/*	$OpenBSD: filecomplete.c,v 1.13 2023/03/08 04:43:05 guenther Exp $ */
/*	$NetBSD: filecomplete.c,v 1.22 2010/12/02 04:42:46 dholland Exp $	*/

/*-
 * Copyright (c) 1997 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jaromir Dolecek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "el.h"
#include "filecomplete.h"

static const wchar_t break_chars[] = L" \t\n\"\\'`@$><=;|&{(";

/********************************/
/* completion functions */

/*
 * does tilde expansion of strings of type ``~user/foo''
 * if ``user'' isn't valid user name or ``txt'' doesn't start
 * w/ '~', returns pointer to strdup()ed copy of ``txt''
 *
 * it's the caller's responsibility to free() the returned string
 */
char *
fn_tilde_expand(const char *txt)
{
	struct passwd pwres, *pass;
	char *temp;
	size_t tempsz, len = 0;
	char pwbuf[1024];

	if (txt[0] != '~')
		return strdup(txt);

	temp = strchr(txt + 1, '/');
	if (temp == NULL) {
		temp = strdup(txt + 1);
		if (temp == NULL)
			return NULL;
	} else {
		len = temp - txt + 1;	/* text until string after slash */
		temp = malloc(len);
		if (temp == NULL)
			return NULL;
		(void)strncpy(temp, txt + 1, len - 2);
		temp[len - 2] = '\0';
	}
	if (temp[0] == 0) {
		if (getpwuid_r(getuid(), &pwres, pwbuf, sizeof(pwbuf), &pass) != 0)
			pass = NULL;
	} else {
		if (getpwnam_r(temp, &pwres, pwbuf, sizeof(pwbuf), &pass) != 0)
			pass = NULL;
	}
	free(temp);		/* value no more needed */
	if (pass == NULL)
		return strdup(txt);

	/* update pointer txt to point at string immedially following */
	/* first slash */
	txt += len;

	tempsz = strlen(pass->pw_dir) + 1 + strlen(txt) + 1;
	temp = malloc(tempsz);
	if (temp == NULL)
		return NULL;
	(void)snprintf(temp, tempsz, "%s/%s", pass->pw_dir, txt);

	return temp;
}


/*
 * return first found file name starting by the ``text'' or NULL if no
 * such file can be found
 * value of ``state'' is ignored
 *
 * it's the caller's responsibility to free the returned string
 */
char *
fn_filename_completion_function(const char *text, int state)
{
	static DIR *dir = NULL;
	static char *filename = NULL, *dirname = NULL, *dirpath = NULL;
	static size_t filename_len = 0;
	struct dirent *entry;
	char *temp;
	size_t tempsz, len;

	if (state == 0 || dir == NULL) {
		temp = strrchr(text, '/');
		if (temp) {
			size_t sz = strlen(temp + 1) + 1;
			char *nptr;
			temp++;
			nptr = realloc(filename, sz);
			if (nptr == NULL) {
				free(filename);
				filename = NULL;
				return NULL;
			}
			filename = nptr;
			(void)strlcpy(filename, temp, sz);
			len = temp - text;	/* including last slash */

			nptr = realloc(dirname, len + 1);
			if (nptr == NULL) {
				free(dirname);
				dirname = NULL;
				return NULL;
			}
			dirname = nptr;
			(void)strncpy(dirname, text, len);
			dirname[len] = '\0';
		} else {
			free(filename);
			if (*text == 0)
				filename = NULL;
			else {
				filename = strdup(text);
				if (filename == NULL)
					return NULL;
			}
			free(dirname);
			dirname = NULL;
		}

		if (dir != NULL) {
			(void)closedir(dir);
			dir = NULL;
		}

		/* support for ``~user'' syntax */

		free(dirpath);
		dirpath = NULL;
		if (dirname == NULL) {
			if ((dirname = strdup("")) == NULL)
				return NULL;
			dirpath = strdup("./");
		} else if (*dirname == '~')
			dirpath = fn_tilde_expand(dirname);
		else
			dirpath = strdup(dirname);

		if (dirpath == NULL)
			return NULL;

		dir = opendir(dirpath);
		if (!dir)
			return NULL;	/* cannot open the directory */

		/* will be used in cycle */
		filename_len = filename ? strlen(filename) : 0;
	}

	/* find the match */
	while ((entry = readdir(dir)) != NULL) {
		/* skip . and .. */
		if (entry->d_name[0] == '.' && (!entry->d_name[1]
		    || (entry->d_name[1] == '.' && !entry->d_name[2])))
			continue;
		if (filename_len == 0)
			break;
		/* otherwise, get first entry where first */
		/* filename_len characters are equal	  */
		if (entry->d_name[0] == filename[0]
#if HAVE_STRUCT_DIRENT_D_NAMLEN
		    && entry->d_namlen >= filename_len
#else
		    && strlen(entry->d_name) >= filename_len
#endif
		    && strncmp(entry->d_name, filename,
			filename_len) == 0)
			break;
	}

