Introduce a mixin plugin with time unit handling helper functions

dream/plugins/TimeSupport.py

+from datetime import datetime
+from datetime import timedelta
+import random
+from pprint import pformat
+
+from dream.plugins import plugin
+
+class TimeSupportMixin(object):
+  """Helper methods to handle time units.
+  """
+  initialized = False
+
+  def initializeTimeSupport(self, data):
+    self.timeUnitPerDay = data['general']['timeUnitPerDay']
+    self.dateFormat = data['general'].get('dateFormat', '%Y/%m/%d %H:%M:%S')
+    # Convert simulation 0 time to real world time
+    self.now = datetime.strptime(data['general']['currentDate'], self.dateFormat)
+    self.initialized = True
+
+  def convertToRealWorldTime(self, simulation_time):
+    """Convert simulation clock time to real world time, as python datetime object.
+    """
+    assert self.initialized, "initializeTimeSupport has not been called"
+    return self.now + timedelta(days=simulation_time/self.timeUnitPerDay)
+
+  def convertToSimulationTime(self, real_world_time):
+    """Convert real world time (as python datetime object) to simulation clock time.
+    """
+    assert self.initialized, "initializeTimeSupport has not been called"
+    raise NotImplementedError
+
+  def getTimeUnitText(self):
+    """Return the time unit as text.
+    """
+    assert self.initialized, "initializeTimeSupport has not been called"
+    if self.timeUnitPerDay == 24 * 60:
+      return 'minute'
+    if self.timeUnitPerDay == 24:
+      return 'hour'
+    if self.timeUnitPerDay == 1:
+      return 'day'
+    if self.timeUnitPerDay == 1/7.:
+      return 'week'
+    if self.timeUnitPerDay == 1/30.:
+      return 'month'
+    if timeUnitPerDay == 1/360.:
+      return 'year'
+    raise ValueError("Unsupported time unit %s" % self.timeUnitPerDay)
+