/* SPDX-License-Identifier: GPL-2.0-or-later
 * Copyright 2001-2002 NaN Holding BV. All rights reserved. */

/** \file
 * \ingroup GHOST
 */

#include "GHOST_DisplayManagerWin32.hh"
#include "GHOST_Debug.hh"

#define WIN32_LEAN_AND_MEAN
#include <windows.h>

/* We do not support multiple monitors at the moment. */
#define COMPILE_MULTIMON_STUBS

#include <multimon.h>

GHOST_DisplayManagerWin32::GHOST_DisplayManagerWin32(void) {}

GHOST_TSuccess GHOST_DisplayManagerWin32::getNumDisplays(uint8_t &numDisplays) const
{
  numDisplays = ::GetSystemMetrics(SM_CMONITORS);
  return numDisplays > 0 ? GHOST_kSuccess : GHOST_kFailure;
}

static BOOL get_dd(DWORD d, DISPLAY_DEVICE *dd)
{
  dd->cb = sizeof(DISPLAY_DEVICE);
  return ::EnumDisplayDevices(NULL, d, dd, 0);
}

GHOST_TSuccess GHOST_DisplayManagerWin32::getNumDisplaySettings(uint8_t display,
                                                                int32_t &numSettings) const
{
  /* When you call #EnumDisplaySettings with #iModeNum set to zero, the operating system
   * initializes and caches information about the display device.
   * When you call #EnumDisplaySettings with #iModeNum set to a non-zero value,
   * the function returns the information that was cached the last time the
   * function was called with #iModeNum set to zero. */

  DISPLAY_DEVICE display_device;
  if (!get_dd(display, &display_device))
    return GHOST_kFailure;

  numSettings = 0;
  DEVMODE dm;
  while (::EnumDisplaySettings(display_device.DeviceName, numSettings, &dm)) {
    numSettings++;
  }
  return GHOST_kSuccess;
}

GHOST_TSuccess GHOST_DisplayManagerWin32::getDisplaySetting(uint8_t display,
                                                            int32_t index,
                                                            GHOST_DisplaySetting &setting) const
{
  DISPLAY_DEVICE display_device;
  if (!get_dd(display, &display_device))
    return GHOST_kFailure;

  GHOST_TSuccess success;
  DEVMODE dm;
  if (::EnumDisplaySettings(display_device.DeviceName, index, &dm)) {
#ifdef WITH_GHOST_DEBUG
    printf("display mode: width=%d, height=%d, bpp=%d, frequency=%d\n",
           dm.dmPelsWidth,
           dm.dmPelsHeight,
           dm.dmBitsPerPel,
           dm.dmDisplayFrequency);
#endif /* WITH_GHOST_DEBUG */
    setting.xPixels = dm.dmPelsWidth;
    setting.yPixels = dm.dmPelsHeight;
    setting.bpp = dm.dmBitsPerPel;
    /* When you call the #EnumDisplaySettings function, the #dmDisplayFrequency member
     * may return with the value 0 or 1. These values represent the display hardware's
     * default refresh rate. This default rate is typically set by switches on a display
     * card or computer motherboard, or by a configuration program that does not use
     * Win32 display functions such as #ChangeDisplaySettings. */

    /* First, we tried to explicitly set the frequency to 60 if #EnumDisplaySettings
     * returned 0 or 1 but this doesn't work since later on an exact match will
     * be searched. And this will never happen if we change it to 60. Now we rely
     * on the default hardware setting. */
    setting.frequency = dm.dmDisplayFrequency;
    success = GHOST_kSuccess;
  }
  else {
    success = GHOST_kFailure;
  }
  return success;
}

GHOST_TSuccess GHOST_DisplayManagerWin32::getCurrentDisplaySetting(
    uint8_t display, GHOST_DisplaySetting &setting) const
{
  return getDisplaySetting(display, ENUM_CURRENT_SETTINGS, setting);
}

GHOST_TSuccess GHOST_DisplayManagerWin32::setCurrentDisplaySetting(
    uint8_t display, const GHOST_DisplaySetting &setting)
{
  DISPLAY_DEVICE display_device;
  if (!get_dd(display, &display_device))
    return GHOST_kFailure;

  GHOST_DisplaySetting match;
  findMatch(display, setting, match);
  DEVMODE dm;
  int i = 0;
  while (::EnumDisplaySettings(display_device.DeviceName, i++, &dm)) {
    if ((dm.dmBitsPerPel == match.bpp) && (dm.dmPelsWidth == match.xPixels) &&
        (dm.dmPelsHeight == match.yPixels) && (dm.dmDisplayFrequency == match.frequency))
    {
      break;
    }
  }
#if 0
  dm.dmBitsPerPel = match.bpp;
  dm.dmPelsWidth = match.xPixels;
  dm.dmPelsHeight = match.yPixels;
  dm.dmDisplayFrequency = match.frequency;
  dm.dmFields = DM_BITSPERPEL | DM_PELSWIDTH | DM_PELSHEIGHT | DM_DISPLAYFREQUENCY;
  dm.dmSize = sizeof(DEVMODE);
  dm.dmDriverExtra = 0;
#endif

#ifdef WITH_GHOST_DEBUG
  printf("display change: Requested settings:\n");
  printf("  dmBitsPerPel=%d\n", dm.dmBitsPerPel);
  printf("  dmPelsWidth=%d\n", dm.dmPelsWidth);
  printf("  dmPelsHeight=%d\n", dm.dmPelsHeight);
  printf("  dmDisplayFrequency=%d\n", dm.dmDisplayFrequency);
#endif /* WITH_GHOST_DEBUG */

  LONG status = ::ChangeDisplaySettings(&dm, CDS_FULLSCREEN);
#ifdef WITH_GHOST_DEBUG
  switch (status) {
    case DISP_CHANGE_SUCCESSFUL:
      printf("display change: The settings change was successful.\n");
      break;
    case DISP_CHANGE_RESTART:
      printf(
          "display change: The computer must be restarted in order for the graphics mode to "
          "work.\n");
      break;
    case DISP_CHANGE_BADFLAGS:
      printf("display change: An invalid set of flags was passed in.\n");
      break;
    case DISP_CHANGE_BADPARAM:
      printf(
          "display change: An invalid parameter was passed in. "
          "This can include an invalid flag or combination of flags.\n");
      break;
    case DISP_CHANGE_FAILED:
      printf("display change: The display driver failed the specified graphics mode.\n");
      break;
    case DISP_CHANGE_BADMODE:
      printf("display change: The graphics mode is not supported.\n");
      break;
    case DISP_CHANGE_NOTUPDATED:
      printf("display change: Windows NT: Unable to write settings to the registry.\n");
      break;
    default:
      printf("display change: Return value invalid\n");
      break;
  }
#endif /* WITH_GHOST_DEBUG */
  return status == DISP_CHANGE_SUCCESSFUL ? GHOST_kSuccess : GHOST_kFailure;
}
