/*
 * Copyright (C) 2023  Patrick McDermott
 *
 * This file is part of opkg-opkg.
 *
 * opkg-opkg 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-opkg 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-opkg.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <time.h>
#include "defs.h"
#include "gzip.h"
#include "i18n.h"
#include "opk.h"
#include "ustar.h"

struct _opkg_opk_opk_seek_name {
	const char                     *name;
	struct _opkg_opk_opk_seek_name *prev;
	struct _opkg_opk_opk_seek_name *next;
};

struct opkg_opk_opk {
	struct _opkg_opk_opk_seek_name *print_control_head;
	struct _opkg_opk_opk_seek_name *print_control_tail;
	struct _opkg_opk_opk_seek_name *print_data_head;
	struct _opkg_opk_opk_seek_name *print_data_tail;
	int                             list_control;
	int                             list_data;
	const char                     *control_dir;
	FILE                           *file;
	char                            file_buffer[8192];
	struct opkg_opk_gzip           *outer_gzip;
	struct opkg_opk_ustar          *outer_ustar;
	struct opkg_opk_gzip           *inner_gzip;
	struct opkg_opk_ustar          *inner_ustar;
	int                             previously_printed;
};

struct opkg_opk_opk *
opkg_opk_opk_init(void)
{
	struct opkg_opk_opk *opk;

	opk = malloc(sizeof(*opk));
	if (opk == NULL) {
		return NULL;
	}

	opk->print_control_head = NULL;
	opk->print_control_tail = NULL;
	opk->print_data_head    = NULL;
	opk->print_data_tail    = NULL;
	opk->list_control       = 0;
	opk->list_data          = 0;
	opk->control_dir        = NULL;
	opk->previously_printed = 0;

	return opk;
}

static int
_opkg_opk_opk_add_seek_name(struct _opkg_opk_opk_seek_name **head,
		struct _opkg_opk_opk_seek_name **tail, const char *name)
{
	struct _opkg_opk_opk_seek_name *new;

	new = malloc(sizeof(*new));
	if (new == NULL) {
		return OPKG_OPK_ERROR;
	}
	if (name[0] == '.' && name[1] == '/') {
		new->name = name + 2;
	} else {
		new->name = name;
	}

	new->prev = *tail;
	new->next = NULL;

	if (*head == NULL) {
		*head = new;
	} else {
		(*tail)->next = new;
	}
	*tail = new;

	return OPKG_OPK_OK;
}

int
opkg_opk_opk_print_control(struct opkg_opk_opk *opk, const char *name)
{
	return _opkg_opk_opk_add_seek_name(&opk->print_control_head,
			&opk->print_control_tail, name);
}

int
opkg_opk_opk_print_data(struct opkg_opk_opk *opk, const char *name)
{
	return _opkg_opk_opk_add_seek_name(&opk->print_data_head,
			&opk->print_data_tail, name);
}

int
opkg_opk_opk_list_control(struct opkg_opk_opk *opk)
{
	opk->list_control = 1;
	return OPKG_OPK_OK;
}

int
opkg_opk_opk_list_data(struct opkg_opk_opk *opk)
{
	opk->list_data = 1;
	return OPKG_OPK_OK;
}

int
opkg_opk_opk_control_dir(struct opkg_opk_opk *opk, const char *dir)
{
	opk->control_dir = dir;
	return OPKG_OPK_OK;
}

static int
_opkg_opk_opk_file_read(void *user_data, char **buffer, size_t *size)
{
	struct opkg_opk_opk *opk = user_data;

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

static int
_opkg_opk_opk_init_inner(struct opkg_opk_opk *opk)
{
	/* Initialize inner gzip decompressor. */
	opk->inner_gzip = opkg_opk_gzip_init_read(
			(opkg_opk_gzip_read_func *) &opkg_opk_ustar_read,
			opk->outer_ustar);
	if (opk->inner_gzip == NULL) {
		fputs(_("Error: Failed to initialize\n"), stderr);
		return OPKG_OPK_ERROR;
	}

