implement basic pruning based on dir name

src/layers/dedupe.py

@@ -1,13 +1,31 @@
-from pathlib import Path
+from log import Log
 from dir import Root
-from layer import Layer
+from . import Layer
+from dir import Artist
 
 
 class Dedupe(Layer):
-    def __init__(self, other: Root, log_path: Path):
-        super().__init__(log_path, "TCD")
+    def __init__(self, other: Root, log: Log):
+        super().__init__(log, "TCD")
         self.other = other
 
+    def _process(self, left: Root):
+        right = self.other
+        existing_artists = right.by_name()
+        for artist in left:
+            artist_name = artist.name
+            if artist_name in existing_artists:
+                self.prune_artist(artist, right[artist_name])
+                if len(artist.contents) == 0:
+                    left.prune(artist_name)
+                    self.log.info('PRN', f"Pruned artist: {artist_name}")
+            else:
+                continue # todo: fuzzy matching
 
-    def __process(self, root: Root):
-        pass
+    def prune_artist(self, left: Artist, right: Artist):
+        existing_albums = right.by_name()
+        for album in left:
+            album_name = album.name
+            if album_name in existing_albums:
+                left.prune(album_name)
+                self.log.info('PRN', f"Pruned album: {album_name}")