minstrel/internal/api/api.go

// Package api implements Minstrel's native JSON surface under /api. It is
// consumed by the built-in web SPA and (eventually) the Flutter client.
// Subsonic-compatible endpoints under /rest are intentionally separate —
// see internal/subsonic — and the two packages must not depend on each other.
package api

import (
	"log/slog"
	"math/rand"
	"path/filepath"
	"time"

	"github.com/go-chi/chi/v5"
	"github.com/jackc/pgx/v5/pgxpool"

	"git.fabledsword.com/bvandeusen/minstrel/internal/acquire"
	"git.fabledsword.com/bvandeusen/minstrel/internal/auth"
	"git.fabledsword.com/bvandeusen/minstrel/internal/catalogue"
	"git.fabledsword.com/bvandeusen/minstrel/internal/config"
	"git.fabledsword.com/bvandeusen/minstrel/internal/coverart"
	"git.fabledsword.com/bvandeusen/minstrel/internal/eventbus"
	"git.fabledsword.com/bvandeusen/minstrel/internal/library"
	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrconfig"
	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrquarantine"
	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrrequests"
	"git.fabledsword.com/bvandeusen/minstrel/internal/mailer"
	"git.fabledsword.com/bvandeusen/minstrel/internal/netsettings"
	"git.fabledsword.com/bvandeusen/minstrel/internal/notifications"
	"git.fabledsword.com/bvandeusen/minstrel/internal/playevents"
	"git.fabledsword.com/bvandeusen/minstrel/internal/playlists"
	"git.fabledsword.com/bvandeusen/minstrel/internal/reacquisition"
	"git.fabledsword.com/bvandeusen/minstrel/internal/recommendation"
	"git.fabledsword.com/bvandeusen/minstrel/internal/recsettings"
	"git.fabledsword.com/bvandeusen/minstrel/internal/tags"
	"git.fabledsword.com/bvandeusen/minstrel/internal/tracks"
)

// Mount attaches /api/* handlers to r. Public endpoints (login) are outside
// RequireUser; everything else is gated by the middleware. The events writer
// is shared with the Subsonic mount so /rest/scrobble feeds the same store.
func Mount(r chi.Router, pool *pgxpool.Pool, logger *slog.Logger, events *playevents.Writer, recCfg config.RecommendationConfig, recSettings *recsettings.Service, lidarrCfg *lidarrconfig.Service, lidarrReqs *lidarrrequests.Service, lidarrQuar *lidarrquarantine.Service, tracksSvc *tracks.Service, playlistsSvc *playlists.Service, coverEnricher *coverart.Enricher, coverSettings *coverart.SettingsService, tagSettings *tags.SettingsService, scanner *library.Scanner, scanCfg library.RunScanConfig, dataDir string, sender mailer.Sender, bus *eventbus.Bus, playlistScheduler *playlists.Scheduler, streamSecret []byte, netSettings *netsettings.Service, reacqSettings *reacquisition.SettingsService, fpSettings *library.FingerprintSettingsService, loudSettings *library.LoudnessSettingsService, acoustIDLookup *library.AcoustIDLookupWorker) {
	rng := rand.New(rand.NewSource(rand.Int63()))
	setupToken, err := auth.NewSetupToken()
	if err != nil {
		// crypto/rand failing means the platform can't make secrets at all;
		// sessions would be minted from the same source. Nothing to degrade to.
		panic("api: mint setup token: " + err.Error())
	}
	logSetupTokenIfNeeded(pool, logger, setupToken)
	h := &handlers{
		pool: pool, logger: logger, events: events, recCfg: recCfg,
		recSettings:         recSettings,
		rng:                 rng.Float64,
		lidarrCfg:           lidarrCfg,
		lidarrRequests:      lidarrReqs,
		lidarrQuarantine:    lidarrQuar,
		tracks:              tracksSvc,
		playlists:           playlistsSvc,
		coverart:            coverEnricher,
		coverSettings:       coverSettings,
		tagSettings:         tagSettings,
		scanner:             scanner,
		scanCfg:             scanCfg,
		dataDir:             dataDir,
		mailer:              sender,
		eventbus:            bus,
		notifier:            notifications.New(pool, bus, logger.With("component", "notifications")),
		playlistScheduler:   playlistScheduler,
		streamSecret:        streamSecret,
		netSettings:         netSettings,
		reacqSettings:       reacqSettings,
		fingerprintSettings: fpSettings,
		loudnessSettings:    loudSettings,
		acoustIDLookup:      acoustIDLookup,
		acquisition:         acquire.NewStore(pool),
		catalogue:           catalogue.New(pool, nil, logger),
		catalogueSearches:   newSearchCache(),
		catalogueArt:        catalogue.NewArt(dataDir, artSources(coverSettings)),
		leveled:             newLeveledRenderer(dataDir, loudSettings, logger),
		librarySize:         recommendation.NewLibrarySize(nil),
		loginGuard:          auth.NewLoginGuard(),
		setupToken:          setupToken,
		requireSetupToken:   true,
		registerLimit:       auth.NewAttemptLimiter(registerPerAddressMax, time.Hour),
		forgotAddressLimit:  auth.NewAttemptLimiter(forgotPerAddressMax, time.Hour),
		forgotEmailLimit:    auth.NewAttemptLimiter(forgotPerEmailMax, time.Hour),
		resetLimit:          auth.NewAttemptLimiter(resetFailuresPerAddressMax, 15*time.Minute),
	}

