from typing import Generic, Iterable, Optional, TypeVar

from bs4 import Tag

T = TypeVar("T")

class WidgetParser:
    def parse_widget(self, tag: Tag) -> Tag:
        raise NotImplementedError


class BaseWidgetParser(WidgetParser):
    SELECT: str

    def __init__(self, select: Optional[str] = None):
        super().__init__()
        self._select = select or self.SELECT

    def parse_widget(self, tag: Tag) -> Tag:
        widget = tag.select_one(self._select)
        if widget is None:
            raise ValueError(self._select)
        return widget


class RowParser(Generic[T]):
    KEY: str

    def parse_row(self, tag: Tag) -> Iterable[T]:
        raise NotImplementedError