/*
Copyright (C) 1996-1997 Id Software, Inc.
Portions Copyright (C) 1999,2000  Nelson Rush.

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.

*/
#include <errno.h>
#include <signal.h>
#include <stdlib.h>
#include <limits.h>
#include <sys/time.h>
#include <sys/types.h>
#include <dir.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <fcntl.h>
#include <stdarg.h>
#include <stdio.h>
#include <sys/stat.h>
#include <string.h>
#include <dpmi.h>
#include <sys/nearptr.h>
#include <conio.h>

#include "quakedef.h"
#include "dosisms.h"

#define MINIMUM_WIN_MEMORY			0x800000
#define MINIMUM_WIN_MEMORY_LEVELPAK	(MINIMUM_WIN_MEMORY + 0x100000)

int			end_of_memory;
qboolean	lockmem, lockunlockmem, unlockmem;
static int	win95;

#define STDOUT	1

#define	KEYBUF_SIZE	256
static unsigned char	keybuf[KEYBUF_SIZE];
static int				keybuf_head=0;
static int				keybuf_tail=0;

static quakeparms_t	quakeparms;
int					sys_checksum;
static double		curtime = 0.0;
static double		lastcurtime = 0.0;
static double		oldtime = 0.0;

static qboolean		isDedicated;

static int			minmem;

float				fptest_temp;

extern char	start_of_memory __asm__("start");

//=============================================================================

// this is totally dependent on cwsdpmi putting the stack right after tge
// global data

// This does evil things in a Win95 DOS box!!!
#if 0
extern byte end;
#define	CHECKBYTE	0xed
void Sys_InitStackCheck (void)
{
	int		i;
	
	for (i=0 ; i<128*1024 ; i++)
		(&end)[i] = CHECKBYTE;
}

void Sys_StackCheck (void)
{
	int		i;
	
	for (i=0 ; i<128*1024 ; i++)
		if ( (&end)[i] != CHECKBYTE )
			break;
	
	Con_Printf ("%i undisturbed stack bytes\n", i);
	if (end != CHECKBYTE)
		Sys_Error ("System stack overflow!");
}
#endif

//=============================================================================

byte        scantokey[128] = 
					{ 
//  0           1       2       3       4       5       6       7 
//  8           9       A       B       C       D       E       F 
	0  ,    27,     '1',    '2',    '3',    '4',    '5',    '6', 
	'7',    '8',    '9',    '0',    '-',    '=',    K_BACKSPACE, 9, // 0 
	'q',    'w',    'e',    'r',    't',    'y',    'u',    'i', 
	'o',    'p',    '[',    ']',    13 ,    K_CTRL,'a',  's',      // 1 
	'd',    'f',    'g',    'h',    'j',    'k',    'l',    ';', 
	'\'' ,    '`',    K_SHIFT,'\\',  'z',    'x',    'c',    'v',      // 2 
	'b',    'n',    'm',    ',',    '.',    '/',    K_SHIFT,'*', 
	K_ALT,' ',   0  ,    K_F1, K_F2, K_F3, K_F4, K_F5,   // 3 
	K_F6, K_F7, K_F8, K_F9, K_F10,0  ,    0  , K_HOME, 
	K_UPARROW,K_PGUP,'-',K_LEFTARROW,'5',K_RIGHTARROW,'+',K_END, //4 
	K_DOWNARROW,K_PGDN,K_INS,K_DEL,0,0,             0,              K_F11, 
	K_F12,0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0,        // 5 
	0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0, 
	0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0,        // 6 
	0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0, 
	0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0         // 7 
					}; 

