Study: Add time / date mode to study.

src/Model/Study.py

@@ -13,6 +13,9 @@ class Study(Serializable):
         # Study general information
         self.name = ""
         self.description = ""
+        # Time system
+        self._time_system = "time"
+        self._date = datetime.fromtimestamp(0)
 
         self.creation_date = datetime.now()
         self.last_modification_date = datetime.now()
@@ -21,13 +24,35 @@ class Study(Serializable):
         # Study data
         self.river = None
 
+    @property
+    def time_system(self):
+        return self._time_system
+
+    def use_time(self):
+        self._time_system = "time"
+
+    def use_date(self, date:datetime):
+        self._time_system = "date"
+        self._date = date
+
+    @property
+    def date(self):
+        return self._date
+
+    @date.setter
+    def date(self, timestamp):
+        self._date = timestamp
+
     @classmethod
     def new(cls):
         return cls()
 
     @classmethod
-    def new(cls, name, description):
+    def new(cls, name, description, date = None):
         me = cls()
         me.name = name
         me.description = description
+        if date is not None:
+            me.use_date()
+            me.date = date
         return me