using System.Text.RegularExpressions; public abstract class SongValidatorBase : ISongValidator { public abstract Task ValidateAsync(Uri songUri); public abstract Task CanExtractSongMetadataAsync(Uri songUri); public abstract bool CanValidateUri(Uri songUri); protected string LookupSpotifyId(string songName, string songArtist) { // TODO: Implement Spotify ID lookup logic return songName + " by " + songArtist; } }