from __future__ import annotations

from datetime import datetime
from typing import Optional

from sqlalchemy import BigInteger, DateTime, ForeignKey, String, func
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.db.base import Base


class User(Base):
    __tablename__ = "users"

    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
    telegram_id: Mapped[int] = mapped_column(BigInteger, unique=True, index=True)
    username: Mapped[Optional[str]] = mapped_column(String(255), nullable=True)
    first_name: Mapped[Optional[str]] = mapped_column(String(255), nullable=True)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        server_default=func.now(),
    )
    referrer_id: Mapped[Optional[int]] = mapped_column(
        ForeignKey("users.id", ondelete="SET NULL"),
        nullable=True,
        index=True,
    )

    referrer: Mapped[Optional[User]] = relationship(
        back_populates="referrals",
        remote_side="User.id",
    )
    referrals: Mapped[list[User]] = relationship(
        back_populates="referrer",
    )