/*
 * Copyright (C) 2023  Patrick McDermott
 *
 * This file is part of opkg-opk.
 *
 * opkg-opk is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * opkg-opk is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with opkg-opk.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "defs.h"
#include "dirent.h"

static int
_opkg_opk_dirent_name_prefix(struct opkg_opk_dirent *dirent, int is_dir,
		char **name_buf, size_t *name_buf_len,
		char **pref_buf, size_t *pref_buf_len,
		size_t *name_len, size_t *pref_len)
{
	size_t   len;
	char   **buf;
	int      sep;

	len = strlen(dirent->name);
	if ((*name_len > 0 || is_dir) && *name_len + len + 1 <= *name_buf_len) {
		/* Space available in name buffer.  Not last node, or is a
		 * directory, so append separator. */
		buf = name_buf;
		*name_len += len + 1;
		sep = 1;
	} else if (*name_len == 0 && *name_len + len <= *name_buf_len) {
		/* Space available in name buffer.  Last node (first in
		 * recursion), so don't append separator. */
		buf = name_buf;
		*name_len += len;
		sep = 0;
	} else if (*pref_len > 0 && *pref_len + len + 1 <= *pref_buf_len) {
		/* Space available in prefix buffer.  Not last node, so append
		 * separator. */
		buf = pref_buf;
		*pref_len += len + 1;
		sep = 1;
	} else if (*pref_len == 0 && *pref_len + len <= *pref_buf_len) {
		/* Space available in prefix buffer.  Last node (first in
		 * recursion), so don't append separator. */
		buf = pref_buf;
		*pref_len += len;
		sep = 0;
	} else {
		/* Both buffers full. */
		return OPKG_OPK_ERROR;
	}
	if (*buf == NULL) {
		/* Caller provided a NULL buffer pointer. */
		return OPKG_OPK_ERROR;
	}

	/* Recurse. */
	if (dirent->parent != NULL &&
			_opkg_opk_dirent_name_prefix(dirent->parent, is_dir,
				name_buf, name_buf_len, pref_buf, pref_buf_len,
				name_len, pref_len) == OPKG_OPK_ERROR) {
		return OPKG_OPK_ERROR;
	}

	/* Copy node name and possibly separator suffix. */
	memcpy(*buf, dirent->name, len);
	*buf += len;
	if (sep == 1) {
		**buf = '/';
		*buf += 1;
	}

	return OPKG_OPK_OK;
}

int
opkg_opk_dirent_name_prefix(struct opkg_opk_dirent *dirent, int is_dir,
		char *name_buf, size_t name_buf_len,
		char *pref_buf, size_t pref_buf_len)
{
	size_t  name_len = 0;
	size_t  pref_len = 0;
	char   *name     = name_buf;
	char   *pref     = pref_buf;

	/* NUL bytes */
	--name_buf_len;
	--pref_buf_len;

	if (_opkg_opk_dirent_name_prefix(dirent, is_dir,
				&name_buf, &name_buf_len,
				&pref_buf, &pref_buf_len,
				&name_len, &pref_len) == OPKG_OPK_ERROR) {
		return OPKG_OPK_ERROR;
	}

	name[name_len] = '\0';
	pref[pref_len] = '\0';

	return OPKG_OPK_OK;
}