Initial commit

backend/app/db/__init__.py

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+"""Database package."""
+

backend/app/db/session.py

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+from collections.abc import Generator
+
+from sqlalchemy import create_engine, inspect, text
+from sqlalchemy.orm import DeclarativeBase, Session, sessionmaker
+
+from app.core.config import settings
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+def build_engine(database_url: str):
+    connect_args: dict[str, object] = {}
+    if database_url.startswith("sqlite"):
+        connect_args["check_same_thread"] = False
+
+    return create_engine(database_url, future=True, connect_args=connect_args)
+
+
+engine = build_engine(settings.database_url)
+SessionLocal = sessionmaker(
+    bind=engine,
+    autoflush=False,
+    autocommit=False,
+    expire_on_commit=False,
+    class_=Session,
+)
+
+
+def get_db() -> Generator[Session, None, None]:
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+
+def init_db() -> None:
+    import app.models  # noqa: F401
+
+    # Keep a lightweight runtime bootstrap for empty local databases so the app
+    # can still start before Alembic is wired into every environment.
+    Base.metadata.create_all(bind=engine)
+    _upgrade_legacy_schema()
+
+
+def _upgrade_legacy_schema() -> None:
+    inspector = inspect(engine)
+    table_names = set(inspector.get_table_names())
+    if "users" not in table_names:
+        return
+
+    existing_columns = {column["name"] for column in inspector.get_columns("users")}
+    if "token_version" in existing_columns:
+        pass
+    else:
+        # Keep this compatibility path narrowly scoped for older local databases
+        # that predate the Alembic baseline migration.
+        with engine.begin() as connection:
+            connection.execute(
+                text(
+                    "ALTER TABLE users "
+                    "ADD COLUMN token_version INTEGER NOT NULL DEFAULT 0"
+                )
+            )
+
+    if "telegram_links" not in table_names:
+        Base.metadata.tables["telegram_links"].create(bind=engine)