####
1G1R
####

ROMSearch operates on a "one game, one ROM" (1G1R) philosophy. This means that for each game, it will find the
ROM file that it believes to be the best. The approach ROMSearch takes is to (1) filter out ROMs that the user does
not want, and then (2) score the remaining ROMs to find an overall "best" ROM.

Filters
-------

Firstly, ROMs are filtered.

* This starts with dat categories the user may not want (by default, this is everything not a game,
  so demos, beta, etc.)
* We then filter out ROMs that don't have languages (or implied languages) that are in the user preferences
* ROMs are filtered if they don't have regions in the user preferences

Scoring
-------

After the initial round of filtering, we then score the ROMs. Some have an ordered priority, which means that
the order the user has selected matters (e.g. USA, World, Europe for regions).

Scores are boosted in this order of priority:

* Has RetroAchievements
* Regions (ordered priority)
* Languages (ordered priority)
* Budget editions
* Versions/revisions
* Improved versions (e.g. EDC)

There are also some demotions that go on. The priority is (from most to least demoted):

* Priority from ``retool`` clonelists
* Modern versions
* Alternate versions
* Demoted versions (e.g. arcade versions)

End result
----------

The final result is that you should get the single best ROM for your preferences. Hooray!