feat: recommend server-generated mixes from Musify and YouTube Music
Mixes are their own concept, not playlists: they live in their own Mixes/MixItems tables, cannot be edited and never show up among the user's playlists. Each item is either a Musify track or a YouTube Music reference, so YouTube songs stream directly instead of being downloaded. A daily Hangfire job seeds the mixes from the listening history: one discovery mix, one daily mix and one per top artist. The per-user YouTube filler query was already in the working tree and rides along here because it shares files with this change.
This commit is contained in:
@@ -0,0 +1,343 @@
|
||||
using ErrorOr;
|
||||
using Mediator;
|
||||
using Microsoft.EntityFrameworkCore;
|
||||
using Microsoft.Extensions.Logging;
|
||||
using Musify.Application.Configuration;
|
||||
using Musify.Application.Contracts;
|
||||
using Musify.Application.Tracks.Responses;
|
||||
using Musify.Domain.Entities;
|
||||
using Musify.Domain.ValueObjects;
|
||||
|
||||
namespace Musify.Application.Mixes
|
||||
{
|
||||
public record GenerateMixesForUserCommand(long UserId)
|
||||
: ICommand<ErrorOr<Success>>;
|
||||
|
||||
public class GenerateMixesForUserCommandHandler(
|
||||
IDatabase database,
|
||||
IYouTubeMusicService youTubeMusicService,
|
||||
MixConfiguration mixConfiguration,
|
||||
ILogger<GenerateMixesForUserCommandHandler> logger)
|
||||
: ICommandHandler<GenerateMixesForUserCommand, ErrorOr<Success>>
|
||||
{
|
||||
private sealed record SeedArtist(Guid Id, string Name);
|
||||
|
||||
private sealed record LocalCandidate(Guid TrackId, string Title, string? Artist, int DurationSeconds);
|
||||
|
||||
private sealed record MixDraft(string Title, string? Subtitle, IReadOnlyList<MixItem> Items);
|
||||
|
||||
private const int TitleLength = 300;
|
||||
private const int ArtistLength = 300;
|
||||
private const int ThumbnailUrlLength = 512;
|
||||
private const int MixTitleLength = 100;
|
||||
|
||||
public async ValueTask<ErrorOr<Success>> Handle(GenerateMixesForUserCommand request, CancellationToken cancellationToken)
|
||||
{
|
||||
var userId = request.UserId;
|
||||
|
||||
var historyTrackIds = await database.ListeningHistories
|
||||
.AsNoTracking()
|
||||
.Where(history => history.UserId == userId)
|
||||
.Select(history => history.TrackId)
|
||||
.Distinct()
|
||||
.ToListAsync(cancellationToken);
|
||||
|
||||
if (historyTrackIds.Count == 0)
|
||||
{
|
||||
logger.LogInformation("User {UserId} has no listening history yet, skipping mix generation", userId);
|
||||
return new Success();
|
||||
}
|
||||
|
||||
var seedArtists = await GetSeedArtistsAsync(historyTrackIds, cancellationToken);
|
||||
|
||||
if (seedArtists.Count == 0)
|
||||
{
|
||||
logger.LogInformation("User {UserId} has no artists to seed mixes from, skipping mix generation", userId);
|
||||
return new Success();
|
||||
}
|
||||
|
||||
var knownVideoIds = await database.ExternalTracks
|
||||
.AsNoTracking()
|
||||
.Where(track => track.Source == TrackSource.YouTube && historyTrackIds.Contains(track.Id))
|
||||
.Select(track => track.ExternalId)
|
||||
.ToListAsync(cancellationToken);
|
||||
|
||||
var excludedVideoIds = new HashSet<string>(knownVideoIds, StringComparer.OrdinalIgnoreCase);
|
||||
|
||||
