Fix error parsing duration for offline YouTube live streams ("P0D" is…

… used for duration in this case).

config/initializers/05-string.rb

@@ -72,8 +72,14 @@ def parse_duration
   end
 
   def parse_pt
-    if /^PT(?:(?<h>\d+)H)?(?:(?<m>\d+)M)?(?:(?<s>\d+)S)?$/ =~ self
+    # https://en.wikipedia.org/wiki/ISO_8601#Durations
+    # Converting year, month and day to seconds is not done properly here because it depends on the start time (see wikipedia), but it is ok because I've only see "P0D" being used by YouTube for offline live streams
+    # P[n]Y[n]M[n]DT[n]H[n]M[n]S
+    if /^P(?:(?<y>\d+)Y)?(?:(?<m>\d+)M)?(?:(?<d>\d+)D)?(?:T(?:(?<h>\d+)H)?(?:(?<m>\d+)M)?(?:(?<s>\d+)S)?)?$/ =~ self
       result = 0
+      result += 31536000 * y.to_i if y # 365 days
+      result += 2592000 * m.to_i if m # 30 days
+      result += 86400 * d.to_i if d # 24 hours
       result += 3600 * h.to_i if h
       result += 60 * m.to_i if m
       result += s.to_i if s