from __future__ import annotations

import uuid
from typing import TYPE_CHECKING

from sqlalchemy import Boolean, Enum, ForeignKey, String
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.db.base import Base, TimestampMixin, UUIDPrimaryKeyMixin
from app.models.enums import NotificationType, SeverityLevel

if TYPE_CHECKING:
    from app.models.company import Company


class NotificationDestination(Base, UUIDPrimaryKeyMixin, TimestampMixin):
    __tablename__ = "notification_destinations"

    user_id: Mapped[uuid.UUID] = mapped_column(
        ForeignKey("users.id", ondelete="CASCADE"), index=True
    )
    type: Mapped[NotificationType] = mapped_column(
        Enum(NotificationType, native_enum=False, length=20)
    )
    # Email address, phone number, or a label for the console provider.
    # Not a secret, but still PII - see SECURITY.md.
    destination_value: Mapped[str] = mapped_column(String(320))
    verified: Mapped[bool] = mapped_column(Boolean, default=False)
    enabled: Mapped[bool] = mapped_column(Boolean, default=True)
    minimum_severity: Mapped[SeverityLevel] = mapped_column(
        Enum(SeverityLevel, native_enum=False, length=20), default=SeverityLevel.MEDIUM
    )

    company_links: Mapped[list[NotificationDestinationCompany]] = relationship(
        back_populates="destination", cascade="all, delete-orphan"
    )


class NotificationDestinationCompany(Base, TimestampMixin):
    """Which companies a destination receives alerts for - a destination
    with zero links is orphaned and gets garbage-collected (see
    notification_destination_service.py) rather than left dangling."""

    __tablename__ = "notification_destination_companies"

    destination_id: Mapped[uuid.UUID] = mapped_column(
        ForeignKey("notification_destinations.id", ondelete="CASCADE"), primary_key=True
    )
    company_id: Mapped[uuid.UUID] = mapped_column(
        ForeignKey("companies.id", ondelete="CASCADE"), primary_key=True
    )

    destination: Mapped[NotificationDestination] = relationship(back_populates="company_links")
    # Read-only path to the company's name for display; Company.notification_links
    # (used only for cascade-delete) writes the same FK from the other direction,
    # hence overlaps= to tell SQLAlchemy that's intentional, not a conflict.
    company: Mapped[Company] = relationship(overlaps="notification_links")