import json
from datetime import datetime
from typing import List, Optional

class Event:
    """Класс события календаря"""
    
    def __init__(self, title: str, date: str, time: str = "", description: str = ""):
        self.title = title
        self.date = date  # формат YYYY-MM-DD
        self.time = time  # формат HH:MM
        self.description = description
    
    def to_dict(self) -> dict:
        """Преобразует событие в словарь для JSON"""
        return {
            "title": self.title,
            "date": self.date,
            "time": self.time,
            "description": self.description
        }
    
    @classmethod
    def from_dict(cls, data: dict) -> 'Event':
        """Создаёт событие из словаря"""
        return cls(
            title=data["title"],
            date=data["date"],
            time=data.get("time", ""),
            description=data.get("description", "")
        )
    
    def __str__(self) -> str:
        time_str = f" в {self.time}" if self.time else ""
        return f"{self.date}{time_str}: {self.title} - {self.description}"