make artist and album hyperlinks in tracklist; refactor navigation to the controller package

ui/controller/routes.go

@@ -0,0 +1,63 @@
+package controller
+
+import "supersonic/backend"
+
+type PageName int
+
+const (
+	Blank PageName = iota
+	Album
+	Albums
+	Artist
+	Artists
+	Genre
+	Genres
+	Favorites
+	NowPlaying
+	Playlist
+	Playlists
+)
+
+type Route struct {
+	Page PageName
+	Arg  string
+}
+
+func AlbumsRoute(sortOrder backend.AlbumSortOrder) Route {
+	return Route{Page: Albums, Arg: string(sortOrder)}
+}
+
+func ArtistRoute(artistID string) Route {
+	return Route{Page: Artist, Arg: artistID}
+}
+
+func AlbumRoute(albumID string) Route {
+	return Route{Page: Album, Arg: albumID}
+}
+
+func FavoritesRoute() Route {
+	return Route{Page: Favorites}
+}
+
+func GenreRoute(genre string) Route {
+	return Route{Page: Genre, Arg: genre}
+}
+
+func GenresRoute() Route {
+	return Route{Page: Genres}
+}
+
+func PlaylistRoute(id string) Route {
+	return Route{Page: Playlist, Arg: id}
+}
+func PlaylistsRoute() Route {
+	return Route{Page: Playlists}
+}
+
+func ArtistsRoute() Route {
+	return Route{Page: Artists}
+}
+
+func NowPlayingRoute() Route {
+	return Route{Page: NowPlaying}
+}