/*

 * Copyright (C) 2011-2012  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"

#if HAVE_WINDOWS_KTM

#include <stdlib.h>

#include <windows.h>

#include <stdio.h>

#include <limits.h>

#include <errno.h>

#include <unistd.h>

#include <fcntl.h>

#include <sys/stat.h>

#include <string.h>

#include <assert.h>

#include <wchar.h>

#include <ktmw32.h>

#include "razor.h"

#include "razor-internal.h"

#define RAZOR_ASCII_ISALPHA(c)	\

			((c) >= 'A' && (c) <= 'Z' || (c) >= 'a' && (c) <= 'z')

static int

razor_valid_root_name2(const wchar_t *name)

{

	if (razor_allow_all_root_names())

		return !wcschr(name, '/');

	return RAZOR_ASCII_ISALPHA(name[0]) && name[1] == ':' &&

	       name[2] == '\0';

}

struct razor_wstr {

	wchar_t *str;

	int len, allocated;

};

static struct razor_wstr *

razor_wstr_create(const char *init, int len)

{

	int n;

	struct razor_wstr *wstr;

	wstr = malloc(sizeof(struct razor_wstr));

	n = MultiByteToWideChar(CP_UTF8, 0, init, len, NULL, 0);

	if (len >= 0 && init[len])

		wstr->len = n++;

	else

		wstr->len = n - 1;

	wstr->allocated = n * 2;

	wstr->str = malloc(wstr->allocated * sizeof(wchar_t));

	if (!wstr->str) {

		free(wstr);

		return NULL;

	}

	(void)MultiByteToWideChar(CP_UTF8, 0, init, len, wstr->str, n);

	if (len >= 0 && init[len])

		wstr->str[wstr->len] = 0;

	return wstr;

}

static int

razor_wstr_append(struct razor_wstr *wstr, const char *s, int len)

{

	int n, allocated;

	wchar_t *str;

	n = MultiByteToWideChar(CP_UTF8, 0, s, len, NULL, 0);

	if (len < 0 || !s[len])

		n--;

	if (wstr->allocated <= wstr->len + n) {

		allocated = (wstr->len + n + 1) * 2;

		str = realloc(wstr->str, allocated * sizeof(wchar_t));

		if (!str)

			return -1;

		wstr->allocated = allocated;

		wstr->str = str;

	}

	(void)MultiByteToWideChar(CP_UTF8, 0, s, len, wstr->str + wstr->len, n);

	wstr->len += n;

	wstr->str[wstr->len] = 0;

	return 0;

}

static void

razor_wstr_destroy(struct razor_wstr *wstr)

{

	free(wstr->str);

	free(wstr);

}

RAZOR_EXPORT struct razor_atomic *

razor_atomic_open(const char *description)

{

	wchar_t *buf;

	struct razor_atomic *atomic;

	atomic = zalloc(sizeof *atomic);

	buf = razor_utf8_to_utf16(description, -1);

	atomic->transaction = CreateTransaction(NULL, 0,

						TRANSACTION_DO_NOT_PROMOTE,

						0, 0, 0, buf);

	free(buf);

	return atomic;

}

void

razor_atomic_set_error_str(struct razor_atomic *atomic, const wchar_t *path,

			   const char *str)

{

	assert(!atomic->error_str);

	free(atomic->error_path);

	if (path)

		atomic->error_path = razor_utf16_to_utf8(path, -1);

	else

		atomic->error_path = NULL;

	atomic->error_str = strdup(str);

}

static void

razor_atomic_set_error(struct razor_atomic *atomic, const wchar_t *path,

		       DWORD error)

{

	wchar_t *buf;

	assert(!atomic->error_str);

	free(atomic->error_path);

	if (path)

		atomic->error_path = razor_utf16_to_utf8(path, -1);

	else

		atomic->error_path = NULL;

	FormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER|

		       FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,

		       NULL, error, MAKELANGID(LANG_NEUTRAL,SUBLANG_DEFAULT),

		       (LPWSTR)&buf, 0, NULL);

	atomic->error_str = razor_utf16_to_utf8(buf, -1);

