from __future__ import annotations

import uuid
from dataclasses import dataclass, asdict
from typing import Dict, Any

from .core import KPIRecord


@dataclass
class DataContract:
    """A minimal, versioned data contract for KPI payloads.

    This is intentionally lightweight for MVP purposes. Each contract
    defines a unique id, a version, a JSON schema-like payload description,
    and privacy controls flags used by aggregators.
    """

    contract_id: str
    version: int
    schema: Dict[str, Any]
    privacy_flags: Dict[str, Any]
    description: str = ""

    def to_dict(self) -> Dict[str, Any]:
        return asdict(self)

    @staticmethod
    def make_new(schema: Dict[str, Any], privacy_flags: Dict[str, Any], description: str = "") -> DataContract:
        return DataContract(
            contract_id=uuid.uuid4().hex,
            version=1,
            schema=schema,
            privacy_flags=privacy_flags,
            description=description,
        )


class ContractRegistry:
    """In-memory registry for data contracts."""

    def __init__(self) -> None:
        self._contracts: Dict[str, DataContract] = {}

    def register(self, contract: DataContract) -> None:
        self._contracts[contract.contract_id] = contract

    def get(self, contract_id: str) -> DataContract | None:
        return self._contracts.get(contract_id)

    def all(self) -> Dict[str, DataContract]:
        return dict(self._contracts)