1 /*
2  * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 /*
18  * Ncurses UI for telescope.
19  *
20  * Text scrolling
21  * ==============
22  *
23  * ncurses allows you to scroll a window, but when a line goes out of
24  * the visible area it's forgotten.  We keep a list of formatted lines
25  * (``visual lines'') that we know fits in the window, and draw them.
26  *
27  * This means that on every resize we have to clear our list of lines
28  * and re-render everything.  A clever approach would be to do this
29  * ``on-demand'', but it's still missing.
30  *
31  */
32 
33 #include <assert.h>
34 #include <curses.h>
35 #include <event.h>
36 #include <locale.h>
37 #include <signal.h>
38 #include <stdarg.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <unistd.h>
42 
43 #include "minibuffer.h"
44 #include "telescope.h"
45 #include "ui.h"
46 #include "utf8.h"
47 
48 static struct event	stdioev, winchev;
49 
50 static void		 restore_curs_x(struct buffer *);
51 
52 static struct vline	*nth_line(struct buffer*, size_t);
53 static int		 readkey(void);
54 static void		 dispatch_stdio(int, short, void*);
55 static void		 handle_clear_echoarea(int, short, void*);
56 static void		 handle_resize(int, short, void*);
57 static void		 handle_resize_nodelay(int, short, void*);
58 static int		 wrap_page(struct buffer*, int);
59 static void		 print_vline(int, int, WINDOW*, struct vline*);
60 static void		 redraw_tabline(void);
61 static void		 redraw_window(WINDOW*, int, int, struct buffer*);
62 static void		 redraw_help(void);
63 static void		 redraw_body(struct tab*);
64 static void		 redraw_modeline(struct tab*);
65 static void		 redraw_minibuffer(void);
66 static void		 do_redraw_echoarea(void);
67 static void		 do_redraw_minibuffer(void);
68 static void		 redraw_tab(struct tab*);
69 static void		 emit_help_item(char*, void*);
70 static void		 rec_compute_help(struct kmap*, char*, size_t);
71 static void		 recompute_help(void);
72 static void		 update_loading_anim(int, short, void*);
73 static void		 stop_loading_anim(struct tab*);
74 
75 static int		 x_offset;
76 
77 struct thiskey thiskey;
78 
79 static struct event	resizeev;
80 static struct timeval	resize_timer = { 0, 250000 };
81 
82 static WINDOW	*tabline, *body, *modeline, *echoarea;
83 
84 int			 body_lines, body_cols;
85 
86 static WINDOW		*help;
87 static struct buffer	 helpwin;
88 static int		 help_lines, help_cols;
89 
90 static int		 side_window;
91 
92 static struct event	clechoev;
93 static struct timeval	clechoev_timer = { 5, 0 };
94 static struct timeval	loadingev_timer = { 0, 250000 };
95 
96 static uint32_t		 tab_counter;
97 
98 static char	keybuf[64];
99 
100 struct kmap global_map,
101 	minibuffer_map,
102 	*current_map,
103 	*base_map;
104 
105 int in_minibuffer;
106 
107 static inline void
108 update_x_offset(void)
109 {
110 	if (olivetti_mode && fill_column < body_cols)
111 		x_offset = (body_cols - fill_column)/2;
112 	else
113 		x_offset = 0;
114 }
115 
116 void
117 save_excursion(struct excursion *place, struct buffer *buffer)
118 {
119 	place->curs_x = buffer->curs_x;
120 	place->curs_y = buffer->curs_y;
121 	place->line_off = buffer->line_off;
122 	place->current_line = buffer->current_line;
123 	place->cpoff = buffer->cpoff;
124 }
125 
126 void
127 restore_excursion(struct excursion *place, struct buffer *buffer)
128 {
129 	buffer->curs_x = place->curs_x;
130 	buffer->curs_y = place->curs_y;
131 	buffer->line_off = place->line_off;
132 	buffer->current_line = place->current_line;
133 	buffer->cpoff = place->cpoff;
134 }
135 
136 static void
137 restore_curs_x(struct buffer *buffer)
138 {
139 	struct vline	*vl;
140 	const char	*prfx;
141 
142 	vl = buffer->current_line;
143 	if (vl == NULL || vl->line == NULL)
144 		buffer->curs_x = buffer->cpoff = 0;
145 	else
