from datetime import datetime

from sqlalchemy import Column, DateTime, ForeignKey, Integer, String

from app.database import Base


class InviteCode(Base):
    """A code an administrator issues so one person can register.

    Single use by default: the point of invite-only is knowing who came in, and
    a code that works forever is a password shared by everyone who has seen it.
    A code is never deleted once used — who it let in is the record worth
    keeping.
    """

    __tablename__ = "invite_codes"

    id = Column(Integer, primary_key=True, index=True)
    code = Column(String(32), unique=True, nullable=False, index=True)
    note = Column(String(200), nullable=True)      # who it was meant for
    created_by = Column(Integer, ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
    created_at = Column(DateTime, default=datetime.utcnow)
    #: Set when someone registers with it. Present means spent.
    used_by = Column(Integer, ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
    used_at = Column(DateTime, nullable=True)
    #: An administrator can withdraw a code that has not been used.
    revoked_at = Column(DateTime, nullable=True)