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Date:: Sat Jul 17 21:06:18 2021 UTC
Message:: correctly compute the x position on "emojified" lines
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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 "defaults.h"
44 #include "minibuffer.h"
45 #include "telescope.h"
46 #include "ui.h"
47 #include "utf8.h"
48 
49 static struct event	stdioev, winchev;
50 
51 static void		 restore_curs_x(struct buffer *);
52 
53 static struct vline	*nth_line(struct buffer*, size_t);
54 static int		 readkey(void);
55 static void		 dispatch_stdio(int, short, void*);
56 static void		 handle_clear_echoarea(int, short, void*);
57 static void		 handle_resize(int, short, void*);
58 static void		 handle_resize_nodelay(int, short, void*);
59 static void		 rearrange_windows(void);
60 static int		 wrap_page(struct buffer*, int);
61 static void		 line_prefix_and_text(struct vline *, char *, size_t, const char **, const char **);
62 static void		 print_vline(int, int, WINDOW*, struct vline*);
63 static void		 redraw_tabline(void);
64 static void		 redraw_window(WINDOW*, int, int, int, struct buffer*);
65 static void		 redraw_help(void);
66 static void		 redraw_body(struct tab*);
67 static void		 redraw_modeline(struct tab*);
68 static void		 redraw_minibuffer(void);
69 static void		 do_redraw_echoarea(void);
70 static void		 do_redraw_minibuffer(void);
71 static void		 do_redraw_minibuffer_compl(void);
72 static void		 place_cursor(int);
73 static void		 redraw_tab(struct tab*);
74 static void		 emit_help_item(char*, void*);
75 static void		 rec_compute_help(struct kmap*, char*, size_t);
76 static void		 recompute_help(void);
77 static void		 update_loading_anim(int, short, void*);
78 static void		 stop_loading_anim(struct tab*);
79 
80 /*
81  * Used to know when we're finished loading.
82  */
83 static int		 operating;
84 
85 static int		 should_rearrange_windows;
86 static int		 too_small;
87 static int		 x_offset;
88 
89 struct thiskey	 thiskey;
90 struct tab	*current_tab;
91 
92 static struct event	resizeev;
93 static struct timeval	resize_timer = { 0, 250000 };
94 
95 static WINDOW	*tabline, *body, *modeline, *echoarea, *minibuffer;
96 
97 int			 body_lines, body_cols;
98 
99 static WINDOW		*help;
100 static struct buffer	 helpwin;
101 static int		 help_lines, help_cols;
102 
103 static int		 side_window;
104 
105 static struct event	clechoev;
106 static struct timeval	clechoev_timer = { 5, 0 };
107 static struct timeval	loadingev_timer = { 0, 250000 };
108 
109 static uint32_t		 tab_counter;
110 
111 static char	keybuf[64];
112 
113 struct kmap global_map,
114 	minibuffer_map,
115 	*current_map,
116 	*base_map;
117 
118 int in_minibuffer;
119 
120 static inline void
121 update_x_offset(void)
122 {
123 	if (olivetti_mode && fill_column < body_cols)
124 		x_offset = (body_cols - fill_column)/2;
125 	else
126 		x_offset = 0;
127 }
128 
129 void
130 save_excursion(struct excursion *place, struct buffer *buffer)
131 {
132 	place->curs_x = buffer->curs_x;
133 	place->curs_y = buffer->curs_y;
134 	place->line_off = buffer->line_off;
135 	place->current_line = buffer->current_line;
136 	place->cpoff = buffer->cpoff;
137 }
138 
139 void
140 restore_excursion(struct excursion *place, struct buffer *buffer)
141 {
142 	buffer->curs_x = place->curs_x;
143 	buffer->curs_y = place->curs_y;
144 	buffer->line_off = place->line_off;
145 	buffer->current_line = place->current_line;
146 	buffer->cpoff = place->cpoff;
147 }
148 
149 static void
150 restore_curs_x(struct buffer *buffer)
151 {
152 	struct vline	*vl;
153 	const char	*prfx;
154 
155 	vl = buffer->current_line;
156 	if (vl == NULL || vl->line == NULL)
157 		buffer->curs_x = buffer->cpoff = 0;
158 	else if (vl->parent->data != NULL)
159 		buffer->curs_x = utf8_snwidth(vl->parent->data+1, buffer->cpoff) + 1;
160 	else
161 		buffer->curs_x = utf8_snwidth(vl->line, buffer->cpoff);
162 
163 	buffer->curs_x += x_offset;
164 
165 	if (vl == NULL)
166 		return;
167 
168 	if (vl->parent->data != NULL)
169 		buffer->curs_x += utf8_swidth_between(vl->parent->line, vl->parent->data);
170 	else {
171 		prfx = line_prefixes[vl->parent->type].prfx1;
172 		buffer->curs_x += utf8_swidth(prfx);
