Show playtime total on session list

Fixes #6
Fixes #25

src/web/tracker/models.py

@@ -3,7 +3,7 @@ from datetime import datetime, timedelta
 from django.conf import settings
 from zoneinfo import ZoneInfo
 from common.util.time import format_duration
-from django.db.models import Sum
+from django.db.models import Sum, F
 
 
 class Game(models.Model):
@@ -32,69 +32,51 @@ class Platform(models.Model):
         return self.name
 
 
+class SessionQuerySet(models.QuerySet):
+    def total_duration(self):
+        result = self.aggregate(
+            duration=Sum(F("duration_calculated") + F("duration_manual"))
+        )
+        return format_duration(result["duration"])
+
+
 class Session(models.Model):
     purchase = models.ForeignKey("Purchase", on_delete=models.CASCADE)
     timestamp_start = models.DateTimeField()
     timestamp_end = models.DateTimeField(blank=True, null=True)
-    duration_manual = models.DurationField(blank=True, null=True)
+    duration_manual = models.DurationField(blank=True, null=True, default=timedelta(0))
     duration_calculated = models.DurationField(blank=True, null=True)
     note = models.TextField(blank=True, null=True)
 
+    objects = SessionQuerySet.as_manager()
+
     def __str__(self):
         mark = ", manual" if self.duration_manual != None else ""
-        return f"{str(self.purchase)} {str(self.timestamp_start.date())} ({self.duration_any()}{mark})"
+        return f"{str(self.purchase)} {str(self.timestamp_start.date())} ({self.duration_formatted()}{mark})"
 
     def finish_now(self):
         self.timestamp_end = datetime.now(ZoneInfo(settings.TIME_ZONE))
 
     def duration_seconds(self) -> timedelta:
-        if self.duration_manual == None:
-            if self.timestamp_end == None or self.timestamp_start == None:
-                return timedelta(0)
-            else:
-                value = self.timestamp_end - self.timestamp_start
-        else:
-            value = self.duration_manual
-        return timedelta(seconds=value.total_seconds())
+        manual = timedelta(0)
+        calculated = timedelta(0)
+        if not self.duration_manual in (None, 0, timedelta(0)):
+            manual = self.duration_manual
+        if self.timestamp_end != None and self.timestamp_start != None:
+            calculated = self.timestamp_end - self.timestamp_start
+        return timedelta(seconds=(manual + calculated).total_seconds())
 
     def duration_formatted(self) -> str:
         result = format_duration(self.duration_seconds(), "%H:%m")
         return result
 
-    def duration_any(self):
-        return (
-            self.duration_formatted()
-            if self.duration_manual == None
-            else self.duration_manual
-        )
-
-    @staticmethod
-    def calculated_sum() -> timedelta:
-        calculated_sum_query = Session.objects.all().aggregate(
-            Sum("duration_calculated")
-        )
-        calculated_sum = (
-            timedelta(0)
-            if calculated_sum_query["duration_calculated__sum"] == None
-            else calculated_sum_query["duration_calculated__sum"]
-        )
-        return calculated_sum
-
-    @staticmethod
-    def manual_sum() -> timedelta:
-        manual_sum_query = Session.objects.all().aggregate(Sum("duration_manual"))
-        manual_sum = (
-            timedelta(0)
-            if manual_sum_query["duration_manual__sum"] == None
-            else manual_sum_query["duration_manual__sum"]
-        )
-        return manual_sum
-
-    @staticmethod
-    def total_sum() -> timedelta:
-        return Session.manual_sum() + Session.calculated_sum()
+    @property
+    def duration_sum(self) -> str:
+        return Session.objects.all().total_duration()
 
     def save(self, *args, **kwargs):
         if self.timestamp_start != None and self.timestamp_end != None:
             self.duration_calculated = self.timestamp_end - self.timestamp_start
+        else:
+            self.duration_calculated = timedelta(0)
         super(Session, self).save(*args, **kwargs)