//***********************************************************************************
//Student Name: Prem Somu 
//Instructor: Dr. Wahab
//Class: CS 476 - Systems Programming
//Description: gDraw is a program that allows 2 or more people to collaborate over
//a white board.
//To execute: gDraw <user@host1> <user@host2> ... <user@hostn>
//***********************************************************************************
#include <X11/Xlib.h>
#include <X11/X.h>
#include <X11/cursorfont.h>
#include <X11/keysym.h>
#include <X11/StringDefs.h>
#include <X11/Xutil.h>
#include <X11/Xos.h>
#include <stdio.h>
#include <string.h>

#define BUFFERSIZE 80
#define WIDTH 200
#define HEIGHT 200
#define MAXUSERS 10
#define TRUE 1
#define FALSE 0

#define MAX(A,B) ((A) > (B) ? (A) : (B))
#define SB_WIDTH  100
#define SB_HEIGHT  38
#define SB_LONGLABEL  50
#define SB_CURSOR XC_hand1
#define SB_INPUTMASK ExposureMask|EnterWindowMask|LeaveWindowMask|ButtonPressMask|ButtonReleaseMask

#define floorButton 0
#define clearButton 1
#define quitButton 2

int clear(),Exit(),stat(),out();

struct {
  Window  window;
  char  label[SB_LONGLABEL];
  int  (*func)();
  int num;
}MenuButton[MAXUSERS][3];

int charwidth, charascent,chardescent;
char buffer[BUFFERSIZE];
int bufsize = BUFFERSIZE;
KeySym keysym;
long statinout;
int charcount,y=TRUE,guy;
int NC,MAX[MAXUSERS];
char input[MAXUSERS][50];
char user[MAXUSERS][50];

XFontStruct *font_info;
Display *display[MAXUSERS];
Window root[MAXUSERS],window[MAXUSERS][2];
GC draw[MAXUSERS],erase[MAXUSERS];
Colormap cmap;
XColor color,ignore;
char *red="red",*green="green",*yellow="yellow",*cyan="cyan",*white="white";
long fgcolor,bgcolor;
char xxx[50];
main(argc,argv)
     int argc;
     char **argv;
{
  int k;
  
  int screen,pointx,pointy;
  long eventmask = ButtonPressMask|ExposureMask|KeyPressMask|ButtonMotionMask|ButtonReleaseMask;
  long gcmask = GCForeground|GCBackground|GCLineWidth|GCCapStyle|GCJoinStyle;
  XEvent event;
  XGCValues gcval;
  XSetWindowAttributes setwinattr;
  int oldx,oldy,curx,cury;
  int i=0,j=0,l,i1,j1,j2,count = 0,x,k0,k1,k2;
  
  if(argc == 1) NC = 1;
  else NC = argc - 1;
  for(i=0;i<NC;i++)
{
  strncpy(input[i],argv[i+1],50);

} 
  strncpy(xxx,input,50);
  for(k0=0;k0<NC;k0++){
    
    for(k1=0;argv[k0+1][k1]!='@';k1++){
      ;
    }
    for(k2=k1+1;argv[k0+1][k2]!='\0';k2++)
      user[k0][k2-k1-1] = argv[k0+1][k2];
    
    user[k0][k2-k1-1] = ':';
    user[k0][k2-k1] = '0';
    user[k0][k2-k1+1] = '\0';
    
  }
  
  
  for(i1=0;i1<NC;i1++){
    MAX[i1]=1;
    for(j1=0;j1<NC;j1++){
      if(strcmp(user[j1],user[i1]) == 0) count++; 
    } 
    if(count > MAX[i1]) MAX[i1] = count;
    count = 0;
    
