#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/param.h>
#include <time.h>

#include <glib.h>

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

#include <gdk/gdk.h>

#include <pango/pango.h>
#include <pango/pango-context.h>
#include <pango/pangox.h>
#include <pango/pangoxft.h>

static void paint(GdkWindow *);
static PangoContext * pango_context;
static Display * display;
static int errorHandler(Display *, XErrorEvent *);

int main ( int argc, char ** argv) {

    XSetWindowAttributes attr;
    Window w;
    GdkWindow * gw;

    if (!(display = XOpenDisplay(XDisplayName(NULL)))) {
	fprintf(stderr, "can't open display");
	_exit(1);
    }

    g_type_init();
    g_thread_init(NULL);
    gdk_init(&argc, &argv);

    XSynchronize(display, True);
    XSetErrorHandler(errorHandler);

    pango_context = pango_xft_get_context(display, DefaultScreen(display));

    attr.override_redirect = 1;
    attr.background_pixel = WhitePixel(display, DefaultScreen(display));
    attr.colormap = DefaultColormap(display, DefaultScreen(display));
    
    w = XCreateWindow(display, DefaultRootWindow(display), 
	    0, 0, 64, 64, 0, CopyFromParent, CopyFromParent,
	    CopyFromParent, CWOverrideRedirect|CWColormap, &attr);

    fprintf(stderr, "Created window %x (root=%x)\n", (int)w,
	    (int)DefaultRootWindow(display));

    XSelectInput(display, w, ButtonPressMask|ExposureMask);

    gw = gdk_window_foreign_new((GdkNativeWindow)w);
    if (!gw) {
	fprintf(stderr, "Can't create by foreign ?\n");
    }

    XMapWindow(display, w);

    while (1) {
	XEvent e;
	XNextEvent(display, &e);

	fprintf(stderr, "an event receivied (%d)\n", e.type);

	if (e.type == Expose) {
	    paint(gw);
	} else if (e.type == ButtonPress) {
	    gdk_window_destroy(gw);
	    XCloseDisplay(display);
	    _exit(0);
	}
    }
}

void paint(GdkWindow * gw) {

    PangoLayout * pgl = pango_layout_new(pango_context);
    
    PangoFontDescription * pgf =
	pango_font_description_from_string("Courier 10");

    GdkGC * gc0;
    GdkGC * gc1;

    GdkVisual * best = gdk_visual_get_best();
    GdkColormap * cmap = gdk_colormap_new(best, FALSE);

    GdkColor fg;
    GdkColor bg;

    GdkPixmap * buf;

    bg.red = bg.green = bg.blue = 0;
    fg.red = fg.green = fg.blue = 65535;

    buf = gdk_pixmap_new(gw, 64, 64, -1);
    gc0 = gdk_gc_new(gw);
    gc1 = gdk_gc_new(buf);

    gdk_colormap_alloc_color(cmap, &bg, TRUE, TRUE);
    gdk_colormap_alloc_color(cmap, &fg, TRUE, TRUE);

    gdk_drawable_set_colormap(buf, cmap);

    pango_layout_set_font_description(pgl, pgf);

    gdk_gc_set_foreground(gc1, &bg);
    gdk_gc_set_background(gc1, &fg);

    gdk_draw_rectangle(buf, gc1, TRUE, 0, 0, 64, 64);

    gdk_gc_set_foreground(gc1, &fg);
    gdk_gc_set_background(gc1, &bg);
    gdk_gc_set_foreground(gc0, &fg);
    gdk_gc_set_background(gc0, &bg);

    pango_layout_set_text(pgl, "Test", -1);

    gdk_draw_layout(buf, gc1, 5, 20, pgl);

    gdk_draw_drawable(gw, gc0, buf, 0, 0, 0, 0, -1, -1);

    pango_font_description_free(pgf);
    g_object_unref(pgl);

    gdk_window_show(gw);

    fprintf(stderr, "paint done\n");
}

int errorHandler(Display * d, XErrorEvent * e) {

    char * buf;

    fprintf(stderr, "error rcvd, serial=%lx, error code=%d\n"
	    "major=%d, minor=%d\n", e->serial, e->error_code,
	    e->request_code, e->minor_code);

    buf = (char *)g_malloc0(1024);
    XGetErrorText(d, e->error_code, buf, 1023);
    fprintf(stderr, "Error info : %s\n", buf);
    g_free(buf);
    return 0;
}