	if (entry) {		/* match found */

#if HAVE_STRUCT_DIRENT_D_NAMLEN
		len = entry->d_namlen;
#else
		len = strlen(entry->d_name);
#endif

		tempsz = strlen(dirname) + len + 1;
		temp = malloc(tempsz);
		if (temp == NULL)
			return NULL;
		(void)snprintf(temp, tempsz, "%s%s", dirname, entry->d_name);
	} else {
		(void)closedir(dir);
		dir = NULL;
		temp = NULL;
	}

	return temp;
}


static const char *
append_char_function(const char *name)
{
	struct stat stbuf;
	char *expname = *name == '~' ? fn_tilde_expand(name) : NULL;
	const char *rs = " ";

	if (stat(expname ? expname : name, &stbuf) == -1)
		goto out;
	if (S_ISDIR(stbuf.st_mode))
		rs = "/";
out:
	if (expname)
		free(expname);
	return rs;
}
/*
 * returns list of completions for text given
 * non-static for readline.
 */
char ** completion_matches(const char *, char *(*)(const char *, int));
char **
completion_matches(const char *text, char *(*genfunc)(const char *, int))
{
	char **match_list = NULL, *retstr, *prevstr;
	size_t match_list_len, max_equal, which, i;
	size_t matches;

	matches = 0;
	match_list_len = 1;
	while ((retstr = (*genfunc) (text, (int)matches)) != NULL) {
		/* allow for list terminator here */
		if (matches + 3 >= match_list_len) {
			char **nmatch_list;
			while (matches + 3 >= match_list_len)
				match_list_len <<= 1;
			nmatch_list = reallocarray(match_list,
			    match_list_len, sizeof(char *));
			if (nmatch_list == NULL) {
				free(match_list);
				return NULL;
			}
			match_list = nmatch_list;

		}
		match_list[++matches] = retstr;
	}

	if (!match_list)
		return NULL;	/* nothing found */

	/* find least denominator and insert it to match_list[0] */
	which = 2;
	prevstr = match_list[1];
	max_equal = strlen(prevstr);
	for (; which <= matches; which++) {
		for (i = 0; i < max_equal &&
		    prevstr[i] == match_list[which][i]; i++)
			continue;
		max_equal = i;
	}

	retstr = malloc(max_equal + 1);
	if (retstr == NULL) {
		free(match_list);
		return NULL;
	}
	(void)strncpy(retstr, match_list[1], max_equal);
	retstr[max_equal] = '\0';
	match_list[0] = retstr;

	/* add NULL as last pointer to the array */
	match_list[matches + 1] = NULL;

	return match_list;
}

/*
 * Sort function for qsort(). Just wrapper around strcasecmp().
 */
static int
_fn_qsort_string_compare(const void *i1, const void *i2)
{
	const char *s1 = ((const char * const *)i1)[0];
	const char *s2 = ((const char * const *)i2)[0];

	return strcasecmp(s1, s2);
}

/*
 * Display list of strings in columnar format on readline's output stream.
 * 'matches' is list of strings, 'num' is number of strings in 'matches',
 * 'width' is maximum length of string in 'matches'.
 *
 * matches[0] is not one of the match strings, but it is counted in
 * num, so the strings are matches[1] *through* matches[num-1].
 */
void
fn_display_match_list (EditLine *el, char **matches, size_t num, size_t width)
{
	size_t line, lines, col, cols, thisguy;
	int screenwidth = el->el_terminal.t_size.h;

	/* Ignore matches[0]. Avoid 1-based array logic below. */
	matches++;
	num--;

	/*
	 * Find out how many entries can be put on one line; count
	 * with one space between strings the same way it's printed.
	 */
	cols = screenwidth / (width + 1);
	if (cols == 0)
		cols = 1;

	/* how many lines of output, rounded up */
	lines = (num + cols - 1) / cols;

	/* Sort the items. */
	qsort(matches, num, sizeof(char *), _fn_qsort_string_compare);

	/*
	 * On the ith line print elements i, i+lines, i+lines*2, etc.
	 */
	for (line = 0; line < lines; line++) {
		for (col = 0; col < cols; col++) {
			thisguy = line + col * lines;
			if (thisguy >= num)
				break;
			(void)fprintf(el->el_outfile, "%s%-*s",
			    col == 0 ? "" : " ", (int)width, matches[thisguy]);
		}
		(void)fprintf(el->el_outfile, "\n");
	}
}

