from __future__ import annotations

import json
from dataclasses import dataclass
from typing import Any


@dataclass(frozen=True)
class PicoEvent:
    button: int
    pin: int
    event: str
    pressed: bool

    def to_dict(self) -> dict[str, Any]:
        return {
            "button": self.button,
            "pin": self.pin,
            "event": self.event,
            "pressed": self.pressed,
        }


def parse_pico_line(raw_line: str) -> PicoEvent | None:
    try:
        payload = json.loads(raw_line)
    except json.JSONDecodeError:
        return None

    if not isinstance(payload, dict):
        return None
    if not {"button", "pin", "event", "pressed"}.issubset(payload):
        return None
    if payload["event"] not in {"down", "up"}:
        return None

    try:
        button = int(payload["button"])
        pin = int(payload["pin"])
    except (TypeError, ValueError):
        return None

    if button < 1 or button > 10:
        return None

    return PicoEvent(button=button, pin=pin, event=payload["event"], pressed=bool(payload["pressed"]))