/*
 * 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 <http://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, 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;

	len = strlen(dirent->name);
	if (*name_len + len <= *name_buf_len) {
		buf = name_buf;
		if (*buf == NULL) {
			return OPKG_OPK_ERROR;
		}
		if (**buf != '\0') {
			++len;
		}
		*name_buf_len -= len;
	} else if (*pref_len + len <= *pref_buf_len) {
		buf = pref_buf;
		if (*buf == NULL) {
			return OPKG_OPK_ERROR;
		}
		if (**buf != '\0') {
			++len;
		}
		*pref_buf_len -= len;
	} else {
		return OPKG_OPK_ERROR;
	}

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

	if (**buf != '\0') {
		**buf = '/';
		*buf += 1;
		--len;
	}
	memcpy(*buf, dirent->name, len);
	*buf += len;

	return OPKG_OPK_OK;
}

int
opkg_opk_dirent_name_prefix(struct opkg_opk_dirent *dirent, 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;

	name_buf[0] = '\0';
	pref_buf[0] = '\0';
	if (_opkg_opk_dirent_name_prefix(dirent, &name_buf, &name_buf_len,
				&pref_buf, &pref_buf_len, &name_len, &pref_len)
			== OPKG_OPK_ERROR) {
		return OPKG_OPK_ERROR;
	}
	name_buf[name_len] = '\0';
	pref_buf[pref_len] = '\0';
	return OPKG_OPK_OK;
}

int
main()
{
	struct opkg_opk_dirent foo = {
		.name   = "foo",
		.parent = NULL,
	};
	struct opkg_opk_dirent bar = {
		.name   = "bar",
		.parent = &foo,
	};
	struct opkg_opk_dirent baz = {
		.name   = "baz",
		.parent = &bar,
	};
	char  name[8];
	char  pref[5];

	if (opkg_opk_dirent_name_prefix(&baz, name, 8, pref, 5) != OPKG_OPK_OK)
	{
		puts("Error building name parts");
		return EXIT_FAILURE;
	}
	puts(name);
	puts(pref);

	return EXIT_SUCCESS;
}