Multi select quick match

[Undergrid]

Adds a feature to allow the user to batch Quick Match the selected audiobooks.

A button is added to the Appbar when one or more audiobooks are selected using the multi-select option (left most button on the below image).

Once clicked, a dialog is shown allowing the user to select the metadata provider and to select whether exiting covers or metadata should be overwritten.

When "Continue" is selected, a quick match is run against each selected audiobook, updating metadata and covers as required.

[advplyr]

Awesome. I think we should initialize the provider to whatever the default provider is for the library.

There are some getters in libraries.js to get a library provider or get the current library.

Also, we can show the user how many items were updated and how many items were unable to find a match.
Currently the quickMatchLibraryItem function is returning a warning if it doesn't find a match. https://github.com/advplyr/audiobookshelf/blob/master/server/scanner/Scanner.js#L695

[Undergrid]

How would you like to show the updated and unmatched count? Would in the toast be okay?

[advplyr]

Yeah that works, the toast message can have line breaks \n.

Eventually we will probably have to change this so that the API request doesn't need to wait for the matches to finish and instead gets the result from a socket event. The reason for that is because some people have very slow systems and the API request will timeout before it finishes.

[Undergrid]

If you can point me at an example of doing that, I can probably get it working that way. Might as well do it properly from the start.

[skyzuma]

is possible to select details if the switch goes to on, like (update only) language, genre, ... (for selected) ?

li > switch > details
ul > swicth > language
ul > switch > genre

[advplyr]

If you can point me at an example of doing that, I can probably get it working that way. Might as well do it properly from the start.

I don't have a good example to point to yet for this. We would need to set some temporary id locally for the quick match request and setup a socket event listener (something like batch_quickmatch_complete). Once finished the backend emits that event including the temporary id so know it is this clients request that was completed.
Most of the socket event listeners are set in the default.vue layout.
If you want to go for this that would be great but up to you.

[advplyr]

is possible to select details if the switch goes to on, like (update only) language, genre, ... (for selected) ?

li > switch > details ul > swicth > language ul > switch > genre

We don't have support for this in the backend and would be a lot of re-working that is out of the scope of this PR

[Undergrid]

So I'm going to look at the websocket part, but in the mean time I've set the provider and added the counts to the toast. The toast looks a little different depending on the counts:

[Undergrid]

@advplyr PR has now been updated as request, including with the websocket feedback etc.

[advplyr]

Works beautifully, thanks!