from datetime import UTC, datetime
from typing import TYPE_CHECKING

from sqlalchemy import INTEGER, DateTime, Enum, ForeignKey, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column, relationship

from db.base import Base
from schemas.enums import NotificationStatus, NotificationType

if TYPE_CHECKING:
    from db.models import Subscription


class ServiceNotification(Base):
    __tablename__ = "service_notifications"

    id: Mapped[int] = mapped_column(
        INTEGER, unique=True, autoincrement=True, primary_key=True, nullable=False
    )
    subscription_id: Mapped[int] = mapped_column(
        ForeignKey("subscriptions.id"), nullable=False, unique=False
    )
    notify_type: Mapped[NotificationType] = mapped_column(
        Enum(NotificationType, name="notificationtype"), nullable=False
    )
    sub_expires_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)

    status: Mapped[NotificationStatus] = mapped_column(
        Enum(NotificationStatus, name="notificationstatus"),
        nullable=False,
        default=NotificationStatus.PENDING,
    )
    dispatched_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=True)
    sent_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=True)
    attempts: Mapped[int] = mapped_column(INTEGER, nullable=False, default=0)

    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        nullable=False,
        default=lambda: datetime.now(UTC),
    )

    __table_args__ = (
        UniqueConstraint(
            "subscription_id",
            "notify_type",
            "sub_expires_at",
            name="uq_subscription_notification",
        ),
    )

    subscription: Mapped["Subscription"] = relationship("Subscription", lazy="selectin")