173 	}
174 }
175 
176 void
177 global_key_unbound(void)
178 {
179 	message("%s is undefined", keybuf);
180 }
181 
182 static struct vline *
183 nth_line(struct buffer *buffer, size_t n)
184 {
185 	struct vline	*vl;
186 	size_t		 i;
187 
188 	i = 0;
189 	TAILQ_FOREACH(vl, &buffer->head, vlines) {
190 		if (i == n)
191 			return vl;
192 		i++;
193 	}
194 
195 	/* unreachable */
196 	abort();
197 }
198 
199 struct buffer *
200 current_buffer(void)
201 {
202 	if (in_minibuffer)
203 		return &ministate.buffer;
204 	return &current_tab->buffer;
205 }
206 
207 static int
208 readkey(void)
209 {
210 	uint32_t state = 0;
211 
212 	if ((thiskey.key = wgetch(body)) == ERR)
213 		return 0;
214 
215 	thiskey.meta = thiskey.key == 27;
216 	if (thiskey.meta) {
217 		thiskey.key = wgetch(body);
218 		if (thiskey.key == ERR || thiskey.key == 27) {
219 			thiskey.meta = 0;
220 			thiskey.key = 27;
221 		}
222 	}
223 
224 	thiskey.cp = 0;
225 	if ((unsigned int)thiskey.key < UINT8_MAX) {
226 		while (1) {
227 			if (!utf8_decode(&state, &thiskey.cp, (uint8_t)thiskey.key))
228 				break;
229 			if ((thiskey.key = wgetch(body)) == ERR) {
230 				message("Error decoding user input");
231 				return 0;
232 			}
233 		}
234 	}
235 
236 	return 1;
237 }
238 
239 static void
240 dispatch_stdio(int fd, short ev, void *d)
241 {
242 	struct keymap	*k;
243 	const char	*keyname;
244 	char		 tmp[5] = {0};
245 
246 	/* TODO: schedule a redraw? */
247 	if (too_small)
248 		return;
249 
250 	if (!readkey())
251 		return;
252 
253 	if (keybuf[0] != '\0')
254 		strlcat(keybuf, " ", sizeof(keybuf));
255 	if (thiskey.meta)
256 		strlcat(keybuf, "M-", sizeof(keybuf));
257 	if (thiskey.cp != 0) {
258 		utf8_encode(thiskey.cp, tmp);
259 		strlcat(keybuf, tmp, sizeof(keybuf));
260 	} else if ((keyname = unkbd(thiskey.key)) != NULL) {
261 		strlcat(keybuf, keyname, sizeof(keybuf));
262 	} else {
263 		tmp[0] = thiskey.key;
264 		strlcat(keybuf, tmp, sizeof(keybuf));
265 	}
266 
267 	TAILQ_FOREACH(k, &current_map->m, keymaps) {
268 		if (k->meta == thiskey.meta &&
269 		    k->key == thiskey.key) {
270 			if (k->fn == NULL)
271 				current_map = &k->map;
272 			else {
273 				current_map = base_map;
274 				strlcpy(keybuf, "", sizeof(keybuf));
275 				k->fn(current_buffer());
276 			}
277 			goto done;
278 		}
279 	}
280 
281 	if (current_map->unhandled_input != NULL)
282 		current_map->unhandled_input();
283 	else
284 		global_key_unbound();
285 
286 	strlcpy(keybuf, "", sizeof(keybuf));
287 	current_map = base_map;
288 
289 done:
290 	if (side_window)
291 		recompute_help();
292 
293 	if (should_rearrange_windows)
294 		rearrange_windows();
295 	redraw_tab(current_tab);
296 }
297 
298 static void
299 handle_clear_echoarea(int fd, short ev, void *d)
300 {
301 	free(ministate.curmesg);
302 	ministate.curmesg = NULL;
303 
304 	redraw_minibuffer();
305 	place_cursor(0);
306 }
307 
308 static void
309 handle_resize(int sig, short ev, void *d)
310 {
311 	if (event_pending(&resizeev, EV_TIMEOUT, NULL)) {
312 		event_del(&resizeev);
313 	}
314 	evtimer_set(&resizeev, handle_resize_nodelay, NULL);
315 	evtimer_add(&resizeev, &resize_timer);
316 }
317 
318 static void
319 handle_resize_nodelay(int s, short ev, void *d)
320 {
321 	endwin();
322 	refresh();
323 	clear();
324 
325 	rearrange_windows();
326 }
327 
328 static void
329 rearrange_windows(void)
330 {
331 	int		 lines;
332 
333 	should_rearrange_windows = 0;
334 
335 	lines = LINES;
336 
337 	if ((too_small = lines < 15)) {
338 		erase();
339 		printw("Window too small.");
340 		refresh();
341 		return;
342 	}
343 
344 	/* move and resize the windows, in reverse order! */
345 
346 	if (in_minibuffer == MB_COMPREAD) {
347 		mvwin(minibuffer, lines-10, 0);
348 		wresize(minibuffer, 10, COLS);
349 		lines -= 10;
350 
351 		wrap_page(&ministate.compl.buffer, COLS);
352 	}
353 
354 	mvwin(echoarea, --lines, 0);
355 	wresize(echoarea, 1, COLS);
356 
357 	mvwin(modeline, --lines, 0);
358 	wresize(modeline, 1, COLS);
359 
360 	body_lines = --lines;
361 	body_cols = COLS;
362 
363 	if (side_window) {
364 		help_cols = 0.3 * COLS;
365 		help_lines = lines;
366 		mvwin(help, 1, 0);
367 		wresize(help, help_lines, help_cols);
368 
