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

#define OPKG_OPK_MAIN_FILE_BUFFER_SIZE_ 8192

struct _opkg_opk_main_file {
	FILE *file;
	char  buffer[OPKG_OPK_MAIN_FILE_BUFFER_SIZE_];
};

static int
_opkg_opk_main_file_read(void *user_data, char **buffer, size_t *size)
{
	struct _opkg_opk_main_file *file = user_data;

	*buffer = file->buffer;
	*size   = fread(file->buffer, 1, OPKG_OPK_MAIN_FILE_BUFFER_SIZE_,
			file->file);
	if (feof(file->file)) {
		return OPKG_OPK_END;
	} else if (ferror(file->file) || *size == 0) {
		return OPKG_OPK_ERROR;
	} else {
		return OPKG_OPK_OK;
	}
}

static int
_opkg_opk_main_extract(const char *file_name, const char *outer_member,
		int (*inner_action)(struct opkg_opk_ustar *))
{
	struct _opkg_opk_main_file    file;
	struct opkg_opk_gzip         *outer_gzip;
	struct opkg_opk_ustar        *outer_ustar;
	char                         *buffer;
	size_t                        size;
	struct opkg_opk_gzip         *inner_gzip;
	struct opkg_opk_ustar        *inner_ustar;

	/* Open outer archive. */
	file.file = fopen(file_name, "rb");
	if (file.file == NULL) {
		fprintf(stderr, "Error: Failed to open file \"%s\"\n",
				file_name);
		goto error0;
	}

	/* Initialize outer gzip decompressor. */
	outer_gzip = opkg_opk_gzip_init(&_opkg_opk_main_file_read, &file);
	if (outer_gzip == NULL) {
		fputs("Error: Failed to initialize\n", stderr);
		goto error1;
	}

	/* Initialize outer ustar unarchiver. */
	outer_ustar = opkg_opk_ustar_init(outer_gzip);
	if (outer_ustar == NULL) {
		fputs("Error: Failed to initialize\n", stderr);
		goto error2;
	}

	/* Check package version. */
	if (opkg_opk_ustar_seek(outer_ustar, 1, "debian-binary") !=
			OPKG_OPK_OK) {
		fputs("Error: Failed to find \"debian-binary\" in archive\n",
				stderr);
		goto error3;
	}
	if (opkg_opk_ustar_read(outer_ustar, &buffer, &size) != OPKG_OPK_OK) {
		fputs("Error: Failed to read \"debian-binary\" in archive\n",
				stderr);
		goto error3;
	}
	if (size < 4 || strncmp(buffer, "2.", 2) != 0) {
		fputs("Error: Unsupported package version\n", stderr);
		goto error3;
	}

	/* Find requested inner archive. */
	if (opkg_opk_ustar_seek(outer_ustar, 1, outer_member) != OPKG_OPK_OK) {
		fprintf(stderr, "Error: Failed to find \"%s\" in archive\n",
				outer_member);
		goto error3;
	}

	/* Initialize inner gzip decompressor. */
	inner_gzip = opkg_opk_gzip_init(
			(opkg_opk_gzip_read_func *) &opkg_opk_ustar_read,
			outer_ustar);
	if (inner_gzip == NULL) {
		fputs("Error: Failed to initialize\n", stderr);
		goto error3;
	}

	/* Initialize inner ustar unarchiver. */
	inner_ustar = opkg_opk_ustar_init(inner_gzip);
	if (inner_ustar == NULL) {
		fputs("Error: Failed to initialize\n", stderr);
		goto error4;
	}

	/* Read control file or list data files. */
	if (inner_action(inner_ustar) != OPKG_OPK_OK) {
		goto error5;
	}

	opkg_opk_ustar_free(inner_ustar);
	opkg_opk_gzip_free(inner_gzip);
	opkg_opk_ustar_free(outer_ustar);
	opkg_opk_gzip_free(outer_gzip);
	fclose(file.file);
	return OPKG_OPK_OK;

 error5:
	opkg_opk_ustar_free(inner_ustar);
 error4:
	opkg_opk_gzip_free(inner_gzip);
 error3:
	opkg_opk_ustar_free(outer_ustar);
 error2:
	opkg_opk_gzip_free(outer_gzip);
 error1:
	fclose(file.file);
 error0:
	return OPKG_OPK_ERROR;
}

