curds: Give tracks their own sort_key() function

I'm about to give playlists a sort_key(), so clean up the existing
function first

Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

curds/playlist/playlist.py

@@ -173,13 +173,7 @@ class Playlist(node.PlaylistNode):
         return field in self.sort_order
 
     def sort_key(self, track):
-        ret = [ ]
-        for field in self.sort_order:
-            val = track[field]
-            if isinstance(val, str):
-                val = ''.join(filter(str.isalnum, val.lower()))
-            ret.append(val)
-        return ret
+        return track.sort_key(self.sort_order)
 
     def track_added(self, index):
         if self.visible == True:

curds/playlist/test_playlist.py

@@ -365,7 +365,7 @@ class TestPlaylist(unittest.TestCase):
     def test_playlist_sort_key(self):
         track   = self.add_tracks([1])[0]
         trackno = track["tracknumber"]
-        artist  = track["artist"].lower().replace(" ", "")
+        artist  = track["artist"].lower()
 
         self.assertEqual(self.plist.sort_key(track), [ ])
         self.assertTrue( self.plist.sort("tracknumber"))

curds/tags.py

@@ -4,6 +4,7 @@ from . import notify
 import mutagen
 import os
 import re
+import unicodedata
 
 discno_map = { "one" : "1", "two" : "2", "three" : "3", "four" : "4", "five" : "5" }
 tag_map    = dict()
@@ -80,6 +81,20 @@ class Track(Tag):
             return None
         return Tag.lookup(t, "new-track")
 
+    def sort_key(self, fields):
+        ret = [ ]
+        for field in fields:
+            val = self[field]
+            if isinstance(val, str):
+                decode = unicodedata.normalize("NFD", val)
+                val    = decode.encode("ascii", "ignore").decode("utf8")
+                words  = val.lower().split()
+                words  = [ ''.join(filter(str.isalnum, w)) for w in words ]
+                words  = [ w for w in words if w not in ["", "a", "the"]]
+                val    = ' '.join(words)
+            ret.append(val)
+        return ret
+
 
 def clear():
     tag_map.clear()

curds/test_tags_track.py

@@ -100,3 +100,15 @@ class TestTrackTag(unittest.TestCase):
         self.assertEqual(t["genre"],       "Test")
         self.assertEqual(t["albumartist"], "Test Artist")
         self.assertIsNone(t["nokey"])
+
+    def test_track_sort_key(self):
+        t = tags.Track.lookup(os.path.join(test_tracks, "01 - Test Track.ogg"))
+        self.assertEqual(t.sort_key(["title"]), [ "test track" ])
+        self.assertEqual(t.sort_key(["title", "tracknumber"]), [ "test track", 1 ])
+
+        t.title = "The Test - Track!"
+        self.assertEqual(t.sort_key(["title"]), [ "test track" ])
+        t.title = "A \"Test\" Track"
+        self.assertEqual(t.sort_key(["title"]), [ "test track" ])
+        t.title = "Test Träck 01"
+        self.assertEqual(t.sort_key(["title"]), [ "test track 01" ])