from contextlib import contextmanager
from typing import Generator, List


@contextmanager
def component_error_message(component_path: List[str]) -> Generator[None, None, None]:
    """
    If an error occurs within the context, format the error message to include
    the component path. E.g.
    ```
    KeyError: "An error occured while rendering components MyPage > MyComponent > MyComponent(slot:content)
    ```
    """
    try:
        yield
    except Exception as err:
        if not hasattr(err, "_components"):
            err._components = []  # type: ignore[attr-defined]

        components = getattr(err, "_components", [])
        components = err._components = [*component_path, *components]  # type: ignore[attr-defined]

        # Access the exception's message, see https://stackoverflow.com/a/75549200/9788634
        if len(err.args) and err.args[0] is not None:
            if not components:
                orig_msg = str(err.args[0])
            else:
                orig_msg = str(err.args[0]).split("\n", 1)[-1]
        else:
            orig_msg = str(err)

        # Format component path as
        # "MyPage > MyComponent > MyComponent(slot:content) > Base(slot:tab)"
        comp_path = " > ".join(components)
        prefix = f"An error occured while rendering components {comp_path}:\n"

        err.args = (prefix + orig_msg,)  # tuple of one

        # `from None` should still raise the original error, but without showing this
        # line in the traceback.
        raise err from None


@contextmanager
def add_slot_to_error_message(component_name: str, slot_name: str) -> Generator[None, None, None]:
    """
    This compliments `component_error_message` and is used inside SlotNode to add
    the slots to the component path in the error message, e.g.:

    ```
    KeyError: "An error occured while rendering components MyPage > MyComponent > MyComponent(slot:content)
    ```
    """
    try:
        yield
    except Exception as err:
        if not hasattr(err, "_components"):
            err._components = []  # type: ignore[attr-defined]

        err._components.insert(0, f"{component_name}(slot:{slot_name})")  # type: ignore[attr-defined]
        raise err from None