From 783ae018c61526f1b5e88f8d82e87c2955ba82bb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Diego=20Elio=20Petten=C3=B2?= <flameeyes@flameeyes.com>
Date: Mon, 1 Jul 2019 20:49:29 +0100
Subject: Introduce an explicit InvalidDateTime exception for meters with unset
 time.

At least the FreeStyle Precision Neo appears to be able to report an invalid
date/time (255/255/255 255:255), probably when the RTC is lost (see issue #58).

This returns a more precise output than N/A, and should suggest to confirm the
date and time setting instead.
---
 glucometerutils/exceptions.py        | 8 ++++++++
 glucometerutils/glucometer.py        | 6 +++---
 glucometerutils/support/freestyle.py | 8 +++++++-
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/glucometerutils/exceptions.py b/glucometerutils/exceptions.py
index 415c97f..1cc8cfd 100644
--- a/glucometerutils/exceptions.py
+++ b/glucometerutils/exceptions.py
@@ -46,3 +46,11 @@ class InvalidGlucoseUnit(Error):
     def __init__(self, unit):
         super(InvalidGlucoseUnit, self).__init__(
             'Invalid glucose unit received:\n%s' % unit)
+
+
+class InvalidDateTime(Error):
+    """The device has an invalid date/time setting."""
+
+    def __init__(self):
+        super(InvalidDateTime, self).__init__(
+            'Invalid date and time for device')
diff --git a/glucometerutils/glucometer.py b/glucometerutils/glucometer.py
index 485b32b..14999a7 100755
--- a/glucometerutils/glucometer.py
+++ b/glucometerutils/glucometer.py
@@ -86,9 +86,9 @@ def main():
         if args.action == 'info':
             try:
                 time_str = device.get_datetime()
-            except ValueError:
-                time_str = 'N/A' #handles value error exception for when time format found isn't expected
-            except NotImplementedError:
+            except exceptions.InvalidDateTime:
+                time_str = 'INVALID'
+            except NotImplementedError, ValueError:  # Catch any leftover ValueError
                 time_str = 'N/A'
             print("{device_info}Time: {time}".format(
                 device_info=str(device_info), time=time_str))
diff --git a/glucometerutils/support/freestyle.py b/glucometerutils/support/freestyle.py
index d18a81f..475d6f5 100644
--- a/glucometerutils/support/freestyle.py
+++ b/glucometerutils/support/freestyle.py
@@ -200,7 +200,13 @@ class FreeStyleHidDevice(hiddevice.HidDevice):
         month, day, year = (int(x) for x in date.split(','))
         hour, minute = (int(x) for x in time.split(','))
 
-        return datetime.datetime(year + 2000, month, day, hour, minute)
+        # At least Precision Neo devices can have an invalid date (bad RTC?),
+        # and report 255 for each field, which is not valid for
+        # datetime.datetime().
+        try:
+            return datetime.datetime(year + 2000, month, day, hour, minute)
+        except ValueError:
+            raise exceptions.InvalidDateTime()
 
     def set_datetime(self, date=datetime.datetime.now()):
         # type: (datetime.datetime) -> datetime.datetime
-- 
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