/*
 * 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 <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "defs.h"
#include "gzip.h"
#include "ustar.h"

struct _opkg_opk_ustar_header {
	unsigned char name     [100];
	unsigned char mode       [8];
	unsigned char uid        [8];
	unsigned char gid        [8];
	unsigned char size      [12];
	unsigned char mtime     [12];
	unsigned char chksum     [8];
	unsigned char typeflag   [1];
	unsigned char linkname [100];
	unsigned char magic      [6];
	unsigned char version    [2];
	unsigned char uname     [32];
	unsigned char gname     [32];
	unsigned char devmajor   [8];
	unsigned char devminor   [8];
	unsigned char prefix   [155];
	unsigned char padding   [12];
} __attribute__((__packed__));

static int
_opkg_opk_ustar_next(struct opkg_opk_gzip_state *gzip_state, const char *member,
		struct _opkg_opk_ustar_header *header, unsigned char **contents)
{
	static unsigned char  record[512];
	       int            ret;
	       char          *size_end;
	       uint32_t       size;
	       unsigned char *contents_cursor;
	       uint32_t       i;

	switch ((ret = opkg_opk_gzip_next_record(gzip_state, header))) {
		case OPKG_OPK_OK:
		case OPKG_OPK_END:
			break;
		case OPKG_OPK_ERROR:
			return OPKG_OPK_ERROR;
	}
	if (strncmp(header->magic, "ustar", strlen("ustar")) != 0) {
		return OPKG_OPK_ERROR;
	}

	size = strtol(header->size, &size_end, 10);
	if (*size_end != '\0') {
		return OPKG_OPK_ERROR;
	}
	for (i = 0; i < (size + 511) / 512; ++i) {
		switch ((ret = opkg_opk_gzip_next_record(gzip_state, record))) {
			case OPKG_OPK_OK:
			case OPKG_OPK_END:
				break;
			case OPKG_OPK_ERROR:
				return OPKG_OPK_ERROR;
		}
	}

	return ret;
}

unsigned char *
opkg_opk_ustar_read(struct opkg_opk_gzip_state *gzip_state, const char *member)
{
	struct _opkg_opk_ustar_header  header;
	int                            ret;
	unsigned char                 *contents;

	while ((ret = _opkg_opk_ustar_next(gzip_state, member,
					&header, &contents)) == OPKG_OPK_OK) {
		/* TODO: End gzip stream */
		return contents;
	}
	return NULL;
}

int
opkg_opk_ustar_list(struct opkg_opk_gzip_state *gzip_state,
		void (*member)(const char *name))
{
	struct _opkg_opk_ustar_header  header;
	int                            ret;

	while ((ret = _opkg_opk_ustar_next(gzip_state, NULL, &header, NULL)) ==
			OPKG_OPK_OK) {
		printf("%s\n", header.name);
	}
	return ret;
}