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 "compat.h"
34 
35 #include <assert.h>
36 #include <curses.h>
37 #include <locale.h>
38 #include <signal.h>
39 #include <stdarg.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <unistd.h>
43 
44 #include "defaults.h"
45 #include "minibuffer.h"
46 #include "session.h"
47 #include "telescope.h"
48 #include "ui.h"
49 #include "utf8.h"
50 
51 static struct event	stdioev, winchev;
52 
53 static void		 set_scroll_position(struct tab *, size_t, size_t);
54 
55 static void		 restore_curs_x(struct buffer *);
56 
57 static int		 readkey(void);
58 static void		 dispatch_stdio(int, short, void*);
59 static void		 handle_resize(int, short, void*);
60 static void		 handle_resize_nodelay(int, short, void*);
61 static void		 rearrange_windows(void);
62 static void		 line_prefix_and_text(struct vline *, char *, size_t, const char **, const char **);
63 static void		 print_vline(int, int, WINDOW*, struct vline*);
64 static void		 redraw_tabline(void);
65 static void		 redraw_window(WINDOW *, int, int, int, int, struct buffer *);
66 static void		 redraw_download(void);
67 static void		 redraw_help(void);
68 static void		 redraw_body(struct tab*);
69 static void		 redraw_modeline(struct tab*);
70 static void		 redraw_minibuffer(void);
71 static void		 do_redraw_echoarea(void);
72 static void		 do_redraw_minibuffer(void);
73 static void		 do_redraw_minibuffer_compl(void);
74 static void		 place_cursor(int);
75 static void		 redraw_tab(struct tab*);
76 static void		 update_loading_anim(int, short, void*);
77 static void		 stop_loading_anim(struct tab*);
78 
79 static int		 should_rearrange_windows;
80 static int		 show_tab_bar;
81 static int		 too_small;
82 static int		 x_offset;
83 
84 struct thiskey	 thiskey;
85 struct tab	*current_tab;
86 
87 static struct event	resizeev;
88 static struct timeval	resize_timer = { 0, 250000 };
89 
90 static WINDOW	*tabline, *body, *modeline, *echoarea, *minibuffer;
91 
92 int			 body_lines, body_cols;
93 
94 static WINDOW		*help;
95 /* not static so we can see them from help.c */
96 struct buffer		 helpwin;
97 int			 help_lines, help_cols;
98 
99 static WINDOW		*download;
100 /* not static so we can see them from download.c */
101 struct buffer		 downloadwin;
102 int			 download_lines;
103 int			 download_cols;
104 
105 static int		 side_window;
106 static int		 in_side_window;
107 
108 static struct timeval	loadingev_timer = { 0, 250000 };
109 
110 static char	keybuf[64];
111 
112 /* XXX: don't forget to init these in main() */
113 struct kmap global_map,
114 	minibuffer_map,
115 	*current_map,
116 	*base_map;
117 
118 static inline void
119 update_x_offset(void)
120 {
121 	if (olivetti_mode && fill_column < body_cols)
122 		x_offset = (body_cols - fill_column)/2;
123 	else
124 		x_offset = 0;
125 }
126 
127 static void
128 set_scroll_position(struct tab *tab, size_t top, size_t cur)
129 {
130 	struct line *last;
131 	struct vline *vl;
132 	size_t i = 0;
133 	int topfound = 0, curfound = 0;
134 
135 	last = TAILQ_FIRST(&tab->buffer.page.head);
136 	TAILQ_FOREACH(vl, &tab->buffer.head, vlines) {
137 		if (last != vl->parent) {
138 			last = vl->parent;
139 			i++;
140 		}
141 
142 		if (!topfound && i == top) {
143 			topfound = 1;
144 			tab->buffer.top_line = vl;
145 		}
146 
147 		if (!curfound && i == cur) {
148 			curfound = 1;
149 			tab->buffer.current_line = vl;
150 			return;
151 		}
152 	}
153 
154 	if (!topfound) {
155 		tab->buffer.top_line = TAILQ_FIRST(&tab->buffer.head);
156 		tab->buffer.current_line = tab->buffer.top_line;
157 	}
158 }
159 
160 void
161 get_scroll_position(struct tab *tab, size_t *top, size_t *cur)
162 {
163 	struct line *l;
164 	int topfound = 0;
165 
166 	*top = 0;
167 	*cur = 0;
168 
169 	if (tab->buffer.top_line == NULL ||
170 	    tab->buffer.current_line == NULL)
171 		return;
172 
173 	TAILQ_FOREACH(l, &tab->buffer.page.head, lines) {
174 		if (tab->buffer.top_line->parent == l)
175 			topfound = 1;
176 		if (tab->buffer.current_line->parent == l)
177 			return;
178 
179 		if (!topfound)
180 			(*top)++;
181 		(*cur)++;
182 	}
183 }
184 
185 void
186 save_excursion(struct excursion *place, struct buffer *buffer)
187 {
188 	place->curs_x = buffer->curs_x;
189 	place->curs_y = buffer->curs_y;
190 	place->line_off = buffer->line_off;
