Add Eternal September.

EternalSeptember/eternalseptember.py

@@ -0,0 +1,50 @@
+import datetime
+import time
+
+EPOCH = datetime.datetime(
+    year=1993,
+    month=9,
+    day=1,
+    tzinfo=datetime.timezone.utc,
+)
+
+def normalize_date(date):
+    if isinstance(date, datetime.datetime):
+        pass
+    elif isinstance(date, (int, float)):
+        date = datetime.datetime.utcfromtimestamp(date)
+        date = date.replace(tzinfo=datetime.timezone.utc)
+    else:
+        raise TypeError('Unrecognized date type.')
+
+    return date
+
+def now():
+    return datetime.datetime.now(datetime.timezone.utc)
+
+def september_day(date):
+    '''
+    Return the ES day of the month for this date.
+    '''
+    date = normalize_date(date)
+    diff = date - EPOCH
+    days = diff.days + 1
+    return days
+
+def september_string(date, strftime):
+    '''
+    Return the ES formatted string for this date.
+    '''
+    date = normalize_date(date)
+    day = str(september_day(date))
+
+    strftime = strftime.replace('%a', date.strftime('%a'))
+    strftime = strftime.replace('%A', date.strftime('%A'))
+    strftime = strftime.replace('%d', day)
+    strftime = strftime.replace('%-d', day)
+
+    date = date.replace(month=EPOCH.month, year=EPOCH.year)
+    return date.strftime(strftime)
+
+if __name__ == '__main__':
+    print(september_string(now(), '%Y %B %d %H:%M:%S'))