from __future__ import annotations

from datetime import datetime, timezone

from sqlalchemy import Boolean, DateTime, ForeignKey, Integer, String, Text
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.core.db.common import CommonBase


class UserAlert(CommonBase):
    """Common role-aware alert table for all dashboards and portals.

    Phase 7H foundation only stores and displays alerts. Later phases can call
    app.modules.alerts.service.create_alert() from task, document, attendance,
    client and consultant workflows without changing this schema.
    """

    __tablename__ = "user_alerts"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    tenant_id: Mapped[int | None] = mapped_column(ForeignKey("tenants.id", ondelete="CASCADE"), nullable=True, index=True)
    branch_id: Mapped[int | None] = mapped_column(ForeignKey("branches.id", ondelete="SET NULL"), nullable=True, index=True)
    user_id: Mapped[int] = mapped_column(ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True)

    role_context: Mapped[str | None] = mapped_column(String(50), nullable=True, index=True)
    alert_type: Mapped[str] = mapped_column(String(80), nullable=False, default="general", index=True)
    priority: Mapped[str] = mapped_column(String(20), nullable=False, default="normal", index=True)
    title: Mapped[str] = mapped_column(String(255), nullable=False)
    message: Mapped[str | None] = mapped_column(Text, nullable=True)
    target_url: Mapped[str | None] = mapped_column(String(500), nullable=True)

    is_read: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False, index=True)
    read_at_utc: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    created_at_utc: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), nullable=False, index=True
    )
    created_by_user_id: Mapped[int | None] = mapped_column(ForeignKey("users.id", ondelete="SET NULL"), nullable=True)

    user = relationship("User", foreign_keys=[user_id])
    created_by = relationship("User", foreign_keys=[created_by_user_id])