working with login and building inventory

trade-hub/backend/app/models.py

@@ -0,0 +1,93 @@
+"""SQLAlchemy models for mutable user data (accounts + personal inventories).
+
+The scunpacked catalog is deliberately NOT modeled here. It stays read-only in
+memory (see app/catalog.py); inventory rows reference catalog items only by
+`class_name`, so the catalog can be replaced wholesale without touching user
+data.
+"""
+from datetime import datetime, timezone
+
+from sqlalchemy import (
+    CheckConstraint,
+    DateTime,
+    ForeignKey,
+    Integer,
+    String,
+    Text,
+    UniqueConstraint,
+)
+from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column, relationship
+
+
+def utcnow() -> datetime:
+    """Timezone-aware current time (portable across SQLite and PostgreSQL)."""
+    return datetime.now(timezone.utc)
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+class User(Base):
+    __tablename__ = "users"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    # Display name as typed at registration.
+    username: Mapped[str] = mapped_column(String(32), nullable=False)
+    # Lowercased form, unique: gives case-insensitive uniqueness without citext.
+    username_key: Mapped[str] = mapped_column(
+        String(32), nullable=False, unique=True, index=True
+    )
+    password_hash: Mapped[str] = mapped_column(String(255), nullable=False)
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, default=utcnow
+    )
+
+    sessions: Mapped[list["UserSession"]] = relationship(
+        back_populates="user", cascade="all, delete-orphan"
+    )
+    inventory: Mapped[list["InventoryEntry"]] = relationship(
+        back_populates="user", cascade="all, delete-orphan"
+    )
+
+
+class UserSession(Base):
+    __tablename__ = "sessions"
+
+    # Only the SHA-256 of the cookie token is persisted.
+    token_hash: Mapped[str] = mapped_column(String(64), primary_key=True)
+    user_id: Mapped[int] = mapped_column(
+        ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True
+    )
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, default=utcnow
+    )
+    expires_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False
+    )
+
+    user: Mapped[User] = relationship(back_populates="sessions")
+
+
+class InventoryEntry(Base):
+    __tablename__ = "inventory_entries"
+    __table_args__ = (
+        UniqueConstraint("user_id", "class_name", name="uq_inventory_user_item"),
+        CheckConstraint("quantity >= 1", name="ck_inventory_quantity_positive"),
+    )
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    user_id: Mapped[int] = mapped_column(
+        ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True
+    )
+    class_name: Mapped[str] = mapped_column(String(255), nullable=False)
+    quantity: Mapped[int] = mapped_column(Integer, nullable=False, default=1)
+    notes: Mapped[str] = mapped_column(Text, nullable=False, default="")
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, default=utcnow
+    )
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, default=utcnow, onupdate=utcnow
+    )
+
+    user: Mapped[User] = relationship(back_populates="inventory")