/*
Copyright (C) 1996-2001 Id Software, Inc.
Copyright (C) 2002-2005 John Fitzgibbons and others
Copyright (C) 2007-2008 Kristian Duske
Copyright (C) 2010-2014 QuakeSpasm developers

This program 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 Foundation; either version 2
of the License, or (at your option) any later version.

This program 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <mmsystem.h>

#include "q_defs.h"

#include <sys/types.h>
#include <errno.h>
#include <io.h>
#include <direct.h>

#include <SDL.h>

bool            isDedicated;
bool    Win95, Win95old, WinNT, WinVista;
cvar_t          sys_throttle = {"sys_throttle", "0.02", CVAR_ARCHIVE};

static HANDLE           hinput, houtput;

#define MAX_HANDLES             32      /* johnfitz -- was 10 */
static FILE             *sys_handles[MAX_HANDLES];


static int32_t findhandle(void)
{
	int32_t i;

	for(i = 1; i < MAX_HANDLES; i++)
	{
		if(!sys_handles[i])
			return i;
	}
	Sys_Error("out of handles");
	return -1;
}

long Sys_filelength(FILE *f)
{
	long            pos, end;

	pos = ftell(f);
	fseek(f, 0, SEEK_END);
	end = ftell(f);
	fseek(f, pos, SEEK_SET);

	return end;
}

int32_t Sys_FileOpenRead(const char *path, int32_t *hndl)
{
	FILE    *f;
	int32_t i, retval;

	i = findhandle();
	f = fopen(path, "rb");

	if(!f)
	{
		*hndl = -1;
		retval = -1;
	}
	else
	{
		sys_handles[i] = f;
		*hndl = i;
		retval = Sys_filelength(f);
	}

	return retval;
}

int32_t Sys_FileOpenWrite(const char *path)
{
	FILE    *f;
	int32_t         i;

	i = findhandle();
	f = fopen(path, "wb");

	if(!f)
		Sys_Error("Error opening %s: %s", path, strerror(errno));

	sys_handles[i] = f;
	return i;
}

void Sys_FileClose(int32_t handle)
{
	fclose(sys_handles[handle]);
	sys_handles[handle] = NULL;
}

void Sys_FileSeek(int32_t handle, int32_t position)
{
	fseek(sys_handles[handle], position, SEEK_SET);
}

int32_t Sys_FileRead(int32_t handle, void *dest, int32_t count)
{
	return fread(dest, 1, count, sys_handles[handle]);
}

int32_t Sys_FileWrite(int32_t handle, const void *data, int32_t count)
{
	return fwrite(data, 1, count, sys_handles[handle]);
}

int32_t Sys_FileTime(const char *path)
{
	FILE    *f;

	f = fopen(path, "rb");

	if(f)
	{
		fclose(f);
		return 1;
	}

	return -1;
}

static char     cwd[1024];

static void Sys_GetBasedir(char *argv0, char *dst, size_t dstsize)
{
	char *tmp;
	size_t rc;

	rc = GetCurrentDirectory(dstsize, dst);
	if(rc == 0 || rc > dstsize)
		Sys_Error("Couldn't determine current directory");

	tmp = dst;
	while(*tmp != 0)
		tmp++;
	while(*tmp == 0 && tmp != dst)
	{
		--tmp;
		if(tmp != dst && (*tmp == '/' || *tmp == '\\'))
			*tmp = 0;
	}
}

typedef enum { dpi_unaware = 0, dpi_system_aware = 1, dpi_monitor_aware = 2 } dpi_awareness;
typedef BOOL (WINAPI *SetProcessDPIAwareFunc)();
typedef HRESULT(WINAPI *SetProcessDPIAwarenessFunc)(dpi_awareness value);

static void Sys_SetDPIAware(void)
{
	HMODULE hUser32, hShcore;
	SetProcessDPIAwarenessFunc setDPIAwareness;
	SetProcessDPIAwareFunc setDPIAware;

	/* Neither SDL 1.2 nor SDL 2.0.3 can handle the OS scaling our window.
	  (e.g. https://bugzilla.libsdl.org/show_bug.cgi?id=2713)
	  Call SetProcessDpiAwareness/SetProcessDPIAware to opt out of scaling.
	*/

	hShcore = LoadLibraryA("Shcore.dll");
	hUser32 = LoadLibraryA("user32.dll");
	setDPIAwareness = (SetProcessDPIAwarenessFunc)(hShcore ? GetProcAddress(hShcore, "SetProcessDpiAwareness") : NULL);
	setDPIAware = (SetProcessDPIAwareFunc)(hUser32 ? GetProcAddress(hUser32, "SetProcessDPIAware") : NULL);

	if(setDPIAwareness)  /* Windows 8.1+ */
		setDPIAwareness(dpi_monitor_aware);
	else if(setDPIAware)  /* Windows Vista-8.0 */
		setDPIAware();

	if(hShcore)
		FreeLibrary(hShcore);
	if(hUser32)
		FreeLibrary(hUser32);
}

static void Sys_SetTimerResolution(void)
{
	/* Set OS timer resolution to 1ms.
	   Works around buffer underruns with directsound and SDL2, but also
	   will make Sleep()/SDL_Dleay() accurate to 1ms which should help framerate
	   stability.
	*/
	timeBeginPeriod(1);
}

void Sys_Init(void)
{
	OSVERSIONINFO   vinfo;

	Sys_SetTimerResolution();
	Sys_SetDPIAware();

	memset(cwd, 0, sizeof(cwd));
	Sys_GetBasedir(NULL, cwd, sizeof(cwd));
	host_parms->basedir = cwd;