146 		buffer->curs_x = utf8_snwidth(vl->line, buffer->cpoff);
147 
148 	buffer->curs_x += x_offset;
149 
150 	if (vl != NULL) {
151 		prfx = line_prefixes[vl->parent->type].prfx1;
152 		buffer->curs_x += utf8_swidth(prfx);
153 	}
154 }
155 
156 void
157 global_key_unbound(void)
158 {
159 	message("%s is undefined", keybuf);
160 }
161 
162 static struct vline *
163 nth_line(struct buffer *buffer, size_t n)
164 {
165 	struct vline	*vl;
166 	size_t		 i;
167 
168 	i = 0;
169 	TAILQ_FOREACH(vl, &buffer->head, vlines) {
170 		if (i == n)
171 			return vl;
172 		i++;
173 	}
174 
175 	/* unreachable */
176 	abort();
177 }
178 
179 struct tab *
180 current_tab(void)
181 {
182 	struct tab *t;
183 
184 	TAILQ_FOREACH(t, &tabshead, tabs) {
185 		if (t->flags & TAB_CURRENT)
186 			return t;
187 	}
188 
189 	/* unreachable */
190 	abort();
191 }
192 
193 struct buffer *
194 current_buffer(void)
195 {
196 	if (in_minibuffer)
197 		return &ministate.buffer;
198 	return &current_tab()->buffer;
199 }
200 
201 static int
202 readkey(void)
203 {
204 	uint32_t state = 0;
205 
206 	if ((thiskey.key = wgetch(body)) == ERR)
207 		return 0;
208 
209 	thiskey.meta = thiskey.key == 27;
210 	if (thiskey.meta) {
211 		thiskey.key = wgetch(body);
212 		if (thiskey.key == ERR || thiskey.key == 27) {
213 			thiskey.meta = 0;
214 			thiskey.key = 27;
215 		}
216 	}
217 
218 	thiskey.cp = 0;
219 	if ((unsigned int)thiskey.key < UINT8_MAX) {
220 		while (1) {
221 			if (!utf8_decode(&state, &thiskey.cp, (uint8_t)thiskey.key))
222 				break;
223 			if ((thiskey.key = wgetch(body)) == ERR) {
224 				message("Error decoding user input");
225 				return 0;
226 			}
227 		}
228 	}
229 
230 	return 1;
231 }
232 
233 static void
234 dispatch_stdio(int fd, short ev, void *d)
235 {
236 	struct keymap	*k;
237 	const char	*keyname;
238 	char		 tmp[5] = {0};
239 
240 	if (!readkey())
241 		return;
242 
243 	if (keybuf[0] != '\0')
244 		strlcat(keybuf, " ", sizeof(keybuf));
245 	if (thiskey.meta)
246 		strlcat(keybuf, "M-", sizeof(keybuf));
247 	if (thiskey.cp != 0) {
248 		utf8_encode(thiskey.cp, tmp);
249 		strlcat(keybuf, tmp, sizeof(keybuf));
250 	} else {
251 		if ((keyname = unkbd(thiskey.key)) != NULL)
252 			strlcat(keybuf, keyname, sizeof(keybuf));
253 		else {
254 			tmp[0] = thiskey.key;
255 			strlcat(keybuf, tmp, sizeof(keybuf));
256 		}
257 	}
258 
259 	TAILQ_FOREACH(k, &current_map->m, keymaps) {
260 		if (k->meta == thiskey.meta &&
261 		    k->key == thiskey.key) {
262 			if (k->fn == NULL)
263 				current_map = &k->map;
264 			else {
265 				current_map = base_map;
266 				strlcpy(keybuf, "", sizeof(keybuf));
267 				k->fn(current_buffer());
268 			}
269 			goto done;
270 		}
271 	}
272 
273 	if (current_map->unhandled_input != NULL)
274 		current_map->unhandled_input();
275 	else
276 		global_key_unbound();
277 
278 	strlcpy(keybuf, "", sizeof(keybuf));
279 	current_map = base_map;
280 
281 done:
282 	if (side_window)
283 		recompute_help();
284 
285 	redraw_tab(current_tab());
286 }
287 
288 static void
289 handle_clear_echoarea(int fd, short ev, void *d)
290 {
291 	free(ministate.curmesg);
292 	ministate.curmesg = NULL;
293 
294 	redraw_minibuffer();
295 	if (in_minibuffer) {
296 		wrefresh(body);
297 		wrefresh(echoarea);
298 	} else {
299 		wrefresh(echoarea);
300 		wrefresh(body);
301 	}
302 }
303 
304 static void
305 handle_resize(int sig, short ev, void *d)
306 {
307 	if (event_pending(&resizeev, EV_TIMEOUT, NULL)) {
308 		event_del(&resizeev);
309 	}
310 	evtimer_set(&resizeev, handle_resize_nodelay, NULL);
311 	evtimer_add(&resizeev, &resize_timer);
312 }
313 
314 static void
315 handle_resize_nodelay(int s, short ev, void *d)
316 {
317 	struct tab	*tab;
318 
319 	endwin();
320 	refresh();
321 	clear();
322 
323 	/* move and resize the windows, in reverse order! */
324 
325 	mvwin(echoarea, LINES-1, 0);
