feat: Sprint 1 foundation - FastAPI scaffold, DB schema, auth, seed data, mock WhatsApp, Docker

app/models/category.py

@@ -0,0 +1,37 @@
+"""Ticket category model with self-referencing parent for sub-categories."""
+
+from __future__ import annotations
+
+from sqlalchemy import ForeignKey, Integer, String
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.core.database import Base
+
+
+class Category(Base):
+    __tablename__ = "categories"
+
+    id: Mapped[int] = mapped_column(primary_key=True, autoincrement=True)
+    type: Mapped[str] = mapped_column(
+        String(20),
+        nullable=False,
+        comment="maintenance, cs, emergency",
+    )
+    name: Mapped[str] = mapped_column(String(100), nullable=False)
+    parent_id: Mapped[int | None] = mapped_column(
+        Integer,
+        ForeignKey("categories.id"),
+        nullable=True,
+    )
+    sla_urgency: Mapped[str | None] = mapped_column(
+        String(10),
+        nullable=True,
+        comment="urgent, high, medium, low",
+    )
+
+    # self-referencing relationship
+    children: Mapped[list[Category]] = relationship("Category", back_populates="parent", cascade="all, delete-orphan")
+    parent: Mapped[Category | None] = relationship("Category", back_populates="children", remote_side="Category.id")
+
+    def __repr__(self) -> str:
+        return f"<Category {self.type}:{self.name}>"