from app.config import get_settings
from app.domain.schemas import PlannerDecision, PolicyResult


class PolicyEngine:
    def __init__(self, existing_payloads: list[dict] | None = None) -> None:
        self.threshold = get_settings().planner_confidence_threshold
        self.existing_payloads = existing_payloads or []

    def evaluate(self, decision: PlannerDecision) -> PolicyResult:
        reasons: list[str] = []
        if decision.confidence < self.threshold:
            reasons.append(f"Confidence {decision.confidence:.2f} is below threshold {self.threshold:.2f}.")
        if decision.arguments in self.existing_payloads:
            reasons.append("Duplicate pending action payload.")
        if decision.tool == "create_guest_reservation" and not decision.arguments.get("event_date"):
            reasons.append("Reservation requires a date.")
        if decision.tool == "create_guest_reservation" and not decision.arguments.get("partner_id"):
            reasons.append("Reservation requires a Wed partner_id.")
        if decision.tool == "create_task" and not decision.arguments.get("title"):
            reasons.append("Task requires a title.")
        return PolicyResult(allowed=not reasons, reasons=reasons)