326 	wresize(echoarea, 1, COLS);
327 
328 	mvwin(modeline, LINES-2, 0);
329 	wresize(modeline, 1, COLS);
330 
331 	body_lines = LINES-3;
332 	body_cols = COLS;
333 
334 	if (side_window) {
335 		help_cols = 0.3 * COLS;
336 		help_lines = LINES-3;
337 		mvwin(help, 1, 0);
338 		wresize(help, help_lines, help_cols);
339 
340 		wrap_page(&helpwin, help_cols);
341 
342 		body_cols = COLS - help_cols - 1;
343 		mvwin(body, 1, help_cols);
344 	} else
345 		mvwin(body, 1, 0);
346 
347 	update_x_offset();
348 	wresize(body, body_lines, body_cols);
349 
350 	wresize(tabline, 1, COLS);
351 
352 	tab = current_tab();
353 
354 	wrap_page(&tab->buffer, body_cols);
355 	redraw_tab(tab);
356 }
357 
358 static int
359 wrap_page(struct buffer *buffer, int width)
360 {
361 	struct line		*l;
362 	const struct line	*top_orig, *orig;
363 	struct vline		*vl;
364 	int			 pre_width;
365 	const char		*prfx;
366 
367 	top_orig = buffer->top_line == NULL ? NULL : buffer->top_line->parent;
368 	orig = buffer->current_line == NULL ? NULL : buffer->current_line->parent;
369 
370 	buffer->top_line = NULL;
371 	buffer->current_line = NULL;
372 
373 	buffer->force_redraw = 1;
374 	buffer->curs_y = 0;
375 	buffer->line_off = 0;
376 
377 	empty_vlist(buffer);
378 
379 	TAILQ_FOREACH(l, &buffer->page.head, lines) {
380 		prfx = line_prefixes[l->type].prfx1;
381 		switch (l->type) {
382 		case LINE_TEXT:
383 		case LINE_LINK:
384 		case LINE_TITLE_1:
385 		case LINE_TITLE_2:
386 		case LINE_TITLE_3:
387 		case LINE_ITEM:
388 		case LINE_QUOTE:
389 		case LINE_PRE_START:
390 		case LINE_PRE_END:
391 			wrap_text(buffer, prfx, l, MIN(fill_column, width));
392 			break;
393 		case LINE_PRE_CONTENT:
394 			if (olivetti_mode)
395 				pre_width = MIN(fill_column, width);
396 			else
397 				pre_width = width;
398 			hardwrap_text(buffer, l, pre_width);
399 			break;
400 		}
401 
402 		if (top_orig == l && buffer->top_line == NULL) {
403 			buffer->line_off = buffer->line_max-1;
404 			buffer->top_line = TAILQ_LAST(&buffer->head, vhead);
405 
406 			while (1) {
407 				vl = TAILQ_PREV(buffer->top_line, vhead, vlines);
408 				if (vl == NULL || vl->parent != orig)
409 					break;
410 				buffer->top_line = vl;
411 				buffer->line_off--;
412 			}
413 		}
414 
415 		if (orig == l && buffer->current_line == NULL) {
416 			buffer->current_line = TAILQ_LAST(&buffer->head, vhead);
417 
418 			while (1) {
419 				vl = TAILQ_PREV(buffer->current_line, vhead, vlines);
420 				if (vl == NULL || vl->parent != orig)
421 					break;
422 				buffer->current_line = vl;
423 			}
424 		}
425 	}
426 
427         if (buffer->current_line == NULL)
428 		buffer->current_line = TAILQ_FIRST(&buffer->head);
429 
430 	if (buffer->top_line == NULL)
431 		buffer->top_line = buffer->current_line;
432 
433 	return 1;
434 }
435 
436 static void
437 print_vline(int off, int width, WINDOW *window, struct vline *vl)
438 {
439 	const char *text;
440 	const char *prfx;
441 	struct line_face *f;
442 	int i, left, x, y;
443 
444 	f = &line_faces[vl->parent->type];
445 
446 	/* unused, set by getyx */
447 	(void)y;
448 
449 	if (!vl->flags)
450 		prfx = line_prefixes[vl->parent->type].prfx1;
451 	else
452 		prfx = line_prefixes[vl->parent->type].prfx2;
453 
454 	text = vl->line;
455 	if (text == NULL)
456 		text = "";
457 
458 	wattr_on(window, body_face.left, NULL);
459 	for (i = 0; i < off; i++)
460 		waddch(window, ' ');
461 	wattr_off(window, body_face.left, NULL);
462 
463 	wattr_on(window, f->prefix, NULL);
464 	wprintw(window, "%s", prfx);
465 	wattr_off(window, f->prefix, NULL);
466 
467 	wattr_on(window, f->text, NULL);
468 	wprintw(window, "%s", text);
469 	wattr_off(window, f->text, NULL);
470 
471 	getyx(window, y, x);
472 
473 	left = width - x;
474 
475 	wattr_on(window, f->trail, NULL);
476 	for (i = 0; i < left - off; ++i)