369 		wrap_page(&helpwin, help_cols);
370 
371 		body_cols = COLS - help_cols - 1;
372 		mvwin(body, 1, help_cols);
373 	} else
374 		mvwin(body, 1, 0);
375 
376 	update_x_offset();
377 	wresize(body, body_lines, body_cols);
378 
379 	wresize(tabline, 1, COLS);
380 
381 	wrap_page(&current_tab->buffer, body_cols);
382 	redraw_tab(current_tab);
383 }
384 
385 static int
386 wrap_page(struct buffer *buffer, int width)
387 {
388 	struct line		*l;
389 	const struct line	*top_orig, *orig;
390 	struct vline		*vl;
391 	int			 pre_width;
392 	const char		*prfx;
393 
394 	top_orig = buffer->top_line == NULL ? NULL : buffer->top_line->parent;
395 	orig = buffer->current_line == NULL ? NULL : buffer->current_line->parent;
396 
397 	buffer->top_line = NULL;
398 	buffer->current_line = NULL;
399 
400 	buffer->force_redraw = 1;
401 	buffer->curs_y = 0;
402 	buffer->line_off = 0;
403 
404 	empty_vlist(buffer);
405 
406 	TAILQ_FOREACH(l, &buffer->page.head, lines) {
407 		prfx = line_prefixes[l->type].prfx1;
408 		switch (l->type) {
409 		case LINE_TEXT:
410 		case LINE_LINK:
411 		case LINE_TITLE_1:
412 		case LINE_TITLE_2:
413 		case LINE_TITLE_3:
414 		case LINE_ITEM:
415 		case LINE_QUOTE:
416 		case LINE_PRE_START:
417 		case LINE_PRE_END:
418 			wrap_text(buffer, prfx, l, MIN(fill_column, width));
419 			break;
420 		case LINE_PRE_CONTENT:
421 			if (olivetti_mode)
422 				pre_width = MIN(fill_column, width);
423 			else
424 				pre_width = width;
425 			hardwrap_text(buffer, l, pre_width);
426 			break;
427 		case LINE_COMPL:
428 		case LINE_COMPL_CURRENT:
429 			wrap_one(buffer, prfx, l, width);
430 			break;
431 		}
432 
433 		if (top_orig == l && buffer->top_line == NULL) {
434 			buffer->line_off = buffer->line_max-1;
435 			buffer->top_line = TAILQ_LAST(&buffer->head, vhead);
436 
437 			while (1) {
438 				vl = TAILQ_PREV(buffer->top_line, vhead, vlines);
439 				if (vl == NULL || vl->parent != orig)
440 					break;
441 				buffer->top_line = vl;
442 				buffer->line_off--;
443 			}
444 		}
445 
446 		if (orig == l && buffer->current_line == NULL) {
447 			buffer->current_line = TAILQ_LAST(&buffer->head, vhead);
448 
449 			while (1) {
450 				vl = TAILQ_PREV(buffer->current_line, vhead, vlines);
451 				if (vl == NULL || vl->parent != orig)
452 					break;
453 				buffer->current_line = vl;
454 			}
455 		}
456 	}
457 
458         if (buffer->current_line == NULL)
459 		buffer->current_line = TAILQ_FIRST(&buffer->head);
460 
461 	if (buffer->top_line == NULL)
462 		buffer->top_line = buffer->current_line;
463 
464 	return 1;
465 }
466 
467 static void
468 line_prefix_and_text(struct vline *vl, char *buf, size_t len,
469     const char **prfx_ret, const char **text_ret)
470 {
471 	int type, i, cont, width;
472 	char *space, *t;
473 
474 	if ((*text_ret = vl->line) == NULL)
475 		*text_ret = "";
476 
477 	cont = vl->flags & L_CONTINUATION;
478 	type = vl->parent->type;
479 	if (!cont)
480 		*prfx_ret = line_prefixes[type].prfx1;
481 	else
482 		*prfx_ret = line_prefixes[type].prfx2;
483 
484 	space = vl->parent->data;
485 	if (!emojify_link || type != LINE_LINK || space == NULL)
486 		return;
487 
488 	if (cont) {
489 		memset(buf, 0, len);
490 		width = utf8_swidth_between(vl->parent->line, space);
491 		for (i = 0; i < width + 1; ++i)
492 			strlcat(buf, " ", len);
493 	} else {
494 		strlcpy(buf, *text_ret, len);
495 		if ((t = strchr(buf, ' ')) != NULL)
496 			*t = '\0';
497 		strlcat(buf, " ", len);
498 
499 		/* skip the emoji */
500                 *text_ret += (space - vl->parent->line) + 1;
501 	}
502 
503 	*prfx_ret = buf;
504 }
505 
506 /*
507  * Core part of the rendering.  It prints a vline starting from the
508  * current cursor position.  Printing a vline consists of skipping
509  * `off' columns (for olivetti-mode), print the correct prefix (which
510  * may be the emoji in case of emojified links-lines), printing the
511  * text itself, filling until width - off and filling off columns
512  * again.
513  */
514 static void
515 print_vline(int off, int width, WINDOW *window, struct vline *vl)
516 {
517 	/*
518 	 * Believe me or not, I've seen emoji ten code points long!
519 	 * That means, to stay large, 4*10 bytes + NUL.