191 	place->top_line = buffer->top_line;
192 	place->current_line = buffer->current_line;
193 	place->cpoff = buffer->cpoff;
194 }
195 
196 void
197 restore_excursion(struct excursion *place, struct buffer *buffer)
198 {
199 	buffer->curs_x = place->curs_x;
200 	buffer->curs_y = place->curs_y;
201 	buffer->line_off = place->line_off;
202 	buffer->top_line = place->top_line;
203 	buffer->current_line = place->current_line;
204 	buffer->cpoff = place->cpoff;
205 }
206 
207 static void
208 restore_curs_x(struct buffer *buffer)
209 {
210 	struct vline	*vl;
211 	const char	*prfx, *text;
212 
213 	vl = buffer->current_line;
214 	if (vl == NULL || vl->line == NULL)
215 		buffer->curs_x = buffer->cpoff = 0;
216 	else if (vl->parent->data != NULL) {
217 		text = vl->parent->data;
218 		buffer->curs_x = utf8_snwidth(text + 1, buffer->cpoff) + 1;
219 	} else
220 		buffer->curs_x = utf8_snwidth(vl->line, buffer->cpoff);
221 
222 	/* small hack: don't olivetti-mode the download pane */
223 	if (buffer != &downloadwin)
224 		buffer->curs_x += x_offset;
225 
226 	if (vl == NULL)
227 		return;
228 
229 	if (vl->parent->data != NULL)
230 		buffer->curs_x += utf8_swidth_between(vl->parent->line,
231 		    vl->parent->data);
232 	else {
233 		prfx = line_prefixes[vl->parent->type].prfx1;
234 		buffer->curs_x += utf8_swidth(prfx);
235 	}
236 }
237 
238 void
239 global_key_unbound(void)
240 {
241 	message("%s is undefined", keybuf);
242 }
243 
244 struct buffer *
245 current_buffer(void)
246 {
247 	if (in_minibuffer)
248 		return &ministate.buffer;
249 	if (in_side_window & SIDE_WINDOW_LEFT)
250 		return &helpwin;
251 	if (in_side_window & SIDE_WINDOW_BOTTOM)
252 		return &downloadwin;
253 	return &current_tab->buffer;
254 }
255 
256 static int
257 readkey(void)
258 {
259 	uint32_t state = 0;
260 
261 	if ((thiskey.key = wgetch(body)) == ERR)
262 		return 0;
263 
264 	thiskey.meta = thiskey.key == '\e';
265 	if (thiskey.meta) {
266 		thiskey.key = wgetch(body);
267 		if (thiskey.key == ERR || thiskey.key == '\e') {
268 			thiskey.meta = 0;
269 			thiskey.key = '\e';
270 		}
271 	}
272 
273 	thiskey.cp = 0;
274 
275 	if ((unsigned int)thiskey.key >= UINT8_MAX)
276 		return 1;
277 
278 	while (1) {
279 		if (!utf8_decode(&state, &thiskey.cp, (uint8_t)thiskey.key))
280 			break;
281 		if ((thiskey.key = wgetch(body)) == ERR) {
282 			message("Error decoding user input");
283 			return 0;
284 		}
285 	}
286 
287 	return 1;
288 }
289 
290 static void
291 dispatch_stdio(int fd, short ev, void *d)
292 {
293 	int		 lk;
294 	const char	*keyname;
295 	char		 tmp[5] = {0};
296 
297 	/* TODO: schedule a redraw? */
298 	if (too_small)
299 		return;
300 
301 	if (!readkey())
302 		return;
303 
304 	if (keybuf[0] != '\0')
305 		strlcat(keybuf, " ", sizeof(keybuf));
306 	if (thiskey.meta)
307 		strlcat(keybuf, "M-", sizeof(keybuf));
308 	if (thiskey.cp != 0) {
309 		utf8_encode(thiskey.cp, tmp);
310 		strlcat(keybuf, tmp, sizeof(keybuf));
311 	} else if ((keyname = unkbd(thiskey.key)) != NULL) {
312 		strlcat(keybuf, keyname, sizeof(keybuf));
313 	} else {
314 		tmp[0] = thiskey.key;
315 		strlcat(keybuf, tmp, sizeof(keybuf));
316 	}
317 
318 	lk = lookup_key(&current_map, &thiskey, current_buffer());
319 	if (lk == LK_UNBOUND) {
320 		if (current_map->unhandled_input != NULL)
321 			current_map->unhandled_input();
322 		else
323 			global_key_unbound();
324 	}
325 	if (lk != LK_ADVANCED_MAP) {
326 		current_map = base_map;
327 		strlcpy(keybuf, "", sizeof(keybuf));
328 	}
329 
330 	if (side_window & SIDE_WINDOW_LEFT)
331 		recompute_help();
332 
333 	if (should_rearrange_windows)
334 		rearrange_windows();
335 	redraw_tab(current_tab);
336 }
337 
338 static void
339 handle_resize(int sig, short ev, void *d)
340 {
341 	if (event_pending(&resizeev, EV_TIMEOUT, NULL)) {
342 		event_del(&resizeev);
343 	}
344 	evtimer_set(&resizeev, handle_resize_nodelay, NULL);
345 	evtimer_add(&resizeev, &resize_timer);
346 }
347 
348 static void
349 handle_resize_nodelay(int s, short ev, void *d)
350 {
351 	endwin();
352 	refresh();
353 	clear();
354 
355 	rearrange_windows();
356 }
357 
358 static inline int
359 should_show_tab_bar(void)
360 {
361 	if (tab_bar_show == -1)
362 		return 0;
363 	if (tab_bar_show == 0)
364 		return 1;
365 
366 	return TAILQ_NEXT(TAILQ_FIRST(&tabshead), tabs) != NULL;
