from __future__ import annotations

import json
import hashlib
from dataclasses import dataclass, asdict, field
from typing import Any, Dict, List


def _digest(data: str) -> str:
    return hashlib.sha256(data.encode("utf-8")).hexdigest()


@dataclass
class LocalProblem:
    id: str
    neighborhood: str
    tasks: List[Dict[str, Any]]  # each task: {type, constraints, etc}
    capacity: int
    equity_budget: float

    def to_json(self) -> str:
        return json.dumps(asdict(self), sort_keys=True)

    @staticmethod
    def from_dict(d: Dict[str, Any]) -> "LocalProblem":
        return LocalProblem(
            id=d["id"],
            neighborhood=d["neighborhood"],
            tasks=d.get("tasks", []),
            capacity=d.get("capacity", 0),
            equity_budget=d.get("equity_budget", 0.0),
        )


@dataclass
class SharedSignals:
    version: int
    signals: Dict[str, Any]

    def to_json(self) -> str:
        return json.dumps(asdict(self), sort_keys=True)


@dataclass
class PlanDelta:
    version: int
    plan: Dict[str, Any]
    provenance: str = "unknown"
    signature: str = ""

    def to_json(self) -> str:
        return json.dumps(asdict(self), sort_keys=True)

    def digest(self) -> str:
        return _digest(self.to_json())


class CryptoProof:
    @staticmethod
    def sign(payload: str, key: str = "default") -> str:
        # Very lightweight placeholder signature (not cryptographically secure)
        return _digest(payload + "|" + key)

    @staticmethod
    def verify(signature: str, payload: str, key: str = "default") -> bool:
        return signature == CryptoProof.sign(payload, key)