Implement importing scrobbles from ListenBrainz

Closes: #162

README.md

@@ -135,6 +135,7 @@ If you would like to import your previous scrobbles, use the command `maloja imp
 
 * a Last.fm export generated by [benfoxall's website](https://benjaminbenben.com/lastfm-to-csv/) ([GitHub page](https://github.com/benfoxall/lastfm-to-csv))
 * an official [Spotify data export file](https://www.spotify.com/us/account/privacy/)
+* an official [ListenBrainz export file](https://listenbrainz.org/profile/export/)
 * the export of another Maloja instance
 
 ⚠️ Never import your data while maloja is running. When you need to do import inside docker container start it in shell mode instead and perform import before starting the container as mentioned above.

maloja/proccontrol/tasks/import_scrobbles.py

@@ -49,6 +49,11 @@ def import_scrobbles(inputf):
 		typeid,typedesc = "maloja","Maloja"
 		importfunc = parse_maloja
 
+	# username_lb-YYYY-MM-DD.json
+	elif re.match(".*_lb-[0-9-]+\.json",filename):
+		typeid,typedesc = "listenbrainz","ListenBrainz"
+		importfunc = parse_listenbrainz
+
 	else:
 		print("File",inputf,"could not be identified as a valid import source.")
 		return result
@@ -308,6 +313,28 @@ def parse_lastfm(inputf):
 				yield ('FAIL',None,f"{row} (Line {line}) could not be parsed. Scrobble not imported. ({repr(e)})")
 				continue
 
+def parse_listenbrainz(inputf):
+
+	with open(inputf,'r') as inputfd:
+		data = json.load(inputfd)
+
+	for entry in data:
+
+		try:
+			track_metadata = entry['track_metadata']
+			additional_info = track_metadata.get('additional_info', {})
+
+			yield ("CONFIDENT_IMPORT",{
+				'track_title': track_metadata['track_name'],
+				'track_artists': additional_info.get('artist_names') or track_metadata['artist_name'],
+				'track_length': int(additional_info.get('duration_ms', 0) / 1000) or additional_info.get('duration'),
+				'album_name': track_metadata.get('release_name'),
+				'scrobble_time': entry['listened_at'],
+				'scrobble_duration': None,
+			},'')
+		except Exception as e:
+			yield ('FAIL',None,f"{entry} could not be parsed. Scrobble not imported. ({repr(e)})")
+			continue
 
 def parse_maloja(inputf):