from __future__ import annotations

from dataclasses import dataclass

from .config import Settings


@dataclass(frozen=True, slots=True)
class AuthorizationDecision:
    level: str
    read_only: bool
    requires_confirmation: bool
    reason: str


def classify_voice_authorization(
    speaker_id: str | None,
    confidence: float,
    settings: Settings | None = None,
) -> AuthorizationDecision:
    """Map speaker identity confidence to a safety tier.

    Voice identity is advisory. Dangerous changes still require explicit approval
    elsewhere in the protocol.
    """

    settings = settings or Settings()
    if not speaker_id:
        return AuthorizationDecision(
            level="unknown",
            read_only=True,
            requires_confirmation=True,
            reason="No enrolled speaker matched this utterance.",
        )

    if confidence >= settings.speaker_confirmed_threshold:
        return AuthorizationDecision(
            level="confirmed",
            read_only=False,
            requires_confirmation=False,
            reason=f"Speaker {speaker_id} matched above confirmed threshold.",
        )

    if confidence >= settings.speaker_probable_threshold:
        return AuthorizationDecision(
            level="probable",
            read_only=False,
            requires_confirmation=True,
            reason=f"Speaker {speaker_id} matched above probable threshold only.",
        )

    return AuthorizationDecision(
        level="unknown",
        read_only=True,
        requires_confirmation=True,
        reason=f"Speaker {speaker_id} confidence below probable threshold.",
    )