// Emacs style mode select   -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id:$
//
// Copyright (C) 1993-1996 by id Software, Inc.
//
// 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.
//
// $Log:$
//
// DESCRIPTION:
//	DOOM graphics stuff for X11, UNIX.
//
//-----------------------------------------------------------------------------

#include <stdlib.h>
#include <unistd.h>
#include <sys/ipc.h>
#include <sys/shm.h>

#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/keysym.h>

#include <X11/extensions/XShm.h>

#include <stdarg.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>

#include <netinet/in.h>
#include <errno.h>
#include <signal.h>

#include "../doomstat.h"
#include "../i_system.h"
#include "../i_video.h"
#include "../v_video.h"
#include "../m_argv.h"
#include "../d_main.h"

#include "../doomdef.h"

static Display*	X_display=0;
static Window		X_mainWindow;
static Visual*		X_visual;
static GC		X_gc;
static XEvent		X_event;
static int		X_screen;
static XVisualInfo	X_visualinfo;
static XImage*		image;
static int		X_width;
static int		X_height;

// MIT SHared Memory extension.
static boolean		doShm;

static XShmSegmentInfo	X_shminfo;
static int		X_shmeventtype;

// Fake mouse handling.
// This cannot work properly w/o DGA.
// Needs an invisible mouse cursor at least.
static boolean		grabMouse;
static Cursor		nullCursor;


//
//  Translates the key currently in X_event
//

static int xlatekey(void)
{

    int rc;

    switch(rc = XKeycodeToKeysym(X_display, X_event.xkey.keycode, 0))
    {
      case XK_Left:	rc = KEY_LEFTARROW;	break;
      case XK_Right:	rc = KEY_RIGHTARROW;	break;
      case XK_Down:	rc = KEY_DOWNARROW;	break;
      case XK_Up:	rc = KEY_UPARROW;	break;
      case XK_Escape:	rc = KEY_ESCAPE;	break;
      case XK_Return:	rc = KEY_ENTER;		break;
      case XK_Tab:	rc = KEY_TAB;		break;
      case XK_F1:	rc = KEY_F1;		break;
      case XK_F2:	rc = KEY_F2;		break;
      case XK_F3:	rc = KEY_F3;		break;
      case XK_F4:	rc = KEY_F4;		break;
      case XK_F5:	rc = KEY_F5;		break;
      case XK_F6:	rc = KEY_F6;		break;
      case XK_F7:	rc = KEY_F7;		break;
      case XK_F8:	rc = KEY_F8;		break;
      case XK_F9:	rc = KEY_F9;		break;
      case XK_F10:	rc = KEY_F10;		break;
      case XK_F11:	rc = KEY_F11;		break;
      case XK_F12:	rc = KEY_F12;		break;
	
      case XK_BackSpace:
      case XK_Delete:	rc = KEY_BACKSPACE;	break;

      case XK_Pause:	rc = KEY_PAUSE;		break;

      case XK_KP_Equal:
      case XK_equal:	rc = KEY_EQUALS;	break;

      case XK_KP_Subtract:
      case XK_minus:	rc = KEY_MINUS;		break;

      case XK_Shift_L:
      case XK_Shift_R:
	rc = KEY_RSHIFT;
	break;
	
      case XK_Control_L:
      case XK_Control_R:
	rc = KEY_RCTRL;
	break;
	
      case XK_Alt_L:
      case XK_Meta_L:
      case XK_Alt_R:
      case XK_Meta_R:
	rc = KEY_RALT;
	break;
	
      default:
	if (rc >= XK_space && rc <= XK_asciitilde)
	    rc = rc - XK_space + ' ';
	if (rc >= 'A' && rc <= 'Z')
	    rc = rc - 'A' + 'a';
	break;
    }

    return rc;

}


static int	lastmousex = 0;
static int	lastmousey = 0;
static boolean	shmFinished;

static void IB_GetEvent(void)
{

    event_t event;
    static int button_state;