477 		waddch(window, ' ');
478 	wattr_off(window, f->trail, NULL);
479 
480 	wattr_on(window, body_face.right, NULL);
481 	for (i = 0; i < off; i++)
482 		waddch(window, ' ');
483 	wattr_off(window, body_face.right, NULL);
484 
485 }
486 
487 static void
488 redraw_tabline(void)
489 {
490 	struct tab	*tab;
491 	size_t		 toskip, ots, tabwidth, space, x;
492 	int		 current, y, truncated;
493 	const char	*title;
494 	char		 buf[25];
495 
496 	x = 0;
497 
498 	/* unused, but setted by a getyx */
499 	(void)y;
500 
501 	tabwidth = sizeof(buf)+1;
502 	space = COLS-2;
503 
504 	toskip = 0;
505 	TAILQ_FOREACH(tab, &tabshead, tabs) {
506 		toskip++;
507 		if (tab->flags & TAB_CURRENT)
508 			break;
509 	}
510 
511 	if (toskip * tabwidth < space)
512 		toskip = 0;
513 	else {
514 		ots = toskip;
515 		toskip--;
516                 while (toskip != 0 &&
517 		    (ots - toskip+1) * tabwidth < space)
518 			toskip--;
519 	}
520 
521 	werase(tabline);
522 	wattr_on(tabline, tab_face.background, NULL);
523 	wprintw(tabline, toskip == 0 ? " " : "<");
524 	wattr_off(tabline, tab_face.background, NULL);
525 
526 	truncated = 0;
527 	TAILQ_FOREACH(tab, &tabshead, tabs) {
528 		if (truncated)
529 			break;
530 		if (toskip != 0) {
531 			toskip--;
532 			continue;
533 		}
534 
535 		getyx(tabline, y, x);
536 		if (x + sizeof(buf)+2 >= (size_t)COLS)
537 			truncated = 1;
538 
539 		current = tab->flags & TAB_CURRENT;
540 
541 		if (*(title = tab->buffer.page.title) == '\0')
542 			title = tab->hist_cur->h;
543 
544 		if (tab->flags & TAB_URGENT)
545 			strlcpy(buf, "!", sizeof(buf));
546 		else
547 			strlcpy(buf, " ", sizeof(buf));
548 
549                 if (strlcat(buf, title, sizeof(buf)) >= sizeof(buf)) {
550 			/* truncation happens */
551 			strlcpy(&buf[sizeof(buf)-4], "...", 4);
552 		} else {
553 			/* pad with spaces */
554 			while (strlcat(buf, "    ", sizeof(buf)) < sizeof(buf))
555 				/* nop */ ;
556 		}
557 
558 		if (current)
559 			wattr_on(tabline, tab_face.current, NULL);
560 		else
561 			wattr_on(tabline, tab_face.tab, NULL);
562 
563 		wprintw(tabline, "%s", buf);
564 		if (TAILQ_NEXT(tab, tabs) != NULL)
565 			wprintw(tabline, " ");
566 
567 		if (current)
568 			wattr_off(tabline, tab_face.current, NULL);
569 		else
570 			wattr_off(tabline, tab_face.tab, NULL);
571 	}
572 
573 	wattr_on(tabline, tab_face.background, NULL);
574 	for (; x < (size_t)COLS; ++x)
575 		waddch(tabline, ' ');
576 	if (truncated)
577 		mvwprintw(tabline, 0, COLS-1, ">");
578 	wattr_off(tabline, tab_face.background, NULL);
579 }
580 
581 /*
582  * Compute the first visible line around vl.  Try to search forward
583  * until the end of the buffer; if a visible line is not found, search
584  * backward.  Return NULL if no viable line was found.
585  */
586 static inline struct vline *
587 adjust_line(struct vline *vl, struct buffer *buffer)
588 {
589 	struct vline *t;
590 
591 	if (!(vl->parent->flags & L_HIDDEN))
592 		return vl;
593 
594 	/* search forward */
595 	for (t = vl;
596 	     t != NULL && t->parent->flags & L_HIDDEN;
597 	     t = TAILQ_NEXT(t, vlines))
598 		;		/* nop */
599 
600 	if (t != NULL)
601 		return t;
602 
603 	/* search backward */
604 	for (t = vl;
605 	     t != NULL && t->parent->flags & L_HIDDEN;
606 	     t = TAILQ_PREV(t, vhead, vlines))
607 		;		/* nop */
608 
609 	return t;
610 }
611 
612 static void
613 redraw_window(WINDOW *win, int height, int width, struct buffer *buffer)
614 {
615         struct vline	*vl;
616 	int		 l, onscreen;
617 
618 	restore_curs_x(buffer);
619 
620 	/*
621 	 * TODO: ignoring buffer->force_update and always
622 	 * re-rendering.  In theory we can recompute the y position
623 	 * without a re-render, and optimize here.  It's not the only
624 	 * optimisation possible here, wscrl wolud also be an
625 	 * interesting one.