  }
  

  for(i=0;i<NC;i++){
    if(!(display[i] = XOpenDisplay(user[i]))){
      perror("XopenDisplay");
      exit(1);
    }
  }
  
  
  for(i=0;i<NC;i++){
    root[i] = RootWindow(display[i],screen = DefaultScreen(display[i]));
    
    cmap = DefaultColormap (display[i], screen);
    XAllocNamedColor(display[i], cmap, cyan, &color, &ignore);
    bgcolor = color.pixel;
    
    fgcolor = BlackPixel(display[i],screen);
    
    
    window[i][1] = XCreateSimpleWindow(display[i],root[i],0,0,600,600,2,fgcolor,bgcolor);
    window[i][2] = XCreateSimpleWindow(display[i],window[i][1],0,450,600,150,2,fgcolor,bgcolor);
    
    

    gcval.foreground = fgcolor;
    gcval.background = bgcolor;
    gcval.line_width = 2;
    gcval.cap_style = CapRound;
    gcval.join_style = JoinRound;
    draw[i] = XCreateGC(display[i],window[i][1],gcmask,&gcval);
    
    gcval.foreground = bgcolor;
    gcval.background = fgcolor;
    gcval.line_width = 15;
    gcval.cap_style = CapRound;
    gcval.join_style = JoinRound;
    erase[i]= XCreateGC(display[i],window[i][1],gcmask,&gcval);
    
    setwinattr.backing_store = Always;
    XChangeWindowAttributes(display[i],window[i][1],CWBackingStore,&setwinattr);
    XChangeWindowAttributes(display[i],window[i][2],CWBackingStore,&setwinattr);

    XMapWindow(display[i],window[i][1]);
    XMapWindow(display[i],window[i][2]);
    
    
    load_font(i);
    defineCtrl(i);
    
    XGrabButton(display[i],AnyButton,AnyModifier,window[i][1],TRUE,ButtonPressMask | ButtonMotionMask | ButtonReleaseMask,GrabModeAsync,GrabModeAsync,window[i][1],XCreateFontCursor(display[i],XC_crosshair));
 
    XSelectInput(display[i],window[i][1],eventmask);
    XSelectInput(display[i],window[i][2],SB_INPUTMASK);

 }


  MakeButton( 45, 60, "FREE", stat, floorButton);
  MakeButton( 245, 60, "CLEAR", clear, clearButton);
  MakeButton( 445, 60, "QUIT",Exit, quitButton);
  
  for(;;){
    for(i=0;i<NC;i++){
      for(j2=0;j2<=2;j2++){
	
	if(XCheckWindowEvent(display[i], MenuButton[i][j2].window, 
			     SB_INPUTMASK, &event ))
	  {	
	    HandleButton( j2, &event,i );
	    
	  }
      }
      
      if(XCheckWindowEvent(display[i],window[i][1],eventmask,&event)){
	if(MenuButton[i][0].num == 1){    
	  switch(event.type){
	  case Expose:
	    break;
	  case ButtonPress:
	    x = 0;
	    if(event.xbutton.button == Button1) x = 1;
	    else if(event.xbutton.button == Button3) x = 2;
	    oldx=event.xbutton.x;
	    oldy= event.xbutton.y;
	    
	    
	  case MotionNotify:
	    if(x == 1){
	      for (l=0; l<NC; l++) 
		XDrawLine(display[l],window[l][1],draw[l],oldx,oldy,
			  curx=event.xmotion.x, cury=event.xmotion.y);
	      oldx=curx;
	      oldy=cury;
	      for (l=0; l<NC; l++)
		XFlush(display[l]);
	    }
	    else if(x == 2){
	      for (l=0; l<NC; l++) 
		XDrawLine(display[l],window[l][1],erase[l],oldx,oldy,
			  curx=event.xmotion.x, cury=event.xmotion.y);
	      oldx=curx;
	      oldy=cury;
	      for (l=0; l<NC; l++)
		XFlush(display[l]);
	    }
	    
	    break;
	    
	  case ButtonRelease:
	    break;
	    
	  case KeyPress:	
	    charcount = XLookupString(&event,buffer,10,&keysym, &statinout);
	    buffer[charcount]='\0';
	    