	r.Route("/api", func(api chi.Router) {
		api.Post("/auth/login", h.handleLogin)
		api.Post("/auth/register", h.handleRegister)
		api.Get("/auth/setup-status", h.handleSetupStatus)
		api.Post("/auth/forgot-password", h.handleForgotPassword)
		api.Post("/auth/reset-password", h.handleResetPassword)

		// Stream lives outside authed.Group so it can accept EITHER a
		// session (resolved by the OptionalUser middleware) OR a signed
		// query token (UPnP / Sonos path; see streamAuthOk). The
		// middleware attaches user to context when a valid cookie /
		// bearer is present but does NOT 401 on absence; the handler's
		// own streamAuthOk performs the actual auth check. See the
		// design at
		// docs/superpowers/specs/2026-06-03-android-output-picker-upnp-design.md.
		api.With(auth.OptionalUser(pool, logger)).Get("/tracks/{id}/stream", h.handleGetStream)
		// Extension-bearing alias so Sonos's URL probe can identify the
		// audio format from the path. The {ext} param is consumed by chi
		// and ignored by the handler (which keys off {id}). See task #610.
		api.With(auth.OptionalUser(pool, logger)).Get("/tracks/{id}/stream.{ext}", h.handleGetStream)
		// The leveled stream for Sonos/UPnP (M464 #5001): session or a
		// leveled token, like the plain stream.
		api.With(auth.OptionalUser(pool, logger)).Get("/tracks/{id}/leveled.flac", h.handleGetLeveledStream)

