A very long and convoluted regex to dissect a properly named file for music.

a_filename_parse.regex

(?P<originalartist>.+?) -(?: (?P<albumname>(?:(?! - ).)+) -(?: (?<tracknumber>(?:[0-9][0-9])))?)? (?P<songtitle>(?P<songname>(?:(?! \(ft\.).)+) ?(?:\(ft\. (?P<originalfeaturing>(?:[^)]+?(?:(?=\))|, ))+)\))?(?: \((?:(?P<productionartist>(?:(?!\1 ).+)?) )?(?P<songtype>(?:Remix|VIP|Cover|Version|Instrumental|Parody|Mashup))(?: ft\. (?P<additionalfeaturing>(?:[^)]+?(?:(?=\))|, ))+))?\))?)

b_filename_build.js

// An example of how to construct a filename that the regex can parse in javascript.
var filename = originalartist +' - '+ 
	(albumname ? albumname +' - '+ (tracknumber ? tracknumber : '') : '') + 
	(!albumname ? (tracknumber ? tracknumber + ' ' : '') : '') + songname + 
	(featuring ? '(ft. '+ (featuring instanceof Array ? join(', ',featuring) : featuring) +')') +
	(songtype ? 
		'('+ (additionalartist ? additionalartist : '') + 
			songtype + 
			(additionalfeaturing ? ' ft. '+ 
			(additionalfeaturing instanceof Array ? join(', ',additionalfeaturing) : additionalfeaturing) : '') +
		')' : '' 
	);

c_README

Notes: 
1)	The "additionalartist" match MIGHT contain additional text aside from the artist's name. 
	EX: Artist - Song (Second Artist FooBar Remix)
	The "additionalartist" match would result in 'Second Artist FooBar' and the songtype would be 'Remix'
2)	If the original "albumname" contains the ' - ' catch sequence, it will stop before that sequence.
	EX: Artist - Album - Subalbum - Song
	The "albumname" match would result in 'Album' and not 'Album - Subalbum'. To fix, simply change one of the characters in the catch sequence to something else, or remove a space.
	EX: Artist - Album . Subalbum - Song
	The "albumname" match would correctly result in 'Album . Subalbum'
3)	The "albumname" match must be present for a the "tracknumber" match to fit. Otherwise any "tracknumber" value will spill over to the "songtitle" match.
4)	Matches that fall inside a literal ( ) pair in the regex MUST be wrapped in a literal ( ) pair or the results will fail for those matches.
5)	There are probably a couple more notes I'm forgetting... I'll add them if I think of them.