Add error pop-up if admin is trying to add a user to event host group

physionet-django/console/templates/console/user_management.html

@@ -9,13 +9,13 @@
 {% block content %}
 
 <div class="col-md-9 no-pd">
-  {% if perms.self.invite_event_host%}
-    {% if user|has_group:'Event Host' %}
+  {% if perms.self.invite_event_host %}
       <form action="{% url 'event_invite_host' subject.username %}" method="post" class="form-signin" onsubmit="return confirm('Are you sure you would like to add this user as an event host?')">
       {% csrf_token %}
       <button class="btn btn-success btn-fixed" id="invite_host_button">Invite event host</button>
       </form>
-    {% endif %}
+    {% elif is_event_host %}
+      <p>{{ subject.username }} is already an Event host.</p>
   {% endif %}
   <h1>{{ subject.get_full_name }} ({{ subject.username }})</h1>
   <br />

physionet-django/console/views.py

@@ -3121,14 +3121,19 @@ def event_invite_host(request, username):
     """
     Gives the user permissions to be an event host
     """
-    if request.method == 'POST':
-        try:
-            user = get_object_or_404(User, username=username)
-            group = Group.objects.get(name='Event Host')
+    try:
+        user = get_object_or_404(User, username=username)
+        group = Group.objects.get(name='Event Host')
+        is_event_host = user.groups.filter(name='Event Host').exists()
+
+        if not is_event_host and request.method == 'POST':
             user.groups.add(group)
             user.save()
             messages.success(request, f"{user} has been added to the Event Host group.")
-        except User.DoesNotExist:
-            messages.error(request, "User not found.")
+        elif is_event_host:
+            messages.error(request, f"{user} is already an Event Host.")
+
+    except User.DoesNotExist:
+        messages.error(request, "User not found.")
 
     return redirect(reverse('user_management', args=[username]))