/*
 * Copyright (C) 2008  Kristian Høgsberg <krh@redhat.com>
 * Copyright (C) 2008  Red Hat, Inc
 * Copyright (C) 2009, 2011  J. Ali Harlow <ali@juiblex.co.uk>
 *
 * This program 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 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <dirent.h>
#include <unistd.h>
#include <fcntl.h>
#include <limits.h>
#include <assert.h>
#ifdef MSWIN_API
#include <shlobj.h>
#endif

#include "razor.h"
#include "razor-internal.h"

#ifndef O_BINARY
#define O_BINARY	0
#endif

static const char system_repo_filename[] = "system.rzdb";
/*
 * system_lock_filename is chosen to be the same as the pre v0.3
 * next_repo_filename. This means that once a system has been
 * updated by a v0.3+ copy of razor all pre v0.3 versions of razor
 * will see the system as permenantly locked.
 */
static const char system_lock_filename[] = "system-next.rzdb";
static const char system_tmp_filename[] = "system.tmp";
#ifdef MSWIN_API
#define RAZOR_ROOT_PATH	NULL
#else
#define RAZOR_ROOT_PATH	"/var/lib/razor"
#endif
static const char *razor_root_path = RAZOR_ROOT_PATH;

struct razor_root {
	struct razor_set *system;
	struct razor_set *next;
	struct razor_atomic *atomic;
	int handle;
	char *path, *new_path;
};

static void
razor_root_init(void)
{
#ifdef MSWIN_API
	static char root_path[MAX_PATH];
	if (!razor_root_path) {
		SHGetFolderPath(NULL,
			CSIDL_COMMON_APPDATA | CSIDL_FLAG_DONT_VERIFY, NULL, 0,
			root_path);
		strcat(root_path, "\\Razor");
		razor_root_path = root_path;
	}
#endif
}

RAZOR_EXPORT int
razor_root_create(const char *root)
{
	int retval;
	struct stat buf;
	struct razor_set *set;
	struct razor_atomic *atomic;
	char *path;

	assert (root != NULL);

	razor_root_init();
	if (root[0] == '\0') {
		/* root is file system root */
	} else if (stat(root, &buf) < 0) {
		if (mkdir(root, 0777) < 0) {
			fprintf(stderr,
				"could not create install root \"%s\"\n",
				root);
			return -1;
		}
		fprintf(stderr, "created install root \"%s\"\n", root);
	} else if (!S_ISDIR(buf.st_mode)) {
		fprintf(stderr,
			"install root \"%s\" exists, but is not a directory\n",
			root);
		return -1;
	}

	path = razor_concat(root, razor_root_path, "/", system_repo_filename,
			    NULL);
	retval = !stat(path, &buf);
	free(path);
	if (retval) {
		fprintf(stderr,
			"a razor install root is already initialized\n");
		return retval;
	}

	atomic = razor_atomic_open("Create initial package set");
	path = razor_concat(razor_root_path, "/", system_repo_filename, NULL);
	razor_atomic_make_dirs(atomic, root, path);
	set = razor_set_create();
	razor_set_write(set, atomic, path, RAZOR_SECTION_ALL);
	free(path);
	retval = razor_atomic_commit(atomic);
	if (retval)
		fprintf(stderr, "could not write initial package set\n");
	razor_set_unref(set);
	razor_atomic_destroy(atomic);

	return retval;
}

RAZOR_EXPORT struct razor_root *
razor_root_open(const char *root, struct razor_atomic *atomic)
{
	struct razor_root *image;
	char *lock_path;
	int r;

	assert (root != NULL);

	razor_root_init();
	image = malloc(sizeof *image);
	if (image == NULL) {
		razor_atomic_abort(atomic, "Not enough memory");
		return NULL;
	}

	image->atomic = atomic;

	image->system = razor_set_create_without_root();
	if (image->system == NULL) {
		free(image);
		razor_atomic_abort(atomic, "Not enough memory");
		return NULL;
	}

	lock_path = razor_concat(root, razor_root_path, "/",
				 system_lock_filename, NULL);

	r = razor_set_aquire_lock(image->system, lock_path, 1);

	free(lock_path);

	if (r < 0) {
		razor_atomic_abort(atomic,
				   "Failed to aquire exclusive system lock");
		razor_set_unref(image->system);
		free(image);
		return NULL;
	}

	image->new_path = razor_concat(root, razor_root_path, "/",
				       system_tmp_filename, NULL);
	image->handle = razor_atomic_create_file(atomic, image->new_path,
						 S_IRWXU | S_IRWXG | S_IRWXO);
	if (image->handle < 0) {
		free(image->new_path);
		razor_set_unref(image->system);
		free(image);
		return NULL;
	}

	image->path = razor_concat(root, razor_root_path, "/",
				   system_repo_filename, NULL);

	if (razor_set_bind_sections(image->system, atomic, image->path)) {
		unlink(image->new_path);
		free(image->new_path);
		free(image->path);
		razor_set_unref(image->system);
		free(image);
		return NULL;
	}

	return image;
}

RAZOR_EXPORT struct razor_set *
razor_root_open_read_only(const char *root, struct razor_atomic *atomic)
{
	char *path;
	struct razor_set *set;

	assert (root != NULL);

	razor_root_init();
	set = razor_set_create_without_root();
	if (set == NULL) {
		razor_atomic_abort(atomic, "Not enough memory");
		return NULL;
	}

	path = razor_concat(root, razor_root_path, "/", system_lock_filename,
			    NULL);
	if (razor_set_aquire_lock(set, path, 0) < 0) {
		razor_atomic_abort(atomic, "Failed to aquire non-exclusive "
					   "system lock");
		free(path);
		razor_set_unref(set);
		return NULL;
	}

	free(path);
	path = razor_concat(root, razor_root_path, "/", system_repo_filename,
			    NULL);

	if (razor_set_bind_sections(set, atomic, path)) {
		razor_set_unref(set);
		set = NULL;
	}

	free(path);

	return set;
}

RAZOR_EXPORT struct razor_set *
razor_root_get_system_set(struct razor_root *root)
{
	assert (root != NULL);

	return root->system;
}

RAZOR_EXPORT int
razor_root_close(struct razor_root *root)
{
	assert (root != NULL);

	razor_set_unref(root->system);
	razor_atomic_close(root->atomic, root->handle);
	razor_atomic_remove(root->atomic, root->new_path);
	free(root->path);
	free(root->new_path);
	free(root);

	return 0;
}

RAZOR_EXPORT void
razor_root_update(struct razor_root *root, struct razor_set *next)
{
	assert (root != NULL);
	assert (next != NULL);

	razor_root_init();
	razor_set_write_to_handle(next, root->atomic, root->handle,
				  RAZOR_SECTION_ALL);
	root->next = next;

	/* Sync the new repo file so the new package set is on disk
	 * before we start upgrading. */
	razor_atomic_sync(root->atomic, root->handle);
}

RAZOR_EXPORT int
razor_root_commit(struct razor_root *root)
{
	int retval;
	assert (root != NULL);

	razor_atomic_close(root->atomic, root->handle);
	retval = razor_atomic_rename_file(root->atomic, root->new_path,
					  root->path);
	razor_set_unref(root->system);
	free(root->path);
	free(root->new_path);
	free(root);

	return retval;
}