var youTubeByArtist = await SearchYouTubeAsync(seedArtists, excludedVideoIds, cancellationToken);
|
||||
var localByArtist = await GetLocalCandidatesAsync(seedArtists, historyTrackIds, cancellationToken);
|
||||
|
||||
var drafts = BuildDrafts(seedArtists, localByArtist, youTubeByArtist);
|
||||
|
||||
if (drafts.Count == 0)
|
||||
{
|
||||
logger.LogInformation("No candidate songs found for user {UserId}, skipping mix generation", userId);
|
||||
return new Success();
|
||||
}
|
||||
|
||||
await ReplaceMixesAsync(userId, drafts, cancellationToken);
|
||||
|
||||
try
|
||||
{
|
||||
await database.SaveChangesAsync(cancellationToken);
|
||||
}
|
||||
catch (Exception exception)
|
||||
{
|
||||
logger.LogError(exception, "Failed to generate mixes for user {UserId}", userId);
|
||||
return Error.Failure(description: $"Failed to generate mixes for user {userId}");
|
||||
}
|
||||
|
||||
logger.LogInformation("Generated {Count} mixes for user {UserId}", drafts.Count, userId);
|
||||
return new Success();
|
||||
}
|
||||
|
||||
private async Task<List<SeedArtist>> GetSeedArtistsAsync(
|
||||
IReadOnlyList<Guid> historyTrackIds,
|
||||
CancellationToken cancellationToken)
|
||||
{
|
||||
var ranked = await database.TrackArtists
|
||||
.AsNoTracking()
|
||||
.Where(trackArtist => historyTrackIds.Contains(trackArtist.TrackId))
|
||||
.GroupBy(trackArtist => trackArtist.ArtistId)
|
||||
.Select(group => new { ArtistId = group.Key, Listens = group.Count() })
|
||||
.OrderByDescending(entry => entry.Listens)
|
||||
.Take(mixConfiguration.SeedArtistCount)
|
||||
.ToListAsync(cancellationToken);
|
||||
|
||||
var artistIds = ranked.Select(entry => entry.ArtistId).ToList();
|
||||
|
||||
var names = await database.Artists
|
||||
.AsNoTracking()
|
||||
.Where(artist => artistIds.Contains(artist.Id))
|
||||
.ToDictionaryAsync(artist => artist.Id, artist => artist.Name, cancellationToken);
|
||||
|
||||
return [.. ranked
|
||||
.Where(entry => names.ContainsKey(entry.ArtistId))
|
||||
.Select(entry => new SeedArtist(entry.ArtistId, names[entry.ArtistId]))];
|
||||
}
|
||||
|
||||
private async Task<Dictionary<Guid, List<MixItem>>> SearchYouTubeAsync(
|
||||
IReadOnlyList<SeedArtist> seedArtists,
|
||||
HashSet<string> excludedVideoIds,
|
||||
CancellationToken cancellationToken)
|
||||
{
|
||||
var byArtist = new Dictionary<Guid, List<MixItem>>();
|
||||
|
||||
foreach (var seed in seedArtists)
|
||||
{
|
||||
var searchResult = await youTubeMusicService.SearchSongsAsync(seed.Name, string.Empty, cancellationToken);
|
||||
if (searchResult.IsError)
|
||||
{
|
||||
logger.LogWarning("YouTube Music search failed for seed artist {Artist}: {Error}",
|
||||
seed.Name, searchResult.FirstError.Description);
|
||||
byArtist[seed.Id] = [];
|
||||
continue;
|
||||
}
|
||||
|
||||
var songs = new List<MixItem>();
|
||||
foreach (var song in searchResult.Value.Items.Take(mixConfiguration.YouTubeResultsPerSeed))
|
||||
{
|
||||
if (!excludedVideoIds.Add(song.VideoId))
|
||||
continue;
|
||||
|
||||
songs.Add(new MixItem
|
||||
{
|
||||
MixId = Guid.Empty,
|
||||
Source = MixItemSource.YouTube,
|
||||
VideoId = song.VideoId,
|
||||
Title = Truncate(song.Title, TitleLength),
|
||||
Artist = Truncate(song.Artist, ArtistLength),
|
||||
ThumbnailUrl = Truncate(youTubeMusicService.ResolveArtworkUrl(song.ThumbnailUrl), ThumbnailUrlLength),
|