    // put event-grabbing stuff in here
    XNextEvent(X_display, &X_event);
    switch (X_event.type)
    {
      case KeyPress:
	event.type = ev_keydown;
	event.data1 = xlatekey();
	D_PostEvent(&event);
	// fprintf(stderr, "k");
	break;
      case KeyRelease:
	event.type = ev_keyup;
	event.data1 = xlatekey();
	D_PostEvent(&event);
	// fprintf(stderr, "ku");
	break;
      case ButtonPress:
        switch (X_event.xbutton.button)
	{
	    case Button1:
		button_state |= 1;
		break;
	    case Button2:
		button_state |= 2;
		break;
	    case Button3:
		button_state |= 4;
		break;
	}
	event.type = ev_mouse;
	event.data1 = button_state;
	event.data2 = event.data3 = 0;
	D_PostEvent(&event);
	// fprintf(stderr, "b");
	break;
      case ButtonRelease:
        switch (X_event.xbutton.button)
	{
	    case Button1:
		button_state &= ~1;
		break;
	    case Button2:
		button_state &= ~2;
		break;
	    case Button3:
		button_state &= ~4;
		break;
	}
	event.type = ev_mouse;
	event.data1 = button_state;
	event.data2 = event.data3 = 0;
	D_PostEvent(&event);
	// fprintf(stderr, "bu");
	break;
      case MotionNotify:
	event.type = ev_mouse;
	event.data1 = button_state;
	event.data2 = (X_event.xmotion.x - lastmousex) << 2;
	event.data3 = (lastmousey - X_event.xmotion.y) << 2;

	if (event.data2 || event.data3)
	{
	    lastmousex = X_event.xmotion.x;
	    lastmousey = X_event.xmotion.y;
	    if (X_event.xmotion.x != X_width/2 ||
		X_event.xmotion.y != X_height/2)
	    {
		D_PostEvent(&event);
		// fprintf(stderr, "m");
	    }
	}
	break;
	
      case Expose:
      case ConfigureNotify:
	break;
	
      default:
	if (doShm && X_event.type == X_shmeventtype) shmFinished = true;
	break;
    }

}

static Cursor
createnullcursor
( Display*	display,
  Window	root )
{
    Pixmap cursormask;
    XGCValues xgc;
    GC gc;
    XColor dummycolour;
    Cursor cursor;

    cursormask = XCreatePixmap(display, root, 1, 1, 1/*depth*/);
    xgc.function = GXclear;
    gc =  XCreateGC(display, cursormask, GCFunction, &xgc);
    XFillRectangle(display, cursormask, gc, 0, 0, 1, 1);
    dummycolour.pixel = 0;
    dummycolour.red = 0;
    dummycolour.flags = 04;
    cursor = XCreatePixmapCursor(display, cursormask, cursormask,
				 &dummycolour,&dummycolour, 0,0);
    XFreePixmap(display,cursormask);
    XFreeGC(display,gc);
    return cursor;
}

//
// IB_StartTic
//
void IB_StartTic (void)
{

    if (!X_display)
	return;

    while (XPending(X_display))
	IB_GetEvent();

    // Warp the pointer back to the middle of the window
    //  or it will wander off - that is, the game will
    //  loose input focus within X11.
    if (grabMouse)
    {
	XWarpPointer( X_display,
		      None,
		      X_mainWindow,
		      0, 0,
		      0, 0,
		      X_width/2, X_height/2);
    }

}


void IB_GetFramebuffer(unsigned char **pixels, size_t *pitch)
{
    *pixels = (unsigned char*)image->data;
    *pitch = X_width * 4;
}


//
// IB_FinishUpdate
//
void IB_FinishUpdate (void)
{
    if (doShm)
    {

	if (!XShmPutImage(	X_display,
				X_mainWindow,
				X_gc,
				image,
				0, 0,
				0, 0,
				X_width, X_height,
				True ))
	    I_Error("XShmPutImage() failed\n");

	// wait for it to finish and processes all input events
	shmFinished = false;
	do
	{
	    IB_GetEvent();
	} while (!shmFinished);

    }
    else
    {

	// draw the image
	XPutImage(	X_display,
			X_mainWindow,
			X_gc,
			image,
			0, 0,
			0, 0,
			X_width, X_height );

	// sync up with server
	XSync(X_display, False);

    }

}


void IB_GetColor (unsigned char* bytes, unsigned char red, unsigned char green, unsigned char blue)
{
    bytes[0] = blue;
    bytes[1] = green;
    bytes[2] = red;
}


//
// This function is probably redundant,
//  if XShmDetach works properly.
// ddt never detached the XShm memory,
//  thus there might have been stale
//  handles accumulating.
//
static void grabsharedmemory(size_t size)
{

  int			key = ('d'<<24) | ('o'<<16) | ('o'<<8) | 'm';
  struct shmid_ds	shminfo;
  int			minsize = 320*200;
  int			id;
  int			rc;
  // UNUSED int done=0;
  int			pollution=5;
  
