From c55b14e6c4ed2f6b8cc5fba65370029b8b5fbf1b Mon Sep 17 00:00:00 2001
From: Jaisen Mathai <jaisen@jmathai.com>
Date: Tue, 12 Jan 2016 20:44:15 -0800
Subject: [PATCH] gh-74 Check for existing EXIF field before writing and create
 if needed. Add test case.

---
 elodie/media/photo.py            |  9 +++++++--
 elodie/tests/helper.py           |  1 -
 elodie/tests/media/photo_test.py | 22 ++++++++++++++++++++++
 3 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/elodie/media/photo.py b/elodie/media/photo.py
index e1fd499..0dd20c1 100644
--- a/elodie/media/photo.py
+++ b/elodie/media/photo.py
@@ -171,8 +171,13 @@ class Photo(Media):
         exif_metadata = pyexiv2.ImageMetadata(source)
         exif_metadata.read()
 
-        exif_metadata['Exif.Photo.DateTimeOriginal'].value = time
-        exif_metadata['Exif.Image.DateTime'].value = time
+        # Writing exif with pyexiv2 differs if the key already exists so we
+        #   handle both cases here.
+        for key in ['Exif.Photo.DateTimeOriginal', 'Exif.Image.DateTime']:
+            if(key in exif_metadata):
+                exif_metadata[key].value = time
+            else:
+                exif_metadata[key] = pyexiv2.ExifTag(key, time)
 
         exif_metadata.write()
         return True
diff --git a/elodie/tests/helper.py b/elodie/tests/helper.py
index d9176db..023726c 100644
--- a/elodie/tests/helper.py
+++ b/elodie/tests/helper.py
@@ -1,7 +1,6 @@
 import hashlib
 import os
 import random
-import shutil
 import string
 import tempfile
 
diff --git a/elodie/tests/media/photo_test.py b/elodie/tests/media/photo_test.py
index 9db42f3..41809b6 100644
--- a/elodie/tests/media/photo_test.py
+++ b/elodie/tests/media/photo_test.py
@@ -116,6 +116,28 @@ def test_is_not_valid():
 
     assert not photo.is_valid()
 
+def test_set_date_taken_with_missing_datetimeoriginal():
+    # When datetimeoriginal (or other key) is missing we have to add it gh-74
+    # https://github.com/jmathai/elodie/issues/74
+    temporary_folder, folder = helper.create_working_folder()
+
+    origin = '%s/photo.jpg' % folder
+    shutil.copyfile(helper.get_file('no-exif.jpg'), origin)
+
+    photo = Photo(origin)
+    status = photo.set_date_taken(datetime.datetime(2013, 9, 30, 7, 6, 5))
+
+    assert status == True, status
+
+    photo_new = Photo(origin)
+    metadata = photo_new.get_metadata()
+
+    date_taken = metadata['date_taken']
+
+    shutil.rmtree(folder)
+
+    assert date_taken == (2013, 9, 30, 7, 6, 5, 0, 273, 0), metadata['date_taken']
+
 def test_set_date_taken():
     temporary_folder, folder = helper.create_working_folder()