367 }
368 
369 static void
370 rearrange_windows(void)
371 {
372 	int		 lines;
373 	int		 minibuffer_lines;
374 
375 	should_rearrange_windows = 0;
376 	show_tab_bar = should_show_tab_bar();
377 
378 	lines = LINES;
379 
380 	/* 3 lines for the ui and 12 for the  */
381 	if ((too_small = lines < 15)) {
382 		erase();
383 		printw("Window too small.");
384 		refresh();
385 		return;
386 	}
387 
388 	/* move and resize the windows, in reverse order! */
389 
390 	if (in_minibuffer == MB_COMPREAD) {
391 		minibuffer_lines = MIN(10, lines/2);
392 		mvwin(minibuffer, lines - minibuffer_lines, 0);
393 		wresize(minibuffer, minibuffer_lines, COLS);
394 		lines -= minibuffer_lines;
395 
396 		wrap_page(&ministate.compl.buffer, COLS);
397 	}
398 
399 	mvwin(echoarea, --lines, 0);
400 	wresize(echoarea, 1, COLS);
401 
402 	mvwin(modeline, --lines, 0);
403 	wresize(modeline, 1, COLS);
404 
405 	if (side_window & SIDE_WINDOW_BOTTOM) {
406 		download_lines = MIN(5, lines/2);
407 		download_cols = COLS;
408 		mvwin(download, lines - download_lines, 0);
409 		wresize(download, download_lines, download_cols);
410 		lines -= download_lines;
411 
412 		wrap_page(&downloadwin, download_cols);
413 	}
414 
415 	body_lines = show_tab_bar ? --lines : lines;
416 	body_cols = COLS;
417 
418 	/*
419 	 * Here we make the assumption that show_tab_bar is either 0
420 	 * or 1, and reuse that as argument to mvwin.
421 	 */
422 	if (side_window & SIDE_WINDOW_LEFT) {
423 		help_cols = 0.3 * COLS;
424 		help_lines = lines;
425 		mvwin(help, show_tab_bar, 0);
426 		wresize(help, help_lines, help_cols);
427 
428 		wrap_page(&helpwin, help_cols);
429 
430 		body_cols = COLS - help_cols - 1;
431 		mvwin(body, show_tab_bar, help_cols);
432 	} else
433 		mvwin(body, show_tab_bar, 0);
434 
435 	update_x_offset();
436 	wresize(body, body_lines, body_cols);
437 
438 	if (show_tab_bar)
439 		wresize(tabline, 1, COLS);
440 
441 	wrap_page(&current_tab->buffer, body_cols);
442 	redraw_tab(current_tab);
443 }
444 
445 static void
446 line_prefix_and_text(struct vline *vl, char *buf, size_t len,
447     const char **prfx_ret, const char **text_ret)
448 {
449 	int type, i, cont, width;
450 	char *space, *t;
451 
452 	if ((*text_ret = vl->line) == NULL)
453 		*text_ret = "";
454 
455 	cont = vl->flags & L_CONTINUATION;
456 	type = vl->parent->type;
457 	if (!cont)
458 		*prfx_ret = line_prefixes[type].prfx1;
459 	else
460 		*prfx_ret = line_prefixes[type].prfx2;
461 
462 	space = vl->parent->data;
463 	if (!emojify_link || type != LINE_LINK || space == NULL)
464 		return;
465 
466 	if (cont) {
467 		memset(buf, 0, len);
468 		width = utf8_swidth_between(vl->parent->line, space);
469 		for (i = 0; i < width + 1; ++i)
470 			strlcat(buf, " ", len);
471 	} else {
472 		strlcpy(buf, *text_ret, len);
473 		if ((t = strchr(buf, ' ')) != NULL)
474 			*t = '\0';
475 		strlcat(buf, " ", len);
476 
477 		/* skip the emoji */
478 		*text_ret += (space - vl->parent->line) + 1;
479 	}
480 
481 	*prfx_ret = buf;
482 }
483 
484 static inline void
485 print_vline_descr(int width, WINDOW *window, struct vline *vl)
486 {
487 	int x, y, goal;
488 
489 	switch (vl->parent->type) {
490 	case LINE_COMPL:
491 	case LINE_COMPL_CURRENT:
492 		goal = width/2;
493 		break;
494 	case LINE_DOWNLOAD:
495 	case LINE_DOWNLOAD_DONE:
496 		goal = width/4;
497 		break;
498 	case LINE_HELP:
499 		goal = 8;
500 		break;
501 	default:
502 		return;
503 	}
504 
505 	if (vl->parent->alt == NULL)
506 		return;
507 
508 	(void)y;
509 	getyx(window, y, x);
510 
511 	if (goal <= x)
512 		wprintw(window, " ");
513 	for (; goal > x; ++x)
514 		wprintw(window, " ");
515 
516 	wprintw(window, "%s", vl->parent->alt);
517 }
518 
519 /*
520  * Core part of the rendering.  It prints a vline starting from the
521  * current cursor position.  Printing a vline consists of skipping
522  * `off' columns (for olivetti-mode), print the correct prefix (which
523  * may be the emoji in case of emojified links-lines), printing the
524  * text itself, filling until width - off and filling off columns
525  * again.
526  */
527 static void
528 print_vline(int off, int width, WINDOW *window, struct vline *vl)
529 {
530 	/*
531 	 * Believe me or not, I've seen emoji ten code points long!
532 	 * That means, to stay large, 4*10 bytes + NUL.