520 	 */
521 	char emojibuf[41] = {0};
522 	const char *text, *prfx;
523 	struct line_face *f;
524 	int i, left, x, y;
525 
526 	f = &line_faces[vl->parent->type];
527 
528 	/* unused, set by getyx */
529 	(void)y;
530 
531 	line_prefix_and_text(vl, emojibuf, sizeof(emojibuf), &prfx, &text);
532 
533 	wattr_on(window, body_face.left, NULL);
534 	for (i = 0; i < off; i++)
535 		waddch(window, ' ');
536 	wattr_off(window, body_face.left, NULL);
537 
538 	wattr_on(window, f->prefix, NULL);
539 	wprintw(window, "%s", prfx);
540 	wattr_off(window, f->prefix, NULL);
541 
542 	wattr_on(window, f->text, NULL);
543 	wprintw(window, "%s", text);
544 	wattr_off(window, f->text, NULL);
545 
546 	getyx(window, y, x);
547 
548 	left = width - x;
549 
550 	wattr_on(window, f->trail, NULL);
551 	for (i = 0; i < left - off; ++i)
552 		waddch(window, ' ');
553 	wattr_off(window, f->trail, NULL);
554 
555 	wattr_on(window, body_face.right, NULL);
556 	for (i = 0; i < off; i++)
557 		waddch(window, ' ');
558 	wattr_off(window, body_face.right, NULL);
559 
560 }
561 
562 static void
563 redraw_tabline(void)
564 {
565 	struct tab	*tab;
566 	size_t		 toskip, ots, tabwidth, space, x;
567 	int		 current, y, truncated, pair;
568 	const char	*title;
569 	char		 buf[25];
570 
571 	x = 0;
572 
573 	/* unused, but setted by a getyx */
574 	(void)y;
575 
576 	tabwidth = sizeof(buf)+1;
577 	space = COLS-2;
578 
579 	toskip = 0;
580 	TAILQ_FOREACH(tab, &tabshead, tabs) {
581 		toskip++;
582 		if (tab == current_tab)
583 			break;
584 	}
585 
586 	if (toskip * tabwidth < space)
587 		toskip = 0;
588 	else {
589 		ots = toskip;
590 		toskip--;
591                 while (toskip != 0 &&
592 		    (ots - toskip+1) * tabwidth < space)
593 			toskip--;
594 	}
595 
596 	werase(tabline);
597 	wattr_on(tabline, tab_face.background, NULL);
598 	wprintw(tabline, toskip == 0 ? " " : "<");
599 	wattr_off(tabline, tab_face.background, NULL);
600 
601 	truncated = 0;
602 	TAILQ_FOREACH(tab, &tabshead, tabs) {
603 		if (truncated)
604 			break;
605 		if (toskip != 0) {
606 			toskip--;
607 			continue;
608 		}
609 
610 		getyx(tabline, y, x);
611 		if (x + sizeof(buf)+2 >= (size_t)COLS)
612 			truncated = 1;
613 
614 		current = tab == current_tab;
615 
616 		if (*(title = tab->buffer.page.title) == '\0')
617 			title = tab->hist_cur->h;
618 
619 		if (tab->flags & TAB_URGENT)
620 			strlcpy(buf, "!", sizeof(buf));
621 		else
622 			strlcpy(buf, " ", sizeof(buf));
623 
624                 if (strlcat(buf, title, sizeof(buf)) >= sizeof(buf)) {
625 			/* truncation happens */
626 			strlcpy(&buf[sizeof(buf)-4], "...", 4);
627 		} else {
628 			/* pad with spaces */
629 			while (strlcat(buf, "    ", sizeof(buf)) < sizeof(buf))
630 				/* nop */ ;
631 		}
632 
633 		pair = current ? tab_face.current : tab_face.tab;
634 		wattr_on(tabline, pair, NULL);
635 		wprintw(tabline, "%s", buf);
636 		wattr_off(tabline, pair, NULL);
637 
638 		wattr_on(tabline, tab_face.background, NULL);
639 		if (TAILQ_NEXT(tab, tabs) != NULL)
640 			wprintw(tabline, "│");
641 		wattr_off(tabline, tab_face.background, NULL);
642 	}
643 
644 	wattr_on(tabline, tab_face.background, NULL);
645 	for (; x < (size_t)COLS; ++x)
646 		waddch(tabline, ' ');
647 	if (truncated)
648 		mvwprintw(tabline, 0, COLS-1, ">");
649 	wattr_off(tabline, tab_face.background, NULL);
650 }
651 
652 /*
653  * Compute the first visible line around vl.  Try to search forward
654  * until the end of the buffer; if a visible line is not found, search
655  * backward.  Return NULL if no viable line was found.
656  */
657 struct vline *
658 adjust_line(struct vline *vl, struct buffer *buffer)
659 {
660 	struct vline *t;
661 
662 	if (vl == NULL)
663 		return NULL;
664 
665 	if (!(vl->parent->flags & L_HIDDEN))
666 		return vl;
667 
668 	/* search forward */
669 	for (t = vl;
670 	     t != NULL && t->parent->flags & L_HIDDEN;
671 	     t = TAILQ_NEXT(t, vlines))
672 		;		/* nop */
673 
674 	if (t != NULL)
675 		return t;
676 
677 	/* search backward */
678 	for (t = vl;
679 	     t != NULL && t->parent->flags & L_HIDDEN;
680 	     t = TAILQ_PREV(t, vhead, vlines))
681 		;		/* nop */
682 
683 	return t;
684 }
685 
686 static void
687 redraw_window(WINDOW *win, int off, int height, int width, struct buffer *buffer)
688 {
689         struct vline	*vl;
690 	int		 l, onscreen;
691 
692 	restore_curs_x(buffer);
693 
694 	/*
695 	 * TODO: ignoring buffer->force_update and always
696 	 * re-rendering.  In theory we can recompute the y position
697 	 * without a re-render, and optimize here.  It's not the only
698 	 * optimisation possible here, wscrl wolud also be an
699 	 * interesting one.
