Add age_format template tag

We are still yet to internationalize that, but for now, it works fine in
English

booking/templatetags/booking_tags.py

@@ -0,0 +1,87 @@
+from django import template
+import math
+
+register = template.Library()
+
+def is_number(s):
+    try:
+        float(s)
+        return True
+    except ValueError:
+        return False
+
+@register.filter
+def age_format(value, arg = None):
+    if not is_number(value):
+        return value
+
+    ret = u""
+
+    years = math.floor(value / 31536000)
+    remainder = value % 31536000
+
+    if years > 0:
+        ret += u"%d year%s" % (years, "" if years == 1 else "s")
+
+        if arg != None:
+            return ret
+
+    months = math.floor(remainder / 2592000)
+    remainder = remainder % 2592000
+
+    if months > 0:
+        if (ret != ""):
+            ret += " "
+
+        ret += u"%d month%s" % (months, "" if months == 1 else "s")
+
+        if arg != None:
+            return ret
+
+    days = math.floor(remainder / 86400)
+    remainder = remainder % 86400
+
+    if arg != None and days == 0:
+        days = 1
+
+    if days > 0:
+        if (ret != ""):
+            ret += " "
+
+        ret += u"%d day%s" % (days, "" if days == 1 else "s")
+
+        if arg != None:
+            return ret
+
+    if arg != None:
+        raise RuntimeError("Value is strange, we should never arrive here!")
+
+    hours = math.floor(remainder / 3600)
+    remainder = remainder % 3600
+
+    if hours > 0:
+        if (ret != ""):
+            ret += " "
+
+        ret += u"%d hour%s" % (hours, "" if hours == 1 else "s")
+
+    minutes = math.floor(remainder / 60)
+
+    if minutes > 0:
+        if (ret != ""):
+            ret += " "
+
+        ret += u"%d minute%s" % (minutes, "" if minutes == 1 else "s")
+
+    seconds = round(remainder % 60)
+
+    if seconds > 0:
+        if (ret != ""):
+            ret += " "
+
+        ret += u"%d second%s" % (seconds, "" if seconds == 1 else "s")
+
+    if ret == "":
+        ret = "a few moments"
+
+    return ret

booking/tests.py

@@ -3,6 +3,7 @@ from django.utils import timezone
 
 import datetime
 
+from .templatetags import booking_tags
 from .models import Duck
 
 class FrontTest(TestCase):
@@ -25,3 +26,39 @@ class DuckAgeTest(TestCase):
     def test_duck_is_from_the_future(self):
         future_duck = Duck(donated_at = timezone.now() + datetime.timedelta(days = 2))
         self.assertEqual(future_duck.age(), -1)
+
+    def test_duck_age_formatter(self):
+        self.assertEqual(booking_tags.age_format("aoeu"), "aoeu")
+        self.assertEqual(booking_tags.age_format(0), "a few moments")
+        self.assertEqual(booking_tags.age_format(1), "1 second")
+        self.assertEqual(booking_tags.age_format(2), "2 seconds")
+        self.assertEqual(booking_tags.age_format(60), "1 minute")
+        self.assertEqual(booking_tags.age_format(61), "1 minute 1 second")
+        self.assertEqual(booking_tags.age_format(62), "1 minute 2 seconds")
+        self.assertEqual(booking_tags.age_format(120), "2 minutes")
+        self.assertEqual(booking_tags.age_format(3600), "1 hour")
+        self.assertEqual(booking_tags.age_format(3601), "1 hour 1 second")
+        self.assertEqual(booking_tags.age_format(3660), "1 hour 1 minute")
+        self.assertEqual(booking_tags.age_format(3720), "1 hour 2 minutes")
+        self.assertEqual(booking_tags.age_format(7200), "2 hours")
+        self.assertEqual(booking_tags.age_format(86400), "1 day")
+        self.assertEqual(booking_tags.age_format(86401), "1 day 1 second")
+        self.assertEqual(booking_tags.age_format(86460), "1 day 1 minute")
+        self.assertEqual(booking_tags.age_format(90000), "1 day 1 hour")
+        self.assertEqual(booking_tags.age_format(93600), "1 day 2 hours")
+        self.assertEqual(booking_tags.age_format(172800), "2 days")
+        self.assertEqual(booking_tags.age_format(2592000), "1 month")
+        self.assertEqual(booking_tags.age_format(2592001), "1 month 1 second")
+        self.assertEqual(booking_tags.age_format(2592060), "1 month 1 minute")
+        self.assertEqual(booking_tags.age_format(2595600), "1 month 1 hour")
+        self.assertEqual(booking_tags.age_format(2678400), "1 month 1 day")
+        self.assertEqual(booking_tags.age_format(2764800), "1 month 2 days")
+        self.assertEqual(booking_tags.age_format(5184000), "2 months")
+        self.assertEqual(booking_tags.age_format(31536000), "1 year")
+        self.assertEqual(booking_tags.age_format(31536001), "1 year 1 second")
+        self.assertEqual(booking_tags.age_format(31536060), "1 year 1 minute")
+        self.assertEqual(booking_tags.age_format(31539600), "1 year 1 hour")
+        self.assertEqual(booking_tags.age_format(31622400), "1 year 1 day")
+        self.assertEqual(booking_tags.age_format(34128000), "1 year 1 month")
+        self.assertEqual(booking_tags.age_format(36720000), "1 year 2 months")
+        self.assertEqual(booking_tags.age_format(63072000), "2 years")