add accumulation of captured time

model/TimeSlot.py

@@ -42,3 +42,8 @@ class TimeSlot():
 
     def end_now(self):
         self.end = datetime.now()
+
+    def duration(self) -> datetime.timedelta:
+        end = self.end
+        if not end: end = datetime.now()
+        return self.end - self.start

model/TimeSlotContainer.py

@@ -1,4 +1,6 @@
-from datetime import date, datetime
+import re
+
+from datetime import date, datetime, timedelta
 from model.DataStore import DataStore
 from model.TimeSlot import TimeSlot
 
@@ -43,5 +45,12 @@ class TimeSlotContainer:
     def delete_time_slot(self, ts: TimeSlot):
         raise NotImplementedError
 
+    def accumulate_duration(self, query: str) -> timedelta:
+        pattern = re.compile(query)
+        return sum([ts.duration() for ts in self._ds.get_all_time_slots()
+                    if pattern.search(ts.name) ], start=timedelta(0))
 
-time_slot_container = TimeSlotContainer(DataStore("data.json"))
+try:
+    time_slot_container = TimeSlotContainer(DataStore("data.json"))
+except FileNotFoundError:
+    time_slot_container = TimeSlotContainer(DataStore("data.json", create=True))