static int
_opkg_opk_main_read_control(struct opkg_opk_ustar *ustar)
{
	char   *buffer;
	size_t  size;
	int     ret;

	if (opkg_opk_ustar_seek(ustar, 2, "control", "./control") !=
			OPKG_OPK_OK) {
		fputs("Error: Failed to find control file\n", stderr);
		return OPKG_OPK_ERROR;
	}
	while ((ret = opkg_opk_ustar_read(ustar, &buffer, &size)) ==
			OPKG_OPK_OK) {
		fwrite(buffer, 1, size, stdout);
	}
	if (ret == OPKG_OPK_ERROR) {
		fputs("Error: Failed to read control file\n", stderr);
		return OPKG_OPK_ERROR;
	}

	return OPKG_OPK_OK;
}

static int
_opkg_opk_main_list_members(struct opkg_opk_ustar *ustar)
{
	struct opkg_opk_ustar_member *head;
	struct opkg_opk_ustar_member *tail;
	struct opkg_opk_ustar_member *member;
	int                           ret;
	size_t                        uname_len;
	size_t                        uname_len_max;
	size_t                        gname_len;
	size_t                        gname_len_max;
	uint64_t                      size_max;
	char                          fmt[29];
	                              /* "%c%s %-32s/%-32s %11d %s %s\n" */
	char                          mode[10];
	char                          mtime[20];

	/* Build singly-linked list and find maximum column widths. */
	head = NULL;
	uname_len_max = 0;
	gname_len_max = 0;
	size_max      = 0;
	while ((ret = opkg_opk_ustar_list(ustar, &member)) == OPKG_OPK_OK) {
		if (head == NULL) {
			head = member;
		} else {
			tail->next = member;
		}
		tail = member;
		uname_len = strlen(member->uname);
		if (uname_len > uname_len_max) {
			uname_len_max = uname_len;
		}
		gname_len = strlen(member->gname);
		if (gname_len > gname_len_max) {
			gname_len_max = gname_len;
		}
		if (member->size > size_max) {
			size_max = member->size;
		}
	}
	if (ret == OPKG_OPK_ERROR) {
		fputs("Error: Failed to list data files\n", stderr);
		return OPKG_OPK_ERROR;
	}
	tail->next = NULL;

	/* Print and free members. */
	snprintf(fmt, sizeof(fmt), "%%c%%s %%-%zus/%%-%zus %%%lid %%s %%s\n",
			uname_len, gname_len, lrint(ceil(log10(size_max))));
	for (member = head; member != NULL;) {
		if (member->mode & 00400) mode[0] = 'r'; else mode[0] = '-';
		if (member->mode & 00200) mode[1] = 'w'; else mode[1] = '-';
		if (member->mode & 00100) mode[2] = 'x'; else mode[2] = '-';
		if (member->mode & 04000) mode[2] = 's';
		if (member->mode & 00040) mode[3] = 'r'; else mode[3] = '-';
		if (member->mode & 00020) mode[4] = 'w'; else mode[4] = '-';
		if (member->mode & 00010) mode[5] = 'x'; else mode[5] = '-';
		if (member->mode & 02000) mode[5] = 's';
		if (member->mode & 00004) mode[6] = 'r'; else mode[6] = '-';
		if (member->mode & 00002) mode[7] = 'w'; else mode[7] = '-';
		if (member->mode & 00001) mode[8] = 'x'; else mode[8] = '-';
		if (member->mode & 01000) mode[8] = 't';
		mode[9] = '\0';
		strftime(mtime, sizeof(mtime), "%Y-%m-%d %H:%M:%S",
				localtime(&member->mtime));
		printf(fmt,
				member->type, mode,
				member->uname, member->gname,
				member->size, mtime, member->name);
		head   = member;
		member = member->next;
		free(head);
	}

	return OPKG_OPK_OK;
}

int
main(int argc, char *argv[])
{
	if (_opkg_opk_main_extract(argv[1], "control.tar.gz",
			&_opkg_opk_main_read_control) != OPKG_OPK_OK) {
		return EXIT_FAILURE;
	}
	puts("");
	if (_opkg_opk_main_extract(argv[1], "data.tar.gz",
			&_opkg_opk_main_list_members) != OPKG_OPK_OK) {
		return EXIT_FAILURE;
	}

	return EXIT_SUCCESS;
}