byte        shiftscantokey[128] = 
					{ 
//  0           1       2       3       4       5       6       7 
//  8           9       A       B       C       D       E       F 
	0  ,    27,     '!',    '@',    '#',    '$',    '%',    '^', 
	'&',    '*',    '(',    ')',    '_',    '+',    K_BACKSPACE, 9, // 0 
	'Q',    'W',    'E',    'R',    'T',    'Y',    'U',    'I', 
	'O',    'P',    '{',    '}',    13 ,    K_CTRL,'A',  'S',      // 1 
	'D',    'F',    'G',    'H',    'J',    'K',    'L',    ':', 
	'"' ,    '~',    K_SHIFT,'|',  'Z',    'X',    'C',    'V',      // 2 
	'B',    'N',    'M',    '<',    '>',    '?',    K_SHIFT,'*', 
	K_ALT,' ',   0  ,    K_F1, K_F2, K_F3, K_F4, K_F5,   // 3 
	K_F6, K_F7, K_F8, K_F9, K_F10,0  ,    0  , K_HOME, 
	K_UPARROW,K_PGUP,'_',K_LEFTARROW,'%',K_RIGHTARROW,'+',K_END, //4 
	K_DOWNARROW,K_PGDN,K_INS,K_DEL,0,0,             0,              K_F11, 
	K_F12,0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0,        // 5 
	0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0, 
	0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0,        // 6 
	0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0, 
	0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0  ,    0         // 7 
					}; 

void TrapKey(void)
{
//	static int ctrl=0;
	keybuf[keybuf_head] = dos_inportb(0x60);
	dos_outportb(0x20, 0x20);
	/*
	if (scantokey[keybuf[keybuf_head]&0x7f] == K_CTRL)
		ctrl=keybuf[keybuf_head]&0x80;
	if (ctrl && scantokey[keybuf[keybuf_head]&0x7f] == 'c')
		Sys_Error("ctrl-c hit\n");
	*/
	keybuf_head = (keybuf_head + 1) & (KEYBUF_SIZE-1);
}

#define SC_UPARROW              0x48
#define SC_DOWNARROW    0x50
#define SC_LEFTARROW            0x4b
#define SC_RIGHTARROW   0x4d
#define SC_LEFTSHIFT   0x2a
#define SC_RIGHTSHIFT   0x36
#define SC_RIGHTARROW   0x4d

void MaskExceptions (void);
void Sys_InitFloatTime (void);
void Sys_PushFPCW_SetHigh (void);
void Sys_PopFPCW (void);

#define LEAVE_FOR_CACHE (512*1024)		//FIXME: tune
#define LOCKED_FOR_MALLOC (128*1024)	//FIXME: tune


void Sys_DetectWin95 (void)
{
	__dpmi_regs				r;

	r.x.ax = 0x160a;		/* Get Windows Version */
	__dpmi_int(0x2f, &r);

	if(r.x.ax || r.h.bh < 4)	/* Not windows or earlier than Win95 */
	{
		win95 = 0;
		lockmem = true;
		lockunlockmem = false;
		unlockmem = true;
	}
	else
	{
		win95 = 1;
		lockunlockmem = COM_CheckParm ("-winlockunlock");

		if (lockunlockmem)
			lockmem = true;
		else
			lockmem = COM_CheckParm ("-winlock");

		unlockmem = lockmem && !lockunlockmem;
	}
}


void *dos_getmaxlockedmem(int *size)
{
	__dpmi_free_mem_info	meminfo;
	__dpmi_meminfo			info;
	int						working_size;
	void					*working_memory;
	int						last_locked;
	int						extra, 	i, j, allocsize;
	static char				*msg = "Locking data...";
	int						m, n;
	byte					*x;
 
// first lock all the current executing image so the locked count will
// be accurate.  It doesn't hurt to lock the memory multiple times
	last_locked = __djgpp_selector_limit + 1;
	info.size = last_locked - 4096;
	info.address = __djgpp_base_address + 4096;

	if (lockmem)
	{
		if(__dpmi_lock_linear_region(&info))
		{
			Sys_Error ("Lock of current memory at 0x%lx for %ldKb failed!\n",
						info.address, info.size/1024);
		}
	}

