# -*- coding: utf-8 -*-
"""
SyncItem — Datenmodell fuer synchronisierbare Elemente.

Jedes SyncItem hat eine eindeutige ID, einen Datentyp und
Nutzdaten. Last-Write-Wins wird ueber updated_at gesteuert.
"""

import uuid
from dataclasses import dataclass, field
from datetime import datetime, timezone
from typing import Any


def _now_iso() -> str:
    """Gibt den aktuellen Zeitpunkt als ISO 8601 UTC String zurueck."""
    return datetime.now(timezone.utc).isoformat()


@dataclass
class SyncItem:
    """Ein synchronisierbares Datenelement."""

    item_id: str = field(default_factory=lambda: str(uuid.uuid4()))
    data_type: str = ""           # z.B. "notes.note"
    data: dict[str, Any] = field(default_factory=dict)
    created_at: str = field(default_factory=_now_iso)
    updated_at: str = field(default_factory=_now_iso)
    deleted: bool = False         # Soft-Delete
    source_id: str = ""           # MAC-Adresse oder "server"
    version: int = 1              # Monoton steigend

    def to_dict(self) -> dict[str, Any]:
        """Konvertiert das Item in ein Dictionary."""
        return {
            "item_id": self.item_id,
            "data_type": self.data_type,
            "data": self.data,
            "created_at": self.created_at,
            "updated_at": self.updated_at,
            "deleted": self.deleted,
            "source_id": self.source_id,
            "version": self.version,
        }

    @classmethod
    def from_dict(cls, data: dict[str, Any]) -> "SyncItem":
        """Erstellt ein SyncItem aus einem Dictionary."""
        return cls(
            item_id=data.get("item_id", str(uuid.uuid4())),
            data_type=data.get("data_type", ""),
            data=data.get("data", {}),
            created_at=data.get("created_at", _now_iso()),
            updated_at=data.get("updated_at", _now_iso()),
            deleted=data.get("deleted", False),
            source_id=data.get("source_id", ""),
            version=data.get("version", 1),
        )