	/* userdirs not really necessary for windows guys.
	 * can be done if necessary, though... */
	host_parms->userdir = host_parms->basedir; /* code elsewhere relies on this ! */

	vinfo.dwOSVersionInfoSize = sizeof(vinfo);

	if(!GetVersionEx(&vinfo))
		Sys_Error("Couldn't get OS info");

	if((vinfo.dwMajorVersion < 4) ||
	                (vinfo.dwPlatformId == VER_PLATFORM_WIN32s))
	{
		Sys_Error("QuakeSpasm requires at least Win95 or NT 4.0");
	}

	if(vinfo.dwPlatformId == VER_PLATFORM_WIN32_NT)
	{
		SYSTEM_INFO info;
		WinNT = true;
		if(vinfo.dwMajorVersion >= 6)
			WinVista = true;
		GetSystemInfo(&info);
		host_parms->numcpus = info.dwNumberOfProcessors;
		if(host_parms->numcpus < 1)
			host_parms->numcpus = 1;
	}
	else
	{
		WinNT = false; /* Win9x or WinME */
		host_parms->numcpus = 1;
		if((vinfo.dwMajorVersion == 4) && (vinfo.dwMinorVersion == 0))
		{
			Win95 = true;
			/* Win95-gold or Win95A can't switch bpp automatically */
			if(vinfo.szCSDVersion[1] != 'C' && vinfo.szCSDVersion[1] != 'B')
				Win95old = true;
		}
	}
	Sys_Printf("Detected %" PRIi32 " CPUs\n", host_parms->numcpus);

	if(isDedicated)
	{
		if(!AllocConsole())
		{
			isDedicated = false;    /* so that we have a graphical error dialog */
			Sys_Error("Couldn't create dedicated server console");
		}

		hinput = GetStdHandle(STD_INPUT_HANDLE);
		houtput = GetStdHandle(STD_OUTPUT_HANDLE);
	}
}

void Sys_mkdir(const char *path)
{
	if(CreateDirectory(path, NULL) != 0)
		return;
	if(GetLastError() != ERROR_ALREADY_EXISTS)
		Sys_Error("Unable to create directory %s", path);
}

static const char errortxt1[] = "\nERROR-OUT BEGIN\n\n";
static const char errortxt2[] = "\nQUAKE ERROR: ";

void Sys_Error(const char *error, ...)
{
	va_list         argptr;
	char            text[1024];
	DWORD           dummy;

	host_parms->errstate++;

	va_start(argptr, error);
	q_vsnprintf(text, sizeof(text), error, argptr);
	va_end(argptr);

	if(isDedicated)
		WriteFile(houtput, errortxt1, strlen(errortxt1), &dummy, NULL);
	/* SDL will put these into its own stderr log,
	   so print to stderr even in graphical mode. */
	fputs(errortxt1, stderr);
	Host_Shutdown();
	fputs(errortxt2, stderr);
	fputs(text, stderr);
	fputs("\n\n", stderr);
	if(!isDedicated)
		PL_ErrorDialog(text);
	else
	{
		WriteFile(houtput, errortxt2, strlen(errortxt2), &dummy, NULL);
		WriteFile(houtput, text,      strlen(text),      &dummy, NULL);
		WriteFile(houtput, "\r\n",    2,                 &dummy, NULL);
		SDL_Delay(3000);        /* show the console 3 more seconds */
	}

	exit(1);
}

void Sys_Printf(const char *fmt, ...)
{
	va_list         argptr;
	char            text[1024];
	DWORD           dummy;

	va_start(argptr, fmt);
	q_vsnprintf(text, sizeof(text), fmt, argptr);
	va_end(argptr);

	if(isDedicated)
	{
		WriteFile(houtput, text, strlen(text), &dummy, NULL);
	}
	else
	{
		/* SDL will put these into its own stdout log,
		   so print to stdout even in graphical mode. */
		fputs(text, stdout);
	}
}

void Sys_Quit(void)
{
	Host_Shutdown();

	if(isDedicated)
		FreeConsole();

	exit(0);
}

double Sys_DoubleTime(void)
{
	return SDL_GetTicks() / 1000.0;
}

const char *Sys_ConsoleInput(void)
{
	static char     con_text[256];
	static int32_t  textlen;
	INPUT_RECORD    recs[1024];
	int32_t         ch;
	DWORD           dummy, numread, numevents;

	for(;;)
	{
		if(GetNumberOfConsoleInputEvents(hinput, &numevents) == 0)
			Sys_Error("Error getting # of console events");

		if(! numevents)
			break;

		if(ReadConsoleInput(hinput, recs, 1, &numread) == 0)
			Sys_Error("Error reading console input");

		if(numread != 1)
			Sys_Error("Couldn't read console input");

		if(recs[0].EventType == KEY_EVENT)
		{
			if(recs[0].Event.KeyEvent.bKeyDown == FALSE)
			{
				ch = recs[0].Event.KeyEvent.uChar.AsciiChar;

				switch(ch)
				{
				case '\r':
					WriteFile(houtput, "\r\n", 2, &dummy, NULL);

					if(textlen != 0)
					{
						con_text[textlen] = 0;
						textlen = 0;
						return con_text;
					}

					break;

				case '\b':
					WriteFile(houtput, "\b \b", 3, &dummy, NULL);
					if(textlen != 0)
						textlen--;

					break;

				default:
					if(ch >= ' ')
					{
						WriteFile(houtput, &ch, 1, &dummy, NULL);
						con_text[textlen] = ch;
						textlen = (textlen + 1) & 0xff;
					}

					break;
				}
			}
		}
	}

	return NULL;
}

void Sys_Sleep(uint32_t msecs)
{
	SDL_Delay(msecs);
}

void Sys_SendKeyEvents(void)
{
	IN_Commands();          //ericw -- allow joysticks to add keys so they can be used to confirm SCR_ModalMessage
	IN_SendKeyEvents();
}