def filter_move(path_old, path_new):
    if dirname(path_old) == dirname(path_new):
        label = "rename"
        path_new = basename(path_new)
    else:
        label = "move"
    return "%s %s to %s" % (T.green(label), T.underline(path_old), T.underline(path_new)), 0

def format_move(path_old, path_new):
    path_old = abspath(path_old)
    path_new = abspath(path_new)
    if dirname(path_old) == dirname(path_new):
        label = "rename"
        path_new = basename(path_new)
    else:
        label = "move"
    return "%s %s to %s" % (T.green(label), T.underline(path_old), T.underline(path_new))

def format_open(path, flags):
    path = abspath(path)
    if path in allowed_files:
        return None
    elif (flags & O_CREAT) and not exists(path):
        return "%s %s" % (T.cyan("create file"), T.underline(path))
    elif (flags & O_TRUNC) and exists(path):
        return "%s %s" % (T.red("truncate file"), T.underline(path))
    else:
        return None

def filter_change_owner(path, owner, group):
    if owner == -1:
        label = "change group"
        owner = getgrgid(group)[0]
    elif group == -1:
        label = "change owner"
        owner = getpwuid(owner)[0]
    else:
        label = "change owner"
        owner = getpwuid(owner)[0] + ":" + getgrgid(group)[0]
    return "%s of %s to %s" % (T.yellow(label), T.underline(path), T.bold(owner)), 0

def filter_mknod(path, type):
    if exists(path):
        return None, None
    elif (type & S_IFCHR):
        label = "create character special file"
    elif (type & S_IFBLK):
        label = "create block special file"
    elif (type & S_IFIFO):
        label = "create named pipe"
    elif (type & S_IFSOCK):
        label = "create socket"
    else:
        # mknod(2): "Zero file type is equivalent to type S_IFREG"
        label = "create file"
    return "%s %s" % (T.cyan(label), T.underline(path)), 0

def filter_open(process, path, flags):
    if path in allowed_files:
        return None, None
    if (flags & O_CREAT) and not exists(path):
        operation = "%s %s" % (T.cyan("create file"), T.underline(path))
    elif (flags & O_TRUNC) and exists(path):
        operation = "%s %s" % (T.red("truncate file"), T.underline(path))
    else:
        operation = None
    if (flags & O_WRONLY) or (flags & O_RDWR) or (flags & O_APPEND) or (operation is not None):
        # File might be written to later, so we need to track the file descriptor
        return_value = process.register_path(path)
    else:
        return_value = None
    return operation, return_value

def filter_change_permissions(path, permissions):
    return "%s of %s to %s" % (T.yellow("change permissions"), T.underline(path),
                               T.bold(format_permissions(permissions))), 0

def format_create_directory(path):
    return "%s %s" % (T.cyan("create directory"), T.underline(abspath(path)))

def format_create_link(path_source, path_target, symbolic):
    label = "create symbolic link" if symbolic else "create hard link"
    return "%s from %s to %s" % (T.cyan(label), T.underline(abspath(path_source)), T.underline(abspath(path_target)))

def format_write(file_descriptor, byte_count):
    if file_descriptor in file_descriptors:
        path = file_descriptors[file_descriptor]
        return "%s %s to %s" % (T.red("write"), T.bold("%d bytes" % byte_count), T.underline(path))
    else:
        return None

def filter_write(process, file_descriptor, byte_count):
    if process.is_tracked_descriptor(file_descriptor):
        path = process.descriptor_path(file_descriptor)
        return "%s %s to %s" % (T.red("write"), T.bold("%d bytes" % byte_count), T.underline(path)), byte_count
    else:
        return None, None

def filter_delete(path):
    return "%s %s" % (T.red("delete"), T.underline(path)), 0

def filter_create_directory(path):
    return "%s %s" % (T.cyan("create directory"), T.underline(path)), 0

def format_delete(path):
    return "%s %s" % (T.red("delete"), T.underline(path))