from typing import List

from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.extensions import db

class Collection(db.Model):
    id: Mapped[int] = mapped_column(primary_key=True)
    name: Mapped[str] = mapped_column(unique=True, nullable=False)
    
    tasks: Mapped[List['Task']] = relationship("Task", back_populates="collection")
    users: Mapped[List['User']] = relationship("User", cascade="all, delete-orphan", back_populates="collection")
    
    def exists(name: str):
        collections = Collection.query.filter_by(name=name).all()
        
        return len(collections) > 0