from datetime import datetime
from typing import Any, Dict, Optional
from pydantic import BaseModel, Field
import json
import uuid

class Message(BaseModel):
    id: str = Field(default_factory=lambda: str(uuid.uuid4()))
    queue: str
    payload: Dict[str, Any]
    created_at: datetime = Field(default_factory=datetime.utcnow)
    retry_count: int = Field(default=0)
    max_retries: int = Field(default=3)
    next_retry_at: Optional[datetime] = Field(default=None)
    error: Optional[str] = Field(default=None)

    def to_json(self) -> str:
        return json.dumps({
            "id": self.id,
            "queue": self.queue,
            "payload": self.payload,
            "created_at": self.created_at.isoformat(),
            "retry_count": self.retry_count,
            "max_retries": self.max_retries,
            "next_retry_at": self.next_retry_at.isoformat() if self.next_retry_at else None,
            "error": self.error
        })

    @classmethod
    def from_json(cls, data: str) -> "Message":
        json_data = json.loads(data)
        json_data["created_at"] = datetime.fromisoformat(json_data["created_at"])
        if json_data["next_retry_at"]:
            json_data["next_retry_at"] = datetime.fromisoformat(json_data["next_retry_at"])
        return cls(**json_data)