#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <math.h>

#define PROMPT_BUFSIZE 32

#define X_ENTER_KEY 36
#define X_BACKSPACE 22

#define X_Q_KEY     24
#define X_W_KEY     25
#define X_E_KEY     26

#define X_A_KEY     38
#define X_S_KEY     39
#define X_D_KEY     40


#define TEXT_CORNER_OFFSET 100



int main(void) {

  char text_prompt_buffer[PROMPT_BUFSIZE] = ""; 

   Display *display;
   Window window;
   XEvent event;
   Colormap colormap;
   int screen;
   
   XColor background_color;
   XColor foreground_color;
   XTextItem text_prompt;
   XGCValues text_prompt_formatting;
   GC text_prompt_gc; 

   int text_buffer_space;
   unsigned int channel_step;
   int is_prompt = 1;


   unsigned int textpos_y;


   XFontStruct* font;
   
   XWindowAttributes win_info;




 
   if((display = XOpenDisplay(NULL)) == NULL) {
      printf("Couldn't open display due to fatal error: %s\n", strerror(errno));
      exit(errno);
   }
 
   screen = DefaultScreen(display);
   
   //background colormap
   colormap = DefaultColormap(display, screen);
   background_color.red = 1000;
   background_color.green = 0;
   background_color.blue = 60000;

   //text colormap
   foreground_color.red = 0xffff - background_color.red;
   foreground_color.green = 0xffff - background_color.green;
   foreground_color.blue = 0xffff - background_color.blue;

   XAllocColor(display, colormap, &background_color);
   XAllocColor(display, colormap, &foreground_color);
   
   

   window = XCreateSimpleWindow(display, RootWindow(display, screen), 
       10, 10, 
       100, 100, 
       0,
       background_color.pixel,
       background_color.pixel); //last arg is color

   XMapWindow(display, window);
   XSelectInput(display, window, KeyPressMask | ExposureMask);
   XGetWindowAttributes(display, window, &win_info); 
   channel_step = 0xffff / pow((win_info.depth / 3), 2) ;


   //text struct
   text_prompt.chars = text_prompt_buffer;
   text_prompt.nchars = strlen(text_prompt_buffer);
   text_prompt.delta = 0; //what?
   text_prompt.font = None; 

   //text formatting struct
   text_prompt_formatting.foreground = foreground_color.pixel;

   text_prompt_gc = XCreateGC(display, window, GCForeground | GCLineWidth, &text_prompt_formatting);
   font = XLoadQueryFont(display, "-*-helvetica-medium-r-normal-*-20-*"); 
   XSetFont(display, text_prompt_gc, font->fid);
         
   XGetWindowAttributes(display, window, &win_info); 
   textpos_y = win_info.height - TEXT_CORNER_OFFSET;


   for(;;) {
     XNextEvent(display, &event);
     switch (event.type) {
       case KeyPress:
         printf("-->%i\n", event.xkey.keycode);
         if(is_prompt) {
           XClearWindow(display, window);

           text_buffer_space = PROMPT_BUFSIZE - text_prompt.nchars;

           if(event.xkey.keycode == X_BACKSPACE) {
             if(text_buffer_space < PROMPT_BUFSIZE) {
                text_prompt.nchars--;
             }
           }
           else if(text_buffer_space > 0) { 
             text_prompt.nchars += XLookupString(&event.xkey, text_prompt_buffer + text_prompt.nchars, text_buffer_space, NULL, NULL);
           }
           XDrawText(display, window, text_prompt_gc, TEXT_CORNER_OFFSET, textpos_y, &text_prompt, 1);
         }
         else {
           printf("%i\n", win_info.depth);
           switch(event.xkey.keycode) {
             case X_ENTER_KEY:
               break;
             case X_Q_KEY:
               break;
             case X_W_KEY:
               break;
             case X_E_KEY:
               break;
             case X_A_KEY:
               break;
             case X_S_KEY:
               break;
             case X_D_KEY:
               break;
             default:
               break; 
           }
         }


         
         XDrawText(display, window, text_prompt_gc, TEXT_CORNER_OFFSET, textpos_y, &text_prompt, 1);
         break;
       case Expose:
         XGetWindowAttributes(display, window, &win_info); 
         textpos_y = win_info.height - TEXT_CORNER_OFFSET;
         XDrawText(display, window, text_prompt_gc, TEXT_CORNER_OFFSET, textpos_y, &text_prompt, 1);
         printf("%i\n", textpos_y);
         break;
       default:
         printf("testing\n");
         break;
    }
   }
 
 
   return 0;
}