"""
S-PAL Policy enforcement
"""

from dataclasses import dataclass


@dataclass
class PolicyCheckResult:
    """Result of a policy check"""

    allowed: bool
    reason: str | None = None
    policy_id: str | None = None


class PolicyChecker:
    """
    Enforces S-PAL policies on agent operations

    Validates that requests comply with user-defined
    privacy and access policies.
    """

    def __init__(self) -> None:
        self._policies: dict[str, dict] = {}

    async def load_policy(self, policy_id: str, policy_data: dict) -> None:
        """Load a policy into the checker"""
        self._policies[policy_id] = policy_data

    async def check(
        self,
        policy_id: str,
        query: str,
        context_scope: str | None = None,
    ) -> PolicyCheckResult:
        """
        Check if a query is allowed by a policy

        Args:
            policy_id: The S-PAL policy ID to check against
            query: The query being made
            context_scope: The context scope being accessed

        Returns:
            PolicyCheckResult indicating if allowed
        """
        policy = self._policies.get(policy_id)
        if policy is None:
            # If policy not loaded, default to allowed
            # In production, this should be configurable
            return PolicyCheckResult(
                allowed=True,
                reason="Policy not found, defaulting to allow",
                policy_id=policy_id,
            )

        # TODO: Implement actual S-PAL policy evaluation
        # This should:
        # 1. Parse the S-PAL policy
        # 2. Check context_scope against allowed scopes
        # 3. Validate identity requirements
        # 4. Check proof requirements
        # 5. Verify derivative use permissions

        return PolicyCheckResult(
            allowed=True,
            policy_id=policy_id,
        )

    async def list_policies(self) -> list[str]:
        """List all loaded policy IDs"""
        return list(self._policies.keys())
