Read Rebroadcast Delay from database in tvmaze.py

The tvmaze.py metadata grabber script has been updated
to acquire an optional Rebroadcast Delay from the
MythTv database. The database is only read when we
know it's a 'Lookup by Timestamp' and no Rebroadcast
Delay has been specified on the command line.

This allows us to use the Rebroadcast Delay without
having to update the callers of the grabber to add
a new argument.

Refs: MythTV#717

mythtv/programs/scripts/metadata/Television/tvmaze.py

@@ -150,6 +150,7 @@ def buildNumbers(args, opts):
     from MythTV.utility.dt import posixtzinfo
     from MythTV.tvmaze import tvmaze_api as tvmaze
     from MythTV import datetime
+    from MythTV import MythDB
     from lxml import etree
     from datetime import timedelta
 
@@ -214,7 +215,10 @@ def buildNumbers(args, opts):
     # check whether the 'subtitle' is really a timestamp
     try:
         dtInLocalZone = datetime.strptime(tvsubtitle, "%Y-%m-%d %H:%M:%S") # defaults to local timezone
+    except ValueError:
+        dtInLocalZone = None
 
+    if dtInLocalZone:
         # The user may optionally specify a 'Broadcast Delay'.
         #
         #   https://en.wikipedia.org/wiki/Broadcast_delay
@@ -227,8 +231,10 @@ def buildNumbers(args, opts):
         #   to air in local primetime hours to improve accessibility
         #   and viewership.
         #
-        # There are also some broadcasts which are shown without a
-        # Broadcast Delay, such as live sporting events. When we are
+        # The initial broadcast happens in the eastern region(s).
+        # Rebroadcasts with delays happen in regions further west.
+        # There are also some programs which are shown in all regions
+        # without any delay, such as live sporting events. When we are
         # looking for a match by timestamp, we may need to try both
         # with and without a rebroadcast delay. For example, for an
         # 8pm show in New York:
@@ -243,15 +249,25 @@ def buildNumbers(args, opts):
         #  Pacific/Honolulu    -10    240         15:00   19:00     7pm
         #
         # The Rebroadcast Delay (in minutes) may be specified
-        # with a 3rd argument.
-        if len(args) > 2:
-            rbDelayMinutes = int(args[2])
-        else:
+        # with a 3rd argument or in the MythTv database.
+        try:
+            if len(args) > 2:
+                rbDelayMinutes = int(args[2])
+            else:
+                db = MythDB()
+                rbd = db.settings['NULL']['RebroadcastDelay']
+                if rbd:
+                    rbDelayMinutes = int(rbd)
+                    if rbDelayMinutes == 0:
+                        rbDelayMinutes = None
+                else:
+                    rbDelayMinutes = None
+
+        except ValueError:
             rbDelayMinutes = None
 
-    except ValueError:
-        dtInLocalZone = None
-        rbDelayMinutes = None
+        if opts.debug:
+            print('Rebroadcast Delay =', rbDelayMinutes)
 
     matchesFound = 0
     best_ep_quality = 0.5   # require at least this quality on string match