		api.Group(func(authed chi.Router) {
			authed.Use(auth.RequireUser(pool, netSettings.Hops))
			authed.Post("/auth/logout", h.handleLogout)
			authed.Get("/me", h.handleGetMe)
			authed.Get("/me/system-playlists-status", h.handleGetSystemPlaylistsStatus)
			authed.Get("/me/recommendation-metrics", h.handleGetRecommendationMetrics)
			authed.Get("/me/listenbrainz", h.handleGetListenBrainz)
			authed.Put("/me/listenbrainz", h.handlePutListenBrainz)
			authed.Get("/me/history", h.handleGetMyHistory)
			authed.Put("/me/password", h.handleChangePassword)
			authed.Put("/me/profile", h.handleUpdateMyProfile)
			authed.Put("/me/timezone", h.handlePutTimezone)
			authed.Get("/me/normalization", h.handleGetMyNormalization)
			authed.Put("/me/normalization", h.handlePutMyNormalization)
			authed.Post("/me/api-token", h.handleRegenerateMyAPIToken)
			authed.Get("/me/subsonic-password", h.handleGetMySubsonicPassword)
			authed.Post("/me/subsonic-password", h.handleGenerateMySubsonicPassword)
			authed.Delete("/me/subsonic-password", h.handleClearMySubsonicPassword)
			authed.Get("/me/sessions", h.handleListMySessions)
			authed.Delete("/me/sessions/{id}", h.handleRevokeMySession)
			authed.Post("/me/sessions/logout-others", h.handleRevokeMyOtherSessions)
			authed.Get("/me/notifications", h.handleListMyNotifications)
			authed.Get("/me/notifications/unread-count", h.handleMyUnreadNotificationCount)
			authed.Post("/me/notifications/read-all", h.handleMarkAllMyNotificationsRead)
			authed.Post("/me/notifications/{id}/read", h.handleMarkMyNotificationRead)
			authed.Get("/me/notification-settings", h.handleGetMyNotificationSettings)
			authed.Put("/me/notification-settings", h.handlePutMyNotificationSettings)

			authed.Get("/artists", h.handleListArtists)
			authed.Get("/artists/{id}", h.handleGetArtist)
			authed.Get("/artists/{id}/tracks", h.handleGetArtistTracks)
			authed.Get("/artists/{id}/similar", h.handleGetSimilarArtists)
			authed.Get("/artists/{id}/top-tracks", h.handleGetArtistTopTracks)
			authed.Get("/albums/{id}", h.handleGetAlbum)
			authed.Get("/albums/{id}/cover", h.handleGetCover)
			authed.Get("/library/shuffle", h.handleLibraryShuffle)
			authed.Get("/library/albums", h.handleListLibraryAlbums)
			// Browse indexes (#367). Genre filtering rides
			// /library/albums?genre= rather than a path segment, because raw
			// ID3 genres contain slashes ("Rock/Pop") that a path can't carry.
			authed.Get("/library/genres", h.handleListGenres)
			authed.Get("/library/years", h.handleListAlbumYears)
			authed.Get("/library/sync", h.handleLibrarySync)
			// Before /tracks/{id} for readability; chi prefers the static
			// segment either way.
			authed.Get("/tracks/replay-gain", h.handleGetReplayGain)
			authed.Get("/tracks/{id}", h.handleGetTrack)
			// /tracks/{id}/stream is mounted above with OptionalUser so
			// it can accept either a session or a signed token.
			authed.Get("/search", h.handleSearch)
			authed.Get("/radio", h.handleRadio)
			authed.Get("/discover/suggestions", h.handleListSuggestions)
			// Snooze = "not right now", time-boxed and self-expiring
			// (#2374). Not a dislike — see the migration for why.
			authed.Post("/discover/suggestions/{mbid}/snooze", h.handleSnoozeSuggestion)
			authed.Delete("/discover/suggestions/{mbid}/snooze", h.handleUnsnoozeSuggestion)
			authed.Get("/discover/snoozes", h.handleListSuggestionSnoozes)
			authed.Get("/home", h.handleGetHome)
			authed.Get("/home/index", h.handleGetHomeIndex)
			authed.Post("/events", h.handleEvents)
			authed.Get("/events/stream", h.handleEventsStream)
			// UPnP / Sonos cast slice: issue a short-lived HMAC stream URL
			// the speaker can fetch without the user's session. See the
			// design at
			// docs/superpowers/specs/2026-06-03-android-output-picker-upnp-design.md.
			authed.Post("/cast/stream-token", h.handleCastStreamToken)
			authed.Post("/likes/tracks/{id}", h.handleLikeTrack)
			authed.Delete("/likes/tracks/{id}", h.handleUnlikeTrack)
			authed.Post("/likes/albums/{id}", h.handleLikeAlbum)
			authed.Delete("/likes/albums/{id}", h.handleUnlikeAlbum)
			authed.Post("/likes/artists/{id}", h.handleLikeArtist)
			authed.Delete("/likes/artists/{id}", h.handleUnlikeArtist)
			authed.Get("/likes/tracks", h.handleListLikedTracks)
			authed.Get("/likes/albums", h.handleListLikedAlbums)
			authed.Get("/likes/artists", h.handleListLikedArtists)
			authed.Get("/likes/ids", h.handleGetLikedIDs)