	/* Initialize inner ustar unarchiver. */
	opk->inner_ustar = opkg_opk_ustar_init(opk->inner_gzip);
	if (opk->inner_ustar == NULL) {
		fputs(_("Error: Failed to initialize\n"), stderr);
		opkg_opk_gzip_free(opk->inner_gzip);
		return OPKG_OPK_ERROR;
	}

	return OPKG_OPK_OK;
}

static void
_opkg_opk_opk_free_inner(struct opkg_opk_opk *opk)
{
	opkg_opk_ustar_free(opk->inner_ustar);
	opkg_opk_gzip_free(opk->inner_gzip);
}

static int
_opkg_opk_opk_check_name(const char *member_name,
		struct _opkg_opk_opk_seek_name **head,
		struct _opkg_opk_opk_seek_name **tail)
{
	struct _opkg_opk_opk_seek_name *seek_name;

	if (member_name[0] == '.' && member_name[1] == '/') {
		member_name += 2;
	}

	/* Check each requested name. */
	for (seek_name = *head; seek_name != NULL; seek_name = seek_name->next)
	{
		if (strcmp(member_name, seek_name->name) == 0) {
			if (seek_name->prev != NULL) {
				seek_name->prev->next = seek_name->next;
			} else {
				/* This was the head.  Update. */
				*head = seek_name->next;
			}
			if (seek_name->next != NULL) {
				seek_name->next->prev = seek_name->prev;
			} else {
				/* This was the tail.  Update. */
				*tail = seek_name->prev;
			}
			free(seek_name);
			return OPKG_OPK_OK;
		}
	}

	return OPKG_OPK_ERROR;  /* Member not found */
}

static int
_opkg_opk_opk_read_control(struct opkg_opk_opk *opk)
{
	struct stat                     stat_buf;
	char                           *path;
	struct opkg_opk_ustar_member   *member;
	int                             ret_list;
	FILE                           *fp;
	int                             print;
	int                             ret_read;
	char                           *buffer;
	size_t                          size;
	struct _opkg_opk_opk_seek_name *seek_name;

	if (opk->control_dir != NULL) {
		if (stat(opk->control_dir, &stat_buf) == 0) {
			if (!S_ISDIR(stat_buf.st_mode)) {
				fputs(_("Error: Cannot create control directory"
							"\n"), stderr);
				return OPKG_OPK_ERROR;
			}
		} else if (mkdir(opk->control_dir, 0755) != 0) {
			fputs(_("Error: Cannot create control directory"
						"\n"), stderr);
			return OPKG_OPK_ERROR;
		}
		path = malloc(strlen(opk->control_dir) +
				OPKG_OPK_USTAR_NAME_SIZE + 1);
		if (path == NULL) {
			return OPKG_OPK_ERROR;
		}
	} else if (opk->list_control == 0 && opk->print_control_head == NULL) {
		/* Not listing or printing any control files. */
		return OPKG_OPK_OK;
	}

	if (_opkg_opk_opk_init_inner(opk) != OPKG_OPK_OK) {
		if (opk->control_dir != NULL) {
			free(path);
		}
		return OPKG_OPK_ERROR;
	}

	while ((ret_list = opkg_opk_ustar_list(opk->inner_ustar, &member)) ==
			OPKG_OPK_OK) {
		/* Remove leading "./" if present and skip if nothing's left. */
		buffer = member->name;
		if (buffer[0] == '.' && buffer[1] == '/') {
			buffer += 2;
		}
		if (buffer[0] == '\0') {
			free(member);
			continue;
		}

		/* Open file for extraction. */
		if (opk->control_dir != NULL) {
			if (sprintf(path, "%s/%s", opk->control_dir,
						member->name) <= 0) {
				free(member);
				_opkg_opk_opk_free_inner(opk);
				free(path);
				return OPKG_OPK_ERROR;
			}
			fp = fopen(path, "wb");
			if (fp == NULL) {
				fputs(_("Error: Failed to extract control file"
							"\n"), stderr);
				free(member);
				_opkg_opk_opk_free_inner(opk);
				free(path);
				return OPKG_OPK_ERROR;
			}
		}

		if (opk->list_control > 0) {
			puts(buffer);
			opk->previously_printed = 1;
		}

		if (opk->print_control_head != NULL &&
				_opkg_opk_opk_check_name(member->name,
					&opk->print_control_head,
					&opk->print_control_tail) ==
				OPKG_OPK_OK) {
			/* Name requested for printing. */
			print = 1;
		} else {
			print = 0;
		}
		free(member);
		if (print == 1 && opk->previously_printed == 1) {
			puts("");
		}
		while ((ret_read = opkg_opk_ustar_read(opk->inner_ustar,
						&buffer, &size)) == OPKG_OPK_OK)
		{
			if (print == 1 && fwrite(buffer, 1, size, stdout) !=
					size) {
				fputs(_("Error: Failed to print control file\n")
						, stderr);
				_opkg_opk_opk_free_inner(opk);
				if (opk->control_dir != NULL) {
					free(path);
				}
				return OPKG_OPK_ERROR;
			}
			if (opk->control_dir != NULL && fwrite(buffer, 1, size,
						fp) != size) {
				fputs(_("Error: Failed to write control file\n")
						, stderr);
				_opkg_opk_opk_free_inner(opk);
				free(path);
				return OPKG_OPK_ERROR;
			}
		}
		if (ret_read == OPKG_OPK_ERROR) {
			fputs(_("Error: Failed to read control file\n"),
					stderr);
			_opkg_opk_opk_free_inner(opk);
			if (opk->control_dir != NULL) {
				free(path);
			}
			return OPKG_OPK_ERROR;
		}
		opk->previously_printed = 1;