533 	 */
534 	char emojibuf[41] = {0};
535 	const char *text, *prfx;
536 	struct line_face *f;
537 	int i, left, x, y;
538 
539 	f = &line_faces[vl->parent->type];
540 
541 	/* unused, set by getyx */
542 	(void)y;
543 
544 	if (vl->parent->type == LINE_FRINGE && fringe_ignore_offset)
545 		off = 0;
546 
547 	line_prefix_and_text(vl, emojibuf, sizeof(emojibuf), &prfx, &text);
548 
549 	wattr_on(window, body_face.left, NULL);
550 	for (i = 0; i < off; i++)
551 		waddch(window, ' ');
552 	wattr_off(window, body_face.left, NULL);
553 
554 	wattr_on(window, f->prefix, NULL);
555 	wprintw(window, "%s", prfx);
556 	wattr_off(window, f->prefix, NULL);
557 
558 	wattr_on(window, f->text, NULL);
559 	wprintw(window, "%s", text);
560 	print_vline_descr(width, window, vl);
561 	wattr_off(window, f->text, NULL);
562 
563 	getyx(window, y, x);
564 
565 	left = width - x;
566 
567 	wattr_on(window, f->trail, NULL);
568 	for (i = 0; i < left - off; ++i)
569 		waddch(window, ' ');
570 	wattr_off(window, f->trail, NULL);
571 
572 	wattr_on(window, body_face.right, NULL);
573 	for (i = 0; i < off; i++)
574 		waddch(window, ' ');
575 	wattr_off(window, body_face.right, NULL);
576 
577 }
578 
579 static void
580 redraw_tabline(void)
581 {
582 	struct tab	*tab;
583 	size_t		 toskip, ots, tabwidth, space, x;
584 	int		 current, y, truncated, pair;
585 	const char	*title;
586 	char		 buf[25];
587 
588 	x = 0;
589 
590 	/* unused, but setted by a getyx */
591 	(void)y;
592 
593 	tabwidth = sizeof(buf)+1;
594 	space = COLS-2;
595 
596 	toskip = 0;
597 	TAILQ_FOREACH(tab, &tabshead, tabs) {
598 		toskip++;
599 		if (tab == current_tab)
600 			break;
601 	}
602 
603 	if (toskip * tabwidth <= space)
604 		toskip = 0;
605 	else {
606 		ots = toskip;
607 		toskip--;
608 		while (toskip != 0 &&
609 		    (ots - toskip+1) * tabwidth < space)
610 			toskip--;
611 	}
612 
613 	werase(tabline);
614 	wattr_on(tabline, tab_face.background, NULL);
615 	wprintw(tabline, toskip == 0 ? " " : "<");
616 	wattr_off(tabline, tab_face.background, NULL);
617 
618 	truncated = 0;
619 	TAILQ_FOREACH(tab, &tabshead, tabs) {
620 		if (truncated)
621 			break;
622 		if (toskip != 0) {
623 			toskip--;
624 			continue;
625 		}
626 
627 		getyx(tabline, y, x);
628 		if (x + sizeof(buf)+2 >= (size_t)COLS)
629 			truncated = 1;
630 
631 		current = tab == current_tab;
632 
633 		if (*(title = tab->buffer.page.title) == '\0')
634 			title = tab->hist_cur->h;
635 
636 		if (tab->flags & TAB_URGENT)
637 			strlcpy(buf, "!", sizeof(buf));
638 		else
639 			strlcpy(buf, " ", sizeof(buf));
640 
641 		if (strlcat(buf, title, sizeof(buf)) >= sizeof(buf)) {
642 			/* truncation happens */
643 			strlcpy(&buf[sizeof(buf)-4], "...", 4);
644 		} else {
645 			/* pad with spaces */
646 			while (strlcat(buf, "    ", sizeof(buf)) < sizeof(buf))
647 				/* nop */ ;
648 		}
649 
650 		pair = current ? tab_face.current : tab_face.tab;
651 		wattr_on(tabline, pair, NULL);
652 		wprintw(tabline, "%s", buf);
653 		wattr_off(tabline, pair, NULL);
654 
655 		wattr_on(tabline, tab_face.background, NULL);
656 		if (TAILQ_NEXT(tab, tabs) != NULL)
657 			wprintw(tabline, "┃");
658 		wattr_off(tabline, tab_face.background, NULL);
659 	}
660 
661 	wattr_on(tabline, tab_face.background, NULL);
662 	for (; x < (size_t)COLS; ++x)
663 		waddch(tabline, ' ');
664 	if (truncated)
665 		mvwprintw(tabline, 0, COLS-1, ">");
666 	wattr_off(tabline, tab_face.background, NULL);
667 }
668 
669 /*
670  * Compute the first visible line around vl.  Try to search forward
671  * until the end of the buffer; if a visible line is not found, search
672  * backward.  Return NULL if no viable line was found.
673  */
674 struct vline *
675 adjust_line(struct vline *vl, struct buffer *buffer)
676 {
677 	struct vline *t;
678 
679 	if (vl == NULL)
680 		return NULL;
681 
682 	if (!(vl->parent->flags & L_HIDDEN))
683 		return vl;
684 
685 	/* search forward */
686 	for (t = vl;
687 	     t != NULL && t->parent->flags & L_HIDDEN;
688 	     t = TAILQ_NEXT(t, vlines))
689 		;		/* nop */
690 
691 	if (t != NULL)
692 		return t;
693 
694 	/* search backward */
695 	for (t = vl;
696 	     t != NULL && t->parent->flags & L_HIDDEN;
697 	     t = TAILQ_PREV(t, vhead, vlines))
698 		;		/* nop */
699 
700 	return t;
701 }
702 
703 static void
704 redraw_window(WINDOW *win, int off, int height, int width,
705     int show_fringe, struct buffer *buffer)
706 {
707 	struct vline	*vl;
708 	int		 onscreen = 0, l = 0;
709 
710 	restore_curs_x(buffer);
711 
712 	/*
713 	 * TODO: ignoring buffer->force_update and always
714 	 * re-rendering.  In theory we can recompute the y position
715 	 * without a re-render, and optimize here.  It's not the only
716 	 * optimisation possible here, wscrl wolud also be an
717 	 * interesting one.