626 	 */
627 
628 again:
629 	werase(win);
630 	buffer->curs_y = 0;
631 
632 	if (TAILQ_EMPTY(&buffer->head))
633 		goto end;
634 
635 	buffer->top_line = adjust_line(buffer->top_line, buffer);
636 	if (buffer->top_line == NULL)
637 		goto end;
638 
639 	buffer->current_line = adjust_line(buffer->current_line, buffer);
640 
641 	l = 0;
642 	onscreen = 0;
643 	for (vl = buffer->top_line; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
644 		if (vl->parent->flags & L_HIDDEN)
645 			continue;
646 
647 		wmove(win, l, 0);
648 		print_vline(x_offset, width, win, vl);
649 
650 		if (vl == buffer->current_line)
651 			onscreen = 1;
652 
653 		if (!onscreen)
654 			buffer->curs_y++;
655 
656 		l++;
657 		if (l == height)
658 			break;
659 	}
660 
661 	if (!onscreen) {
662 		for (; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
663 			if (vl == buffer->current_line)
664 				break;
665 			if (vl->parent->flags & L_HIDDEN)
666 				continue;
667 			buffer->line_off++;
668 			buffer->top_line = TAILQ_NEXT(buffer->top_line, vlines);
669 		}
670 
671 		goto again;
672 	}
673 
674 	buffer->last_line_off = buffer->line_off;
675 	buffer->force_redraw = 0;
676 end:
677 	wmove(win, buffer->curs_y, buffer->curs_x);
678 }
679 
680 static void
681 redraw_help(void)
682 {
683 	redraw_window(help, help_lines, help_cols, &helpwin);
684 }
685 
686 static void
687 redraw_body(struct tab *tab)
688 {
689 	static struct tab *last_tab;
690 
691 	if (last_tab != tab)
692 		tab->buffer.force_redraw =1;
693 	last_tab = tab;
694 
695 	redraw_window(body, body_lines, body_cols, &tab->buffer);
696 }
697 
698 static inline char
699 trust_status_char(enum trust_state ts)
700 {
701 	switch (ts) {
702 	case TS_UNKNOWN:	return 'u';
703 	case TS_UNTRUSTED:	return '!';
704 	case TS_TEMP_TRUSTED:	return '!';
705 	case TS_TRUSTED:	return 'v';
706 	case TS_VERIFIED:	return 'V';
707 	default:		return 'X';
708 	}
709 }
710 
711 static void
712 redraw_modeline(struct tab *tab)
713 {
714 	double		 pct;
715 	int		 x, y, max_x, max_y;
716 	const char	*mode = tab->buffer.page.name;
717 	const char	*spin = "-\\|/";
718 
719 	werase(modeline);
720 	wattr_on(modeline, modeline_face.background, NULL);
721 	wmove(modeline, 0, 0);
722 
723 	wprintw(modeline, "-%c%c %s ",
724 	    spin[tab->loading_anim_step],
725 	    trust_status_char(tab->trust),
726 	    mode == NULL ? "(none)" : mode);
727 
728 	pct = (tab->buffer.line_off + tab->buffer.curs_y) * 100.0 / tab->buffer.line_max;
729 
730 	if (tab->buffer.line_max <= (size_t)body_lines)
731                 wprintw(modeline, "All ");
732 	else if (tab->buffer.line_off == 0)
733                 wprintw(modeline, "Top ");
734 	else if (tab->buffer.line_off + body_lines >= tab->buffer.line_max)
735 		wprintw(modeline, "Bottom ");
736 	else
737 		wprintw(modeline, "%.0f%% ", pct);
738 
739 	wprintw(modeline, "%d/%d %s ",
740 	    tab->buffer.line_off + tab->buffer.curs_y,
741 	    tab->buffer.line_max,
742 	    tab->hist_cur->h);
743 
744 	getyx(modeline, y, x);
745 	getmaxyx(modeline, max_y, max_x);
746 
747 	(void)y;
748 	(void)max_y;
749 
750 	for (; x < max_x; ++x)
751 		waddstr(modeline, "-");
752 
753 	wattr_off(modeline, modeline_face.background, NULL);
754 }
755 
756 static void
757 redraw_minibuffer(void)
758 {
759 	wattr_on(echoarea, minibuffer_face.background, NULL);
760 	werase(echoarea);
761 
762 	if (in_minibuffer)
763 		do_redraw_minibuffer();
764 	else
765 		do_redraw_echoarea();
766 
767 	wattr_off(echoarea, minibuffer_face.background, NULL);
768 }
769 
770 static void
771 do_redraw_echoarea(void)
772 {
773 	struct tab *tab;
774 
775 	if (ministate.curmesg != NULL)
776                 wprintw(echoarea, "%s", ministate.curmesg);
777 	else if (*keybuf != '\0')
778 		waddstr(echoarea, keybuf);
779 	else {
