better plan actual comparison

rowers/models.py

@@ -1805,6 +1805,26 @@ class TrainingPlan(models.Model):
         else:
             createmacrofillers(self)
 
+    def length(self):
+        startdate = self.startdate
+        enddate = self.enddate
+        return (enddate-startdate).days
+
+    def overlap(self,startdate,enddate):
+        is_overlapped = max(self.startdate, startdate) < min(self.enddate, enddate)
+        if not is_overlapped:
+            return 0
+
+        if startdate >= self.startdate:
+            if self.enddate >= enddate:
+                return (enddate-startdate).days
+            else:
+                return (self.enddate-startdate).days
+        elif startdate < self.startdate:
+            if enddate >= self.enddate:
+                return (self.enddate-self.startdate).days
+            else:
+                return (enddate-self.startdate).days
 
 def check_trainingplan_on_change(sender, **kwargs):
     instance = kwargs.pop('instance', None)