/*	$OpenBSD: help.c,v 1.37 2023/03/08 04:43:11 guenther Exp $	*/

/* This file is in the public domain. */

/*
 * Help functions for Mg 2
 */

#include <sys/queue.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>

#include "def.h"
#include "funmap.h"
#include "kbd.h"
#include "key.h"
#include "macro.h"

static int	showall(struct buffer *, KEYMAP *, char *);
static int	findbind(KEYMAP *, PF, char *, size_t);

/*
 * Read a key from the keyboard, and look it up in the keymap.
 * Display the name of the function currently bound to the key.
 */
int
desckey(int f, int n)
{
	KEYMAP	*curmap;
	PF	 funct;
	int	 c, m, i, num;
	char	*pep;
	char	 dprompt[80];

	if (inmacro)
		return (TRUE);	/* ignore inside keyboard macro */

	num = strlcpy(dprompt, "Describe key briefly: ", sizeof(dprompt));
	if (num >= sizeof(dprompt))
		num = sizeof(dprompt) - 1;
	pep = dprompt + num;
	key.k_count = 0;
	m = curbp->b_nmodes;
	curmap = curbp->b_modes[m]->p_map;
	for (;;) {
		for (;;) {
			ewprintf("%s", dprompt);
			pep[-1] = ' ';
			pep = getkeyname(pep, sizeof(dprompt) - (pep - dprompt),
			    key.k_chars[key.k_count++] = c = getkey(FALSE));
			if ((funct = doscan(curmap, c, &curmap)) != NULL)
				break;
			*pep++ = '-';
			*pep = '\0';
		}
		if (funct != rescan)
			break;
		if (ISUPPER(key.k_chars[key.k_count - 1])) {
			funct = doscan(curmap,
			    TOLOWER(key.k_chars[key.k_count - 1]), &curmap);
			if (funct == NULL) {
				*pep++ = '-';
				*pep = '\0';
				continue;
			}
			if (funct != rescan)
				break;
		}
nextmode:
		if (--m < 0)
			break;
		curmap = curbp->b_modes[m]->p_map;
		for (i = 0; i < key.k_count; i++) {
			funct = doscan(curmap, key.k_chars[i], &curmap);
			if (funct != NULL) {
				if (i == key.k_count - 1 && funct != rescan)
					goto found;
				funct = rescan;
				goto nextmode;
			}
		}
		*pep++ = '-';
		*pep = '\0';
	}
found:
	if (funct == rescan || funct == selfinsert)
		ewprintf("%k is not bound to any function");
	else if ((pep = (char *)function_name(funct)) != NULL)
		ewprintf("%k runs the command %s", pep);
	else
		ewprintf("%k is bound to an unnamed function");
	return (TRUE);
}

/*
 * This function creates a table, listing all of the command
 * keys and their current bindings, and stores the table in the
 * *help* pop-up buffer.  This lets Mg produce its own wall chart.
 */
int
wallchart(int f, int n)
{
	int		 m;
	struct buffer		*bp;

	bp = bfind("*help*", TRUE);
	if (bclear(bp) != TRUE)
		/* clear it out */
		return (FALSE);
	bp->b_flag |= BFREADONLY;
	for (m = curbp->b_nmodes; m > 0; m--) {
		if ((addlinef(bp, "Local keybindings for mode %s:",
				curbp->b_modes[m]->p_name) == FALSE) ||
		    (showall(bp, curbp->b_modes[m]->p_map, "") == FALSE) ||
		    (addline(bp, "") == FALSE))
			return (FALSE);
	}
	if ((addline(bp, "Global bindings:") == FALSE) ||
	    (showall(bp, fundamental_map, "") == FALSE))
		return (FALSE);
	return (popbuftop(bp, WNONE));
}

static int
showall(struct buffer *bp, KEYMAP *map, char *prefix)
{
	KEYMAP	*newmap;
	char	 buf[80], keybuf[16];
	PF	 fun;
	int	 c;

	if (addline(bp, "") == FALSE)
		return (FALSE);

	/* XXX - 256 ? */
	for (c = 0; c < 256; c++) {
		fun = doscan(map, c, &newmap);
		if (fun == rescan || fun == selfinsert)
			continue;
		getkeyname(buf, sizeof(buf), c);
		(void)snprintf(keybuf, sizeof(keybuf), "%s%s ", prefix, buf);
		if (fun == NULL) {
			if (showall(bp, newmap, keybuf) == FALSE)
				return (FALSE);
		} else {
			if (addlinef(bp, "%-16s%s", keybuf,
				    function_name(fun)) == FALSE)
				return (FALSE);
		}
	}
	return (TRUE);
}

int
help_help(int f, int n)
{
	KEYMAP	*kp;
	PF	 funct;

	if ((kp = name_map("help")) == NULL)
		return (FALSE);
	ewprintf("a b c: ");
	do {
		funct = doscan(kp, getkey(FALSE), NULL);
	} while (funct == NULL || funct == help_help);

	if (macrodef && macrocount < MAXMACRO)
		macro[macrocount - 1].m_funct = funct;

	return ((*funct)(f, n));
}

int
apropos_command(int f, int n)
{
	struct buffer		*bp;
	struct list		*fnames, *el;
	char		 string[32];

	if (eread("apropos: ", string, sizeof(string), EFNUL | EFNEW) == NULL)
		return (ABORT);
	/* FALSE means we got a 0 character string, which is fine */
	bp = bfind("*help*", TRUE);
	if (bclear(bp) == FALSE)
		return (FALSE);

	fnames = complete_function_list("");
	for (el = fnames; el != NULL; el = el->l_next) {
		char buf[32];

		if (strstr(el->l_name, string) == NULL)
			continue;

		buf[0] = '\0';
		findbind(fundamental_map, name_function(el->l_name),
		    buf, sizeof(buf));

		if (addlinef(bp, "%-32s%s", el->l_name,  buf) == FALSE) {
			free_file_list(fnames);
			return (FALSE);
		}
	}
	free_file_list(fnames);
	return (popbuftop(bp, WNONE));
}

static int
findbind(KEYMAP *map, PF fun, char *buf, size_t len)
{
	KEYMAP	*newmap;
	PF	 nfun;
	char	 buf2[16], keybuf[16];
	int	 c;

	/* XXX - 256 ? */
	for (c = 0; c < 256; c++) {
		nfun = doscan(map, c, &newmap);
		if (nfun == fun) {
			getkeyname(buf, len, c);
			return (TRUE);
		}
		if (nfun == NULL) {
			if (findbind(newmap, fun, buf2, sizeof(buf2)) == TRUE) {
				getkeyname(keybuf, sizeof(keybuf), c);
				(void)snprintf(buf, len, "%s %s", keybuf, buf2);
				return (TRUE);
			}
		}
	}
	return (FALSE);
}