	    if (strcmp (buffer, "quit") == 0 )  Exit(i,stat,2);
	    else if (charcount == 1){
	      for(k=0;k<charcount;k++)
		if (keysym >= XK_space && keysym <= XK_asciitilde)
		  PutChar (buffer,i);
	      
		else if (keysym == XK_BackSpace  ||  keysym ==XK_Delete)
		  DelChar(buffer,i);
	    }
	    break;
	    
	    
	  default:
	    fprintf(stderr,"UnExpected Event : %d\n",event.type);
	  }
	}
      }
    }
  }
}

load_font(j1)
     int j1;
{
  
  char   *fontname = "9x15";
  if ((font_info = XLoadQueryFont(display[j1], fontname)) == NULL) {
    (void) fprintf(stderr,"Could not get font\n");
    exit( -1 );
  }
  XSetFont(display[j1], draw[j1], font_info->fid);
  charwidth = font_info -> max_bounds.width;
  charascent = font_info -> max_bounds.ascent;
  chardescent = font_info -> max_bounds.descent;
  
}

defineCtrl(j2)
int j2;
{
  KeySym modlist[j2][2];
  unsigned int list_len = 1;
  modlist[j2][0] = XK_Control_L;
  XRebindKeysym(display[j2],XK_q,modlist[j2],list_len,"quit",4);
}

PutChar(buffer,i)
     char buffer[];
     int i;
{
  int winx, winy,j3;
  int rwinx, rwiny;
  unsigned int maskret;
  Window rootret, childret;
  for(j3=0;j3<NC;j3++){
    XQueryPointer(display[i], window[i][1], &rootret, &childret,
		  &rwinx, &rwiny, &winx, &winy, &maskret);

    
    XDrawString(display[j3],window[j3][1],draw[j3],winx,winy,buffer,strlen(buffer));
   
    XWarpPointer(display[j3],NULL,NULL,0,0,0,0,(charwidth/MAX[j3])+1,0);
    XFlush(display[j3]);
  }
  
}

DelChar(buffer,j4)
     char buffer[];
     int j4;
     
{
  
  int winx, winy;
  int rwinx, rwiny;
  unsigned int maskret;
  Window rootret, childret;
  int j5;
  for(j5=0;j5<NC;j5++){
    
    XQueryPointer(display[j4], window[j4][1], &rootret, &childret,
		  &rwinx, &rwiny, &winx, &winy, &maskret);
    XFillRectangle(display[j5],window[j5][1],erase[j5],winx,
		   winy-charascent,charwidth*2,(charascent+chardescent));
    XWarpPointer(display[j5], NULL, NULL, 0,0,0,0,-(charwidth/MAX[j5]),0);
    XFlush(display[j5]);
    
  }
  
}

MakeButton( x, y, label, fun, id)
     int      x,y;      /* Where to put it */
     char      *label;      /* What to put in it */
     int (*fun)();
     int      id;
{
  int j2;
   Cursor   tempcursor;
   XSetWindowAttributes setwinattr1;
   int screen1;
   
   for(j2=0;j2<NC;j2++){
   screen1 = DefaultScreen(display[j2]);
   strncpy(MenuButton[j2][id].label, label, SB_LONGLABEL );
   
   MenuButton[j2][id].func = fun;
   MenuButton[j2][id].num = 0;
   cmap = DefaultColormap (display[j2], screen1);
   if(id == 0)
     XAllocNamedColor(display[j2], cmap, yellow, &color, &ignore);
   else  XAllocNamedColor(display[j2], cmap, white, &color, &ignore);
   
   bgcolor = color.pixel;
   
   
   MenuButton[j2][id].window = XCreateSimpleWindow( display[j2],window[j2][2],x, y, SB_WIDTH, SB_HEIGHT, 2,BlackPixel(display[j2],screen1),bgcolor);
   
