Media tracks subsystem, jukebox UI genres

code/controllers/subsystems/media_tracks.dm

@@ -0,0 +1,67 @@
+SUBSYSTEM_DEF(media_tracks)
+	name = "Media Tracks"
+	flags = SS_NO_FIRE
+	init_order = INIT_ORDER_MEDIA_TRACKS
+	
+	/// Every track, including secret
+	var/list/all_tracks = list()
+	/// Non-secret jukebox tracks
+	var/list/jukebox_tracks = list()
+	/// Lobby music tracks
+	var/list/lobby_tracks = list()
+
+/datum/controller/subsystem/media_tracks/Initialize()
+	load_tracks()
+	sort_tracks()
+
+/datum/controller/subsystem/media_tracks/proc/load_tracks()
+	for(var/filename in config.jukebox_track_files)
+		report_progress("Loading jukebox track: [filename]")
+		
+		if(!fexists(filename))
+			error("File not found: [filename]")
+			continue
+		
+		var/list/jsonData = json_decode(file2text(filename))
+		
+		if(!istype(jsonData))
+			error("Failed to read tracks from [filename], json_decode failed.")
+			continue
+		
+		for(var/entry in jsonData)
+			
+			// Critical problems that will prevent the track from working
+			if(!istext(entry["url"]))
+				error("Jukebox entry in [filename]: bad or missing 'url'. Tracks must have a URL.")
+				continue
+			if(!istext(entry["title"]))
+				error("Jukebox entry in [filename]: bad or missing 'title'. Tracks must have a title.")
+				continue
+			if(!isnum(entry["duration"]))
+				error("Jukebox entry in [filename]: bad or missing 'duration'. Tracks must have a duration (in deciseconds).")
+				continue
+
+			// Noncritical problems, we can keep going anyway, but warn so it can be fixed
+			if(!istext(entry["artist"]))
+				warning("Jukebox entry in [filename], [entry["title"]]: bad or missing 'artist'. Please consider crediting the artist.")
+			if(!istext(entry["genre"]))
+				warning("Jukebox entry in [filename], [entry["title"]]: bad or missing 'genre'. Please consider adding a genre.")
+				
+			var/datum/track/T = new(entry["url"], entry["title"], entry["duration"], entry["artist"], entry["genre"])
+			
+			T.secret = entry["secret"] ? 1 : 0
+			T.lobby = entry["lobby"] ? 1 : 0
+			
+			all_tracks += T
+
+/datum/controller/subsystem/media_tracks/proc/sort_tracks()
+	report_progress("Sorting media tracks...")
+	sortTim(all_tracks, /proc/cmp_media_track_asc)
+	
+	jukebox_tracks.Cut()
+	
+	for(var/datum/track/T in all_tracks)
+		if(!T.secret)
+			jukebox_tracks += T
+		if(T.lobby)
+			lobby_tracks += T