	LocalFree(buf);

}

RAZOR_EXPORT int

razor_atomic_commit(struct razor_atomic *atomic)

{

	int retval;

	if (razor_atomic_in_error_state(atomic))

		return -1;

	retval = !CommitTransaction(atomic->transaction);

	if (retval) {

		razor_atomic_set_error(atomic, NULL, GetLastError());

		RollbackTransaction(atomic->transaction);

	}

	CloseHandle(atomic->transaction);

	atomic->transaction = INVALID_HANDLE_VALUE;

	return retval;

}

RAZOR_EXPORT void

razor_atomic_destroy(struct razor_atomic *atomic)

{

	int i;

	for(i = 0; i < atomic->n_files; i++) {

		if (atomic->files[i].h != INVALID_HANDLE_VALUE) {

			CloseHandle(atomic->files[i].h);

			free(atomic->files[i].path);

		}

	}

	free(atomic->files);

	if (atomic->transaction != INVALID_HANDLE_VALUE) {

		RollbackTransaction(atomic->transaction);

		CloseHandle(atomic->transaction);

	}

	free(atomic->error_path);

	free(atomic->error_str);

	free(atomic->error_msg);

	free(atomic);

}

RAZOR_EXPORT int

razor_atomic_make_dirs(struct razor_atomic *atomic, const char *root,

		       const char *path)

{

	struct razor_wstr *buffer;

	const char *slash, *next;

	WIN32_FILE_ATTRIBUTE_DATA fa;

	DWORD err;

	int r, creating = 0;

	if (razor_atomic_in_error_state(atomic))

		return -1;

	buffer = razor_wstr_create(root, -1);

	slash = path;

	for (; *slash != '\0'; slash = next) {

		next = strpbrk(slash + 1, "/\\");

		if (next == NULL)

			break;

		razor_wstr_append(buffer, slash, next - slash);

		if (!creating) {

			if (razor_valid_root_name2(buffer->str))

				continue;

			r = GetFileAttributesTransactedW(buffer->str,

							 GetFileExInfoStandard,

							 &fa,

							 atomic->transaction);

			if (!r) {

				err = GetLastError();

				if (err == ERROR_FILE_NOT_FOUND) {

					creating = 1;

				} else {

					razor_atomic_set_error(atomic,

							       buffer->str,

							       err);

					razor_wstr_destroy(buffer);

					return -1;

				}

			} else if (!(fa.dwFileAttributes&

				     FILE_ATTRIBUTE_DIRECTORY)) {

				razor_atomic_set_error_str(atomic, buffer->str,

							   "Not a directory");

				razor_wstr_destroy(buffer);

				return -1;

			}

		}

		if (creating) {

			if (!CreateDirectoryTransactedW(NULL, buffer->str, NULL,

							atomic->transaction)) {

				razor_atomic_set_error(atomic, buffer->str,

						       GetLastError());

				razor_wstr_destroy(buffer);

				return -1;

			}

			/* FIXME: What to do about permissions for dirs we

			 * have to create but are not in the cpio archive? */

		}

	}

	razor_wstr_destroy(buffer);

	return 0;

}

RAZOR_EXPORT int

razor_atomic_remove(struct razor_atomic *atomic, const char *path)

{

	wchar_t *buf;

	DWORD err;

	if (razor_atomic_in_error_state(atomic))

		return -1;

	buf = razor_utf8_to_utf16(path, -1);

	if (DeleteFileTransactedW(buf, atomic->transaction)) {

		free(buf);

		return 0;

	}

	err = GetLastError();

	if (err == ERROR_FILE_NOT_FOUND || err == ERROR_PATH_NOT_FOUND) {

		free(buf);

		return 0;

	}

	if (SetFileAttributesTransactedW(buf, FILE_ATTRIBUTE_NORMAL,

					 atomic->transaction)) {

		if (DeleteFileTransactedW(buf, atomic->transaction)) {

			free(buf);

			return 0;

		}

		err = GetLastError();

	}

	if (RemoveDirectoryTransactedW(buf, atomic->transaction) ||

	    GetLastError() == ERROR_DIR_NOT_EMPTY) {

		free(buf);

		return 0;

	}

	/*

	 * It would be tempting to use:

	 * 	MoveFileEx(path, NULL, MOVEFILE_DELAY_UNTIL_REBOOT)

	 * but unless we can guarantee that the system will be rebooted

	 * before we (or some other application) write another file with the

	 * same path, this is likely to cause more problems than it solves.

