/*      $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);
}