718 	 */
719 
720 again:
721 	werase(win);
722 	buffer->curs_y = 0;
723 
724 	if (TAILQ_EMPTY(&buffer->head))
725 		goto end;
726 
727 	if (buffer->top_line == NULL)
728 		buffer->top_line = TAILQ_FIRST(&buffer->head);
729 
730 	buffer->top_line = adjust_line(buffer->top_line, buffer);
731 	if (buffer->top_line == NULL)
732 		goto end;
733 
734 	buffer->current_line = adjust_line(buffer->current_line, buffer);
735 
736 	for (vl = buffer->top_line; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
737 		if (vl->parent->flags & L_HIDDEN)
738 			continue;
739 
740 		wmove(win, l, 0);
741 		print_vline(off, width, win, vl);
742 
743 		if (vl == buffer->current_line)
744 			onscreen = 1;
745 
746 		if (!onscreen)
747 			buffer->curs_y++;
748 
749 		l++;
750 		if (l == height)
751 			break;
752 	}
753 
754 	if (!onscreen) {
755 		for (; vl != NULL; vl = TAILQ_NEXT(vl, vlines)) {
756 			if (vl == buffer->current_line)
757 				break;
758 			if (vl->parent->flags & L_HIDDEN)
759 				continue;
760 			buffer->line_off++;
761 			buffer->top_line = TAILQ_NEXT(buffer->top_line, vlines);
762 		}
763 
764 		if (vl != NULL)
765 			goto again;
766 	}
767 
768 	buffer->last_line_off = buffer->line_off;
769 	buffer->force_redraw = 0;
770 end:
771 	for (; show_fringe && l < height; l++)
772 		print_vline(off, width, win, &fringe);
773 
774 	wmove(win, buffer->curs_y, buffer->curs_x);
775 }
776 
777 static void
778 redraw_download(void)
779 {
780 	redraw_window(download, 0, download_lines, COLS, 0, &downloadwin);
781 }
782 
783 static void
784 redraw_help(void)
785 {
786 	redraw_window(help, 0, help_lines, help_cols, 1, &helpwin);
787 }
788 
789 static void
790 redraw_body(struct tab *tab)
791 {
792 	static struct tab *last_tab;
793 
794 	if (last_tab != tab)
795 		tab->buffer.force_redraw =1;
796 	last_tab = tab;
797 
798 	redraw_window(body, x_offset, body_lines, body_cols, 1, &tab->buffer);
799 }
800 
801 static inline char
802 trust_status_char(enum trust_state ts)
803 {
804 	switch (ts) {
805 	case TS_UNKNOWN:	return '-';
806 	case TS_UNTRUSTED:	return '!';
807 	case TS_TEMP_TRUSTED:	return '!';
808 	case TS_TRUSTED:	return 'v';
809 	case TS_VERIFIED:	return 'V';
810 	default:		return 'X';
811 	}
812 }
813 
814 static void
815 redraw_modeline(struct tab *tab)
816 {
817 	struct buffer	*buffer;
818 	double		 pct;
819 	int		 x, y, max_x, max_y;
820 	const char	*mode;
821 	const char	*spin = "-\\|/";
822 
823 	buffer = current_buffer();
824 	mode = buffer->page.name;
825 
826 	werase(modeline);
827 	wattr_on(modeline, modeline_face.background, NULL);
828 	wmove(modeline, 0, 0);
829 
830 	wprintw(modeline, "-%c%c- %s ",
831 	    spin[tab->loading_anim_step],
832 	    trust_status_char(tab->trust),
833 	    mode == NULL ? "(none)" : mode);
834 
835 	pct = (buffer->line_off + buffer->curs_y) * 100.0
836 		/ buffer->line_max;
837 
838 	if (buffer->line_max <= (size_t)body_lines)
839 		wprintw(modeline, "All ");
840 	else if (buffer->line_off == 0)
841 		wprintw(modeline, "Top ");
842 	else if (buffer->line_off + body_lines >= buffer->line_max)
843 		wprintw(modeline, "Bottom ");
844 	else
845 		wprintw(modeline, "%.0f%% ", pct);
846 
847 	wprintw(modeline, "%zu/%zu %s ",
848 	    buffer->line_off + buffer->curs_y,
849 	    buffer->line_max,
850 	    tab->hist_cur->h);
851 
852 	getyx(modeline, y, x);
853 	getmaxyx(modeline, max_y, max_x);
854 
855 	(void)y;
856 	(void)max_y;
857 
858 	for (; x < max_x; ++x)
859 		waddstr(modeline, "-");
860 
861 	wattr_off(modeline, modeline_face.background, NULL);
862 }
863 
864 static void
865 redraw_minibuffer(void)
866 {
867 	wattr_on(echoarea, minibuffer_face.background, NULL);
868 	werase(echoarea);
869 
870 	if (in_minibuffer)
871 		do_redraw_minibuffer();
872 	else
873 		do_redraw_echoarea();
874 
875 	if (in_minibuffer == MB_COMPREAD)
876 		do_redraw_minibuffer_compl();
877 