	__dpmi_get_free_memory_information(&meminfo);

	if (!win95)		/* Not windows or earlier than Win95 */
	{
		working_size = meminfo.maximum_locked_page_allocation_in_pages * 4096;
	}
	else
	{
		working_size = meminfo.largest_available_free_block_in_bytes -
				LEAVE_FOR_CACHE;
	}

	working_size &= ~0xffff;		/* Round down to 64K */
	working_size += 0x10000;

	do
	{
		working_size -= 0x10000;		/* Decrease 64K and try again */
		working_memory = sbrk(working_size);
	} while (working_memory == (void *)-1);

	extra = 0xfffc - ((unsigned)sbrk(0) & 0xffff);

	if (extra > 0)
	{
		sbrk(extra);
		working_size += extra;
	}

// now grab the memory
	info.address = last_locked + __djgpp_base_address;

	if (!win95)
	{
	    info.size = __djgpp_selector_limit + 1 - last_locked;

		while (info.size > 0 && __dpmi_lock_linear_region(&info))
		{
			info.size -= 0x1000;
			working_size -= 0x1000;
			sbrk(-0x1000);
		}
	}
	else
	{			/* Win95 section */
		j = COM_CheckParm("-winmem");

		if (standard_quake)
			minmem = MINIMUM_WIN_MEMORY;
		else
			minmem = MINIMUM_WIN_MEMORY_LEVELPAK;

		if (j)
		{
			allocsize = ((int)(Q_atoi(com_argv[j+1]))) * 0x100000 +
					LOCKED_FOR_MALLOC;

			if (allocsize < (minmem + LOCKED_FOR_MALLOC))
				allocsize = minmem + LOCKED_FOR_MALLOC;
		}
		else
		{
			allocsize = minmem + LOCKED_FOR_MALLOC;
		}

		if (!lockmem)
		{
		// we won't lock, just sbrk the memory
			info.size = allocsize;
			goto UpdateSbrk;
		}

		// lock the memory down
		write (STDOUT, msg, strlen (msg));

		for (j=allocsize ; j>(minmem + LOCKED_FOR_MALLOC) ;
			 j -= 0x100000)
		{
			info.size = j;
	
			if (!__dpmi_lock_linear_region(&info))
				goto Locked;
	
			write (STDOUT, ".", 1);
		}

	// finally, try with the absolute minimum amount
		for (i=0 ; i<10 ; i++)
		{
			info.size = minmem + LOCKED_FOR_MALLOC;

			if (!__dpmi_lock_linear_region(&info))
				goto Locked;
		}

		Sys_Error ("Can't lock memory; %d Mb lockable RAM required. "
				   "Try shrinking smartdrv.", info.size / 0x100000);

Locked:

UpdateSbrk:

		info.address += info.size;
		info.address -= __djgpp_base_address + 4; // ending point, malloc align
		working_size = info.address - (int)working_memory;
		sbrk(info.address-(int)sbrk(0));		// negative adjustment
	}


	if (lockunlockmem)
	{
		__dpmi_unlock_linear_region (&info);
		printf ("Locked and unlocked %d Mb data\n", working_size / 0x100000);
	}
	else if (lockmem)
	{
		printf ("Locked %d Mb data\n", working_size / 0x100000);
	}
	else
	{
		printf ("Allocated %d Mb data\n", working_size / 0x100000);
	}

// touch all the memory to make sure it's there. The 16-page skip is to
// keep Win 95 from thinking we're trying to page ourselves in (we are
// doing that, of course, but there's no reason we shouldn't)
	x = (byte *)working_memory;

	for (n=0 ; n<4 ; n++)
	{
		for (m=0 ; m<(working_size - 16 * 0x1000) ; m += 4)
		{
			sys_checksum += *(int *)&x[m];
			sys_checksum += *(int *)&x[m + 16 * 0x1000];
		}
	}

// give some of what we locked back for malloc before returning.  Done
// by cheating and passing a negative value to sbrk
	working_size -= LOCKED_FOR_MALLOC;
	sbrk( -(LOCKED_FOR_MALLOC));
	*size = working_size;
	return working_memory;
}


void Sys_Sleep(void)
{
}


char *Sys_ConsoleInput(void)
{
	static char	text[256];
	static int	len = 0;
	char		ch;

	if (!isDedicated)
		return NULL;

	if (! kbhit())
		return NULL;

	ch = getche();

	switch (ch)
	{
		case '\r':
			putch('\n');
			if (len)
			{
				text[len] = 0;
				len = 0;
				return text;
			}
			break;

		case '\b':
			putch(' ');
			if (len)
			{
				len--;
				putch('\b');
			}
			break;

		default:
			text[len] = ch;
			len = (len + 1) & 0xff;
			break;
	}

	return NULL;
}

void Sys_Init(void)
{

	MaskExceptions ();