  // try to use what was here before
  do
  {
    id = shmget((key_t) key, minsize, 0777); // just get the id
    if (id != -1)
    {
      rc=shmctl(id, IPC_STAT, &shminfo); // get stats on it
      if (!rc) 
      {
	if (shminfo.shm_nattch)
	{
	  fprintf(stderr, "User %d appears to be running "
		  "DOOM.  Is that wise?\n", shminfo.shm_cpid);
	  key++;
	}
	else
	{
	  if (getuid() == shminfo.shm_perm.cuid)
	  {
	    rc = shmctl(id, IPC_RMID, 0);
	    if (!rc)
	      fprintf(stderr,
		      "Was able to kill my old shared memory\n");
	    else
	      I_Error("Was NOT able to kill my old shared memory");
	    
	    id = shmget((key_t)key, size, IPC_CREAT|0777);
	    if (id==-1)
	      I_Error("Could not get shared memory");
	    
	    rc=shmctl(id, IPC_STAT, &shminfo);
	    
	    break;
	    
	  }
	  if (size >= shminfo.shm_segsz)
	  {
	    fprintf(stderr,
		    "will use %d's stale shared memory\n",
		    shminfo.shm_cpid);
	    break;
	  }
	  else
	  {
	    fprintf(stderr,
		    "warning: can't use stale "
		    "shared memory belonging to id %d, "
		    "key=0x%x\n",
		    shminfo.shm_cpid, key);
	    key++;
	  }
	}
      }
      else
      {
	I_Error("could not get stats on key=%d", key);
      }
    }
    else
    {
      id = shmget((key_t)key, size, IPC_CREAT|0777);
      if (id==-1)
      {
	fprintf(stderr, "errno=%d\n", errno);
	I_Error("Could not get any shared memory");
      }
      break;
    }
  } while (--pollution);
  
  if (!pollution)
  {
    I_Error("Sorry, system too polluted with stale "
	    "shared memory segments.\n");
    }	
  
  X_shminfo.shmid = id;
  
  // attach to the shared memory segment
  image->data = X_shminfo.shmaddr = shmat(id, 0, 0);
  
  fprintf(stderr, "shared memory id=%d, addr=0x%p\n", id,
	  (void*) (image->data));
}

static void I_Quit_Wrapper(int dummy)
{
    (void)dummy;

    I_Quit();
}

void IB_InitGraphics(const char *title, size_t screen_width, size_t screen_height, size_t *bytes_per_pixel)
{

    char*		displayname;
    char*		d;
    int			n;
    int			pnum;
    int			x=0;
    int			y=0;
    
    // warning: char format, different type arg
    char		xsign=' ';
    char		ysign=' ';
    
    int			oktodraw;
    unsigned long	attribmask;
    XSetWindowAttributes attribs;
    XGCValues		xgcvalues;
    int			valuemask;

    signal(SIGINT, I_Quit_Wrapper);

    X_width = screen_width;
    X_height = screen_height;

    // check for command-line display name
    if ( (pnum=M_CheckParm("-disp")) ) // suggest parentheses around assignment
	displayname = myargv[pnum+1];
    else
	displayname = 0;

    // check for command-line geometry
    if ( (pnum=M_CheckParm("-geom")) ) // suggest parentheses around assignment
    {
	// warning: char format, different type arg 3,5
	n = sscanf(myargv[pnum+1], "%c%d%c%d", &xsign, &x, &ysign, &y);
	
	if (n==2)
	    x = y = 0;
	else if (n==6)
	{
	    if (xsign == '-')
		x = -x;
	    if (ysign == '-')
		y = -y;
	}
	else
	    I_Error("bad -geom parameter");
    }

    // open the display
    X_display = XOpenDisplay(displayname);
    if (!X_display)
    {
	if (displayname)
	    I_Error("Could not open display [%s]", displayname);
	else
	    I_Error("Could not open display (DISPLAY=[%s])", getenv("DISPLAY"));
    }

    // use the default visual 
    X_screen = DefaultScreen(X_display);
    if (!XMatchVisualInfo(X_display, X_screen, 24, TrueColor, &X_visualinfo))
	I_Error("xdoom currently only supports 24-bit TrueColor screens");
    X_visual = X_visualinfo.visual;

