DDD refactor: domain-based structure + dependency injection

- Restructured to DDD domains (user/, auth/, admin/, core/)
- Renamed src/ → app/ to match FastAPI conventions
- Removed all src.* import prefixes
- Converted services to DI pattern (removed @staticmethod)
- Created dependencies.py in each domain for service injection
- Updated all routes to inject services via Depends()
- Kept capital letter model naming (User.py, RefreshToken.py)
- Updated Docker, alembic, and test files
- Set PYTHONPATH=/app/app for clean imports

Import style:
- Relative within domain: from .User import User
- No prefix for core: from core.database import ...
- Domain name for cross-domain: from user.repository import ...

Author: CarterPerez-dev

backend/alembic/env.py

@@ -11,8 +11,10 @@
 from sqlalchemy.ext.asyncio import async_engine_from_config
 
 from config import settings
-from models import Base
+from core.Base import Base
 from core.enums import SafeEnum
+from user.User import User
+from auth.RefreshToken import RefreshToken
 
 
 config = context.config

backend/app/admin/routes.py

@@ -17,10 +17,7 @@
     settings,
     UserRole,
 )
-from core.dependencies import (
-    DBSession,
-    RequireRole,
-)
+from core.dependencies import RequireRole
 from core.responses import (
     AUTH_401,
     CONFLICT_409,
@@ -34,7 +31,7 @@
     UserUpdateAdmin,
 )
 from user.User import User
-from user.service import UserService
+from user.dependencies import UserServiceDep
 
 
 router = APIRouter(prefix = "/admin", tags = ["admin"])
@@ -51,7 +48,7 @@
     },
 )
 async def list_users(
-    db: DBSession,
+    user_service: UserServiceDep,
     _: AdminOnly,
     page: int = Query(default = 1,
                       ge = 1),
@@ -64,7 +61,7 @@ async def list_users(
     """
     List all users (admin only)
     """
-    return await UserService.list_users(db, page, size)
+    return await user_service.list_users(page, size)
 
 
 @router.post(
@@ -78,14 +75,14 @@ async def list_users(
     },
 )
 async def create_user(
-    db: DBSession,
+    user_service: UserServiceDep,
     _: AdminOnly,
     user_data: AdminUserCreate,
 ) -> UserResponse:
     """
     Create a new user (admin only, bypasses registration)
     """
-    return await UserService.admin_create_user(db, user_data)
+    return await user_service.admin_create_user(user_data)
 
 
 @router.get(
@@ -98,14 +95,14 @@ async def create_user(
     },
 )
 async def get_user(
-    db: DBSession,
+    user_service: UserServiceDep,
     _: AdminOnly,
     user_id: UUID,
 ) -> UserResponse:
     """
     Get user by ID (admin only)
     """
-    return await UserService.get_user_by_id(db, user_id)
+    return await user_service.get_user_by_id(user_id)
 
 
 @router.patch(
@@ -119,15 +116,15 @@ async def get_user(
     },
 )
 async def update_user(
-    db: DBSession,
+    user_service: UserServiceDep,
     _: AdminOnly,
     user_id: UUID,
     user_data: UserUpdateAdmin,
 ) -> UserResponse:
     """
     Update user (admin only)
     """
-    return await UserService.admin_update_user(db, user_id, user_data)
+    return await user_service.admin_update_user(user_id, user_data)
 
 
 @router.delete(
@@ -140,11 +137,11 @@ async def update_user(
     },
 )
 async def delete_user(
-    db: DBSession,
+    user_service: UserServiceDep,
     _: AdminOnly,
     user_id: UUID,
 ) -> None:
     """
     Delete user (admin only, hard delete)
     """
-    await UserService.admin_delete_user(db, user_id)
+    await user_service.admin_delete_user(user_id)

backend/app/auth/dependencies.py

@@ -0,0 +1,21 @@
+"""
+ⒸAngelaMos | 2025
+dependencies.py
+"""
+
+from typing import Annotated
+
+from fastapi import Depends
+
+from core.dependencies import DBSession
+from .service import AuthService
+
+
+def get_auth_service(db: DBSession) -> AuthService:
+    """
+    Dependency to inject AuthService instance
+    """
+    return AuthService(db)
+
+
+AuthServiceDep = Annotated[AuthService, Depends(get_auth_service)]

backend/app/auth/routes.py

@@ -21,7 +21,6 @@
 from core.dependencies import (
     ClientIP,
     CurrentUser,
-    DBSession,
 )
 from core.security import (
     clear_refresh_cookie,
@@ -35,8 +34,8 @@
     TokenWithUserResponse,
 )
 from user.schemas import UserResponse
-from .service import AuthService
-from user.service import UserService
+from .dependencies import AuthServiceDep
+from user.dependencies import UserServiceDep
 from core.responses import AUTH_401
 
 
@@ -52,16 +51,15 @@
 async def login(
     request: Request,
     response: Response,
-    db: DBSession,
+    auth_service: AuthServiceDep,
     ip: ClientIP,
     form_data: Annotated[OAuth2PasswordRequestForm,
                          Depends()],
 ) -> TokenWithUserResponse:
     """
     Login with email and password
     """
-    result, refresh_token = await AuthService.login(
-        db,
+    result, refresh_token = await auth_service.login(
         email=form_data.username,
         password=form_data.password,
         ip_address=ip,
@@ -76,7 +74,7 @@ async def login(
     responses = {**AUTH_401}
 )
 async def refresh_token(
-    db: DBSession,
+    auth_service: AuthServiceDep,
     ip: ClientIP,
     refresh_token: str | None = Cookie(None),
 ) -> TokenResponse:
@@ -85,8 +83,7 @@ async def refresh_token(
     """
     if not refresh_token:
         raise TokenError("Refresh token required")
-    return await AuthService.refresh_tokens(
-        db,
+    return await auth_service.refresh_tokens(
         refresh_token,
         ip_address = ip
     )
@@ -99,29 +96,29 @@ async def refresh_token(
 )
 async def logout(
     response: Response,
-    db: DBSession,
+    auth_service: AuthServiceDep,
     refresh_token: str | None = Cookie(None),
 ) -> None:
     """
     Logout current session
     """
     if not refresh_token:
         raise TokenError("Refresh token required")
-    await AuthService.logout(db, refresh_token)
+    await auth_service.logout(refresh_token)
     clear_refresh_cookie(response)
 
 
 @router.post("/logout-all", responses = {**AUTH_401})
 async def logout_all(
     response: Response,
-    db: DBSession,
+    auth_service: AuthServiceDep,
     current_user: CurrentUser,
 ) -> dict[str,
           int]:
     """
     Logout from all devices
     """
-    count = await AuthService.logout_all(db, current_user)
+    count = await auth_service.logout_all(current_user)
     clear_refresh_cookie(response)
     return {"revoked_sessions": count}
 
@@ -140,15 +137,14 @@ async def get_current_user(current_user: CurrentUser) -> UserResponse:
     responses = {**AUTH_401}
 )
 async def change_password(
-    db: DBSession,
+    user_service: UserServiceDep,
     current_user: CurrentUser,
     data: PasswordChange,
 ) -> None:
     """
     Change current user password
     """
-    await UserService.change_password(
-        db,
+    await user_service.change_password(
         current_user,
         data.current_password,
         data.new_password,