feat(android): similar-artists strip + top-tracks on artist detail

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

android/app/src/main/java/com/fabledsword/minstrel/api/endpoints/LibraryApi.kt

@@ -2,6 +2,7 @@ package com.fabledsword.minstrel.api.endpoints
 
 import com.fabledsword.minstrel.models.wire.AlbumDetailWire
 import com.fabledsword.minstrel.models.wire.ArtistDetailWire
+import com.fabledsword.minstrel.models.wire.ArtistWire
 import com.fabledsword.minstrel.models.wire.TrackWire
 import retrofit2.http.GET
 import retrofit2.http.Path
@@ -35,9 +36,26 @@ interface LibraryApi {
     @GET("api/artists/{id}/tracks")
     suspend fun getArtistTracks(@Path("id") id: String): List<TrackWire>
 
+    @GET("api/artists/{id}/similar")
+    suspend fun getSimilarArtists(
+        @Path("id") id: String,
+        @Query("limit") limit: Int = SIMILAR_ARTISTS_LIMIT,
+    ): List<ArtistWire>
+
+    @GET("api/artists/{id}/top-tracks")
+    suspend fun getArtistTopTracks(
+        @Path("id") id: String,
+        @Query("limit") limit: Int = TOP_TRACKS_LIMIT,
+    ): List<TrackWire>
+
     @GET("api/albums/{id}")
     suspend fun getAlbumDetail(@Path("id") id: String): AlbumDetailWire
 
     @GET("api/library/shuffle")
     suspend fun shuffleLibrary(@Query("limit") limit: Int = 100): List<TrackWire>
+
+    private companion object {
+        const val SIMILAR_ARTISTS_LIMIT = 12
+        const val TOP_TRACKS_LIMIT = 5
+    }
 }

android/app/src/main/java/com/fabledsword/minstrel/library/data/LibraryRepository.kt

@@ -105,6 +105,22 @@ class LibraryRepository @Inject constructor(
     suspend fun fetchArtistTracks(id: String): List<TrackRef> =
         api.getArtistTracks(id).map { it.toDomain() }
 
+    /**
+     * Pulls related artists for the ArtistDetail "Similar artists"
+     * strip. Network-only — non-critical UI, callers swallow failures
+     * and render nothing rather than blocking the screen.
+     */
+    suspend fun fetchSimilarArtists(id: String): List<ArtistRef> =
+        api.getSimilarArtists(id).map { it.toDomain() }
+
+    /**
+     * Pulls the artist's top tracks for the ArtistDetail "Top tracks"
+     * panel. Network-only; tapping a row plays this exact list as a
+     * queue, so no persistence is needed.
+     */
+    suspend fun fetchArtistTopTracks(id: String): List<TrackRef> =
+        api.getArtistTopTracks(id).map { it.toDomain() }
+
     /**
      * Pulls the album detail (AlbumRef + tracks), persists both, and
      * returns the in-memory snapshot. Lets the AlbumDetail screen

android/app/src/main/java/com/fabledsword/minstrel/library/ui/ArtistDetailScreen.kt

@@ -1,3 +1,5 @@
+@file:Suppress("TooManyFunctions") // Compose screen + private helper composables
+
 package com.fabledsword.minstrel.library.ui
 