780 		/* If nothing else, show the URL at point */
781 		tab = current_tab();
782 		if (tab->buffer.current_line != NULL &&
783 		    tab->buffer.current_line->parent->type == LINE_LINK)
784 			waddstr(echoarea, tab->buffer.current_line->parent->alt);
785 	}
786 }
787 
788 static void
789 do_redraw_minibuffer(void)
790 {
791 	size_t		 off_y, off_x = 0;
792 	const char	*start, *c;
793 
794 	/* unused, set by getyx */
795 	(void)off_y;
796 
797 	mvwprintw(echoarea, 0, 0, "%s", ministate.prompt);
798 	if (ministate.hist_cur != NULL)
799 		wprintw(echoarea, "(%zu/%zu) ",
800 		    ministate.hist_off + 1,
801 		    ministate.history->len);
802 
803 	getyx(echoarea, off_y, off_x);
804 
805 	start = ministate.hist_cur != NULL
806 		? ministate.hist_cur->h
807 		: ministate.buf;
808 	c = utf8_nth(ministate.buffer.current_line->line,
809 	    ministate.buffer.cpoff);
810 	while (utf8_swidth_between(start, c) > (size_t)COLS/2) {
811 		start = utf8_next_cp(start);
812 	}
813 
814 	waddstr(echoarea, start);
815 
816 	if (ministate.curmesg != NULL)
817 		wprintw(echoarea, " [%s]", ministate.curmesg);
818 
819 	wmove(echoarea, 0, off_x + utf8_swidth_between(start, c));
820 }
821 
822 static void
823 redraw_tab(struct tab *tab)
824 {
825 	if (side_window) {
826 		redraw_help();
827 		wnoutrefresh(help);
828 	}
829 
830 	redraw_tabline();
831 	redraw_body(tab);
832 	redraw_modeline(tab);
833 	redraw_minibuffer();
834 
835 	wnoutrefresh(tabline);
836 	wnoutrefresh(modeline);
837 
838 	if (in_minibuffer) {
839 		wnoutrefresh(body);
840 		wnoutrefresh(echoarea);
841 	} else {
842 		wnoutrefresh(echoarea);
843 		wnoutrefresh(body);
844 	}
845 
846 	doupdate();
847 }
848 
849 static void
850 emit_help_item(char *prfx, void *fn)
851 {
852 	struct line	*l;
853 	struct cmd	*cmd;
854 
855 	for (cmd = cmds; cmd->cmd != NULL; ++cmd) {
856 		if (fn == cmd->fn)
857 			break;
858 	}
859 	assert(cmd != NULL);
860 
861 	if ((l = calloc(1, sizeof(*l))) == NULL)
862 		abort();
863 
864 	l->type = LINE_TEXT;
865 	l->alt = NULL;
866 
867 	asprintf(&l->line, "%s %s", prfx, cmd->cmd);
868 
869 	if (TAILQ_EMPTY(&helpwin.page.head))
870 		TAILQ_INSERT_HEAD(&helpwin.page.head, l, lines);
871 	else
872 		TAILQ_INSERT_TAIL(&helpwin.page.head, l, lines);
873 }
874 
875 static void
876 rec_compute_help(struct kmap *keymap, char *prfx, size_t len)
877 {
878 	struct keymap	*k;
879 	char		 p[32];
880 	const char	*kn;
881 
882 	TAILQ_FOREACH(k, &keymap->m, keymaps) {
883 		strlcpy(p, prfx, sizeof(p));
884 		if (*p != '\0')
885 			strlcat(p, " ", sizeof(p));
886 		if (k->meta)
887 			strlcat(p, "M-", sizeof(p));
888 		if ((kn = unkbd(k->key)) != NULL)
889 			strlcat(p, kn, sizeof(p));
890 		else
891 			strlcat(p, keyname(k->key), sizeof(p));
892 
893 		if (k->fn == NULL)
894 			rec_compute_help(&k->map, p, sizeof(p));
895 		else
896 			emit_help_item(p, k->fn);
897 	}
898 }
899 
900 static void
901 recompute_help(void)
902 {
903 	char	p[32] = { 0 };
904 
905 	empty_vlist(&helpwin);
906 	empty_linelist(&helpwin);
907 	rec_compute_help(current_map, p, sizeof(p));
908 	wrap_page(&helpwin, help_cols);
909 }
910 
911 void
912 vmessage(const char *fmt, va_list ap)
913 {
914 	if (evtimer_pending(&clechoev, NULL))
915 		evtimer_del(&clechoev);
916 
917 	free(ministate.curmesg);
918 	ministate.curmesg = NULL;
919 
920 	if (fmt != NULL) {
921 		evtimer_set(&clechoev, handle_clear_echoarea, NULL);
922 		evtimer_add(&clechoev, &clechoev_timer);
923 
924 		/* TODO: what to do if the allocation fails here? */
925 		if (vasprintf(&ministate.curmesg, fmt, ap) == -1)
926 			ministate.curmesg = NULL;
927 	}
928 
929 	redraw_minibuffer();
930 	if (in_minibuffer) {
931 		wrefresh(body);
932 		wrefresh(echoarea);
933 	} else {
934 		wrefresh(echoarea);
935 		wrefresh(body);
936 	}
937 }
938 
939 void
940 message(const char *fmt, ...)
