/* xmenu
 * a simple fuzzy-selection menu made with Xlib
 */

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

#include "ui.h"
#include "dynarr.h"

static Display *dsp;
static Window win;
static int scr;
static unsigned long fg, bg;
static XSizeHints szhint;
static GC gc;
static Atom wm_delete_window;

static XFontStruct *freg, *fital;

void
ui_init(int argc, char **argv, UiOpts opt)
{
	dsp = XOpenDisplay(NULL);
	scr = DefaultScreen(dsp);
	fg = BlackPixel(dsp, scr);
	bg = WhitePixel(dsp, scr);

	int scr_width  = XWidthOfScreen(ScreenOfDisplay(dsp, scr));
	int scr_height = XHeightOfScreen(ScreenOfDisplay(dsp, scr));

	szhint = (XSizeHints) { 0 };
	szhint.width = 350;
	szhint.height = 250;
	szhint.flags = PSize;

	win = XCreateSimpleWindow(
		dsp,
		DefaultRootWindow(dsp),
		szhint.x, szhint.y,
		szhint.width, szhint.height,
		2 /* border width */,
		fg, bg);

	/* TODO: replace with modern XSetWMProperties */
	char title[] = "xmenu";
	XSetStandardProperties(dsp, win, title, title,
		None, argv, argc, &szhint);

	gc = XCreateGC(dsp, win, 0, 0);
	XSetBackground(dsp, gc, bg);
	XSetForeground(dsp, gc, fg);

	XSelectInput(dsp, win, KeyPressMask | ExposureMask);

	wm_delete_window = XInternAtom(dsp, "WM_DELETE_WINDOW", False);
	XSetWMProtocols(dsp, win, &wm_delete_window, 1);

	/* TODO: error checking */
	freg = XLoadQueryFont(dsp, "-*-new century schoolbook-medium-r-*-*-24-*-*-*-*-*-*-*");
	fital = XLoadQueryFont(dsp, "-*-new century schoolbook-medium-i-*-*-24-*-*-*-*-*-*-*");

	if (!freg) freg = XLoadQueryFont(dsp, "fixed");
	if (!fital) fital = XLoadQueryFont(dsp, "fixed");

	int w = 0;
	for (int i = 0; i < opt.n; i++) {
		int ow = XTextWidth(freg, opt.v[i].s, opt.v[i].n);
		if (ow > w) w = ow;
	}

	int h = 24 * (opt.n + 1);
	int margin = 64;
	if (w > scr_width - 2*margin) w = scr_width - 2*margin;
	if (h > scr_height - 2*margin) h = scr_height - 2*margin;

	XResizeWindow(dsp, win, w + 32, h + 32);
	XSetTransientForHint(dsp, win, DefaultRootWindow(dsp));
	XMoveWindow(dsp, win,
		(scr_width - w - 32) / 2,
		(scr_height - h - 32) / 2
	);
	XMapRaised(dsp, win);
}

UiKey
xksym_to_uik(KeySym sym)
{
	switch (sym) {
	case XK_Escape: return UIK_ESCAPE;
	case XK_BackSpace: return UIK_BACKSPACE;
	case XK_Up: return UIK_UP;
	case XK_Down: return UIK_DOWN;
	case XK_Left: return UIK_LEFT;
	case XK_Right: return UIK_RIGHT;
	case XK_Return: return UIK_RETURN;
	case XK_Home: return UIK_HOME;
	case XK_End: return UIK_END;
	case XK_Page_Down: return UIK_PGDN;
	case XK_Page_Up: return UIK_PGUP;
	default: return UIK_UNKNOWN;
	}
}

/* TODO: allow selecting options with mouse */

int
ui_wait_event(UiEvent *e)
{
	XEvent ev;
	KeySym sym;
loop:
	XNextEvent(dsp, &ev);
	switch (ev.type) {
	case KeyPress:
		e->type = UI_KEY_DOWN;
		e->key.strn = XLookupString(&ev.xkey, e->key.str, 10, &sym, 0);
		e->key.key = xksym_to_uik(sym);
		return 1;
	case KeyRelease:
		e->type = UI_KEY_UP;
		e->key.strn = XLookupString(&ev.xkey, e->key.str, 10, &sym, 0);
		e->key.key = xksym_to_uik(sym);
		return 1;
	case Expose:
		e->type = UI_REDRAW;
		return 1;
	case ClientMessage:
		if (ev.xclient.data.l[0] == wm_delete_window) {
			e->type = UI_QUIT;
			return 1;
		}
		break;
	}
	fprintf(stderr, "[Unknown event %d]\n", ev.type);
	goto loop;
	return 0;
}

void
ui_draw(Str input, int inpi, int seli, UiOpts o)
{
	XWindowAttributes attr;
	XClearWindow(dsp, win);
	XGetWindowAttributes(dsp, win, &attr);

	/* draw input */

	XSetFont(dsp, gc, fital->fid);
	XDrawString(dsp, win, gc, 16, 32, input.s, input.n);
	int w = XTextWidth(fital, input.s, inpi);
	XDrawLine(dsp, win, gc,
		16 + w, 32 - fital->ascent,
		16 + w, 32 + fital->descent);

	/* draw options */

	XSetFont(dsp, gc, freg->fid);
	int y = 64;

	int lines = (attr.height - 32) / 24;
	int tline = lines / 2;
	int bline = lines - tline;
	int scroll = seli;
	if (scroll > o.n - bline) scroll = o.n - bline;
	if (scroll < tline) scroll = tline;
	int top = scroll - tline;
	int bot = scroll + bline;
	if (top < 0) top = 0;
	if (bot > o.n) bot = o.n;

	for (int i = top; i < bot; i++) {
		if (i == seli) {
			int w = XTextWidth(freg, o.v[i].s, o.v[i].n);
			XFillRectangle(dsp, win, gc,
				12, y - freg->ascent,
				w + 8, freg->descent + freg->ascent);
			XSetForeground(dsp, gc, bg);
			XDrawString(dsp, win, gc, 16, y,
				o.v[i].s, o.v[i].n);
			XSetForeground(dsp, gc, fg);
		} else {
			XDrawString(dsp, win, gc,
				16, y,
				o.v[i].s, o.v[i].n);
		}
		y += 24;
	}
}

void
ui_fini(void)
{
	XFreeFont(dsp, freg);
	XFreeFont(dsp, fital);
	XFreeGC(dsp, gc);
	XDestroyWindow(dsp, win);
	XCloseDisplay(dsp);
}