878 	wattr_off(echoarea, minibuffer_face.background, NULL);
879 }
880 
881 static void
882 do_redraw_echoarea(void)
883 {
884 	struct vline *vl;
885 
886 	if (ministate.curmesg != NULL)
887 		wprintw(echoarea, "%s", ministate.curmesg);
888 	else if (*keybuf != '\0')
889 		waddstr(echoarea, keybuf);
890 	else {
891 		/* If nothing else, show the URL at point */
892 		vl = current_tab->buffer.current_line;
893 		if (vl != NULL && vl->parent->type == LINE_LINK)
894 			waddstr(echoarea, vl->parent->alt);
895 	}
896 }
897 
898 static void
899 do_redraw_minibuffer(void)
900 {
901 	struct buffer	*cmplbuf, *buffer;
902 	size_t		 off_y, off_x = 0;
903 	const char	*start, *c;
904 
905 	cmplbuf = &ministate.compl.buffer;
906 	buffer = &ministate.buffer;
907 	(void)off_y;		/* unused, set by getyx */
908 
909 	wmove(echoarea, 0, 0);
910 
911 	if (in_minibuffer == MB_COMPREAD)
912 		wprintw(echoarea, "(%2zu) ",
913 		    cmplbuf->line_max);
914 
915 	wprintw(echoarea, "%s", ministate.prompt);
916 	if (ministate.hist_cur != NULL)
917 		wprintw(echoarea, "(%zu/%zu) ",
918 		    ministate.hist_off + 1,
919 		    ministate.history->len);
920 
921 	getyx(echoarea, off_y, off_x);
922 
923 	start = ministate.hist_cur != NULL
924 		? ministate.hist_cur->h
925 		: ministate.buf;
926 	c = utf8_nth(buffer->current_line->line, buffer->cpoff);
927 	while (utf8_swidth_between(start, c) > (size_t)COLS/2) {
928 		start = utf8_next_cp(start);
929 	}
930 
931 	waddstr(echoarea, start);
932 
933 	if (ministate.curmesg != NULL)
934 		wprintw(echoarea, " [%s]", ministate.curmesg);
935 
936 	wmove(echoarea, 0, off_x + utf8_swidth_between(start, c));
937 }
938 
939 static void
940 do_redraw_minibuffer_compl(void)
941 {
942 	redraw_window(minibuffer, 0, 10, COLS, 1,
943 	    &ministate.compl.buffer);
944 }
945 
946 /*
947  * Place the cursor in the right ncurses window.  If soft is 1, use
948  * wnoutrefresh (which shouldn't cause any I/O); otherwise use
949  * wrefresh.
950  */
951 static void
952 place_cursor(int soft)
953 {
954 	int (*touch)(WINDOW *);
955 
956 	if (soft)
957 		touch = wnoutrefresh;
958 	else
959 		touch = wrefresh;
960 
961 	if (in_minibuffer) {
962 		if (side_window & SIDE_WINDOW_LEFT)
963 			touch(help);
964 		if (side_window & SIDE_WINDOW_BOTTOM)
965 			touch(download);
966 		touch(body);
967 		touch(echoarea);
968 	} else if (in_side_window & SIDE_WINDOW_LEFT) {
969 		touch(body);
970 		touch(echoarea);
971                 if (in_side_window & SIDE_WINDOW_BOTTOM)
972 			touch(download);
973 		touch(help);
974 	} else if (in_side_window & SIDE_WINDOW_BOTTOM) {
975 		touch(body);
976 		touch(echoarea);
977 		if (in_side_window & SIDE_WINDOW_LEFT)
978 			touch(help);
979 		touch(download);
980 	} else {
981 		if (side_window & SIDE_WINDOW_LEFT)
982 			touch(help);
983 		if (side_window & SIDE_WINDOW_BOTTOM)
984 			touch(download);
985 		touch(echoarea);
986 		touch(body);
987 	}
988 }
989 
990 static void
991 redraw_tab(struct tab *tab)
992 {
993 	if (too_small)
994 		return;
995 
996 	if (side_window & SIDE_WINDOW_LEFT) {
997 		redraw_help();
998 		wnoutrefresh(help);
999 	}
1000 
1001 	if (side_window & SIDE_WINDOW_BOTTOM) {
1002 		redraw_download();
1003 		wnoutrefresh(download);
1004 	}
1005 
1006 	if (show_tab_bar)
1007 		redraw_tabline();
1008 
1009 	redraw_body(tab);
1010 	redraw_modeline(tab);
1011 	redraw_minibuffer();
1012 
1013 	wnoutrefresh(tabline);
1014 	wnoutrefresh(modeline);
1015 
1016 	if (in_minibuffer == MB_COMPREAD)
1017 		wnoutrefresh(minibuffer);
1018 
1019 	place_cursor(1);
1020 
1021 	doupdate();
1022 
1023 	if (set_title)
1024 		dprintf(1, "\033]2;%s - Telescope\a",
1025 		    current_tab->buffer.page.title);
1026 }
1027 
1028 void
1029 start_loading_anim(struct tab *tab)
1030 {
1031 	if (tab->loading_anim)
1032 		return;
1033 	tab->loading_anim = 1;
1034 	evtimer_set(&tab->loadingev, update_loading_anim, tab);
