adapter.py

from __future__ import annotations

from typing import TYPE_CHECKING, Annotated, Union

from pydantic import Field, TypeAdapter

from streamdeck.models.events import DEFAULT_EVENT_MODELS


if TYPE_CHECKING:
    from streamdeck.models.events.base import EventBase, LiteralStrGenericAlias


class EventAdapter:
    """TypeAdapter-encompassing class for handling and extending available event models."""
    def __init__(self) -> None:
        self._models: list[type[EventBase[LiteralStrGenericAlias]]] = []
        self._type_adapter: TypeAdapter[EventBase[LiteralStrGenericAlias]] | None = None

        self._event_names: set[str] = set()
        """A set of all event names that have been registered with the adapter.
        This set starts out containing the default event models defined by the library.
        """

        for model in DEFAULT_EVENT_MODELS:
            self.add_model(model)

    def add_model(self, model: type[EventBase[LiteralStrGenericAlias]]) -> None:
        """Add a model to the adapter, and add the event name of the model to the set of registered event names."""
        self._models.append(model)
        # Models can have multiple event names defined in the Literal args of the event field,
        # so `get_model_event_names()` returns a tuple of all event names, even if there is only one.
        self._event_names.update(model.get_model_event_names())

    def event_name_exists(self, event_name: str) -> bool:
        """Check if an event name has been registered with the adapter."""
        return event_name in self._event_names

    @property
    def type_adapter(self) -> TypeAdapter[EventBase[LiteralStrGenericAlias]]:
        """Get the TypeAdapter instance for the event models."""
        if self._type_adapter is None:
            self._type_adapter = TypeAdapter(
                Annotated[
                    Union[tuple(self._models)],  # noqa: UP007
                    Field(discriminator="event")
                ]
            )

        return self._type_adapter

    def validate_json(self, data: str | bytes) -> EventBase[LiteralStrGenericAlias]:
        """Validate a JSON string or bytes object as an event model."""
        return self.type_adapter.validate_json(data)