||||
DurationSeconds = song.DurationSeconds,
|
||||
IsExplicit = song.IsExplicit
|
||||
});
|
||||
}
|
||||
|
||||
byArtist[seed.Id] = songs;
|
||||
}
|
||||
|
||||
return byArtist;
|
||||
}
|
||||
|
||||
private async Task<Dictionary<Guid, List<MixItem>>> GetLocalCandidatesAsync(
|
||||
IReadOnlyList<SeedArtist> seedArtists,
|
||||
IReadOnlyList<Guid> historyTrackIds,
|
||||
CancellationToken cancellationToken)
|
||||
{
|
||||
var artistIds = seedArtists.Select(seed => seed.Id).ToList();
|
||||
|
||||
var links = await database.TrackArtists
|
||||
.AsNoTracking()
|
||||
.Where(trackArtist => artistIds.Contains(trackArtist.ArtistId) && !historyTrackIds.Contains(trackArtist.TrackId))
|
||||
.Select(trackArtist => new { trackArtist.ArtistId, trackArtist.TrackId })
|
||||
.ToListAsync(cancellationToken);
|
||||
|
||||
var trackIds = links.Select(link => link.TrackId).Distinct().ToList();
|
||||
|
||||
var candidates = await LoadCandidatesAsync(trackIds, cancellationToken);
|
||||
|
||||
var byArtist = new Dictionary<Guid, List<MixItem>>();
|
||||
foreach (var seed in seedArtists)
|
||||
{
|
||||
byArtist[seed.Id] = [.. links
|
||||
.Where(link => link.ArtistId == seed.Id)
|
||||
.Select(link => candidates.GetValueOrDefault(link.TrackId))
|
||||
.Where(candidate => candidate is not null)
|
||||
.Select(candidate => ToMixItem(candidate!))];
|
||||
}
|
||||
|
||||
return byArtist;
|
||||
}
|
||||
|
||||
private async Task<Dictionary<Guid, LocalCandidate>> LoadCandidatesAsync(
|
||||
IReadOnlyList<Guid> trackIds,
|
||||
CancellationToken cancellationToken)
|
||||
{
|
||||
if (trackIds.Count == 0)
|
||||
return [];
|
||||
|
||||
var tracks = await database.Tracks
|
||||
.AsNoTracking()
|
||||
.Where(track => trackIds.Contains(track.Id) && track.LifeCycleStatus == LifeCycleStatus.Active)
|
||||
.Include(track => ((ExternalTrack)track).TrackArtists)
|
||||
.ThenInclude(trackArtist => trackArtist.Artist)
|
||||
.Include(track => ((LocalTrack)track).Owner)
|
||||
.ToListAsync(cancellationToken);
|
||||
|
||||
return tracks
|
||||
.Select(track => TrackApplicationResponse.FromEntity(track, 0))
|
||||
.ToDictionary(
|
||||
response => response.Id,
|
||||
response => new LocalCandidate(response.Id, response.Title, response.Artist, response.Duration));
|
||||
}
|
||||
|
||||
private static MixItem ToMixItem(LocalCandidate candidate) => new()
|
||||
{
|
||||
MixId = Guid.Empty,
|
||||
Source = MixItemSource.Musify,
|
||||
TrackId = candidate.TrackId,
|
||||
Title = candidate.Title,
|
||||
Artist = candidate.Artist,
|
||||
DurationSeconds = candidate.DurationSeconds
|
||||
};
|
||||
|
||||
private List<MixDraft> BuildDrafts(
|
||||
IReadOnlyList<SeedArtist> seedArtists,
|
||||
IReadOnlyDictionary<Guid, List<MixItem>> localByArtist,
|
||||
IReadOnlyDictionary<Guid, List<MixItem>> youTubeByArtist)
|
||||
{
|
||||
var drafts = new List<MixDraft>();
|
||||
|
||||
var everyYouTube = seedArtists.SelectMany(seed => youTubeByArtist[seed.Id]).ToList();
|
||||
var everyLocal = seedArtists.SelectMany(seed => localByArtist[seed.Id]).ToList();
|
||||
|
||||
var discovery = Take(Shuffle(everyYouTube));
|
||||
if (discovery.Count > 0)
|
||||
{
|
||||
drafts.Add(new MixDraft(
|
||||
"Descubrimiento",
|
||||
"Canciones nuevas de YouTube Music que todavía no has escuchado.",
|
||||
discovery));
|