1035 	evtimer_add(&tab->loadingev, &loadingev_timer);
1036 }
1037 
1038 static void
1039 update_loading_anim(int fd, short ev, void *d)
1040 {
1041 	struct tab	*tab = d;
1042 
1043 	tab->loading_anim_step = (tab->loading_anim_step+1)%4;
1044 
1045 	if (tab == current_tab) {
1046 		redraw_modeline(tab);
1047 		wrefresh(modeline);
1048 		wrefresh(body);
1049 		if (in_minibuffer)
1050 			wrefresh(echoarea);
1051 	}
1052 
1053 	evtimer_add(&tab->loadingev, &loadingev_timer);
1054 }
1055 
1056 static void
1057 stop_loading_anim(struct tab *tab)
1058 {
1059 	if (!tab->loading_anim)
1060 		return;
1061 	evtimer_del(&tab->loadingev);
1062 	tab->loading_anim = 0;
1063 	tab->loading_anim_step = 0;
1064 
1065 	if (tab != current_tab)
1066 		return;
1067 
1068 	redraw_modeline(tab);
1069 
1070 	wrefresh(modeline);
1071 	wrefresh(body);
1072 	if (in_minibuffer)
1073 		wrefresh(echoarea);
1074 }
1075 
1076 int
1077 ui_print_colors(void)
1078 {
1079 	int colors = 0, pairs = 0, can_change = 0;
1080 	int columns = 16, lines, color, i, j;
1081 
1082 	initscr();
1083 	if (has_colors()) {
1084 		start_color();
1085 		use_default_colors();
1086 
1087 		colors = COLORS;
1088 		pairs = COLOR_PAIRS;
1089 		can_change = can_change_color();
1090 	}
1091 	endwin();
1092 
1093 	printf("Term info:\n");
1094 	printf("TERM=%s COLORS=%d COLOR_PAIRS=%d can_change_colors=%d\n",
1095 	    getenv("TERM"), colors, pairs, can_change);
1096 	printf("\n");
1097 
1098 	if (colors == 0) {
1099 		printf("No color support\n");
1100 		return 0;
1101 	}
1102 
1103 	printf("Available colors:\n\n");
1104 	lines = (colors - 1) / columns + 1;
1105 	color = 0;
1106 	for (i = 0; i < lines; ++i) {
1107 		for (j = 0; j < columns; ++j, ++color) {
1108 			printf("\033[0;38;5;%dm %03d", color, color);
1109 		}
1110 		printf("\n");
1111 	}
1112 
1113 	printf("\033[0m");
1114 	fflush(stdout);
1115 	return 0;
1116 }
1117 
1118 int
1119 ui_init()
1120 {
1121 	setlocale(LC_ALL, "");
1122 
1123 	if (TAILQ_EMPTY(&global_map.m)) {
1124 		fprintf(stderr, "no keys defined!\n");
1125 		return 0;
1126 	}
1127 
1128 	minibuffer_init();
1129 
1130 	/* initialize download window */
1131 	TAILQ_INIT(&downloadwin.head);
1132 	TAILQ_INIT(&downloadwin.page.head);
1133 
1134 	/* initialize help window */
1135 	TAILQ_INIT(&helpwin.head);
1136 	TAILQ_INIT(&helpwin.page.head);
1137 
1138 	base_map = &global_map;
1139 	current_map = &global_map;
1140 
1141 	initscr();
1142 
1143 	if (enable_colors) {
1144 		if (has_colors()) {
1145 			start_color();
1146 			use_default_colors();
1147 		} else
1148 			enable_colors = 0;
1149 	}
1150 
1151 	config_apply_style();
1152 
1153 	raw();
1154 	noecho();
1155 	nonl();
1156 	intrflush(stdscr, FALSE);
1157 
1158 	if ((tabline = newwin(1, 1, 0, 0)) == NULL)
1159 		return 0;
1160 	if ((body = newwin(1, 1, 0, 0)) == NULL)
1161 		return 0;
1162 	if ((modeline = newwin(1, 1, 0, 0)) == NULL)
1163 		return 0;
1164 	if ((echoarea = newwin(1, 1, 0, 0)) == NULL)
1165 		return 0;
1166 	if ((minibuffer = newwin(1, 1, 0, 0)) == NULL)
1167 		return 0;
1168 	if ((download = newwin(1, 1, 0, 0)) == NULL)
1169 		return 0;
1170 	if ((help = newwin(1, 1, 0, 0)) == NULL)
1171 		return 0;
1172 
1173 	wbkgd(body, body_face.body);
1174 	wbkgd(download, download_face.background);
1175 	wbkgd(echoarea, minibuffer_face.background);
1176 
1177 	update_x_offset();
1178 
1179 	keypad(body, TRUE);
1180 	scrollok(body, FALSE);
1181 
1182 	/* non-blocking input */
1183 	wtimeout(body, 0);
1184 	wtimeout(help, 0);
1185 
1186 	mvwprintw(body, 0, 0, "");
1187 
1188 	return 1;
1189 }
1190 
1191 void
1192 ui_main_loop(void)
1193 {
1194 	evtimer_set(&resizeev, handle_resize, NULL);
1195 
1196 	event_set(&stdioev, 0, EV_READ | EV_PERSIST, dispatch_stdio, NULL);
1197 	event_add(&stdioev, NULL);
1198 
1199 	signal_set(&winchev, SIGWINCH, handle_resize, NULL);
1200 	signal_add(&winchev, NULL);
1201 
1202 	switch_to_tab(current_tab);