   XSelectInput( display[j2], MenuButton[j2][id].window, SB_INPUTMASK );
   tempcursor = XCreateFontCursor( display[j2], SB_CURSOR );
   XDefineCursor( display[j2], MenuButton[j2][id].window, tempcursor );
   setwinattr1.backing_store = Always;
   XChangeWindowAttributes(display[j2], MenuButton[j2][id].window, 
			   CWBackingStore, &setwinattr1);
   XMapWindow(display[j2], MenuButton[j2][id].window );
   
   }
}


int HandleButton( id, event,j)
     int id;
     int j;
     XEvent *event;
{
  
  switch( event->type ) {
  case Expose:
    ExposeButton( j,id );
    break;
  case EnterNotify:
    XDrawRectangle( display[j], MenuButton[j][id].window, 
		    draw[j], 1,1, SB_WIDTH-3, SB_HEIGHT-3 );
    break;
  case LeaveNotify:
    ExposeButton( j,id );
    break;
  case ButtonPress:
    if ( event->xbutton.button == Button1 ) {
      XDrawRectangle( display[j], MenuButton[j][id].window, 
		      draw[j], 0,0, SB_WIDTH-1,SB_HEIGHT-1 );
      
    }
    break;
  case ButtonRelease:
   
    if(id == 0) {redraw(id,j,stat); }
    else if(id == 1) clear(j);
    else Exit(j,stat,id);
    break;
  default:
    break;
  }
}

ExposeButton( j,id )
     int j;
     int id;
{
  int   width, center;
  
  XClearWindow( display[j], MenuButton[j][id].window );
  
  width = XTextWidth( font_info, MenuButton[j][id].label,
		      strlen(MenuButton[j][id].label) );
  center = MAX((SB_WIDTH-width)/2,4);
  XDrawString( display[j], MenuButton[j][id].window, draw[j],
	       center, (font_info->ascent)*2,
	       MenuButton[j][id].label, strlen(MenuButton[j][id].label) );
  XFlush(display[j]);
}



redraw(id,j,fun)
     int id,j;
     int (*fun)();
{
 
  int bgcolor,z,x;
  int screen;
  XSetWindowAttributes setwinattr;
  Cursor tempcursor;
  if(y){

    for(z=0;z<NC;z++){
   
      screen=DefaultScreen(display[z]);
	
	XDestroyWindow(display[z],MenuButton[z][id].window);
	
	strncpy(MenuButton[z][id].label,input[j], SB_LONGLABEL );
	if(j==0)strncpy(MenuButton[z][id].label,xxx, SB_LONGLABEL );
	
	MenuButton[z][id].func = fun;
	
	cmap = DefaultColormap (display[z], screen);
	if(z!=j){
	  MenuButton[z][id].num = 0;
	XAllocNamedColor(display[z], cmap, "red", &color, &ignore);
	}
	else{
	  MenuButton[j][id].num = 1;
	 XAllocNamedColor(display[z], cmap, "green", &color, &ignore); 
	}
	bgcolor = color.pixel;
	
	MenuButton[z][id].window = XCreateSimpleWindow( display[z], window[z][2],45, 60, SB_WIDTH, SB_HEIGHT, 1,BlackPixel(display[z],screen), bgcolor);
	
	tempcursor = XCreateFontCursor( display[z], SB_CURSOR );
	XDefineCursor( display[z], MenuButton[z][id].window, tempcursor );
	XSelectInput( display[z], MenuButton[z][id].window, SB_INPUTMASK );
	
	
	setwinattr.backing_store = Always;
	XChangeWindowAttributes(display[z], MenuButton[z][id].window,CWBackingStore, &setwinattr);
	XMapWindow( display[z], MenuButton[z][id].window );
	     
    }

    y = FALSE;
  }
  else {
    if(MenuButton[j][id].num == 1){
      
      for(z=0;z<NC;z++){
	screen = DefaultScreen(display[z]);
	XDestroyWindow(display[z],MenuButton[z][id].window);
	
	strncpy(MenuButton[z][id].label,"FREE", SB_LONGLABEL );
	
	MenuButton[z][id].func = fun;
	
	cmap = DefaultColormap (display[z], screen);
	