700 	 */
701 
702 again:
703 	werase(win);
704 	buffer->curs_y = 0;
705 
706 	if (TAILQ_EMPTY(&buffer->head))
707 		goto end;
708 
709 	if (buffer->top_line == NULL)
710 		buffer->top_line = TAILQ_FIRST(&buffer->head);
711 
712 	buffer->top_line = adjust_line(buffer->top_line, buffer);
713 	if (buffer->top_line == NULL)
714 		goto end;
715 
716 	buffer->current_line = adjust_line(buffer->current_line, buffer);
717 
718 	l = 0;
719 	onscreen = 0;
720 	for (vl = buffer->top_line; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
721 		if (vl->parent->flags & L_HIDDEN)
722 			continue;
723 
724 		wmove(win, l, 0);
725 		print_vline(off, width, win, vl);
726 
727 		if (vl == buffer->current_line)
728 			onscreen = 1;
729 
730 		if (!onscreen)
731 			buffer->curs_y++;
732 
733 		l++;
734 		if (l == height)
735 			break;
736 	}
737 
738 	if (!onscreen) {
739 		for (; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
740 			if (vl == buffer->current_line)
741 				break;
742 			if (vl->parent->flags & L_HIDDEN)
743 				continue;
744 			buffer->line_off++;
745 			buffer->top_line = TAILQ_NEXT(buffer->top_line, vlines);
746 		}
747 
748 		if (vl != NULL)
749 			goto again;
750 	}
751 
752 	buffer->last_line_off = buffer->line_off;
753 	buffer->force_redraw = 0;
754 end:
755 	wmove(win, buffer->curs_y, buffer->curs_x);
756 }
757 
758 static void
759 redraw_help(void)
760 {
761 	redraw_window(help, 0, help_lines, help_cols, &helpwin);
762 }
763 
764 static void
765 redraw_body(struct tab *tab)
766 {
767 	static struct tab *last_tab;
768 
769 	if (last_tab != tab)
770 		tab->buffer.force_redraw =1;
771 	last_tab = tab;
772 
773 	redraw_window(body, x_offset, body_lines, body_cols, &tab->buffer);
774 }
775 
776 static inline char
777 trust_status_char(enum trust_state ts)
778 {
779 	switch (ts) {
780 	case TS_UNKNOWN:	return 'u';
781 	case TS_UNTRUSTED:	return '!';
782 	case TS_TEMP_TRUSTED:	return '!';
783 	case TS_TRUSTED:	return 'v';
784 	case TS_VERIFIED:	return 'V';
785 	default:		return 'X';
786 	}
787 }
788 
789 static void
790 redraw_modeline(struct tab *tab)
791 {
792 	double		 pct;
793 	int		 x, y, max_x, max_y;
794 	const char	*mode = tab->buffer.page.name;
795 	const char	*spin = "-\\|/";
796 
797 	werase(modeline);
798 	wattr_on(modeline, modeline_face.background, NULL);
799 	wmove(modeline, 0, 0);
800 
801 	wprintw(modeline, "-%c%c %s ",
802 	    spin[tab->loading_anim_step],
803 	    trust_status_char(tab->trust),
804 	    mode == NULL ? "(none)" : mode);
805 
806 	pct = (tab->buffer.line_off + tab->buffer.curs_y) * 100.0
807 		/ tab->buffer.line_max;
808 
809 	if (tab->buffer.line_max <= (size_t)body_lines)
810                 wprintw(modeline, "All ");
811 	else if (tab->buffer.line_off == 0)
812                 wprintw(modeline, "Top ");
813 	else if (tab->buffer.line_off + body_lines >= tab->buffer.line_max)
814 		wprintw(modeline, "Bottom ");
815 	else
816 		wprintw(modeline, "%.0f%% ", pct);
817 
818 	wprintw(modeline, "%d/%d %s ",
819 	    tab->buffer.line_off + tab->buffer.curs_y,
820 	    tab->buffer.line_max,
821 	    tab->hist_cur->h);
822 
823 	getyx(modeline, y, x);
824 	getmaxyx(modeline, max_y, max_x);
825 
826 	(void)y;
827 	(void)max_y;
828 
829 	for (; x < max_x; ++x)
830 		waddstr(modeline, "-");
831 
832 	wattr_off(modeline, modeline_face.background, NULL);
833 }
834 
835 static void
836 redraw_minibuffer(void)
837 {
838 	wattr_on(echoarea, minibuffer_face.background, NULL);
839 	werase(echoarea);
840 
841 	if (in_minibuffer)
842 		do_redraw_minibuffer();
843 	else
844 		do_redraw_echoarea();
845 
846 	if (in_minibuffer == MB_COMPREAD)
847 		do_redraw_minibuffer_compl();
848 
849 	wattr_off(echoarea, minibuffer_face.background, NULL);
850 }
851 
852 static void
853 do_redraw_echoarea(void)
854 {
855 	struct vline *vl;
856 
857 	if (ministate.curmesg != NULL)
858                 wprintw(echoarea, "%s", ministate.curmesg);
859 	else if (*keybuf != '\0')
860 		waddstr(echoarea, keybuf);
861 	else {
862 		/* If nothing else, show the URL at point */
863 		vl = current_tab->buffer.current_line;
864 		if (vl != NULL && vl->parent->type == LINE_LINK)
865 			waddstr(echoarea, vl->parent->alt);
866 	}
867 }
868 
869 static void
870 do_redraw_minibuffer(void)
871 {
872 	size_t		 off_y, off_x = 0;
873 	const char	*start, *c;
874 
875 	/* unused, set by getyx */
876 	(void)off_y;
877 
878 	wmove(echoarea, 0, 0);
879 
880 	if (in_minibuffer == MB_COMPREAD)
881 		wprintw(echoarea, "(%2d) ",
882 		    ministate.compl.buffer.line_max);
883 
884 	wprintw(echoarea, "%s", ministate.prompt);
885 	if (ministate.hist_cur != NULL)
886 		wprintw(echoarea, "(%zu/%zu) ",
887 		    ministate.hist_off + 1,
888 		    ministate.history->len);
889 
890 	getyx(echoarea, off_y, off_x);
891 
892 	start = ministate.hist_cur != NULL
893 		? ministate.hist_cur->h
894 		: ministate.buf;
895 	c = utf8_nth(ministate.buffer.current_line->line,
896 	    ministate.buffer.cpoff);
897 	while (utf8_swidth_between(start, c) > (size_t)COLS/2) {
898 		start = utf8_next_cp(start);
899 	}
900 
901 	waddstr(echoarea, start);
902 
903 	if (ministate.curmesg != NULL)
904 		wprintw(echoarea, " [%s]", ministate.curmesg);
905 
906 	wmove(echoarea, 0, off_x + utf8_swidth_between(start, c));
907 }
908 
909 static void
910 do_redraw_minibuffer_compl(void)
911 {
912 	redraw_window(minibuffer, 0, 10, body_cols,
913 	    &ministate.compl.buffer);
914 }
915 
916 /*
917  * Place the cursor in the right ncurses window.  If soft is 1, use
918  * wnoutrefresh (which shouldn't cause any I/O); otherwise use
919  * wrefresh.