	Sys_SetFPCW ();

    dos_outportb(0x43, 0x34); // set system timer to mode 2
    dos_outportb(0x40, 0);    // for the Sys_DoubleTime() function
    dos_outportb(0x40, 0);

	Sys_InitFloatTime ();

	_go32_interrupt_stack_size = 4 * 1024;;
	_go32_rmcb_stack_size = 4 * 1024;
}

void Sys_Shutdown(void)
{
	if (!isDedicated)
		dos_restoreintr(9);

	if (unlockmem)
	{
		dos_unlockmem (&start_of_memory,
					   end_of_memory - (int)&start_of_memory);
		dos_unlockmem (quakeparms.membase, quakeparms.memsize);
	}
}


#define SC_RSHIFT       0x36 
#define SC_LSHIFT       0x2a 
void Sys_SendKeyEvents (void)
{
	int k, next;
	int outkey;

// get key events

	while (keybuf_head != keybuf_tail)
	{

		k = keybuf[keybuf_tail++];
		keybuf_tail &= (KEYBUF_SIZE-1);

		if (k==0xe0)
			continue;               // special / pause keys
		next = keybuf[(keybuf_tail-2)&(KEYBUF_SIZE-1)];
		if (next == 0xe1)
			continue;                               // pause key bullshit
		if (k==0xc5 && next == 0x9d) 
		{ 
			Key_Event (K_PAUSE, true);
			continue; 
		} 

		// extended keyboard shift key bullshit 
		if ( (k&0x7f)==SC_LSHIFT || (k&0x7f)==SC_RSHIFT ) 
		{ 
			if ( keybuf[(keybuf_tail-2)&(KEYBUF_SIZE-1)]==0xe0 ) 
				continue; 
			k &= 0x80; 
			k |= SC_RSHIFT; 
		} 

		if (k==0xc5 && keybuf[(keybuf_tail-2)&(KEYBUF_SIZE-1)] == 0x9d)
			continue; // more pause bullshit

		outkey = scantokey[k & 0x7f];

		if (k & 0x80)
			Key_Event (outkey, false);
		else
			Key_Event (outkey, true);

	}

}


// =======================================================================
// General routines
// =======================================================================

/*
================
Sys_Printf
================
*/

void Sys_Printf (char *fmt, ...)
{
	va_list		argptr;
	char		text[1024];
	
	va_start (argptr, fmt);
	vsnprintf (text, sizeof(text), fmt, argptr);
	va_end (argptr);

	if (cls.state == ca_dedicated)
		fprintf(stderr, "%s", text);
}

void Sys_AtExit (void)
{

// shutdown only once (so Sys_Error can call this function to shutdown, then
// print the error message, then call exit without exit calling this function
// again)
	Sys_Shutdown();
}


void Sys_Quit (void)
{
	byte	screen[80*25*2];
	byte	*d;
	char			ver[6];
	int			i;
	

// load the sell screen before shuting everything down
	d = COM_LoadHunkFile ("end2.bin"); 
	if (d)
		memcpy (screen, d, sizeof(screen));

// write the version number directly to the end screen
	snprintf(ver, sizeof(ver), " v" VERSION);
	for (i=0 ; i<6 ; i++)
		screen[0*80*2 + 72*2 + i*2] = ver[i];

	Host_Shutdown();

// do the text mode sell screen
	if (d)
	{
		memcpy ((void *)real2ptr(0xb8000), screen,80*25*2); 
	
