_tmp_width)
      )
      crt_screen_setup_aspect(width,height);
   
   ra_tmp_height  = ra_core_height;
   ra_tmp_width   = ra_core_width;

   /* Check if aspect is correct, if notchange */
   if (video_driver_get_aspect_ratio() != fly_aspect)
   {
      video_driver_set_aspect_ratio_value((float)fly_aspect);
      video_driver_apply_state_changes();
   }
}

void crt_video_restore(void)
{
   crt_switch_res(orig_width, orig_height, 0, 60);
}