MewdekoPlayer.cs

 /// <summary>
    /// Contains logic for handling autoplay in a server. Requires either a last.fm API key.
    /// </summary>
    /// <returns>A bool depending on if the api key was correct.</returns>
    public async Task<bool> AutoPlay()
    {
        var autoPlay = await GetAutoPlay();
        if (autoPlay == 0)
            return true;
        var queue = await cache.GetMusicQueue(base.GuildId);
        var lastSong = queue.MaxBy(x => x.Index);
        if (lastSong is null)
            return true;

        LastFmResponse response;
        try
        {
            // sorted info for attempting to fetch data from lastfm
            var fullTitle = lastSong.Track.Title;
            var trackTitle = fullTitle;
            var artistName = lastSong.Track.Author;
            var hyphenIndex = fullTitle.IndexOf(" - ");

            // if the title has a hyphen, split the title and artist, used in cases where the title is formatted as "Artist - Title"
            if (hyphenIndex != -1)
            {
                artistName = fullTitle.Substring(0, hyphenIndex).Trim();
                trackTitle = fullTitle.Substring(hyphenIndex + 3).Trim();
            }

            // remove any extra info from the title that might be in brackets or parentheses
            trackTitle = Regex.Replace(trackTitle, @"\s*\[.*?\]\s*", "", RegexOptions.Compiled);
            trackTitle = Regex.Replace(trackTitle, @"\s*\([^)]*\)\s*", "", RegexOptions.Compiled);
            trackTitle = trackTitle.Trim();

            // Query lastfm the first time with the formatted track title that doesnt contain the artist, with artist data from the track itself
            var apiResponse = await httpClient.GetStringAsync(
                $"http://ws.audioscrobbler.com/2.0/?method=track.getsimilar&artist={Uri.EscapeDataString(artistName)}&track={Uri.EscapeDataString(trackTitle)}&autocorrect=1&api_key={Uri.EscapeDataString(creds.LastFmApiKey)}&format=json");
            response = JsonConvert.DeserializeObject<LastFmResponse>(apiResponse);

            // If the first query returns no results, assume that the title had useful author info, use the split title and author info and try again
            if (response.Similartracks.Track.Count == 0)
            {
                apiResponse = await httpClient.GetStringAsync(
                    $"http://ws.audioscrobbler.com/2.0/?method=track.getsimilar&artist={Uri.EscapeDataString(lastSong.Track.Author)}&track={Uri.EscapeDataString(trackTitle)}&autocorrect=1&api_key={Uri.EscapeDataString(creds.LastFmApiKey)}&format=json");
                response = JsonConvert.DeserializeObject<LastFmResponse>(apiResponse);
            }
        }
        catch (Exception ex)
        {
            Log.Error(ex, "Invalid Last.fm credentials");
            return false;
        }

        // If the response is empty, return true
        if (response.Similartracks.Track.Count == 0)
            return true;

        var queuedTrackNames = new HashSet<string>(queue.Select(q => q.Track.Title));

        // Filter out tracks that are already in the queue
        var filteredTracks = response.Similartracks.Track
            .Where(t => !queuedTrackNames.Contains($"{t.Name}"))
            .ToList();

        // get the amount of tracks to take, either the amount of tracks in the response or the amount of tracks to autoplay
        var toTake = Math.Min(autoPlay, filteredTracks.Count);

        foreach (var rec in filteredTracks.Take(toTake))
        {
            var trackToLoad = await audioService.Tracks.LoadTrackAsync($"{rec.Name} {rec.Artist.Name}", TrackSearchMode.YouTube);
            if (trackToLoad is null)
                continue;
            queue.Add(new MewdekoTrack(queue.Count + 1, trackToLoad, new PartialUser()
            {
                AvatarUrl = client.CurrentUser.GetAvatarUrl(),
                Username = "Mewdeko",
                Id = client.CurrentUser.Id
            }));
            await cache.SetMusicQueue(base.GuildId, queue);
        }

        await cache.SetMusicQueue(base.GuildId, queue);
        return true;
    }