from __future__ import annotations

from django.conf import settings

from .providers import ModerationConfigError, ModerationProvider, Verdict


def moderation_enabled() -> bool:
    return bool(getattr(settings, "MODERATION_ENABLED", False))


def fail_closed() -> bool:
    return bool(getattr(settings, "MODERATION_FAIL_CLOSED", True))


def block_on_review() -> bool:
    return bool(getattr(settings, "MODERATION_BLOCK_ON_REVIEW", False))


def verdict_is_blocking(verdict: Verdict) -> bool:
    if verdict == Verdict.BLOCK:
        return True
    if verdict == Verdict.REVIEW:
        return block_on_review()
    return False


def selected_provider_name() -> str:
    return str(getattr(settings, "MODERATION_PROVIDER", "") or "").strip().lower()


def _build_keyword() -> ModerationProvider:
    from .providers.keyword import KeywordModerationProvider

    return KeywordModerationProvider()


_PROVIDER_BUILDERS = {
    "keyword": _build_keyword,
}


def biz_type(stage: str) -> str:
    return stage


def _build_provider() -> ModerationProvider:
    """按 MODERATION_PROVIDER 选具体厂商。未选 / 未知 → ModerationConfigError（上层按 fail-closed 处理）。"""
    name = selected_provider_name()
    if not name:
        raise ModerationConfigError("MODERATION_PROVIDER 未设置（内容安全厂商未选定）")
    builder = _PROVIDER_BUILDERS.get(name)
    if builder is None:
        raise ModerationConfigError(f"未知内容安全厂商: {name}")
    return builder()


def get_text_provider() -> ModerationProvider:
    return _build_provider()