			// The release catalogue (M502 #5519): request search asks
			// MusicBrainz, and art for what isn't held comes through
			// Minstrel from the enabled cover-art sources.
			authed.Get("/catalogue/search", h.handleCatalogueSearch)
			authed.Get("/catalogue/art/{kind}/{mbid}", h.handleCatalogueArt)

			authed.Post("/requests", h.handleCreateRequest)
			authed.Get("/requests", h.handleListRequests)
			authed.Get("/requests/{id}", h.handleGetRequest)
			authed.Delete("/requests/{id}", h.handleCancelRequest)

			authed.Post("/quarantine", h.handleFlag)
			authed.Delete("/quarantine/{track_id}", h.handleUnflag)
			authed.Get("/quarantine/mine", h.handleListMyQuarantine)

			// Client-reported playback errors (zero-duration tracks,
			// load failures). Admin-only inbox; any user can report.
			authed.Post("/playback-errors", h.handleReportPlaybackError)

			// Device diagnostics ingest (M9). Any signed-in user can
			// POST a batch, but events are only stored when the
			// account's debug_mode_enabled flag is on (handler no-ops
			// otherwise). Admin views live under /admin/diagnostics.
			authed.Post("/diagnostics", h.handleReportDiagnostics)

			// Self-hosted in-app update channel (#397). Auth-gated to
			// prevent anonymous bandwidth abuse on the APK stream;
			// /apk additionally per-user rate-limited.
			authed.Get("/client/version", h.handleClientVersion)
			authed.Get("/client/apk", h.handleClientAPK)

			authed.Route("/admin", func(admin chi.Router) {
				admin.Use(auth.RequireAdmin())
				admin.Get("/lidarr/config", h.handleGetLidarrConfig)
				admin.Put("/lidarr/config", h.handlePutLidarrConfig)
				admin.Post("/lidarr/test", h.handleTestLidarrConnection)
				admin.Get("/acquisition/services", h.handleListAcquisitionServices)
				admin.Post("/acquisition/services", h.handleCreateAcquisitionService)
				admin.Put("/acquisition/services/{code}", h.handleUpdateAcquisitionService)
				admin.Delete("/acquisition/services/{code}", h.handleDeleteAcquisitionService)
				admin.Post("/acquisition/services/{code}/test", h.handleTestAcquisitionService)
				admin.Put("/acquisition/services/{code}/api-key", h.handleSetAcquisitionSecret("api_key"))
				admin.Delete("/acquisition/services/{code}/api-key", h.handleSetAcquisitionSecret("api_key"))
				admin.Put("/acquisition/services/{code}/password", h.handleSetAcquisitionSecret("password"))
				admin.Delete("/acquisition/services/{code}/password", h.handleSetAcquisitionSecret("password"))
				admin.Get("/lidarr/quality-profiles", h.handleListQualityProfiles)
				admin.Get("/lidarr/metadata-profiles", h.handleListMetadataProfiles)
				admin.Get("/lidarr/root-folders", h.handleListRootFolders)
				admin.Get("/requests", h.handleListAdminRequests)
				admin.Post("/requests/{id}/approve", h.handleApproveRequest)
				admin.Post("/requests/{id}/reject", h.handleRejectRequest)

				admin.Get("/quarantine", h.handleListAdminQuarantine)
				admin.Post("/quarantine/{track_id}/resolve", h.handleResolveQuarantine)