	 */

	razor_atomic_set_error(atomic, buf, err);

	free(buf);

	return -1;

}

RAZOR_EXPORT int

razor_atomic_rename_file(struct razor_atomic *atomic, const char *oldpath,

			 const char *newpath)

{

	wchar_t *oldbuf, *newbuf;

	const DWORD flags = MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING;

	if (razor_atomic_in_error_state(atomic))

		return -1;

	newbuf = razor_utf8_to_utf16(newpath, -1);

	oldbuf = razor_utf8_to_utf16(oldpath, -1);

	/*

	 * Passing MOVEFILE_REPLACE_EXISTING to MoveFileTransaction() will

	 * cover every case we care about _except_ replacing an empty

	 * directory with a file. Calling RemoveDirectoryTransacted() will deal

	 * with this case while having no effect in all other cases.

	 */

	(void)RemoveDirectoryTransactedW(newbuf, atomic->transaction);

	if (!MoveFileTransactedW(oldbuf, newbuf, NULL, NULL, flags,

			         atomic->transaction))

		razor_atomic_set_error(atomic, newbuf, GetLastError());

	free(newbuf);

	free(oldbuf);

	return !!atomic->error_str;

}

RAZOR_EXPORT int

razor_atomic_create_dir(struct razor_atomic *atomic, const char *dirname,

			mode_t mode)

{

	wchar_t *buf;

	DWORD err;

	WIN32_FILE_ATTRIBUTE_DATA fa;

	if (razor_atomic_in_error_state(atomic))

		return -1;

	buf = razor_utf8_to_utf16(dirname, -1);

	if (!CreateDirectoryTransactedW(NULL, buf, NULL, atomic->transaction)) {

		err = GetLastError();

		if (err != ERROR_FILE_EXISTS && err != ERROR_ALREADY_EXISTS) {

abort:

			razor_atomic_set_error(atomic, buf, err);

			free(buf);

			return -1;

		}

		if (!GetFileAttributesTransactedW(buf, GetFileExInfoStandard,

						  &fa, atomic->transaction))

			goto abort;

		if (!(fa.dwFileAttributes&FILE_ATTRIBUTE_DIRECTORY)) {

			if (razor_atomic_remove(atomic, dirname)) {

				free(buf);

				return -1;

			}

			if (!CreateDirectoryTransactedW(NULL, buf, NULL,

							atomic->transaction)) {

				err = GetLastError();

				goto abort;

			}

		}

	}

	free(buf);

	return 0;

}

RAZOR_EXPORT int

razor_atomic_create_symlink(struct razor_atomic *atomic, const char *target,

			    const char *path)

{

	if (razor_atomic_in_error_state(atomic))

		return -1;

	/*

	 * This isn't true, but symbolic links under Windows 7

	 * need to know whether the target is a directory or not

	 * and we don't always know that at the time when the

	 * link is created, so it's a convienent lie for now.

	 */

	razor_atomic_set_error_str(atomic, NULL, "Symbolic links not supported "

						 "on this platform");

	return -1;

}

RAZOR_EXPORT int

razor_atomic_create_file(struct razor_atomic *atomic, const char *filename,

			 mode_t mode)

{

	DWORD attribs;

	struct razor_atomic_file *files;

	int i = atomic->n_files;

	if (razor_atomic_in_error_state(atomic))

		return -1;

	files = realloc(atomic->files,

			(atomic->n_files+1) * sizeof(struct razor_atomic_file));

	if (!files) {

		razor_atomic_set_error_str(atomic, NULL, "Not enough memory");

		return -1;

	}

	atomic->n_files++;

	atomic->files = files;

	files[i].path = razor_utf8_to_utf16(filename, -1);

	/*

	 * Passing CREATE_ALWAYS to CreateFileTransacted() will cover

	 * every case we care about _except_ replacing an empty directory

	 * with a file. Calling RemoveDirectoryTransacted() will deal

	 * with this case while having no effect in all other cases.

