Fix optional parameters in url generator

[askvortsov1]

Fixes #1972

Changes proposed in this pull request:

• Select the most fitting paths option instead of the first one to support using url generator with optional parameters
• Add unit tests for this functionality

Reviewers should focus on:

• Any shortcomings in the algorithm I used?
• Any code style recommendations? The variable naming I feel a bit iffy on

Confirmed

• Frontend changes: tested on a local Flarum installation.
• [x[ Backend changes: tests are green (run composer test).

[clarkwinkelmann]

I'm ok with the approach and the unit tests seem fine. I do find the actual implementation quite difficult to read.

Could you try to make clear which variables reference an index and which variables reference a count?

I'm not actually sure what our preference is between snake_case and camelCase but I was under the impression we mostly used camelCase?

[tankerkiller125]

I'll wait to review until the things clark pointed out are fixed. Like clark I also have difficulty reading the actual implementation so some clarification of variables would be great.

[askvortsov1]

Oh boy this code is a mess, not sure what I was thinking when I wrote it... I did a bit of cleanup, that was embarrasing...

[clarkwinkelmann]

That looks much better.

I still find the use of the index as the "number" of parameters a bit confusing. This only works because we expect all $parts to be a repetition of the same elements with further entries just having more elements after the common elements.

This might not be obvious to code readers unfamiliar with Fastroute.

If all $parts are always sorted in ascending number of parts, maybe this could even be simplified to break as soon as one result doesn't have as many matches as the previous entry. Not sure if the optimization is worth it though as most routes will probably only ever have two routes variants at most.