"""Contracts module for CosmosMesh MVP tests.

This module provides minimal, test-friendly data structures for LocalProblem
and a small registry facade GraphOfContracts. The goal is to satisfy unit tests
without pulling in heavy dependencies.
"""

from __future__ import annotations

import json
from dataclasses import dataclass, field
from typing import Any, Dict, Optional


@dataclass
class LocalProblem:
    """Minimal LocalProblem contract used by tests.

    Attributes:
        agent_id: Unique identifier for the agent describing the problem.
        variables: Mapping of decision variables and their current values.
        objective: Dict describing the objective (could be coefficients, type, etc).
        constraints: Dict describing constraints (types and limits).
        version: Protocol version of this contract payload.
    """

    agent_id: str
    variables: Dict[str, float] = field(default_factory=dict)
    objective: Dict[str, Any] = field(default_factory=dict)
    constraints: Dict[str, Any] = field(default_factory=dict)
    version: str = "0.0.1"

    def to_dict(self) -> Dict[str, Any]:
        return {
            "agent_id": self.agent_id,
            "variables": self.variables,
            "objective": self.objective,
            "constraints": self.constraints,
            "version": self.version,
        }

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

    @classmethod
    def from_json(cls, payload: str) -> "LocalProblem":
        data = json.loads(payload)
        return cls(
            agent_id=data["agent_id"],
            variables=data.get("variables", {}),
            objective=data.get("objective", {}),
            constraints=data.get("constraints", {}),
            version=data.get("version", "0.0.1"),
        )


class GraphOfContracts:
    """Tiny in-memory registry of contract names -> versions."""

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

    def register(self, name: str, version: str) -> None:
        self._registry[name] = version

    def get_version(self, name: str) -> Optional[str]:
        return self._registry.get(name)

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


__all__ = ["LocalProblem", "GraphOfContracts"]