941 {
942 	va_list ap;
943 
944 	va_start(ap, fmt);
945 	vmessage(fmt, ap);
946 	va_end(ap);
947 }
948 
949 void
950 start_loading_anim(struct tab *tab)
951 {
952 	if (tab->loading_anim)
953 		return;
954 	tab->loading_anim = 1;
955 	evtimer_set(&tab->loadingev, update_loading_anim, tab);
956 	evtimer_add(&tab->loadingev, &loadingev_timer);
957 }
958 
959 static void
960 update_loading_anim(int fd, short ev, void *d)
961 {
962 	struct tab	*tab = d;
963 
964 	tab->loading_anim_step = (tab->loading_anim_step+1)%4;
965 
966 	if (tab->flags & TAB_CURRENT) {
967 		redraw_modeline(tab);
968 		wrefresh(modeline);
969 		wrefresh(body);
970 		if (in_minibuffer)
971 			wrefresh(echoarea);
972 	}
973 
974 	evtimer_add(&tab->loadingev, &loadingev_timer);
975 }
976 
977 static void
978 stop_loading_anim(struct tab *tab)
979 {
980 	if (!tab->loading_anim)
981 		return;
982 	evtimer_del(&tab->loadingev);
983 	tab->loading_anim = 0;
984 	tab->loading_anim_step = 0;
985 
986 	if (!(tab->flags & TAB_CURRENT))
987 		return;
988 
989 	redraw_modeline(tab);
990 
991 	wrefresh(modeline);
992 	wrefresh(body);
993 	if (in_minibuffer)
994 		wrefresh(echoarea);
995 }
996 
997 void
998 load_url_in_tab(struct tab *tab, const char *url)
999 {
1000 	message("Loading %s...", url);
1001 	start_loading_anim(tab);
1002 	load_url(tab, url);
1003 
1004 	tab->buffer.curs_x = 0;
1005 	tab->buffer.curs_y = 0;
1006 	redraw_tab(tab);
1007 }
1008 
1009 void
1010 switch_to_tab(struct tab *tab)
1011 {
1012 	struct tab	*t;
1013 
1014 	TAILQ_FOREACH(t, &tabshead, tabs) {
1015 		t->flags &= ~TAB_CURRENT;
1016 	}
1017 
1018 	tab->flags |= TAB_CURRENT;
1019 	tab->flags &= ~TAB_URGENT;
1020 }
1021 
1022 unsigned int
1023 tab_new_id(void)
1024 {
1025 	return tab_counter++;
1026 }
1027 
1028 struct tab *
1029 new_tab(const char *url)
1030 {
1031 	struct tab	*tab;
1032 
1033 	if ((tab = calloc(1, sizeof(*tab))) == NULL) {
1034 		event_loopbreak();
1035 		return NULL;
1036 	}
1037 	tab->fd = -1;
1038 
1039 	TAILQ_INIT(&tab->hist.head);
1040 
1041 	TAILQ_INIT(&tab->buffer.head);
1042 
1043 	tab->id = tab_new_id();
1044 	switch_to_tab(tab);
1045 
1046 	if (TAILQ_EMPTY(&tabshead))
1047 		TAILQ_INSERT_HEAD(&tabshead, tab, tabs);
1048 	else
1049 		TAILQ_INSERT_TAIL(&tabshead, tab, tabs);
1050 
1051 	load_url_in_tab(tab, url);
1052 	return tab;
1053 }
1054 
1055 int
1056 ui_init()
1057 {
1058 	setlocale(LC_ALL, "");
1059 
1060 	TAILQ_INIT(&eecmd_history.head);
1061 	TAILQ_INIT(&ir_history.head);
1062 	TAILQ_INIT(&lu_history.head);
1063 
1064 	ministate.line.type = LINE_TEXT;
1065 	ministate.vline.parent = &ministate.line;
1066 	ministate.buffer.current_line = &ministate.vline;
1067 
1068 	/* initialize help window */
1069 	TAILQ_INIT(&helpwin.head);
1070 
1071 	base_map = &global_map;
1072 	current_map = &global_map;
1073 
1074 	initscr();
1075 
1076 	if (enable_colors) {
1077 		if (has_colors()) {
1078 			start_color();
1079 			use_default_colors();
1080 		} else
1081 			enable_colors = 0;
1082 	}
1083 
