#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stdarg.h>
#include <fcntl.h>

#include <X11/Xlib.h>
#include <X11/Xft/Xft.h>
#ifdef XINERAMA
#include <X11/extensions/Xinerama.h>
#endif

#include "config.h"

#define MAX(A, B)               ((A) > (B) ? (A) : (B))
#define MIN(A, B)               ((A) < (B) ? (A) : (B))
#define INTERSECT(x,y,w,h,r)  (MAX(0, MIN((x)+(w),(r).x_org+(r).width)  - MAX((x),(r).x_org)) \
                             * MAX(0, MIN((y)+(h),(r).y_org+(r).height) - MAX((y),(r).y_org)))

//TODO: Make selection possible

#define EXIT_DISMISS 0
#define EXIT_FAIL 1
#define EXIT_ACTION1 2
#define EXIT_ACTION2 3

static Display *dpy;
static Window window;
static int screen;
static int mw, mh;

int exit_code = EXIT_DISMISS;

static void die(const char *format, ...)
{
	va_list ap;
	va_start(ap, format);
	vfprintf(stderr, format, ap);
	fprintf(stderr, "\n");
	va_end(ap);
	exit(EXIT_FAIL);
}

int get_max_len(char *string, XftFont *font, int max_text_width)
{
	int eol = strlen(string);
	XGlyphInfo info;
	XftTextExtentsUtf8(dpy, font, (FcChar8 *)string, eol, &info);

	if (info.width > max_text_width)
	{
		eol = max_text_width / font->max_advance_width;
		info.width = 0;

		while (info.width < max_text_width)
		{
			eol++;
			XftTextExtentsUtf8(dpy, font, (FcChar8 *)string, eol, &info);
		}

		eol--;
	}

	for (int i = 0; i < MIN(eol+1, strlen(string)); i++) 
		if (string[i] == '\n')
		{
			string[i] = ' ';
			return ++i;
		}

	//Don't split in the middle of unicode char
	while (eol && (string[eol] & 0xC0) == 0x80)
		--eol;

	/* uncomment to always split at spaces */
	/* if (info.width <= max_text_width) */
	/* 	return eol; */
	/* int temp = eol; */
	/* while (string[eol] != ' ' && eol) */
	/* 	--eol; */

	/* if (eol == 0) */
	/* 	return temp; */
	/* else */
	/* 	return ++eol; */
	return eol;
}

int main()
{
	if (!(dpy = XOpenDisplay(0)))
		die("Cannot open display");

	screen = DefaultScreen(dpy);
	window = RootWindow(dpy, screen);
	Visual *visual = DefaultVisual(dpy, screen);
	Colormap colormap = DefaultColormap(dpy, screen);

	XSetWindowAttributes attributes;
	attributes.override_redirect = True;
	XftColor color;
	XftColorAllocName(dpy, visual, colormap, background_color, &color);
	attributes.background_pixel = color.pixel;
	XftColorAllocName(dpy, visual, colormap, border_color, &color);
	attributes.border_pixel = color.pixel;

	int num_of_lines = 0;
	int max_text_width = width - 2 * padding;
	int lines_size = 5;
	char **lines = malloc(lines_size * sizeof(char *));
	if (!lines)
		die("malloc failed");

	XftFont *font = XftFontOpenName(dpy, screen, font_pattern);

	static char *buf = NULL;
	static size_t size = 0;
	char *line = NULL;
	while (getline(&buf, &size, stdin) > 0)
	{
                line=buf;
		for (unsigned int eol = get_max_len(line, font, max_text_width); eol; line += eol, num_of_lines++, eol = get_max_len(line, font, max_text_width))
		{
			if (lines_size <= num_of_lines)
			{
				lines = realloc(lines, (lines_size += 5) * sizeof(char *));
				if (!lines)
					die("realloc failed");
			}

			lines[num_of_lines] = malloc((eol + 1) * sizeof(char));
			if (!lines[num_of_lines])
				die("malloc failed");

			strncpy(lines[num_of_lines], line, eol);
			lines[num_of_lines][eol] = '\0';
		}
	}
	free(buf);
	if (num_of_lines == 0)
	      die("stdin is empty");

	unsigned int text_height = font->ascent - font->descent;
	unsigned int height = (num_of_lines - 1) * line_spacing + num_of_lines * text_height + 2 * padding;

	int x, y, di, x_offset, y_offset;
	unsigned int du;
	Window dw;
	if (!XQueryPointer(dpy, window, &dw, &dw, &x, &y, &di, &di, &du))
	      die("Could not query pointer position");
#ifdef XINERAMA
	XineramaScreenInfo *info;
	int n, i=0;

	if ((info = XineramaQueryScreens(dpy, &n))){
	      for (i = 0; i < n; i++)
		      if (INTERSECT(x, y, 1, 1, info[i]) != 0)
			      break;

	  x_offset = info[i].x_org;
	  y_offset = info[i].y_org;
	  mh = info[i].height;
	  mw = info[i].width;
	  XFree(info);
	} else
#endif
	{
	  x_offset = 0;
	  y_offset = 0;
	  mw = DisplayWidth(dpy, screen);
	  mh = DisplayHeight(dpy, screen);
	}

	// Correct on monitor boundary
	int by = y - y_offset + height + border_size + MIN_BORDER_DISTANCE;
	int rx = x - x_offset + width + border_size + MIN_BORDER_DISTANCE;
	if (by > mh)
	  y = MAX(y-(by-mh), 0);
	if (rx > mw)
	  x = MAX(x-(rx-mw), 0);

	window = XCreateWindow(dpy, RootWindow(dpy, screen), x, y, width, height, border_size, DefaultDepth(dpy, screen),
						   CopyFromParent, visual, CWOverrideRedirect | CWBackPixel | CWBorderPixel, &attributes);

	XftDraw *draw = XftDrawCreate(dpy, window, visual, colormap);
	XftColorAllocName(dpy, visual, colormap, font_color, &color);

	XSelectInput(dpy, window, ExposureMask | ButtonPress);
	XMapWindow(dpy, window);

	for (;;)
	{
		XEvent event;
		XNextEvent(dpy, &event);

		if (event.type == Expose)
		{
			XClearWindow(dpy, window);
			for (int i = 0; i < num_of_lines; i++)
				XftDrawStringUtf8(draw, &color, font, padding, line_spacing * i + text_height * (i + 1) + padding,
								  (FcChar8 *)lines[i], strlen(lines[i]));
		}
		else if (event.type == ButtonPress)
		{
			if (event.xbutton.button == DISMISS_BUTTON)
				break;
			else if (event.xbutton.button == ACTION1_BUTTON)
			{
				exit_code = EXIT_ACTION1;
				break;
			}
			else if (event.xbutton.button == ACTION2_BUTTON)
			{
				exit_code = EXIT_ACTION2;
				break;
			}
		}
	}

	for (int i = 0; i < num_of_lines; i++)
		free(lines[i]);

	free(lines);
	XftDrawDestroy(draw);
	XftColorFree(dpy, visual, colormap, &color);
	XftFontClose(dpy, font);
	XCloseDisplay(dpy);

	return exit_code;
}