		/* Close file for extraction. */
		if (opk->control_dir != NULL) {
			if (fclose(fp) != 0) {
				_opkg_opk_opk_free_inner(opk);
				free(path);
				return OPKG_OPK_ERROR;
			}
		}
	}
	if (opk->control_dir != NULL) {
		/* Done with path buffer. */
		free(path);
	}
	if (ret_list == OPKG_OPK_ERROR) {
		fputs(_("Error: Failed to list control files\n"), stderr);
		_opkg_opk_opk_free_inner(opk);
		return OPKG_OPK_ERROR;
	}

	/* Check for files not found. */
	if (opk->print_control_head != NULL) {
		for (seek_name = opk->print_control_head; seek_name != NULL;
				seek_name = seek_name->next) {
			fprintf(stderr, _("Error: Failed to find control file "
						"\"%s\"\n"), seek_name->name);
		}
		_opkg_opk_opk_free_inner(opk);
		return OPKG_OPK_ERROR;
	}

	_opkg_opk_opk_free_inner(opk);

	return OPKG_OPK_OK;
}

static int
_opkg_opk_opk_read_data(struct opkg_opk_opk *opk)
{
	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;
	int                           ret_read;
	char                         *buffer;
	size_t                        size;
	long int                      size_len_max;
	char                          fmt[28];
	                              /* "%c%s %-32s/%-32s %11d %s %s" */
	size_t                        len;
	char                          mode[10];
	char                          mtime[20];

	if (opk->list_data == 0 && opk->print_data_head == NULL) {
		/* Not listing or printing any data files. */
		return OPKG_OPK_OK;
	}

	if (_opkg_opk_opk_init_inner(opk) != OPKG_OPK_OK) {
		return OPKG_OPK_ERROR;
	}

	/* Build singly-linked list and find maximum column widths. */
	head = NULL;
	tail = NULL;
	uname_len_max = 0;
	gname_len_max = 0;
	size_max      = 0;
	while ((ret = opkg_opk_ustar_list(opk->inner_ustar, &member)) ==
			OPKG_OPK_OK) {
		/* If listing, link members and update max column widths. */
		if (opk->list_data > 0) {
			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 (opk->print_data_head == NULL) {
			if (opk->list_data == 0) {
				free(member);
			}
			continue;
		}
		if (_opkg_opk_opk_check_name(member->name,
					&opk->print_data_head,
					&opk->print_data_tail) !=
				OPKG_OPK_OK) {
			/* Name not requested for printing. */
			if (opk->list_data == 0) {
				free(member);
			}
			continue;
		}
		if (opk->list_data == 0) {
			free(member);
		}
		if (opk->previously_printed == 1) {
			puts("");
		}
		while ((ret_read = opkg_opk_ustar_read(opk->inner_ustar,
						&buffer, &size)) == OPKG_OPK_OK)
		{
			if (fwrite(buffer, 1, size, stdout) != size) {
				fputs(_("Error: Failed to print data file\n")
						, stderr);
				_opkg_opk_opk_free_inner(opk);
				return OPKG_OPK_ERROR;
			}
		}
		if (ret_read == OPKG_OPK_ERROR) {
			fputs(_("Error: Failed to read data file\n"),
					stderr);
			_opkg_opk_opk_free_inner(opk);
			return OPKG_OPK_ERROR;
		}
		opk->previously_printed = 1;
	}
	if (ret == OPKG_OPK_ERROR) {
		fputs(_("Error: Failed to list data files\n"), stderr);
		_opkg_opk_opk_free_inner(opk);
		return OPKG_OPK_ERROR;
	}
	if (tail != NULL) {
		tail->next = NULL;
	}

	if (opk->list_data == 0) {
		_opkg_opk_opk_free_inner(opk);
		return OPKG_OPK_OK;
	}