	// set text pos
		regs.x.ax = 0x0200; 
		regs.h.bh = 0; 
		regs.h.dl = 0; 
		regs.h.dh = 22;
		dos_int86 (0x10); 
	}
	else
		printf ("couldn't load endscreen.\n");

	exit(0);
}

void Sys_Error (char *error, ...)
{ 
    va_list     argptr;
    char        string[1024];
    
    va_start (argptr, error);
    vsnprintf (string, sizeof(string), error, argptr);
    va_end (argptr);

	Host_Shutdown();
	fprintf(stderr, "Error: %s\n", string);
// Sys_AtExit is called by exit to shutdown the system
	exit(0);
} 


int Sys_FileOpenRead (char *path, int *handle)
{
	int	h;
	struct stat	fileinfo;
    
	h = open (path, O_RDONLY|O_BINARY, 0666);
	*handle = h;
	if (h == -1)
		return -1;
	
	if (fstat (h,&fileinfo) == -1)
		Sys_Error ("Error fstating %s", path);

	return fileinfo.st_size;
}

int Sys_FileOpenWrite (char *path)
{
	int     handle;

	umask (0);
	
	handle = open(path,O_RDWR | O_BINARY | O_CREAT | O_TRUNC
	, 0666);

	if (handle == -1)
		Sys_Error ("Error opening %s: %s", path,strerror(errno));

	return handle;
}

void Sys_FileClose (int handle)
{
	close (handle);
}

void Sys_FileSeek (int handle, int position)
{
	lseek (handle, position, SEEK_SET);
}

int Sys_FileRead (int handle, void *dest, int count)
{
   return read (handle, dest, count);
}

int Sys_FileWrite (int handle, void *data, int count)
{
	return write (handle, data, count);
}

/*
================
Sys_MakeCodeWriteable
================
*/
void Sys_MakeCodeWriteable (unsigned long startaddr, unsigned long length)
{
	// it's always writeable
}


/*
================
Sys_DoubleTime
================
*/
double Sys_DoubleTime (void)
{
    int				r;
    unsigned		t, tick;
	double			ft, time;
	static int		sametimecount;

	Sys_PushFPCW_SetHigh ();

//{static float t = 0; t=t+0.05; return t;}	// DEBUG

    t = *(unsigned short*)real2ptr(0x46c) * 65536;

    dos_outportb(0x43, 0); // latch time
    r = dos_inportb(0x40);
    r |= dos_inportb(0x40) << 8;
    r = (r-1) & 0xffff;

    tick = *(unsigned short*)real2ptr(0x46c) * 65536;
    if ((tick != t) && (r & 0x8000))
		t = tick;

	ft = (double) (t+(65536-r)) / 1193200.0;
	time = ft - oldtime;
	oldtime = ft;

	if (time < 0)
	{
		if (time > -3000.0)
			time = 0.0;
		else
			time += 3600.0;
	}

	curtime += time;

	if (curtime == lastcurtime)
	{
		sametimecount++;

		if (sametimecount > 100000)
		{
			curtime += 1.0;
			sametimecount = 0;
		}
	}
	else
	{
		sametimecount = 0;
	}

	lastcurtime = curtime;

	Sys_PopFPCW ();

    return curtime;
}


/*
================
Sys_InitFloatTime
================
*/
void Sys_InitFloatTime (void)
{
	int		j;

	Sys_DoubleTime ();

	oldtime = curtime;

	j = COM_CheckParm("-starttime");

	if (j)
	{
		curtime = (double) (Q_atof(com_argv[j+1]));
	}
	else
	{
		curtime = 0.0;
	}
	lastcurtime = curtime;
}


