lastgenre_aliases

- Use the INI format (since YAML and regex is a nightmare...)
- Ship a default aliases file with beets
  - Dont use non-capturing groups use ?: because colons are a problem.
    Also some replacement patterns were bad. Fixed
- Implement loading the aliases.ini file similar to how the whitelist
  file is handled.
- Apply aliases in two places, right after last.fm fetch and after
  collecting existing genres.

beetsplug/lastgenre/__init__.py

@@ -22,7 +22,10 @@ The scraper script used is available here:
 https://gist.github.com/1241307
 """
 
+import codecs
+import configparser
 import os
+import re
 import traceback
 from functools import wraps
 from pathlib import Path
@@ -33,7 +36,7 @@ import yaml
 
 from beets import config, library, plugins, ui
 from beets.library import Album, Item
-from beets.util import plurality, unique_list
+from beets.util import plurality, unique_list, normpath
 
 LASTFM = pylast.LastFMNetwork(api_key=plugins.LASTFM_KEY)
 
@@ -103,6 +106,7 @@ def log_and_pretend(apply_func):
 
 WHITELIST = os.path.join(os.path.dirname(__file__), "genres.txt")
 C14N_TREE = os.path.join(os.path.dirname(__file__), "genres-tree.yaml")
+ALIASES = os.path.join(os.path.dirname(__file__), "aliases.ini")
 
 
 class LastGenrePlugin(plugins.BeetsPlugin):
@@ -125,6 +129,7 @@ class LastGenrePlugin(plugins.BeetsPlugin):
                 "title_case": True,
                 "extended_debug": False,
                 "pretend": False,
+                "aliases": True,
             }
         )
         self.setup()
@@ -137,6 +142,7 @@ class LastGenrePlugin(plugins.BeetsPlugin):
         self._genre_cache = {}
         self.whitelist = self._load_whitelist()
         self.c14n_branches, self.canonicalize = self._load_c14n_tree()
+        self.aliases = self._load_aliases()
 
     def _load_whitelist(self) -> set[str]:
         """Load the whitelist from a text file.
@@ -179,6 +185,35 @@ class LastGenrePlugin(plugins.BeetsPlugin):
             flatten_tree(genres_tree, [], c14n_branches)
         return c14n_branches, canonicalize
 
+    def _load_aliases(self) -> list[str]:
+        """Load configured aliases for a list of tags."""
+        aliases = []
+        aliases_filename = self.config["aliases"].get()
+        if aliases_filename in (
+            True,
+            "",
+            None,
+        ):  # Indicates the default aliases file.
+            aliases_filename = ALIASES
+        if aliases_filename:
+            aliases_filename = normpath(aliases_filename)
+            try:
+                config_parser = configparser.ConfigParser()
+                config_parser.read(aliases_filename, encoding="utf-8")
+                for section in config_parser.sections():
+                    aliases.extend(
+                        {pattern: replacement}
+                        for pattern, replacement in config_parser[
+                            section
+                        ].items()
+                    )
+                self._log.debug(
+                    "Loaded genre aliases from {0}", aliases_filename
+                )
+            except Exception as exc:
+                self._log.error("Error loading aliases file: {0}", exc)
+        return aliases
+
     @property
     def sources(self) -> tuple[str, ...]:
         """A tuple of allowed genre sources. May contain 'track',
@@ -289,6 +324,25 @@ class LastGenrePlugin(plugins.BeetsPlugin):
             return True
         return False
 
+    def _apply_aliases(self, genres):
+        """Apply regex aliases to the genre list."""
+        if not self.aliases or not genres:
+            return genres
+
+        result = genres.copy()
+        for alias_pair in self.aliases:
+            for pattern, replacement in alias_pair.items():
+                try:
+                    result = [
+                        re.sub(pattern, replacement, genre, flags=re.IGNORECASE)
+                        for genre in result
+                    ]
+                except re.error as exc:
+                    self._log.error(
+                        "Regex error in pattern '{0}': {1}", pattern, exc
+                    )
+        return result
+
     # Cached last.fm entity lookups.
 
     def _last_lookup(self, entity, method, *args):
@@ -312,6 +366,11 @@ class LastGenrePlugin(plugins.BeetsPlugin):
         genre = self._genre_cache[key]
         if self.config["extended_debug"]:
             self._log.debug("last.fm (unfiltered) {} tags: {}", entity, genre)
+
+        genre = self._apply_aliases(genre)
+        if self.config["extended_debug"]:
+            self._log.debug("last.fm (aliased) {} tags: {}", entity, genre)
+
         return genre
 
     def fetch_album_genre(self, obj):
@@ -354,6 +413,10 @@ class LastGenrePlugin(plugins.BeetsPlugin):
         else:
             item_genre = obj.get("genre").split(separator)
 
+        item_genre = self._apply_aliases(item_genre)
+        if self.config["extended_debug"]:
+            self._log.debug("Existing genres (aliased): {}", item_genre)
+
         # Filter out empty strings
         return [g for g in item_genre if g]
 

beetsplug/lastgenre/aliases.ini

@@ -0,0 +1,31 @@
+[regexaliases]
+# Common genres with variable spelling
+(?i)electronic[\s-]?music? = Electronic
+(?i)alt[\s-]?rock|alternative(\srock)?|alternative|alt = Alternative Rock
+(?i)hip[\s-]?hop|hiphop|rap = Hip Hop
+down[ /-]*(beat|tempo?) = downtempo
+
+# Common genres with ampersands
+(?i)r[\s&]*b|rhythm and blues = R&B
+d(rum)?[\s]*(&|and|n)?[\s]*b(ass)? = Drum And Bass
+drill[ n/]*bass = drill & bass
+r(hythm)?[ n/]*b(lues)? = rhythm & blues
+rock[ n/]*roll = rock & roll
+
+# Consistent delimiters
+(c|k|j)[ /]*(folk|goth|hip hop|pop|rock|ska|trance) = \g<1>-\g<2>
+(euro(?!p[ae]+n?)|neo|post|tech(?!n[io]))[ /]*(\w+) = \g<1>-\g<2>
+(g?lo)[ /]*fi = \g<1>-fi
+(glitch|hip|jazz|trip)y?([ /]*hip)?[ /]*hop = \g<1> hop
+(p|g)[ /]*funk = \g<1>-funk
+nu[/-]*(disco|jazz|metal|soul) = nu \g<1>
+synth[ /-]+(\w+) = synth\g<1>
+
+# Abbreviation related
+alt(/|er*n(/|ati[fv](es?)?))? = alternative
+avant(/|gard)? = avantgarde
+prog+(/|r*es+(/|i[fv]e?)?)? = progressive
+ps?y(/|ch(/|[aeo]l?del+i[ca]+)?)? = psychedelic
+trad(/|ition(/|al)?)?-? = traditional
+
+