1084 	config_apply_style();
1085 
1086 	raw();
1087 	noecho();
1088 	nonl();
1089 	intrflush(stdscr, FALSE);
1090 
1091 	if ((tabline = newwin(1, COLS, 0, 0)) == NULL)
1092 		return 0;
1093 	if ((body = newwin(LINES - 3, COLS, 1, 0)) == NULL)
1094 		return 0;
1095 	if ((modeline = newwin(1, COLS, LINES-2, 0)) == NULL)
1096 		return 0;
1097 	if ((echoarea = newwin(1, COLS, LINES-1, 0)) == NULL)
1098 		return 0;
1099 	if ((help = newwin(1, 1, 1, 0)) == NULL)
1100 		return 0;
1101 
1102 	body_lines = LINES-3;
1103 	body_cols = COLS;
1104 
1105 	wbkgd(body, body_face.body);
1106 	wbkgd(echoarea, minibuffer_face.background);
1107 
1108 	update_x_offset();
1109 
1110 	keypad(body, TRUE);
1111 	scrollok(body, FALSE);
1112 
1113 	/* non-blocking input */
1114 	wtimeout(body, 0);
1115 
1116 	mvwprintw(body, 0, 0, "");
1117 
1118 	event_set(&stdioev, 0, EV_READ | EV_PERSIST, dispatch_stdio, NULL);
1119 	event_add(&stdioev, NULL);
1120 
1121 	signal_set(&winchev, SIGWINCH, handle_resize, NULL);
1122 	signal_add(&winchev, NULL);
1123 
1124 	return 1;
1125 }
1126 
1127 void
1128 ui_on_tab_loaded(struct tab *tab)
1129 {
1130 	stop_loading_anim(tab);
1131 	message("Loaded %s", tab->hist_cur->h);
1132 
1133 	redraw_tabline();
1134 	wrefresh(tabline);
1135 	if (in_minibuffer)
1136 		wrefresh(echoarea);
1137 	else
1138 		wrefresh(body);
1139 }
1140 
1141 void
1142 ui_on_tab_refresh(struct tab *tab)
1143 {
1144 	wrap_page(&tab->buffer, body_cols);
1145 	if (tab->flags & TAB_CURRENT)
1146 		redraw_tab(tab);
1147 	else
1148 		tab->flags |= TAB_URGENT;
1149 }
1150 
1151 const char *
1152 ui_keyname(int k)
1153 {
1154 	return keyname(k);
1155 }
1156 
1157 void
1158 ui_toggle_side_window(void)
1159 {
1160 	side_window = !side_window;
1161 	if (side_window)
1162 		recompute_help();
1163 
1164 	/*
1165 	 * ugly hack, but otherwise the window doesn't get updated
1166 	 * until I call handle_resize a second time (i.e. C-l).  I
1167 	 * will be happy to know why something like this is needed.
1168 	 */
1169 	handle_resize_nodelay(0, 0, NULL);
1170 	handle_resize_nodelay(0, 0, NULL);
1171 }
1172 
1173 void
1174 ui_schedule_redraw(void)
1175 {
1176 	handle_resize_nodelay(0, 0, NULL);
1177 }
1178 
1179 void
1180 ui_require_input(struct tab *tab, int hide)
1181 {
1182 	/* TODO: hard-switching to another tab is ugly */
1183 	switch_to_tab(tab);
1184 
1185 	enter_minibuffer(ir_self_insert, ir_select, exit_minibuffer,
1186 	    &ir_history);
1187 	strlcpy(ministate.prompt, "Input required: ",
1188 	    sizeof(ministate.prompt));
1189 	redraw_tab(tab);
1190 }
1191 
1192 void
1193 ui_yornp(const char *prompt, void (*fn)(int, struct tab *),
1194     struct tab *data)
1195 {
1196 	yornp(prompt, fn, data);
1197 	redraw_tab(current_tab());
1198 }
1199 
1200 void
1201 ui_read(const char *prompt, void (*fn)(const char*, unsigned int),
1202     unsigned int data)
1203 {
1204 	completing_read(prompt, fn, data);
1205 	redraw_tab(current_tab());
1206 }
1207 
1208 void
1209 ui_end(void)
1210 {
1211 	endwin();
1212 }