feat: auth backend implementation

backend/app/crud.py

@@ -1,5 +1,6 @@
 from sqlalchemy.orm import Session
 from app import models, schemas
+from app.utils import hash_password, verify_password
 
 
 def get_item(db: Session, item_id: int):
@@ -24,3 +25,34 @@ def delete_item(db: Session, item_id: int):
         db.delete(item)
         db.commit()
     return item
+
+
+# User / Auth
+
+
+def authenticate_user(db: Session, username: str, password: str):
+    user = get_user_by_username(db, username)
+    if not user:
+        return None
+    if not verify_password(password, str(user.hashed_password)):
+        return None
+    return user
+
+
+def get_user_by_username(db: Session, username: str):
+    return db.query(models.User).filter(models.User.username == username).first()
+
+
+def get_user_by_email(db: Session, email: str):
+    return db.query(models.User).filter(models.User.email == email).first()
+
+
+def create_user(db: Session, user: schemas.UserCreate):
+    hashed_pw = hash_password(user.password)
+    db_user = models.User(
+        username=user.username, email=user.email, hashed_password=hashed_pw
+    )
+    db.add(db_user)
+    db.commit()
+    db.refresh(db_user)
+    return db_user