[O] Better null safety

src/commands.py

@@ -198,12 +198,9 @@ def enable(update: Update, context: CallbackContext):
     if name not in database.userRequests[user]:
         return "*Error:* %s doesn't exist." % name
 
-    # Check if name is enabled
-    if scheduler.isStarted(user, name):
-        return "*Error:* %s is already enabled." % name
-
     # Start task
-    scheduler.start(user, database.userRequests[user][name])
+    if not scheduler.start(user, database.userRequests[user][name]):
+        return "*Error:* %s is already enabled." % name
 
     return "Started!"
 
@@ -218,11 +215,9 @@ def disable(update: Update, context: CallbackContext):
 
     # Check if name is running
     name = context.args[0]
-    if not scheduler.isStarted(user, name):
+    if not scheduler.stop(user, name):
         return "*Error:* %s isn't enabled." % name
 
-    scheduler.stop(user, name)
-
     return "Removed!"
 
 

src/scheduler.py

@@ -51,6 +51,10 @@ class Scheduler:
 
     def start(self, user: str, request):
         name = request['name']
+
+        if self.isStarted(user, name):
+            return False
+
         if user not in self.tasks:
             self.tasks[user] = {}
 
@@ -61,7 +65,12 @@ class Scheduler:
             request['enabled'] = True
             self.database.save()
 
+        return True
+
     def stop(self, user: str, name: str):
+        if not self.isStarted(user, name):
+            return False
+
         # Stop and remove task
         job = self.tasks[user][name]
         job.enabled = False
@@ -70,6 +79,8 @@ class Scheduler:
         self.database.userRequests[user][name]['enabled'] = False
         self.database.save()
 
+        return True
+
     def isStarted(self, user: str, name: str):
         return user in self.tasks and name in self.tasks[user]