	XAllocNamedColor(display[z], cmap, "yellow", &color, &ignore);
	bgcolor = color.pixel;
	
	MenuButton[z][id].window = XCreateSimpleWindow( display[z], window[z][2],45, 60, SB_WIDTH, SB_HEIGHT, 1,BlackPixel(display[z],screen), bgcolor);
	
	tempcursor = XCreateFontCursor( display[z], SB_CURSOR );
	XDefineCursor( display[z], MenuButton[z][id].window, tempcursor );
	XSelectInput( display[z], MenuButton[z][id].window, SB_INPUTMASK );
	
	
	setwinattr.backing_store = Always;
	XChangeWindowAttributes(display[z], MenuButton[z][id].window, 
				CWBackingStore, &setwinattr);
	XMapWindow( display[z], MenuButton[z][id].window );
	
      }
      MenuButton[j][id].num = 0;
      y = TRUE;
    }
  }
}


clear(j1)
     int j1;
{
  int j;
  if(MenuButton[j1][0].num == 1){ 
    for(j=0;j<NC;j++){
      XClearWindow(display[j],window[j][1]);
      XFlush(display[j]);
    }
  }	
}

stat(j)
     int j;
{
  ;
}

Exit(j,fun,id)
     int j,id;
     int (*fun)();
{ 
  int bgcolor,z,x;
  int screen;
  XSetWindowAttributes setwinattr;
  Cursor tempcursor;
  if(MenuButton[j][0].num == 1){
    for(z=0;z<NC;z++){
      
      XDestroyWindow(display[z],MenuButton[z][0].window);
      screen=DefaultScreen(display[z]);
      strncpy(MenuButton[z][0].label,"FREE", SB_LONGLABEL );
      
      MenuButton[z][0].func = fun;
      MenuButton[z][0].num = 0;
      cmap = DefaultColormap (display[z], screen);
      
      XAllocNamedColor(display[z], cmap, yellow, &color, &ignore);
      bgcolor = color.pixel;
      
      MenuButton[z][0].window = XCreateSimpleWindow( display[z], window[z][2], 45, 60, SB_WIDTH, SB_HEIGHT, 1, BlackPixel(display[z],screen), bgcolor);
      
      tempcursor = XCreateFontCursor( display[z], SB_CURSOR );
      XDefineCursor( display[z], MenuButton[z][0].window, tempcursor );
      XSelectInput( display[z], MenuButton[z][0].window, SB_INPUTMASK );
      
      
      setwinattr.backing_store = Always;
      XChangeWindowAttributes(display[z], MenuButton[z][0].window, 
			      CWBackingStore, &setwinattr);
      XMapWindow( display[z], MenuButton[z][0].window );
      
    }
    MenuButton[j][0].num = 0;
    y = TRUE;
    quit(j);
  }
  else quit(j);
}

quit(n)
     int n;
{
  
  int j,id,i,count=1;
  NC=NC-1;
  
  if(NC <= 0) {
    XDestroyWindow(display[n],window[n][1]);
    exit(-1);
  }

  else{
    XDestroyWindow(display[n],window[n][1]);
    XFlush(display[n]);
    
    for(j=n;j<NC;j++){
      
      display[j] = display[j+1];
      root[j] = root[j+1];
      draw[j] = draw[j+1];
      erase[j] = erase[j+1];
      window[j][1] = window[j+1][1];
      window[j][2] = window[j+1][2];
      strcpy(user[j],user[j+1]);
      strcpy(input[j],input[j+1]);
     
      for(id=0;id<3;id++){
	MenuButton[j][id] = MenuButton[j+1][id];
      }
    }
  }
 
  count = 0;
  for(j=0;j<NC;j++){
     MAX[j] = 1;
    for(i=0;i<NC;i++){
      if(strcmp(user[j],user[i]) == 0) count++; 
    } 
    if(count > MAX[j]) MAX[j] = count;
    count = 0;
  
  }
 strcpy(xxx,input[0]);
}