"""Simple data contracts used by NovaPlan MVP.

- PlanDelta: delta between local and global plans.
- SharedSchedule: aggregated schedule signals from agents.
- ResourceUsage: energy, time, or other resource consumptions.
- PrivacyBudget: basic DP-like budget for an agent (simulated).
- AuditLog: lightweight log entries for governance.
"""
from __future__ import annotations
from dataclasses import dataclass, asdict
from typing import Dict, Any, List
import json

@dataclass
class PlanDelta:
    agent_id: str
    delta: Dict[str, float]
    timestamp: float

    def to_json(self) -> str:
        return json.dumps(asdict(self))

@dataclass
class SharedSchedule:
    schedule: Dict[str, Any]
    timestamp: float

@dataclass
class ResourceUsage:
    agent_id: str
    resources: Dict[str, float]
    timestamp: float

@dataclass
class PrivacyBudget:
    agent_id: str
    budget: float
    timestamp: float

@dataclass
class AuditLog:
    entry_id: str
    message: str
    timestamp: float

def serialize(obj: object) -> str:
    if hasattr(obj, "__dict__"):
        return json.dumps(obj.__dict__)
    return json.dumps(obj)

# Lightweight contract registry for versioning and interoperability
class ContractRegistry:
    _registry: Dict[str, int] = {}

    @classmethod
    def register(cls, name: str, version: int) -> None:
        cls._registry[name] = int(version)

    @classmethod
    def version_of(cls, name: str, default: int | None = None) -> int | None:
        return cls._registry.get(name, default)