 import androidx.compose.animation.Crossfade
@@ -17,7 +19,8 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.GridItemSpan
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
-import androidx.compose.foundation.lazy.grid.items
+import androidx.compose.foundation.lazy.grid.items as gridItems
+import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.material3.Button
 import androidx.compose.material3.ExperimentalMaterial3Api
@@ -46,21 +49,27 @@ import com.composables.icons.lucide.Lucide
 import com.composables.icons.lucide.Play
 import com.composables.icons.lucide.User
 import com.fabledsword.minstrel.library.widgets.AlbumCard
-import com.fabledsword.minstrel.models.ArtistDetailRef
+import com.fabledsword.minstrel.library.widgets.ArtistCard
 import com.fabledsword.minstrel.models.ArtistRef
+import com.fabledsword.minstrel.models.TrackRef
 import com.fabledsword.minstrel.models.albumCoverPath
 import com.fabledsword.minstrel.nav.AlbumDetail
+import com.fabledsword.minstrel.nav.ArtistDetail
+import com.fabledsword.minstrel.shared.formatDuration
 import com.fabledsword.minstrel.shared.widgets.EmptyState
+import com.fabledsword.minstrel.shared.widgets.HorizontalScrollRow
 import com.fabledsword.minstrel.shared.widgets.LikeButton
 import com.fabledsword.minstrel.shared.widgets.PullToRefreshScaffold
 import com.fabledsword.minstrel.shared.widgets.ServerImage
 import com.fabledsword.minstrel.shared.widgets.SkeletonAlbumTile
+import com.fabledsword.minstrel.shared.widgets.TrackRow
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun ArtistDetailScreen(
     navController: NavHostController,
     viewModel: ArtistDetailViewModel = hiltViewModel(),
+    playerViewModel: com.fabledsword.minstrel.player.ui.PlayerViewModel = hiltViewModel(),
 ) {
     val state by viewModel.uiState.collectAsStateWithLifecycle()
     val snackbarHostState = remember { SnackbarHostState() }
@@ -105,12 +114,19 @@ fun ArtistDetailScreen(
                     is ArtistDetailUiState.Success -> {
                         val artistLiked by viewModel.artistLiked
                             .collectAsStateWithLifecycle()
+                        val playerState by playerViewModel.uiState
+                            .collectAsStateWithLifecycle()
                         ArtistBody(
-                            detail = s.detail,
+                            state = s,
                             artistLiked = artistLiked,
+                            playingTrackId = playerState.currentTrack?.id,
                             onPlay = viewModel::playArtist,
                             onToggleLike = viewModel::toggleLikeArtist,
                             onAlbumClick = { id -> navController.navigate(AlbumDetail(id)) },
+                            onTopTrackClick = viewModel::playTopTracks,
+                            onSimilarArtistClick = { id ->
+                                navController.navigate(ArtistDetail(id))
+                            },
                         )
                     }
                 }
@@ -127,12 +143,16 @@ private fun titleFor(state: ArtistDetailUiState): String = when (state) {
 
 @Composable
 private fun ArtistBody(
-    detail: ArtistDetailRef,
+    state: ArtistDetailUiState.Success,
     artistLiked: Boolean,
+    playingTrackId: String?,
     onPlay: () -> Unit,
     onToggleLike: () -> Unit,
     onAlbumClick: (String) -> Unit,
+    onTopTrackClick: (Int) -> Unit,
+    onSimilarArtistClick: (String) -> Unit,
 ) {
+    val detail = state.detail
     LazyVerticalGrid(
         columns = GridCells.Adaptive(minSize = 176.dp),
         modifier = Modifier.fillMaxSize(),
@@ -149,18 +169,96 @@ private fun ArtistBody(
                 onToggleLike = onToggleLike,
             )
         }
+        if (state.topTracks.isNotEmpty()) {
+            item(span = { GridItemSpan(maxLineSpan) }) {
+                TopTracksPanel(
+                    tracks = state.topTracks,
+                    playingTrackId = playingTrackId,
+                    onTrackClick = onTopTrackClick,
+                )
+            }
+        }
+        if (state.similarArtists.isNotEmpty()) {
+            item(span = { GridItemSpan(maxLineSpan) }) {
+                SimilarArtistsStrip(
+                    artists = state.similarArtists,
+                    onArtistClick = onSimilarArtistClick,
+                )
+            }
+        }
         if (detail.albums.isEmpty()) {
             item(span = { GridItemSpan(maxLineSpan) }) {
                 EmptyAlbumsHint()
             }
         } else {
-            items(items = detail.albums, key = { it.id }) { album ->
+            gridItems(items = detail.albums, key = { it.id }) { album ->
                 AlbumCard(album = album, onClick = { onAlbumClick(album.id) })
             }
         }
     }
 }
 