				admin.Get("/playback-errors", h.handleListAdminPlaybackErrors)
				admin.Post("/playback-errors/{id}/resolve", h.handleResolvePlaybackError)
				admin.Post("/quarantine/{track_id}/delete-file", h.handleDeleteQuarantineFile)
				admin.Post("/quarantine/{track_id}/delete-via-lidarr", h.handleDeleteQuarantineViaLidarr)
				admin.Get("/quarantine/actions", h.handleListQuarantineActions)

				admin.Delete("/tracks/{id}", h.handleRemoveTrack)

				admin.Post("/albums/{id}/cover/refetch", h.handleAdminAlbumRefetchCover)
				admin.Post("/covers/refetch-missing", h.handleAdminBulkRefetchCovers)

				admin.Get("/network-settings", h.handleGetNetworkSettings)
				admin.Put("/network-settings", h.handleUpdateNetworkSettings)

				// Policy for turning a missing file back into a Lidarr
				// request (#290). Sits beside the missing-files list it
				// governs rather than under /lidarr, because the operator
				// meets it on the missing-files surface.
				admin.Get("/library/reacquisition", h.handleGetReacquisitionSettings)
				admin.Put("/library/reacquisition", h.handleUpdateReacquisitionSettings)

				admin.Get("/scan/status", h.handleGetScanStatus)
				admin.Post("/scan/run", h.handleTriggerScan)
				// Sits under /library rather than /tracks because what it
				// reports is a property of the library's relationship to disk,
				// and because the destructive /tracks/{id} route above must
				// not be mistaken for it (#2527).
				admin.Get("/library/missing", h.handleListMissingTracks)
				admin.Get("/library/suspect-sources", h.handleListSuspectSources)
				admin.Put("/library/suspect-sources/{id}", h.handleSetSuspectSourceVerdict)

				admin.Get("/library/coverage", h.handleGetLibraryCoverage)
				admin.Get("/library/fingerprints", h.handleGetFingerprintCoverage)
				admin.Get("/library/fingerprint-settings", h.handleGetFingerprintSettings)
				admin.Put("/library/fingerprint-settings", h.handleUpdateFingerprintSettings)
				admin.Get("/library/loudness", h.handleGetLoudnessCoverage)
				admin.Get("/library/loudness-settings", h.handleGetLoudnessSettings)
				admin.Put("/library/loudness-settings", h.handleUpdateLoudnessSettings)
				admin.Get("/library/acoustid", h.handleGetAcoustID)
				admin.Put("/library/acoustid-settings", h.handleUpdateAcoustIDSettings)
				admin.Post("/library/acoustid/run", h.handleRunAcoustIDLookup)
				admin.Get("/library/acoustid/unsettled", h.handleListUnsettledAcoustID)
				// Duplicates report (#3912): proposals from the duplicate sweep, a
				// trigger to sweep now, dismissal, and the merge (#3911), which deletes
				// the removed copies' files after moving their history onto the kept one.
				admin.Get("/library/duplicates", h.handleListDuplicates)
				admin.Get("/library/duplicates/resolved", h.handleListResolvedDuplicates)
				admin.Post("/library/duplicates/sweep", h.handleRunDuplicateSweep)
				admin.Post("/library/duplicates/{id}/dismiss", h.handleDismissDuplicateGroup)
				admin.Post("/library/duplicates/{id}/merge", h.handleMergeDuplicateGroup)

				admin.Get("/invites", h.handleListInvites)
				admin.Post("/invites", h.handleCreateInvite)
				admin.Delete("/invites/{token}", h.handleDeleteInvite)
				admin.Get("/users", h.handleAdminListUsers)
				admin.Put("/users/{id}/admin", h.handleUpdateUserAdmin)
				admin.Post("/users", h.handleAdminCreateUser)
				admin.Delete("/users/{id}", h.handleAdminDeleteUser)
				admin.Post("/users/{id}/reset-password", h.handleAdminResetPassword)
				admin.Put("/users/{id}/auto-approve", h.handleAdminAutoApproveToggle)
				admin.Put("/users/{id}/debug-mode", h.handleAdminDebugModeToggle)

