import uuid
from datetime import datetime, timezone

from sqlalchemy import DateTime, ForeignKey, Index, String, Text, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.database import Base


def _now() -> datetime:
    return datetime.now(timezone.utc)


class Registration(Base):
    __tablename__ = "registrations"
    __table_args__ = (
        UniqueConstraint("championship_id", "user_id", name="uq_registration_champ_user"),
        Index("idx_registrations_championship_id", "championship_id"),
        Index("idx_registrations_user_id", "user_id"),
    )

    id: Mapped[uuid.UUID] = mapped_column(primary_key=True, default=uuid.uuid4)
    championship_id: Mapped[uuid.UUID] = mapped_column(
        ForeignKey("championships.id", ondelete="CASCADE"), nullable=False
    )
    user_id: Mapped[uuid.UUID] = mapped_column(
        ForeignKey("users.id", ondelete="CASCADE"), nullable=False
    )
    category: Mapped[str | None] = mapped_column(String(255))
    level: Mapped[str | None] = mapped_column(String(255))
    notes: Mapped[str | None] = mapped_column(Text)
    status: Mapped[str] = mapped_column(String(20), nullable=False, default="submitted")
    # 'submitted' | 'accepted' | 'rejected' | 'waitlisted'
    submitted_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_now)
    decided_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True))
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_now)
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), default=_now, onupdate=_now
    )

    championship: Mapped["Championship"] = relationship(back_populates="registrations")
    user: Mapped["User"] = relationship(back_populates="registrations")
    notification_logs: Mapped[list["NotificationLog"]] = relationship(
        back_populates="registration"
    )