refactor: Introduce utility functions for exception handling and database operations; update auth and playlist services to use new exception methods

app/services/auth.py

@@ -20,6 +20,11 @@ from app.schemas.auth import (
 )
 from app.services.oauth import OAuthUserInfo
 from app.utils.auth import JWTUtils, PasswordUtils, TokenUtils
+from app.utils.exceptions import (
+    raise_bad_request,
+    raise_not_found,
+    raise_unauthorized,
+)
 
 logger = get_logger(__name__)
 
@@ -39,10 +44,7 @@ class AuthService:
 
         # Check if email already exists
         if await self.user_repo.email_exists(request.email):
-            raise HTTPException(
-                status_code=status.HTTP_400_BAD_REQUEST,
-                detail="Email address is already registered",
-            )
+            raise_bad_request("Email address is already registered")
 
         # Hash the password
         hashed_password = PasswordUtils.hash_password(request.password)
@@ -75,27 +77,18 @@ class AuthService:
         # Get user by email
         user = await self.user_repo.get_by_email(request.email)
         if not user:
-            raise HTTPException(
-                status_code=status.HTTP_401_UNAUTHORIZED,
-                detail="Invalid email or password",
-            )
+            raise_unauthorized("Invalid email or password")
 
         # Check if user is active
         if not user.is_active:
-            raise HTTPException(
-                status_code=status.HTTP_401_UNAUTHORIZED,
-                detail="Account is deactivated",
-            )
+            raise_unauthorized("Account is deactivated")
 
         # Verify password
         if not user.password_hash or not PasswordUtils.verify_password(
             request.password,
             user.password_hash,
         ):
-            raise HTTPException(
-                status_code=status.HTTP_401_UNAUTHORIZED,
-                detail="Invalid email or password",
-            )
+            raise_unauthorized("Invalid email or password")
 
         # Generate access token
         token = self._create_access_token(user)
@@ -110,16 +103,10 @@ class AuthService:
         """Get the current authenticated user."""
         user = await self.user_repo.get_by_id(user_id)
         if not user:
-            raise HTTPException(
-                status_code=status.HTTP_404_NOT_FOUND,
-                detail="User not found",
-            )
+            raise_not_found("User")
 
         if not user.is_active:
-            raise HTTPException(
-                status_code=status.HTTP_401_UNAUTHORIZED,
-                detail="Account is deactivated",
-            )
+            raise_unauthorized("Account is deactivated")
 
         return user