				// Device diagnostics timeline + device overview (M9).
				admin.Get("/diagnostics", h.handleListAdminDiagnostics)
				admin.Get("/diagnostics/devices", h.handleListAdminDiagnosticDevices)

				admin.Get("/cover-sources", h.handleListCoverSources)
				admin.Patch("/cover-sources/{provider_id}", h.handleUpdateCoverSource)
				admin.Post("/cover-sources/{provider_id}/test", h.handleTestCoverSource)
				admin.Post("/cover-sources/research", h.handleResearchMissingArt)

				admin.Get("/tag-sources", h.handleListTagSources)
				admin.Patch("/tag-sources/{provider_id}", h.handleUpdateTagSource)
				admin.Post("/tag-sources/{provider_id}/test", h.handleTestTagSource)
				admin.Post("/tag-sources/research", h.handleResearchTags)

				admin.Get("/smtp-config", h.handleGetSMTPConfig)
				admin.Put("/smtp-config", h.handleUpdateSMTPConfig)
				admin.Post("/smtp-config/test", h.handleTestSMTPConfig)
				admin.Get("/notification-email", h.handleGetNotificationEmail)
				admin.Put("/notification-email", h.handleUpdateNotificationEmail)

				// Recommendation tuning lab (#1250): scoring-weight
				// profiles + taste-build knobs, DB-backed, live effect.
				admin.Get("/recommendation-tuning", h.handleGetRecommendationTuning)
				admin.Patch("/recommendation-tuning/{scope}", h.handlePatchRecommendationTuning)
				admin.Post("/recommendation-tuning/{scope}/reset", h.handleResetRecommendationTuning)
				// Weekly outcome trends + knob-turn markers (#1251).
				admin.Get("/recommendation-trends", h.handleGetRecommendationTrends)
			})

			authed.Get("/playlists", h.handleListPlaylists)
			authed.Post("/playlists", h.handleCreatePlaylist)
			authed.Get("/playlists/{id}", h.handleGetPlaylist)
			authed.Patch("/playlists/{id}", h.handleUpdatePlaylist)
			authed.Delete("/playlists/{id}", h.handleDeletePlaylist)
			authed.Post("/playlists/{id}/tracks", h.handleAppendTracks)
			authed.Delete("/playlists/{id}/tracks/{position}", h.handleRemovePlaylistTrack)
			authed.Put("/playlists/{id}/tracks", h.handleReorderPlaylist)
			authed.Get("/playlists/{id}/cover", h.handleGetPlaylistCover)
			authed.Post("/playlists/system/{kind}/refresh", h.handleSystemPlaylistRefresh)
			authed.Get("/playlists/system/{kind}/shuffle", h.handleSystemPlaylistShuffle)
		})
	})
}

