from abc import ABC, abstractmethod
from typing import Callable, Protocol


class AlarmSound(Protocol):
    """Audio capability injected into a style so it can own its ringing tone.

    Styles stay free of pygame/GPIO imports (the API process imports them only
    for name validation); the runner supplies a concrete implementation.
    """

    def play_music(self, path: str) -> None:
        """Load and play a music file on an endless loop."""
        ...

    def play_beep(self) -> None:
        """Play one short beep tone."""
        ...


class AlarmStyle(ABC):
    """A pluggable alarm behaviour.

    A style owns *its own ringing tone* (via the injected ``sound``) and
    decides when the alarm stops and what the LED does. It never touches
    hardware directly: ``set_led`` and ``sound`` are injected by the runner, so
    styles stay import-safe in the API process (no GPIO/pygame).

    Lifecycle: construct once with ``set_led``/``sound``/``music_file``; call
    ``start()`` to begin ringing (kick off the tone and initial LED); then call
    ``update`` every tick. Return ``False`` from ``update`` to stop the alarm.
    """

    def __init__(
        self,
        set_led: Callable[[bool], None],
        sound: AlarmSound,
        music_file: str | None = None,
    ):
        self.set_led = set_led
        self.sound = sound
        self.music_file = music_file

    def start(self) -> None:
        """Begin ringing. Override to start the style's tone / initial LED."""

    @abstractmethod
    def update(self, now: float, is_pressed: bool) -> bool:
        """Advance the style by one tick.

        Args:
            now: current time (``time.time()`` from the runner).
            is_pressed: whether the button is currently held down.

        Returns:
            True to keep ringing, False to stop.
        """