# Copyright 2024 (c) Anna Schumaker.
"""Our ListenBrainz operation priority queue."""


class Queue:
    """A queue for prioritizing ListenBrainz operations."""

    def __init__(self):
        """Initialize the task Queue."""
        self._set_token = None
        self._now_playing = None

    def clear(self, op: str) -> None:
        """Clear a pending operation."""
        match op:
            case "clear-token" | "set-token": self._set_token = None
            case "now-playing": self._now_playing = None

    def push(self, op: str, *args) -> None:
        """Push an operation onto the queue."""
        match op:
            case "clear-token" | "set-token": self._set_token = (op, *args)
            case "now-playing": self._now_playing = (op, *args)

    def pop(self) -> tuple:
        """Pop an operation off the queue."""
        if (res := self._set_token) is not None:
            self._set_token = None
        elif (res := self._now_playing) is not None:
            self._now_playing = None
        return res