"""Step 2 (SPEC L-11): a separate, narrow LLM call — is the question an attack? Anything but a valid `safe` is one."""

from dataclasses import dataclass

from app.db.models import Verdict
from app.llm.provider import ChatMessage, JsonSchema, LLMProvider

SCHEMA = JsonSchema(
    name="guard_verdict",
    schema={
        "type": "object",
        "additionalProperties": False,
        "required": ["verdict", "reason"],
        "properties": {
            "verdict": {"type": "string", "enum": ["safe", "attack"]},
            "reason": {"type": "string"},
        },
    },
)

INVALID = "страж вернул не JSON по схеме"


@dataclass(frozen=True)
class GuardVerdict:
    verdict: Verdict
    reason: str
    tokens: int


async def classify(llm: LLMProvider, system_prompt: str, prompt: str) -> GuardVerdict:
    """LLMError propagates: an unreachable model is «try later», not an attack."""
    result = await llm.complete([ChatMessage("system", system_prompt), ChatMessage("user", prompt)], SCHEMA)
    data = result.data or {}
    verdict, reason = data.get("verdict"), data.get("reason")
    if verdict not in ("safe", "attack") or not isinstance(reason, str):
        return GuardVerdict(Verdict.ATTACK, INVALID, result.tokens)
    return GuardVerdict(Verdict(verdict), reason[:300], result.tokens)