from .I18N import _


# Klasa pomocnicza do monitorowania postępu uploadu
class ProgressFile:
    def __init__(self, f, callback, total_size, cancel_event=None):
        self.f = f
        self.callback = callback
        self.cancel_event = cancel_event
        self.total_size = total_size
        self.read_bytes = 0

    def read(self, size=-1):
        # Check for cancellation before reading more data
        if self.cancel_event is not None and self.cancel_event.is_set():
            raise Exception(_("Upload cancelled by user."))

        data = self.f.read(size)
        self.read_bytes += len(data)
        self.callback(self.read_bytes, self.total_size)
        return data

    def __getattr__(self, attr):
        return getattr(self.f, attr)