Add lastgenre plugin cli options to query explicit for albums and / or tracks.

[rain0r]

Also fetch genres for single tracks via query.

[sampsyo]

Hi! This is a nice start, but doing the same actions to both albums and items matching the same query is likely to do a bunch of redundant work in most cases. For example, the query beatles will match both some albums and the tracks on those albums, so the command would fetch the genres for those tracks twice.

I think the right thing to do is to put this behind a command-line option: one that switches between album and item mode. As you'll see in most other plugin-provided commands, there's an -a flag that switches to album mode. We could do the same thing, but make this the default—and require something like -A to switch back to item mode.

[rain0r]

Added the parser options, what do you think?

[sampsyo]

Cool! This arrangement, however, does make it possible for albums and tracks to be enabled simultaneously. It would be nice if this were a proper switch: i.e., track and album mode negated one another, and only one could be active at a time.

Also, can you please call the track mode "item" mode, for uniformity with other commands?

Finally, could you please look into the Travis failures, add documentation, and write a quick changelog entry?

[rain0r]

Cool! This arrangement, however, does make it possible for albums and tracks to be enabled simultaneously. It would be nice if this were a proper switch: i.e., track and album mode negated one another, and only one could be active at a time.

Also, can you please call the track mode "item" mode, for uniformity with other commands?

Finally, could you please look into the Travis failures, add documentation, and write a quick changelog entry?

Done

[sampsyo]

Looking good! If you can bear with me, I have a few more suggestions:

• A clean way to do the "mutual excursion" thing would be to have the CLI flags control a single option variable. (This is the case in most other plugins and commands, if you take a look at that code.) To both option constructors, you can add dest='album'. Then, the -A option can use action='store_false' and the -a one can use action='store_true'. Then, the code for the command can just use if opts.album: and else: for the two cases.
• In the documentation, can you please explain how to use the new switch? That is, say that the command matches albums by default. If you want to look up genres for individual tracks (and singletons) instead, use -A.
• Please see the way that other plugin features are described in the changeling. We use ReST syntax like this: :doc:`/plugins/lastgenre`: Some change here..

[rain0r]

No problem, I'm happy if someone has an eye on code quality ;-)

Now it works like this:

$ beet lastgenre -a
# albums
$ beet lastgenre -A
# items 
$ beet lastgenre 
# albums

Also updated the doc.

[rain0r]

If this goes through, #3219 can also be closed.

[sampsyo]

Awesome! Thank you for your persistent work on this. 🐟 Merged!

[JOJ0]

Renamed to a more self-explanatory name even though it's an older PR. Since I'm working on something related to this feature, I might reference it and appreciate a better name.