	 */

	(void)RemoveDirectoryTransactedW(files[i].path, atomic->transaction);

	if (mode & S_IWUSR)

		attribs = FILE_ATTRIBUTE_NORMAL;

	else

		attribs = FILE_ATTRIBUTE_READONLY;

	files[i].h = CreateFileTransactedW(files[i].path, GENERIC_WRITE,

					   0, NULL, CREATE_ALWAYS, attribs,

					   NULL, atomic->transaction, NULL,

					   NULL);

	if (files[i].h == INVALID_HANDLE_VALUE) {

		razor_atomic_set_error(atomic, files[i].path, GetLastError());

		free(files[i].path);

		atomic->n_files--;

		return -1;

	}

	return i;

}

RAZOR_EXPORT int

razor_atomic_write(struct razor_atomic *atomic, int handle, const void *data,

		   size_t size)

{

	DWORD written;

	if (razor_atomic_in_error_state(atomic))

		return -1;

	assert(handle < atomic->n_files);

	assert(atomic->files[handle].h != INVALID_HANDLE_VALUE);

	while(size) {

		if (!WriteFile(atomic->files[handle].h, data, size, &written,

			       NULL)) {

			razor_atomic_set_error(atomic,

					       atomic->files[handle].path,

					       GetLastError());

			(void)CloseHandle(atomic->files[handle].h);

			free(atomic->files[handle].path);

			atomic->files[handle].path = NULL;

			atomic->files[handle].h = INVALID_HANDLE_VALUE;

			return -1;

		}

		data += written;

		size -= written;

	}

	return 0;

}

RAZOR_EXPORT int

razor_atomic_sync(struct razor_atomic *atomic, int handle)

{

	HANDLE h;

	if (razor_atomic_in_error_state(atomic))

		return -1;

	assert(handle < atomic->n_files);

	assert(atomic->files[handle].h != INVALID_HANDLE_VALUE);

	if (!CloseHandle(atomic->files[handle].h)) {

		razor_atomic_set_error(atomic, atomic->files[handle].path,

				       GetLastError());

		free(atomic->files[handle].path);

		atomic->files[handle].path = NULL;

		atomic->files[handle].h = INVALID_HANDLE_VALUE;

		return -1;

	}

	h = CreateFileTransactedW(atomic->files[handle].path, GENERIC_WRITE, 0,

				  NULL, OPEN_EXISTING, 0, NULL,

				  atomic->transaction, NULL, NULL);

	atomic->files[handle].h = h;

	if (atomic->files[handle].h == INVALID_HANDLE_VALUE) {

		razor_atomic_set_error(atomic, atomic->files[handle].path,

				       GetLastError());

		free(atomic->files[handle].path);

		atomic->files[handle].path = NULL;

		return -1;

	}

	return !!atomic->error_str;

}

RAZOR_EXPORT int

razor_atomic_close(struct razor_atomic *atomic, int handle)

{

	if (razor_atomic_in_error_state(atomic))

		return -1;

	assert(handle < atomic->n_files);

	assert(atomic->files[handle].h != INVALID_HANDLE_VALUE);

	if (!CloseHandle(atomic->files[handle].h))

		razor_atomic_set_error(atomic, atomic->files[handle].path,

				       GetLastError());

	free(atomic->files[handle].path);

	atomic->files[handle].path = NULL;

	atomic->files[handle].h = INVALID_HANDLE_VALUE;

	while(atomic->n_files > 0 &&

	      atomic->files[atomic->n_files-1].h == INVALID_HANDLE_VALUE)

		atomic->n_files--;

	return !!atomic->error_str;

}

#endif		/* HAVE_WINDOWS_KTM */