type handlers struct {
	pool        *pgxpool.Pool
	logger      *slog.Logger
	events      *playevents.Writer
	recCfg      config.RecommendationConfig
	recSettings *recsettings.Service
	rng         func() float64
	// librarySize memoises the track count that sizes the candidate pool
	// (#3880). Held here rather than counted per request: the count is a
	// full table scan, and library size only moves when a scan runs.
	librarySize      *recommendation.LibrarySize
	lidarrCfg        *lidarrconfig.Service
	lidarrRequests   *lidarrrequests.Service
	lidarrQuarantine *lidarrquarantine.Service
	tracks           *tracks.Service
	playlists        *playlists.Service
	coverart         *coverart.Enricher
	coverSettings    *coverart.SettingsService
	tagSettings      *tags.SettingsService
	scanner          *library.Scanner
	scanCfg          library.RunScanConfig
	dataDir          string
	mailer           mailer.Sender
	eventbus         *eventbus.Bus
	// notifier writes the notifications inbox (M489). Nil-safe: a nil
	// notifier records nothing, which is what most handler tests want.
	notifier          *notifications.Notifier
	playlistScheduler *playlists.Scheduler
	// reacqSettings is the DB-backed policy for auto re-acquisition of
	// missing files (milestone #290) — grace window, backoff, attempt caps.
	// Cached in the service, so the admin card reads it without a query.
	reacqSettings *reacquisition.SettingsService
	// fingerprintSettings is the fingerprinting policy (M400 #3913), the same
	// instance the scanner and the fingerprint workers read, so a save from the
	// admin card reaches them without a restart. Nil serves the defaults.
	fingerprintSettings *library.FingerprintSettingsService
	// loudnessSettings is the loudness analysis policy (M464 #4995), the same
	// instance the loudness backfill reads. Nil serves the defaults.
	loudnessSettings *library.LoudnessSettingsService
	// acoustIDLookup is the AcoustID lookup worker (M401): its settings, its
	// status and "look up now". Nil serves the defaults (off).
	acoustIDLookup *library.AcoustIDLookupWorker
	// acquisition is the operator's indexers and download clients (M502).
	acquisition *acquire.Store
	// catalogue is the release catalogue read from MusicBrainz, and
	// catalogueArt the images for what isn't held (M502 #5519).
	catalogue    *catalogue.Service
	catalogueArt *catalogue.Art
	// catalogueSearches reuses recent MusicBrainz answers; nil asks every
	// time, which is what handler tests get.
	catalogueSearches *searchCache
	// leveled renders the leveled streams handed to Sonos/UPnP speakers
	// (M464 #5001). Nil when its cache directory cannot be made: a level
	// request then gets the plain stream.
	leveled *library.LeveledRenderer
	// setupToken must accompany the first registration while no users exist
	// (see auth.SetupToken). requireSetupToken is set by Mount, the only
	// production constructor; tests that build handlers directly leave it
	// off unless they are testing it.
	setupToken        *auth.SetupToken
	requireSetupToken bool
	// loginGuard throttles failed logins per account and per address, and
	// the limiters below cap the other unauthenticated auth routes. All are
	// nil-safe, so tests that build handlers directly run unthrottled.
	loginGuard         *auth.LoginGuard
	registerLimit      *auth.AttemptLimiter
	forgotAddressLimit *auth.AttemptLimiter
	forgotEmailLimit   *auth.AttemptLimiter
	resetLimit         *auth.AttemptLimiter
	// netSettings caches the trusted reverse-proxy depth read by the auth
	// middleware on every request and edited from the admin network card.
	netSettings *netsettings.Service
	// streamSecret is the HMAC key used by SignStreamToken /
	// VerifyStreamToken to authenticate the UPnP-speaker stream path
	// (see internal/api/stream_token.go and the design at
	// docs/superpowers/specs/2026-06-03-android-output-picker-upnp-design.md).
	// nil in slice 1; slice 2 wires the env-var-with-app_preferences-
	// fallback loader. A nil secret leaves the cookie path intact and
	// makes the token path unreachable (HMAC of empty key won't match
	// anything a client mints), which is the desired slice-1 default.
	streamSecret []byte
}

// newLeveledRenderer makes the leveled-stream renderer, caching under the
// data directory. A failure is logged and leaves leveling off for speakers.
func newLeveledRenderer(dataDir string, settings *library.LoudnessSettingsService, logger *slog.Logger) *library.LeveledRenderer {
	r, err := library.NewLeveledRenderer(filepath.Join(dataDir, "leveled-cache"), settings, logger)
	if err != nil {
		logger.Error("api: leveled streams unavailable", "err", err)
		return nil
	}
	return r
}

// artSources hands the art cache the cover-art settings, or nothing when
// there are none: a nil *SettingsService inside the interface would not
// compare equal to nil and would be called.
func artSources(s *coverart.SettingsService) catalogue.ArtSources {
	if s == nil {
		return nil
	}
	return s
}