diff --git a/index.py b/index.py
index 0b87b12..2c2dc70 100644
--- a/index.py
+++ b/index.py
@@ -1,58 +1,77 @@
 from __future__ import print_function
 
 import time
-from typing import Any, Dict, Optional
+from typing import Any
 
-from fastapi import FastAPI
+from fastapi import FastAPI, HTTPException
 
 from typing import Optional
 
 from sqlmodel import Field, Session, SQLModel, create_engine, select
 
+
 class User(SQLModel, table=True):
-    # TODO change the default value to the timestamp that the user is created
-    id: Optional[int] = Field(default=None, primary_key=True)
+    id: Optional[int] = Field(default=int(time.time()), primary_key=True)
     name: str
     secret_name: str
     age: Optional[str] = None
-      
+
+
 engine = create_engine("sqlite:///database.db")
 SQLModel.metadata.create_all(engine)
 # Create an instance of the API class
 app = FastAPI()
 
+
 @app.get("/")
-async def root():
+async def root():  # some information (about the user) is missing here
     # TODO include the user's name if they are logged in
-    return {"message": "Hello {}".format("World")}
+    with Session(engine) as session:
+        logged_in = False
+
+        # Either it must be checked here whether the user is logged in or the possibility of logging in must be given
+        # and the input data must be compared with those from the database.
+        # I would have to read something about authentication with FastAPI before implementing this assignment,
+        # but I would take this as a baseline: https://fastapi.tiangolo.com/tutorial/security/get-current-user/
+
+        user = User(name="Dummy", secret_name="dummyuser")  # TODO replace with real user name
+        if logged_in:
+            return {"message": "Hello {}".format(user.name)}
+        return {"message": "Hello {}".format("World")}
 
 
 @app.post("/user")
 async def create_new_user(*, user: User):
     with Session(engine) as session:
-      session.add(user)
-      session.commit()
-    # TODO return the User ID
-    return {"message": "User created"}
-    
+        # check if user ID exists
+        #   Alternatively, the ID could be increased by (e. g.) 1 each, but since the default value time.time()
+        #   is of the float data type, but the default of the data model is int, this would have a big negative impact
+        #   on performance when adding many users at once.
+        #   Or one has to use float as data type or another library than "time"
+        statement = select(User).where(User.id == user.id)
+        user_count = len(session.exec(statement).all())
+        if user_count > 0:
+            return {"message": "User {} already exists".format(user.id)}
+
+        # add user to DB
+        session.add(user)
+        session.commit()
+
+        return {"message": "User {} created".format(user.id)}  # was wrong indented
+
+
 @app.get("/user/{id}")
 async def get_user(id: int):
-  with Session(engine) as session:
-     # TODO return the user based on the ID (and an error if not)
-     statement = select(User).where(User.name == id)
-     user = session.exec(statement).first()
-     return {"user": user}
+    with Session(engine) as session:
+        statement = select(User).where(User.id == id)  # was User.name
+        user = session.exec(statement).first()
+        if user is not None:
+            return {"user": user}
+        else:
+            raise HTTPException(status_code=404, detail="User {} could not be found".format(id))
+
 
 @app.get("/api/webhooks")
 async def handle_hook(*, event: Any):
     id = event.payload.conversation.id
     return {"message": "Hello World"}
-  
-
-
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-