920  */
921 static void
922 place_cursor(int soft)
923 {
924 	int (*touch)(WINDOW *);
925 
926 	if (soft)
927 		touch = wnoutrefresh;
928 	else
929 		touch = wrefresh;
930 
931 	if (in_minibuffer) {
932 		touch(body);
933 		touch(echoarea);
934 	} else {
935 		touch(echoarea);
936 		touch(body);
937 	}
938 }
939 
940 static void
941 redraw_tab(struct tab *tab)
942 {
943 	if (too_small)
944 		return;
945 
946 	if (side_window) {
947 		redraw_help();
948 		wnoutrefresh(help);
949 	}
950 
951 	redraw_tabline();
952 	redraw_body(tab);
953 	redraw_modeline(tab);
954 	redraw_minibuffer();
955 
956 	wnoutrefresh(tabline);
957 	wnoutrefresh(modeline);
958 
959 	if (in_minibuffer == MB_COMPREAD)
960 		wnoutrefresh(minibuffer);
961 
962 	place_cursor(1);
963 
964 	doupdate();
965 
966 	if (set_title)
967 		dprintf(1, "\033]0;%s - Telescope\a",
968 		    current_tab->buffer.page.title);
969 }
970 
971 static void
972 emit_help_item(char *prfx, void *fn)
973 {
974 	struct line	*l;
975 	struct cmd	*cmd;
976 
977 	for (cmd = cmds; cmd->cmd != NULL; ++cmd) {
978 		if (fn == cmd->fn)
979 			break;
980 	}
981 	assert(cmd != NULL);
982 
983 	if ((l = calloc(1, sizeof(*l))) == NULL)
984 		abort();
985 
986 	l->type = LINE_TEXT;
987 	l->alt = NULL;
988 
989 	asprintf(&l->line, "%s %s", prfx, cmd->cmd);
990 
991 	if (TAILQ_EMPTY(&helpwin.page.head))
992 		TAILQ_INSERT_HEAD(&helpwin.page.head, l, lines);
993 	else
994 		TAILQ_INSERT_TAIL(&helpwin.page.head, l, lines);
995 }
996 
997 static void
998 rec_compute_help(struct kmap *keymap, char *prfx, size_t len)
999 {
1000 	struct keymap	*k;
1001 	char		 p[32];
1002 	const char	*kn;
1003 
1004 	TAILQ_FOREACH(k, &keymap->m, keymaps) {
1005 		strlcpy(p, prfx, sizeof(p));
1006 		if (*p != '\0')
1007 			strlcat(p, " ", sizeof(p));
1008 		if (k->meta)
1009 			strlcat(p, "M-", sizeof(p));
1010 		if ((kn = unkbd(k->key)) != NULL)
1011 			strlcat(p, kn, sizeof(p));
1012 		else
1013 			strlcat(p, keyname(k->key), sizeof(p));
1014 
1015 		if (k->fn == NULL)
1016 			rec_compute_help(&k->map, p, sizeof(p));
1017 		else
1018 			emit_help_item(p, k->fn);
1019 	}
1020 }
1021 
1022 static void
1023 recompute_help(void)
1024 {
1025 	char	p[32] = { 0 };
1026 
1027 	empty_vlist(&helpwin);
1028 	empty_linelist(&helpwin);
1029 	rec_compute_help(current_map, p, sizeof(p));
1030 	wrap_page(&helpwin, help_cols);
1031 }
1032 
1033 void
1034 vmessage(const char *fmt, va_list ap)
1035 {
1036 	if (evtimer_pending(&clechoev, NULL))
1037 		evtimer_del(&clechoev);
1038 
1039 	free(ministate.curmesg);
1040 	ministate.curmesg = NULL;
1041 
1042 	if (fmt != NULL) {
1043 		evtimer_set(&clechoev, handle_clear_echoarea, NULL);
1044 		evtimer_add(&clechoev, &clechoev_timer);
1045 
1046 		/* TODO: what to do if the allocation fails here? */
1047 		if (vasprintf(&ministate.curmesg, fmt, ap) == -1)
1048 			ministate.curmesg = NULL;
1049 	}
1050 
1051 	redraw_minibuffer();
1052         place_cursor(0);
1053 }
1054 
1055 void
1056 message(const char *fmt, ...)
