group bugs and authorization improvements by codex

auth.py

@@ -93,13 +93,22 @@ def login():
 @auth_bp.route("/register", methods=["GET", "POST"])
 def register():
     if request.method == "POST":
-        user = User(name=request.form["name"])
-        user.set_password(request.form["password"])
-        group_id = user.get_group_id(request.form["password"])
-        if group_id > 0:
-            user.group_id = group_id
-            db.session.add(user)
-            db.session.commit()
+        name = request.form["name"].strip()
+        password = request.form["password"]
+
+        existing_user = User.query.filter_by(name=name).first()
+        if existing_user:
+            return render_template("register.html", error="That name is already registered.")
+
+        user = User(name=name)
+        group_id = user.set_group_id(password)
+        if group_id == 0:
+            return render_template("register.html", error="Unknown registration key.")
+
+        user.set_password(password)
+        user.group_id = group_id
+        db.session.add(user)
+        db.session.commit()
         return render_template("pending.html")
     return render_template("register.html")
 
@@ -130,4 +139,4 @@ def change_pwd():
         Log.info(f"Authorization failure for user '{request.form["name"]}' ")
 
         return render_template(url_for("lists.home"))
-    return render_template("change_pwd.html")
+    return render_template("change_pwd.html")