	/* Print and free members. */
	if (opk->previously_printed == 1) {
		puts("");
	}
	ret = OPKG_OPK_OK;
	size_len_max = lrint(ceil(log10(size_max)));
	snprintf(fmt, sizeof(fmt), "%%c%%s %%-%zus/%%-%zus %%%lid %%s %%s",
			uname_len_max, gname_len_max, size_len_max);
	len = 34 + uname_len_max + gname_len_max + size_len_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));
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wformat-nonliteral"
		if (printf(fmt, member->type, mode,
				member->uname, member->gname,
				member->size, mtime, member->name) !=
				(int) (len + strlen(member->name))) {
			ret = OPKG_OPK_ERROR;
		}
#pragma GCC diagnostic pop
		if (member->type == 'l' && printf(" -> %s", member->linkname) !=
				(int) (strlen(member->linkname) + 4)) {
			ret = OPKG_OPK_ERROR;
		}
		if (puts("") == EOF) {
			ret = OPKG_OPK_ERROR;
		}
		head   = member;
		member = member->next;
		free(head);
	}

	opk->previously_printed = 1;

	_opkg_opk_opk_free_inner(opk);

	return ret;
}

int
opkg_opk_opk_read(struct opkg_opk_opk *opk, const char *file_name)
{
	int                           ret;
	struct opkg_opk_ustar_member *member;
	char                         *version_buffer;
	size_t                        version_size;

	ret = OPKG_OPK_OK;

	/* Open outer archive. */
	opk->file = fopen(file_name, "rb");
	if (opk->file == NULL) {
		fprintf(stderr, _("Error: Failed to open file \"%s\"\n"),
				file_name);
		ret = OPKG_OPK_ERROR;
		goto out0;
	}

	/* Initialize outer gzip decompressor. */
	opk->outer_gzip = opkg_opk_gzip_init_read(&_opkg_opk_opk_file_read,
			opk);
	if (opk->outer_gzip == NULL) {
		fputs(_("Error: Failed to initialize\n"), stderr);
		ret = OPKG_OPK_ERROR;
		goto out1;
	}

	/* Initialize outer ustar unarchiver. */
	opk->outer_ustar = opkg_opk_ustar_init(opk->outer_gzip);
	if (opk->outer_ustar == NULL) {
		fputs(_("Error: Failed to initialize\n"), stderr);
		ret = OPKG_OPK_ERROR;
		goto out2;
	}

	/* Check package version. */
	if (opkg_opk_ustar_list(opk->outer_ustar, &member) != OPKG_OPK_OK ||
			strcmp(member->name, "debian-binary") != 0) {
		free(member);
		fputs(_("Error: Failed to find \"debian-binary\" in archive\n"),
				stderr);
		ret = OPKG_OPK_ERROR;
		goto out3;
	}
	free(member);
	if (opkg_opk_ustar_read(opk->outer_ustar,
				&version_buffer, &version_size) !=
			OPKG_OPK_OK) {
		fputs(_("Error: Failed to read \"debian-binary\" in archive\n"),
				stderr);
		ret = OPKG_OPK_ERROR;
		goto out3;
	}
	if (version_size < 4 || strncmp(version_buffer, "2.", 2) != 0)
	{
		fputs(_("Error: Unsupported package version\n"), stderr);
		ret = OPKG_OPK_ERROR;
		goto out3;
	}

	/* Read control archive. */
	if (opkg_opk_ustar_list(opk->outer_ustar, &member) != OPKG_OPK_OK ||
			strcmp(member->name, "control.tar.gz") != 0) {
		free(member);
		fputs(_("Error: Failed to find \"control.tar.gz\" in archive\n")
				, stderr);
		return OPKG_OPK_ERROR;
	}
	free(member);
	if (_opkg_opk_opk_read_control(opk) != OPKG_OPK_OK) {
		ret = OPKG_OPK_ERROR;
		goto out3;
	}

	/* Read data archive. */
	if (opkg_opk_ustar_list(opk->outer_ustar, &member) != OPKG_OPK_OK ||
			strcmp(member->name, "data.tar.gz") != 0) {
		free(member);
		fputs(_("Error: Failed to find \"data.tar.gz\" in archive\n"),
				stderr);
		return OPKG_OPK_ERROR;
	}
	free(member);
	if (_opkg_opk_opk_read_data(opk) != OPKG_OPK_OK) {
		ret = OPKG_OPK_ERROR;
		goto out3;
	}

 out3:
	opkg_opk_ustar_free(opk->outer_ustar);
 out2:
	opkg_opk_gzip_free(opk->outer_gzip);
 out1:
	fclose(opk->file);
 out0:
	return ret;
}

void
opkg_opk_opk_free(struct opkg_opk_opk *opk)
{
	struct _opkg_opk_opk_seek_name *name;

	while (opk->print_control_head != NULL) {
		name                    = opk->print_control_head;
		opk->print_control_head = opk->print_control_head->next;
		free(name);
	}
	while (opk->print_data_head != NULL) {
		name                 = opk->print_data_head;
		opk->print_data_head = opk->print_data_head->next;
		free(name);
	}
	free(opk);
}