1057 {
1058 	va_list ap;
1059 
1060 	va_start(ap, fmt);
1061 	vmessage(fmt, ap);
1062 	va_end(ap);
1063 }
1064 
1065 void
1066 start_loading_anim(struct tab *tab)
1067 {
1068 	if (tab->loading_anim)
1069 		return;
1070 	tab->loading_anim = 1;
1071 	evtimer_set(&tab->loadingev, update_loading_anim, tab);
1072 	evtimer_add(&tab->loadingev, &loadingev_timer);
1073 }
1074 
1075 static void
1076 update_loading_anim(int fd, short ev, void *d)
1077 {
1078 	struct tab	*tab = d;
1079 
1080 	tab->loading_anim_step = (tab->loading_anim_step+1)%4;
1081 
1082 	if (tab == current_tab) {
1083 		redraw_modeline(tab);
1084 		wrefresh(modeline);
1085 		wrefresh(body);
1086 		if (in_minibuffer)
1087 			wrefresh(echoarea);
1088 	}
1089 
1090 	evtimer_add(&tab->loadingev, &loadingev_timer);
1091 }
1092 
1093 static void
1094 stop_loading_anim(struct tab *tab)
1095 {
1096 	if (!tab->loading_anim)
1097 		return;
1098 	evtimer_del(&tab->loadingev);
1099 	tab->loading_anim = 0;
1100 	tab->loading_anim_step = 0;
1101 
1102 	if (tab != current_tab)
1103 		return;
1104 
1105 	redraw_modeline(tab);
1106 
1107 	wrefresh(modeline);
1108 	wrefresh(body);
1109 	if (in_minibuffer)
1110 		wrefresh(echoarea);
1111 }
1112 
1113 void
1114 load_url_in_tab(struct tab *tab, const char *url)
1115 {
1116 	if (!operating) {
1117 		load_url(tab, url);
1118 		return;
1119 	}
1120 
1121 	message("Loading %s...", url);
1122 	start_loading_anim(tab);
1123 	load_url(tab, url);
1124 
1125 	redraw_tab(tab);
1126 }
1127 
1128 void
1129 switch_to_tab(struct tab *tab)
1130 {
1131 	current_tab = tab;
1132 	tab->flags &= ~TAB_URGENT;
1133 
1134 	if (operating && tab->flags & TAB_LAZY)
1135 		load_url_in_tab(tab, tab->hist_cur->h);
1136 }
1137 
1138 unsigned int
1139 tab_new_id(void)
1140 {
1141 	return tab_counter++;
1142 }
1143 
1144 struct tab *
1145 new_tab(const char *url)
1146 {
1147 	struct tab	*tab;
1148 
1149 	if ((tab = calloc(1, sizeof(*tab))) == NULL) {
1150 		event_loopbreak();
1151 		return NULL;
1152 	}
1153 	tab->fd = -1;
1154 
1155 	TAILQ_INIT(&tab->hist.head);
1156 
1157 	TAILQ_INIT(&tab->buffer.head);
1158 
1159 	tab->id = tab_new_id();
1160 	if (!operating)
1161 		tab->flags |= TAB_LAZY;
1162 	switch_to_tab(tab);
1163 
1164 	if (TAILQ_EMPTY(&tabshead))
1165 		TAILQ_INSERT_HEAD(&tabshead, tab, tabs);
1166 	else
1167 		TAILQ_INSERT_TAIL(&tabshead, tab, tabs);
1168 
1169 	load_url_in_tab(tab, url);
1170 	return tab;
1171 }
1172 
1173 int
1174 ui_print_colors(void)
1175 {
1176 	int colors = 0, pairs = 0, can_change = 0;
1177 	int columns = 16, lines, color, i, j;
1178 
1179 	initscr();
1180 	if (has_colors()) {
1181 		start_color();
1182 		use_default_colors();
1183 
1184 		colors = COLORS;
1185 		pairs = COLOR_PAIRS;
1186 		can_change = can_change_color();
1187 	}
1188 	endwin();
1189 
1190 	printf("Term info:\n");
1191 	printf("TERM=%s COLORS=%d COLOR_PAIRS=%d can_change_colors=%d\n",
1192 	    getenv("TERM"), colors, pairs, can_change);
1193 	printf("\n");
1194 
1195 	if (colors == 0) {
1196 		printf("No color support\n");
1197 		return 0;
1198 	}
1199 
1200 	printf("Available colors:\n\n");
1201 	lines = (colors - 1) / columns + 1;
1202 	color = 0;
1203 	for (i = 0; i < lines; ++i) {
1204 		for (j = 0; j < columns; ++j, ++color) {
1205 			printf("\033[0;38;5;%dm %03d", color, color);
1206 		}
1207 		printf("\n");
1208 	}
1209 
1210 	printf("\033[0m");
1211 	fflush(stdout);
1212 	return 0;
1213 }
1214 
1215 int
1216 ui_init()
1217 {
1218 	setlocale(LC_ALL, "");
1219 
1220 	TAILQ_INIT(&eecmd_history.head);
1221 	TAILQ_INIT(&ir_history.head);
1222 	TAILQ_INIT(&lu_history.head);
1223 
1224 	ministate.line.type = LINE_TEXT;
1225 	ministate.vline.parent = &ministate.line;
1226 	ministate.buffer.current_line = &ministate.vline;
1227 
1228 	/* initialize help window */
1229 	TAILQ_INIT(&helpwin.head);
1230 
1231 	base_map = &global_map;
1232 	current_map = &global_map;
1233 
