I've spent 2 hours troubleshooting why none of my music had genre tag.
It was because the single `genre`, without `s` doesn't seem to cover any
good ganre tags... at least it didn't on my opus files
looking at the code:
7ecd86101e/mediafile.py (L1669-L2167)
i don't honestly know why anyone created the single `ganre` field in the
first place
This utilises regex substitution in the substitute plugin. The previous
approach only used regex to match the pattern, then replaced it with a
static string. This change allows more complex substitutions, where the
output depends on the input.
### Example use case
Say we want to keep only the first artist of a multi-artist credit, as
in the following list:
```
Neil Young & Crazy Horse -> Neil Young
Michael Hurley, The Holy Modal Rounders, Jeffrey Frederick & The Clamtones -> Michael Hurley
James Yorkston and the Athletes -> James Yorkston
````
This would previously have required three separate rules, one for each
resulting artist. By using a regex substitution, we can get the desired
behaviour in a single rule:
```yaml
substitute:
^(.*?)(,| &| and).*: \1
```
(Capture the text until the first `,` ` &` or ` and`, then use that
capture group as the output)
### Notes
I've kept the previous behaviour of only applying the first matching
rule, but I'm not 100% sure it's the ideal approach.
I can imagine both cases where you want to apply several rules in
sequence and cases where you want to stop after the first match.
- Refactored Tekstowo backend to fetch lyrics directly from song pages.
- Added `encode` method to convert artist and title to their URL format,
where non-alphanumeric characters are replaced with underscores.
- Removed the now redundant search functionality and associated tests.
- Simplified `extract_lyrics` method to directly parse lyrics without
any checks.