/*
 * Complete the word at or before point,
 * 'what_to_do' says what to do with the completion.
 * \t   means do standard completion.
 * `?' means list the possible completions.
 * `*' means insert all of the possible completions.
 * `!' means to do standard completion, and list all possible completions if
 * there is more than one.
 *
 * Note: '*' support is not implemented
 *       '!' could never be invoked
 */
int
fn_complete(EditLine *el,
	char *(*complet_func)(const char *, int),
	char **(*attempted_completion_function)(const char *, int, int),
	const wchar_t *word_break, const wchar_t *special_prefixes,
	const char *(*app_func)(const char *), size_t query_items,
	int *completion_type, int *over, int *point, int *end)
{
	const LineInfoW *li;
	wchar_t *temp;
        char **matches;
	const wchar_t *ctemp;
	size_t len;
	int what_to_do = '\t';
	int retval = CC_NORM;

	if (el->el_state.lastcmd == el->el_state.thiscmd)
		what_to_do = '?';

	/* readline's rl_complete() has to be told what we did... */
	if (completion_type != NULL)
		*completion_type = what_to_do;

	if (!complet_func)
		complet_func = fn_filename_completion_function;
	if (!app_func)
		app_func = append_char_function;

	/* We now look backwards for the start of a filename/variable word */
	li = el_wline(el);
	ctemp = li->cursor;
	while (ctemp > li->buffer
	    && !wcschr(word_break, ctemp[-1])
	    && (!special_prefixes || !wcschr(special_prefixes, ctemp[-1]) ) )
		ctemp--;

	len = li->cursor - ctemp;
	temp = reallocarray(NULL, len + 1, sizeof(*temp));
	(void)wcsncpy(temp, ctemp, len);
	temp[len] = '\0';

	/* these can be used by function called in completion_matches() */
	/* or (*attempted_completion_function)() */
	if (point != NULL)
		*point = (int)(li->cursor - li->buffer);
	if (end != NULL)
		*end = (int)(li->lastchar - li->buffer);

	if (attempted_completion_function) {
		int cur_off = (int)(li->cursor - li->buffer);
		matches = (*attempted_completion_function) (
		    ct_encode_string(temp, &el->el_scratch),
		    (int)(cur_off - len), cur_off);
	} else
		matches = NULL;
	if (!attempted_completion_function ||
	    (over != NULL && !*over && !matches))
		matches = completion_matches(
		    ct_encode_string(temp, &el->el_scratch), complet_func);

	if (over != NULL)
		*over = 0;

	if (matches) {
		int i;
		size_t matches_num, maxlen, match_len, match_display=1;

		retval = CC_REFRESH;
		/*
		 * Only replace the completed string with common part of
		 * possible matches if there is possible completion.
		 */
		if (matches[0][0] != '\0') {
			el_deletestr(el, (int) len);
			el_winsertstr(el,
			    ct_decode_string(matches[0], &el->el_scratch));
		}

		if (what_to_do == '?')
			goto display_matches;

		if (matches[2] == NULL && strcmp(matches[0], matches[1]) == 0) {
			/*
			 * We found exact match. Add a space after
			 * it, unless we do filename completion and the
			 * object is a directory.
			 */
			el_winsertstr(el,
			    ct_decode_string((*app_func)(matches[0]),
			    &el->el_scratch));
		} else if (what_to_do == '!') {
    display_matches:
			/*
			 * More than one match and requested to list possible
			 * matches.
			 */

			for(i = 1, maxlen = 0; matches[i]; i++) {
				match_len = strlen(matches[i]);
				if (match_len > maxlen)
					maxlen = match_len;
			}
			/* matches[1] through matches[i-1] are available */
			matches_num = i - 1;

			/* newline to get on next line from command line */
			(void)fprintf(el->el_outfile, "\n");

			/*
			 * If there are too many items, ask user for display
			 * confirmation.
			 */
			if (matches_num > query_items) {
				(void)fprintf(el->el_outfile,
				    "Display all %zu possibilities? (y or n) ",
				    matches_num);
				(void)fflush(el->el_outfile);
				if (getc(stdin) != 'y')
					match_display = 0;
				(void)fprintf(el->el_outfile, "\n");
			}

			if (match_display) {
				/*
				 * Interface of this function requires the
				 * strings be matches[1..num-1] for compat.
				 * We have matches_num strings not counting
				 * the prefix in matches[0], so we need to
				 * add 1 to matches_num for the call.
				 */
				fn_display_match_list(el, matches,
				    matches_num+1, maxlen);
			}
			retval = CC_REDISPLAY;
		} else if (matches[0][0]) {
			/*
			 * There was some common match, but the name was
			 * not complete enough. Next tab will print possible
			 * completions.
			 */
			el_beep(el);
		} else {
			/* lcd is not a valid object - further specification */
			/* is needed */
			el_beep(el);
			retval = CC_NORM;
		}

		/* free elements of array and the array itself */
		for (i = 0; matches[i]; i++)
			free(matches[i]);
		free(matches);
		matches = NULL;
	}
	free(temp);
	return retval;
}

/*
 * el-compatible wrapper around rl_complete; needed for key binding
 */
unsigned char
_el_fn_complete(EditLine *el, int ch __attribute__((__unused__)))
{
	return (unsigned char)fn_complete(el, NULL, NULL,
	    break_chars, NULL, NULL, 100,
	    NULL, NULL, NULL, NULL);
}