1234 	initscr();
1235 
1236 	if (enable_colors) {
1237 		if (has_colors()) {
1238 			start_color();
1239 			use_default_colors();
1240 		} else
1241 			enable_colors = 0;
1242 	}
1243 
1244 	config_apply_style();
1245 
1246 	raw();
1247 	noecho();
1248 	nonl();
1249 	intrflush(stdscr, FALSE);
1250 
1251 	if ((tabline = newwin(1, COLS, 0, 0)) == NULL)
1252 		return 0;
1253 	if ((body = newwin(LINES - 3, COLS, 1, 0)) == NULL)
1254 		return 0;
1255 	if ((modeline = newwin(1, COLS, LINES-2, 0)) == NULL)
1256 		return 0;
1257 	if ((echoarea = newwin(1, COLS, LINES-1, 0)) == NULL)
1258 		return 0;
1259 	if ((minibuffer = newwin(1, COLS, LINES-1, 0)) == NULL)
1260 		return 0;
1261 	if ((help = newwin(1, 1, 1, 0)) == NULL)
1262 		return 0;
1263 
1264 	body_lines = LINES-3;
1265 	body_cols = COLS;
1266 
1267 	wbkgd(body, body_face.body);
1268 	wbkgd(echoarea, minibuffer_face.background);
1269 
1270 	update_x_offset();
1271 
1272 	keypad(body, TRUE);
1273 	scrollok(body, FALSE);
1274 
1275 	/* non-blocking input */
1276 	wtimeout(body, 0);
1277 
1278 	mvwprintw(body, 0, 0, "");
1279 
1280 	/*
1281 	 * Dummy so libevent2 won't complain that no event_base is set
1282 	 * when checking event_pending for the first time
1283 	 */
1284 	evtimer_set(&clechoev, handle_clear_echoarea, NULL);
1285 	evtimer_add(&clechoev, &clechoev_timer);
1286 	evtimer_set(&resizeev, handle_resize, NULL);
1287 	evtimer_add(&resizeev, &resize_timer);
1288 
1289 	event_set(&stdioev, 0, EV_READ | EV_PERSIST, dispatch_stdio, NULL);
1290 	event_add(&stdioev, NULL);
1291 
1292 	signal_set(&winchev, SIGWINCH, handle_resize, NULL);
1293 	signal_add(&winchev, NULL);
1294 
1295 	return 1;
1296 }
1297 
1298 void
1299 ui_main_loop(void)
1300 {
1301 	operating = 1;
1302 	switch_to_tab(current_tab);
1303 	redraw_tab(current_tab);
1304 
1305 	event_dispatch();
1306 }
1307 
1308 void
1309 ui_on_tab_loaded(struct tab *tab)
1310 {
1311 	stop_loading_anim(tab);
1312 	message("Loaded %s", tab->hist_cur->h);
1313 
1314 	redraw_tabline();
1315 	wrefresh(tabline);
1316 	place_cursor(0);
1317 }
1318 
1319 void
1320 ui_on_tab_refresh(struct tab *tab)
1321 {
1322 	wrap_page(&tab->buffer, body_cols);
1323 	if (tab == current_tab)
1324 		redraw_tab(tab);
1325 	else
1326 		tab->flags |= TAB_URGENT;
1327 }
1328 
1329 const char *
1330 ui_keyname(int k)
1331 {
1332 	return keyname(k);
1333 }
1334 
1335 void
1336 ui_toggle_side_window(void)
1337 {
1338 	side_window = !side_window;
1339 	if (side_window)
1340 		recompute_help();
1341 
1342 	/*
1343 	 * ugly hack, but otherwise the window doesn't get updated
1344 	 * until I call rearrange_windows a second time (e.g. via
1345 	 * C-l).  I will be happy to know why something like this is
1346 	 * needed.
1347 	 */
1348 	rearrange_windows();
1349 	rearrange_windows();
1350 }
1351 
1352 void
1353 ui_schedule_redraw(void)
1354 {
1355 	should_rearrange_windows = 1;
1356 }
1357 
1358 void
1359 ui_require_input(struct tab *tab, int hide)
1360 {
1361 	/* TODO: hard-switching to another tab is ugly */
1362 	switch_to_tab(tab);
1363 
1364 	enter_minibuffer(ir_self_insert, ir_select, exit_minibuffer,
1365 	    &ir_history, NULL, NULL);
1366 	strlcpy(ministate.prompt, "Input required: ",
1367 	    sizeof(ministate.prompt));
1368 	redraw_tab(tab);
1369 }
1370 
1371 void
1372 ui_yornp(const char *prompt, void (*fn)(int, struct tab *),
1373     struct tab *data)
1374 {
1375 	yornp(prompt, fn, data);
1376 	redraw_tab(current_tab);
1377 }
1378 
1379 void
1380 ui_read(const char *prompt, void (*fn)(const char*, struct tab *),
1381     struct tab *data)
1382 {
1383 	completing_read(prompt, fn, data);
1384 	redraw_tab(current_tab);
1385 }
1386 
1387 void
1388 ui_suspend(void)
1389 {
1390 	endwin();
1391 
1392 	kill(getpid(), SIGSTOP);
1393 
1394 	refresh();
1395 	clear();
1396 	rearrange_windows();
1397 }
1398 
1399 void
1400 ui_end(void)
1401 {
1402 	endwin();
1403 }