    // check for the MITSHM extension
    doShm = XShmQueryExtension(X_display);

    // even if it's available, make sure it's a local connection
    if (doShm)
    {
	if (!displayname) displayname = (char *) getenv("DISPLAY");
	if (displayname)
	{
	    d = displayname;
	    while (*d && (*d != ':')) d++;
	    if (*d) *d = 0;
	    if (!(!strcasecmp(displayname, "unix") || !*displayname)) doShm = false;
	}
    }

    if (doShm)
	fprintf(stderr, "Using MITSHM extension\n");

    // setup attributes for main window
    attribmask = CWEventMask | CWBorderPixel;
    attribs.event_mask =
	KeyPressMask
	| KeyReleaseMask
	// | PointerMotionMask | ButtonPressMask | ButtonReleaseMask
	| ExposureMask;

    attribs.border_pixel = 0;

    // create the main window
    X_mainWindow = XCreateWindow(	X_display,
					RootWindow(X_display, X_screen),
					x, y,
					X_width, X_height,
					0, // borderwidth
					24, // depth
					InputOutput,
					X_visual,
					attribmask,
					&attribs );

    nullCursor = createnullcursor( X_display, X_mainWindow );

    // create the GC
    valuemask = GCGraphicsExposures;
    xgcvalues.graphics_exposures = False;
    X_gc = XCreateGC(	X_display,
  			X_mainWindow,
  			valuemask,
  			&xgcvalues );

    // map the window
    XMapWindow(X_display, X_mainWindow);

    // wait until it is OK to draw
    oktodraw = 0;
    while (!oktodraw)
    {
	XNextEvent(X_display, &X_event);
	if (X_event.type == Expose
	    && !X_event.xexpose.count)
	{
	    oktodraw = 1;
	}
    }

    if (doShm)
    {

	X_shmeventtype = XShmGetEventBase(X_display) + ShmCompletion;

	// create the image
	image = XShmCreateImage(	X_display,
					X_visual,
					24,
					ZPixmap,
					0,
					&X_shminfo,
					X_width,
					X_height );

	grabsharedmemory(image->bytes_per_line * image->height);


	// UNUSED
	// create the shared memory segment
	// X_shminfo.shmid = shmget (IPC_PRIVATE,
	// image->bytes_per_line * image->height, IPC_CREAT | 0777);
	// if (X_shminfo.shmid < 0)
	// {
	// perror("");
	// I_Error("shmget() failed in InitGraphics()");
	// }
	// fprintf(stderr, "shared memory id=%d\n", X_shminfo.shmid);
	// attach to the shared memory segment
	// image->data = X_shminfo.shmaddr = shmat(X_shminfo.shmid, 0, 0);
	

	if (!image->data)
	{
	    perror("");
	    I_Error("shmat() failed in InitGraphics()");
	}

	// get the X server to attach to it
	if (!XShmAttach(X_display, &X_shminfo))
	    I_Error("XShmAttach() failed in InitGraphics()");

    }
    else
    {
	image = XCreateImage(	X_display,
    				X_visual,
    				24,
    				ZPixmap,
    				0,
    				(char*)malloc(X_width * X_height * 4),
    				X_width, X_height,
    				32,
    				X_width*4 );

    }

    XStoreName(X_display, X_mainWindow, title);

    *bytes_per_pixel = 4;
}


void IB_ShutdownGraphics(void)
{
  // Detach from X server
  if (!XShmDetach(X_display, &X_shminfo))
	    I_Error("XShmDetach() failed in I_ShutdownGraphics()");

  // Release shared memory.
  shmdt(X_shminfo.shmaddr);
  shmctl(X_shminfo.shmid, IPC_RMID, 0);

  // Paranoia.
  image->data = NULL;
}


void IB_GrabMouse(boolean grab)
{
    grabMouse = grab;

    if (grab)
    {
	XGrabPointer(X_display, X_mainWindow, True,
		     ButtonPressMask|ButtonReleaseMask|PointerMotionMask,
		     GrabModeAsync, GrabModeAsync,
		     X_mainWindow, None, CurrentTime);
	XDefineCursor(X_display, X_mainWindow, nullCursor);
    }
    else
    {
	XUngrabPointer(X_display, CurrentTime);
	XUndefineCursor(X_display, X_mainWindow);
    }
}