Do not create protocols if the type already has one on that day

/close #97
/close #187

models/database.py

@@ -105,6 +105,12 @@ class ProtocolType(DatabaseModel):
             return None
         return candidates[0]
 
+    def get_protocols_on_date(self, protocol_date):
+        return [
+            protocol for protocol in self.protocols
+            if protocol.date == protocol_date
+        ]
+
     def has_public_view_right(self, user, check_networks=True):
         return (
             self.has_public_anonymous_view_right(check_networks=check_networks)
@@ -423,7 +429,12 @@ class Protocol(DatabaseModel):
             tzinfo=tz.tzlocal())
 
     @staticmethod
-    def create_new_protocol(protocoltype, date, start_time=None):
+    def create_new_protocol(
+            protocoltype, date, start_time=None, allow_duplicate=False):
+        if not allow_duplicate:
+            duplicate_candidates = protocoltype.get_protocols_on_date(date)
+            if duplicate_candidates:
+                return duplicate_candidates[0]
         if start_time is None:
             start_time = protocoltype.usual_time
         protocol = Protocol(

tasks.py

@@ -492,6 +492,7 @@ def parse_protocol_async_inner(protocol):
         if len(protocol_tag.values) > 1:
             new_protocol_time = datetime.strptime(
                 protocol_tag.values[1], "%H:%M")
+        if not protocol.protocoltype.get_protocols_on_date(new_protocol_date):
             Protocol.create_new_protocol(
                 protocol.protocoltype, new_protocol_date, new_protocol_time)