||||
}
|
||||
|
||||
var daily = Take(Interleave(Shuffle(everyLocal), Shuffle(everyYouTube)));
|
||||
if (daily.Count > 0)
|
||||
{
|
||||
drafts.Add(new MixDraft(
|
||||
"Tu mezcla diaria",
|
||||
"Lo que más escuchas, con alguna sorpresa nueva.",
|
||||
daily));
|
||||
}
|
||||
|
||||
foreach (var seed in seedArtists.Take(mixConfiguration.ArtistMixCount))
|
||||
{
|
||||
var items = Take(Interleave(Shuffle(localByArtist[seed.Id]), Shuffle(youTubeByArtist[seed.Id])));
|
||||
if (items.Count == 0)
|
||||
continue;
|
||||
|
||||
drafts.Add(new MixDraft(
|
||||
Truncate($"Mezcla: {seed.Name}", MixTitleLength),
|
||||
$"Canciones de {seed.Name} en Musify y en YouTube Music.",
|
||||
items));
|
||||
}
|
||||
|
||||
return drafts;
|
||||
}
|
||||
|
||||
private List<MixItem> Take(IEnumerable<MixItem> items) =>
|
||||
[.. items.Take(mixConfiguration.ItemsPerMix)];
|
||||
|
||||
private static string Truncate(string value, int maxLength) =>
|
||||
value.Length <= maxLength ? value : value[..maxLength];
|
||||
|
||||
private static List<MixItem> Shuffle(IEnumerable<MixItem> items) =>
|
||||
[.. items.OrderBy(_ => Guid.NewGuid())];
|
||||
|
||||
private static List<MixItem> Interleave(IReadOnlyList<MixItem> first, IReadOnlyList<MixItem> second)
|
||||
{
|
||||
var merged = new List<MixItem>(first.Count + second.Count);
|
||||
for (var index = 0; index < Math.Max(first.Count, second.Count); index++)
|
||||
{
|
||||
if (index < first.Count)
|
||||
merged.Add(first[index]);
|
||||
if (index < second.Count)
|
||||
merged.Add(second[index]);
|
||||
}
|
||||
|
||||
return merged;
|
||||
}
|
||||
|
||||
private async Task ReplaceMixesAsync(long userId, IReadOnlyList<MixDraft> drafts, CancellationToken cancellationToken)
|
||||
{
|
||||
var previousMixes = await database.Mixes
|
||||
.Where(mix => mix.UserId == userId)
|
||||
.ToListAsync(cancellationToken);
|
||||
|
||||
if (previousMixes.Count > 0)
|
||||
{
|
||||
var previousIds = previousMixes.Select(mix => mix.Id).ToList();
|
||||
var previousItems = await database.MixItems
|
||||
.Where(item => previousIds.Contains(item.MixId))
|
||||
.ToListAsync(cancellationToken);
|
||||
|
||||
database.MixItems.RemoveRange(previousItems);
|
||||
database.Mixes.RemoveRange(previousMixes);
|
||||
}
|
||||
|
||||
var today = DateOnly.FromDateTime(DateTime.UtcNow);
|
||||
|
||||
for (var position = 0; position < drafts.Count; position++)
|
||||
{
|
||||
var draft = drafts[position];
|
||||
var mix = new Mix
|
||||
{
|
||||
UserId = userId,
|
||||
Title = draft.Title,
|
||||
Subtitle = draft.Subtitle,
|
||||
GeneratedOn = today,
|
||||
Position = position
|
||||
};
|
||||
|
||||
await database.Mixes.AddAsync(mix, cancellationToken);
|
||||
|
||||
for (var itemPosition = 0; itemPosition < draft.Items.Count; itemPosition++)
|
||||
{
|
||||
var item = draft.Items[itemPosition];
|
||||
await database.MixItems.AddAsync(new MixItem
|
||||
{
|
||||
MixId = mix.Id,
|
||||
Position = itemPosition,
|
||||
Source = item.Source,
|
||||
TrackId = item.TrackId,
|
||||
VideoId = item.VideoId,
|
||||
Title = item.Title,
|
||||
Artist = item.Artist,
|
||||
ThumbnailUrl = item.ThumbnailUrl,
|
||||
DurationSeconds = item.DurationSeconds,
|
||||
IsExplicit = item.IsExplicit
|
||||
}, cancellationToken);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user