1203 	rearrange_windows();
1204 }
1205 
1206 void
1207 ui_on_tab_loaded(struct tab *tab)
1208 {
1209 	stop_loading_anim(tab);
1210 	message("Loaded %s", tab->hist_cur->h);
1211 
1212 	if (tab->hist_cur->current_off != 0 &&
1213 	    tab->buffer.current_line == TAILQ_FIRST(&tab->buffer.head)) {
1214 		set_scroll_position(tab, tab->hist_cur->line_off,
1215 		    tab->hist_cur->current_off);
1216 		redraw_tab(tab);
1217 		return;
1218 	}
1219 
1220 	if (show_tab_bar)
1221 		redraw_tabline();
1222 
1223 	wrefresh(tabline);
1224 	place_cursor(0);
1225 }
1226 
1227 void
1228 ui_on_tab_refresh(struct tab *tab)
1229 {
1230 	wrap_page(&tab->buffer, body_cols);
1231 	if (tab == current_tab)
1232 		redraw_tab(tab);
1233 	else
1234 		tab->flags |= TAB_URGENT;
1235 }
1236 
1237 void
1238 ui_on_download_refresh(void)
1239 {
1240 	if (side_window & SIDE_WINDOW_BOTTOM) {
1241 		recompute_downloads();
1242 		redraw_tab(current_tab);
1243 	}
1244 }
1245 
1246 const char *
1247 ui_keyname(int k)
1248 {
1249 	return keyname(k);
1250 }
1251 
1252 void
1253 ui_toggle_side_window(int kind)
1254 {
1255 	if (in_side_window & kind)
1256 		ui_other_window();
1257 
1258 	side_window ^= kind;
1259 	if (side_window & SIDE_WINDOW_LEFT)
1260 		recompute_help();
1261 	if (side_window & SIDE_WINDOW_BOTTOM)
1262 		recompute_downloads();
1263 
1264 	/*
1265 	 * ugly hack, but otherwise the window doesn't get updated
1266 	 * until I call rearrange_windows a second time (e.g. via
1267 	 * C-l).  I will be happy to know why something like this is
1268 	 * needed.
1269 	 */
1270 	rearrange_windows();
1271 	rearrange_windows();
1272 }
1273 
1274 void
1275 ui_show_downloads_pane(void)
1276 {
1277 	if (!(side_window & SIDE_WINDOW_BOTTOM))
1278 		ui_toggle_side_window(SIDE_WINDOW_BOTTOM);
1279 }
1280 
1281 void
1282 ui_schedule_redraw(void)
1283 {
1284 	should_rearrange_windows = 1;
1285 }
1286 
1287 void
1288 ui_require_input(struct tab *tab, int hide, int proto)
1289 {
1290 	void (*fn)(void);
1291 
1292 	if (proto == PROTO_GEMINI)
1293 		fn = ir_select_gemini;
1294 	else if (proto == PROTO_GOPHER)
1295 		fn = ir_select_gopher;
1296 	else
1297 		abort();
1298 
1299 	/* TODO: hard-switching to another tab is ugly */
1300 	switch_to_tab(tab);
1301 
1302 	enter_minibuffer(sensible_self_insert, fn, exit_minibuffer,
1303 	    &ir_history, NULL, NULL);
1304 	strlcpy(ministate.prompt, "Input required: ",
1305 	    sizeof(ministate.prompt));
1306 	redraw_tab(tab);
1307 }
1308 
1309 void
1310 ui_after_message_hook(void)
1311 {
1312 	redraw_minibuffer();
1313 	place_cursor(0);
1314 }
1315 
1316 void
1317 ui_yornp(const char *prompt, void (*fn)(int, struct tab *),
1318     struct tab *data)
1319 {
1320 	yornp(prompt, fn, data);
1321 	redraw_tab(current_tab);
1322 }
1323 
1324 void
1325 ui_read(const char *prompt, void (*fn)(const char*, struct tab *),
1326     struct tab *data, const char *input)
1327 {
1328 	minibuffer_read(prompt, fn, data);
1329 
1330 	if (input != NULL) {
1331 		strlcpy(ministate.buf, input, sizeof(ministate.buf));
1332 		cmd_move_end_of_line(&ministate.buffer);
1333 	}
1334 
1335 	redraw_tab(current_tab);
1336 }
1337 
1338 void
1339 ui_other_window(void)
1340 {
1341 	if (in_side_window & SIDE_WINDOW_LEFT &&
1342 	    side_window & SIDE_WINDOW_BOTTOM)
1343 		in_side_window = SIDE_WINDOW_BOTTOM;
1344 	else if (in_side_window)
1345 		in_side_window = 0;
1346 	else if (!in_side_window && side_window & SIDE_WINDOW_LEFT)
1347 		in_side_window = SIDE_WINDOW_LEFT;
1348 	else if (!in_side_window && side_window)
1349 		in_side_window = SIDE_WINDOW_BOTTOM;
1350 	else
1351 		message("No other window to select");
1352 }
1353 
1354 void
1355 ui_suspend(void)
1356 {
1357 	endwin();
1358 
1359 	kill(getpid(), SIGSTOP);
1360 
1361 	refresh();
1362 	clear();
1363 	rearrange_windows();
1364 }
1365 
1366 void
1367 ui_end(void)
1368 {
1369 	endwin();
1370 }