Refactor architecture documentation and enhance security features

- Updated architecture constraints documentation to include detailed sections on technical, organizational, regulatory, environmental, and performance constraints.
- Created separate markdown files for each type of constraint for better organization and clarity.
- Revised the architecture scope section to provide a clearer overview of the system's key areas.
- Enhanced the solution strategy documentation with detailed explanations of the client-server architecture, technology choices, trade-offs, and future considerations.
- Added comprehensive descriptions of backend and frontend components, middleware, and utilities in the architecture documentation.
- Migrated UI, templates, and styling notes to a dedicated section for better structure.
- Updated requirements.txt to include missing dependencies.
- Refactored user authentication logic in the users.py and security.py files to improve code organization and maintainability, including the integration of OAuth2 password bearer token handling.

services/security.py

@@ -1,8 +1,13 @@
 from datetime import datetime, timedelta
 from typing import Any, Union
 
-from jose import jwt
+from fastapi import HTTPException, status, Depends
+from fastapi.security import OAuth2PasswordBearer
+from jose import jwt, JWTError
 from passlib.context import CryptContext
+from sqlalchemy.orm import Session
+
+from config.database import get_db
 
 
 ACCESS_TOKEN_EXPIRE_MINUTES = 30
@@ -11,6 +16,8 @@ ALGORITHM = "HS256"
 
 pwd_context = CryptContext(schemes=["pbkdf2_sha256"], deprecated="auto")
 
+oauth2_scheme = OAuth2PasswordBearer(tokenUrl="users/login")
+
 
 def create_access_token(
     subject: Union[str, Any], expires_delta: Union[timedelta, None] = None
@@ -30,3 +37,23 @@ def verify_password(plain_password: str, hashed_password: str) -> bool:
 
 def get_password_hash(password: str) -> str:
     return pwd_context.hash(password)
+
+
+async def get_current_user(token: str = Depends(oauth2_scheme), db: Session = Depends(get_db)):
+    from models.user import User
+    credentials_exception = HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail="Could not validate credentials",
+        headers={"WWW-Authenticate": "Bearer"},
+    )
+    try:
+        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
+        username = payload.get("sub")
+        if username is None:
+            raise credentials_exception
+    except JWTError:
+        raise credentials_exception
+    user = db.query(User).filter(User.username == username).first()
+    if user is None:
+        raise credentials_exception
+    return user