from pydantic import BaseModel
from typing import List, Optional
from datetime import datetime
from bson import ObjectId

class Lesson(BaseModel):
    lesson_name: str
    markdown_lesson_file_link: str
    markdown_prompt_file_name: str
    markdown_score_prompt_file_link: str

class Chapter(BaseModel):
    chapter_name: str
    lessons: List[Lesson]

class Material(BaseModel):
    _id: ObjectId
    name: str
    description: Optional[str] = None
    teacher_id: str
    created_at: datetime
    updated_at: datetime
    image_url: Optional[str] = None # 封面图片的url
    chapters: List[Chapter]