/*
================
Sys_GetMemory
================
*/
void Sys_GetMemory(void)
{
	int		j, tsize;

	j = COM_CheckParm("-mem");
	if (j)
	{
		quakeparms.memsize = (int) (Q_atof(com_argv[j+1]) * 1024 * 1024);
		quakeparms.membase = malloc (quakeparms.memsize);
	}
	else
	{
		quakeparms.membase = dos_getmaxlockedmem (&quakeparms.memsize);
	}

	fprintf(stderr, "malloc'd: %d\n", quakeparms.memsize);

	if (COM_CheckParm ("-heapsize"))
	{
		tsize = Q_atoi (com_argv[COM_CheckParm("-heapsize") + 1]) * 1024;

		if (tsize < quakeparms.memsize)
			quakeparms.memsize = tsize;
	}
}


/*
================
Sys_PageInProgram

walks the text, data, and bss to make sure it's all paged in so that the
actual physical memory detected by Sys_GetMemory is correct.
================
*/
void Sys_PageInProgram(void)
{
	int		i, j;

	end_of_memory = (int)sbrk(0);

	if (lockmem)
	{
		if (dos_lockmem ((void *)&start_of_memory,
						 end_of_memory - (int)&start_of_memory))
			Sys_Error ("Couldn't lock text and data");
	}

	if (lockunlockmem)
	{
		dos_unlockmem((void *)&start_of_memory,
						 end_of_memory - (int)&start_of_memory);
		printf ("Locked and unlocked %d Mb image\n",
				(end_of_memory - (int)&start_of_memory) / 0x100000);
	}
	else if (lockmem)
	{
		printf ("Locked %d Mb image\n",
				(end_of_memory - (int)&start_of_memory) / 0x100000);
	}
	else
	{
		printf ("Loaded %d Mb image\n",
				(end_of_memory - (int)&start_of_memory) / 0x100000);
	}

// touch the entire image, doing the 16-page skip so Win95 doesn't think we're
// trying to page ourselves in
	for (j=0 ; j<4 ; j++)
	{
		for(i=(int)&start_of_memory ; i<(end_of_memory - 16 * 0x1000) ; i += 4)
		{
			sys_checksum += *(int *)i;
			sys_checksum += *(int *)(i + 16 * 0x1000);
		}
	}
}


/*
================
Sys_NoFPUExceptionHandler
================
*/
void Sys_NoFPUExceptionHandler(int whatever)
{
	printf ("\nError: Quake requires a floating-point processor\n");
	exit (0);
}


/*
================
Sys_DefaultExceptionHandler
================
*/
void Sys_DefaultExceptionHandler(int whatever)
{
}


/*
================
main
================
*/
int main (int c, char **v)
{
	double			time, oldtime, newtime;
	extern void (*dos_error_func)(char *, ...);
	static	char	cwd[1024];

	printf ("Quake v%s\n", VERSION);
	
// make sure there's an FPU
	signal(SIGNOFP, Sys_NoFPUExceptionHandler);
	signal(SIGABRT, Sys_DefaultExceptionHandler);
	signal(SIGALRM, Sys_DefaultExceptionHandler);
	signal(SIGKILL, Sys_DefaultExceptionHandler);
	signal(SIGQUIT, Sys_DefaultExceptionHandler);
	signal(SIGINT, Sys_DefaultExceptionHandler);

	if (fptest_temp >= 0.0)
		fptest_temp += 0.1;

	COM_InitArgv (c, v);

	quakeparms.argc = com_argc;
	quakeparms.argv = com_argv;

	dos_error_func = Sys_Error;

	Sys_DetectWin95 ();
	Sys_PageInProgram ();
	Sys_GetMemory ();

	atexit (Sys_AtExit);	// in case we crash

	getwd (cwd);
	if (cwd[Q_strlen(cwd)-1] == '/') cwd[Q_strlen(cwd)-1] = 0;
	quakeparms.basedir = cwd; //"f:/quake";

	isDedicated = (COM_CheckParm ("-dedicated") != 0);

	Sys_Init ();

	if (!isDedicated)
		dos_registerintr(9, TrapKey);

//Sys_InitStackCheck ();
	
	Host_Init(&quakeparms);

//Sys_StackCheck ();

//Con_Printf ("Top of stack: 0x%x\n", &time);
	oldtime = Sys_DoubleTime ();
	while (1)
	{
		newtime = Sys_DoubleTime ();
		time = newtime - oldtime;

		if (cls.state == ca_dedicated && (time<sys_ticrate.value))
			continue;

		Host_Frame (time);

//Sys_StackCheck ();

		oldtime = newtime;
	}
}