"""Schwierigkeitsstufen: wie schnell die Koffer einlaufen.

``hard`` entspricht dem Tempo des Altstands (6 bzw. 2 Pixel pro Frame bei
120 fps = 720 bzw. 240 Pixel pro Sekunde).
"""

from __future__ import annotations

from dataclasses import dataclass


@dataclass(frozen=True, slots=True)
class Difficulty:
    """Eine Stufe. ``speed_fast`` gilt bis kurz vor der Barriere, dann ``speed_slow``."""

    key: str
    label: str
    speed_fast: float
    speed_slow: float

    def __str__(self) -> str:
        return self.label


DIFFICULTIES: tuple[Difficulty, ...] = (
    Difficulty("easy", "Easy", speed_fast=420.0, speed_slow=140.0),
    Difficulty("normal", "Normal", speed_fast=570.0, speed_slow=190.0),
    Difficulty("hard", "Hard", speed_fast=720.0, speed_slow=240.0),
)

DEFAULT_DIFFICULTY: Difficulty = DIFFICULTIES[1]


def by_key(key: str) -> Difficulty:
    for difficulty in DIFFICULTIES:
        if difficulty.key == key:
            return difficulty
    return DEFAULT_DIFFICULTY