beetsplug: cleanup for 'missing -a' code

* Use full name for musicbrainzngs import
* Use beets internal logging facilities
* Match releases by release id
* Convert some strings to Unicode
* Remove unnecessary MB rate-limiting
* Remove unnecessary imports

Signed-off-by: Quentin Young <qlyoung@qlyoung.net>

beetsplug/missing.py

@@ -18,10 +18,7 @@
 """
 from __future__ import division, absolute_import, print_function
 
-import time
-import beets
-import musicbrainzngs as m
-import sys
+import musicbrainzngs
 
 from musicbrainzngs.musicbrainz import MusicBrainzError
 from beets.autotag import hooks
@@ -171,41 +168,38 @@ def _missing_albums(self, lib, args):
             albums_by_artist[artist] = artistalbs
 
         # build dict mapping artist to list of all albums
-        m.set_useragent('beets', beets.__version__, 'http://beets.io/')
-
         for artist, albums in albums_by_artist.items():
             if artist[1] is None or artist[1] == "":
-                print_(u"[!] No musicbrainz ID for artist {}, skipping."
-                       .format(artist[0]), stream=sys.stderr)
+                self._log.info(
+                    u"No musicbrainz ID for artist {}, skipping.",
+                    artist[0]
+                )
                 continue
 
             try:
-                releases = m.browse_releases(artist=artist[1])['release-list']
+                resp = musicbrainzngs.browse_release_groups(artist=artist[1])
+                release_groups = resp['release-group-list']
             except MusicBrainzError as err:
-                print_(u"[!] Couldn't fetch info for artist '{}' ({}) - '{}'"
-                       .format(artist[0], artist[1], err), stream=sys.stderr)
+                self._log.info(
+                    u"Couldn't fetch info for artist '{}' ({}) - '{}'",
+                    artist[0], artist[1], err
+                )
                 continue
 
             missing = []
             present = []
-            for release in releases:
-                missing.append(release)
+            for rg in release_groups:
+                missing.append(rg)
                 for alb in albums:
-                    # compare by title, don't care about specific releases
-                    if alb['album'].lower() == release['title'].lower():
-                        missing.remove(release)
-                        present.append(release)
+                    if alb['mb_releasegroupid'] == rg['id']:
+                        missing.remove(rg)
+                        present.append(rg)
                         break
 
-            missing_titles = {release['title'] for release in missing}
-
-            prefix_miss = "{} - ".format(artist[0])
-
-            for release in missing_titles:
-                print_(u"{}{}".format(prefix_miss, release))
+            missing_titles = {rg['title'] for rg in missing}
 
-            # respect musicbrainz rate limits
-            time.sleep(1)
+            for release_title in missing_titles:
+                print_(u"{} - {}".format(artist[0], release_title))
 
     def _missing(self, album):
         """Query MusicBrainz to determine items missing from `album`.