+@Composable
+private fun TopTracksPanel(
+    tracks: List<TrackRef>,
+    playingTrackId: String?,
+    onTrackClick: (Int) -> Unit,
+) {
+    Column(modifier = Modifier.fillMaxWidth()) {
+        Text(
+            text = "Top tracks",
+            style = MaterialTheme.typography.titleLarge,
+            color = MaterialTheme.colorScheme.onBackground,
+            modifier = Modifier.padding(horizontal = 16.dp, vertical = 8.dp),
+        )
+        tracks.forEachIndexed { index, track ->
+            TopTrackRow(
+                track = track,
+                nowPlaying = track.id == playingTrackId,
+                onClick = { onTrackClick(index) },
+            )
+        }
+    }
+}
+
+@Composable
+private fun TopTrackRow(
+    track: TrackRef,
+    nowPlaying: Boolean,
+    onClick: () -> Unit,
+) {
+    TrackRow(
+        title = track.title,
+        artist = track.artistName,
+        trackId = track.id,
+        onClick = onClick,
+        nowPlaying = nowPlaying,
+        trailing = {
+            Text(
+                text = formatDuration(track.durationSec, zero = "--:--"),
+                style = MaterialTheme.typography.bodySmall,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.padding(start = 12.dp),
+            )
+        },
+    )
+}
+
+@Composable
+private fun SimilarArtistsStrip(
+    artists: List<ArtistRef>,
+    onArtistClick: (String) -> Unit,
+) {
+    HorizontalScrollRow(title = "Similar artists") {
+        items(items = artists, key = { it.id }) { artist ->
+            ArtistCard(
+                artist = artist,
+                onClick = { onArtistClick(artist.id) },
+            )
+        }
+    }
+}
+
 @Composable
 private fun ArtistHeader(
     artist: ArtistRef,
@@ -270,7 +368,7 @@ private fun SkeletonArtistAlbumsGrid() {
         horizontalArrangement = Arrangement.spacedBy(8.dp),
         modifier = Modifier.fillMaxSize(),
     ) {
-        items(SKELETON_ARTIST_GRID_TILES) { SkeletonAlbumTile() }
+        gridItems(SKELETON_ARTIST_GRID_TILES) { SkeletonAlbumTile() }
     }
 }
 
@@ -314,6 +412,6 @@ private fun SeededArtistLoading(seed: ArtistRef) {
                 }
             }
         }
-        items(SKELETON_ARTIST_GRID_TILES) { SkeletonAlbumTile() }
+        gridItems(SKELETON_ARTIST_GRID_TILES) { SkeletonAlbumTile() }
     }
 }

android/app/src/main/java/com/fabledsword/minstrel/library/ui/ArtistDetailViewModel.kt

@@ -9,6 +9,7 @@ import com.fabledsword.minstrel.library.data.LibraryRepository
 import com.fabledsword.minstrel.likes.data.LikesRepository
 import com.fabledsword.minstrel.models.ArtistDetailRef
 import com.fabledsword.minstrel.models.ArtistRef
+import com.fabledsword.minstrel.models.TrackRef
 import com.fabledsword.minstrel.nav.ArtistDetail
 import com.fabledsword.minstrel.nav.DetailSeedCache
 import com.fabledsword.minstrel.player.PlayerController
@@ -23,13 +24,18 @@ import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.receiveAsFlow
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
+import timber.log.Timber
 import javax.inject.Inject
 
 private const val SHARE_STOP_TIMEOUT_MS = 5_000L
 
 sealed interface ArtistDetailUiState {
     data class Loading(val seed: ArtistRef? = null) : ArtistDetailUiState
-    data class Success(val detail: ArtistDetailRef) : ArtistDetailUiState
+    data class Success(
+        val detail: ArtistDetailRef,
+        val similarArtists: List<ArtistRef> = emptyList(),
+        val topTracks: List<TrackRef> = emptyList(),
+    ) : ArtistDetailUiState
     data class Error(val message: String) : ArtistDetailUiState
 }
 
@@ -82,6 +88,7 @@ class ArtistDetailViewModel @Inject constructor(
         try {
             val detail = repository.refreshArtistDetail(artistId)
             internal.value = ArtistDetailUiState.Success(detail)
+            loadSecondarySections()
         } catch (
             @Suppress("TooGenericExceptionCaught") e: Throwable,
         ) {
@@ -89,6 +96,31 @@ class ArtistDetailViewModel @Inject constructor(
         }
     }
 
+    /**
+     * Pulls the non-critical "Similar artists" + "Top tracks" sections
+     * and folds them into the live Success state. Each failure is
+     * swallowed (logged only) — these sections render absent rather than
+     * blocking, so the core artist view never depends on them.
+     */
+    private suspend fun loadSecondarySections() {
+        val similar = sectionOrEmpty { repository.fetchSimilarArtists(artistId) }
+        val top = sectionOrEmpty { repository.fetchArtistTopTracks(artistId) }
+        val current = internal.value
+        if (current is ArtistDetailUiState.Success) {
+            internal.value = current.copy(similarArtists = similar, topTracks = top)
+        }
+    }
+
+    private inline fun <T> sectionOrEmpty(block: () -> List<T>): List<T> =
+        try {
+            block()
+        } catch (
+            @Suppress("TooGenericExceptionCaught") e: Throwable,
+        ) {
+            Timber.w(e, "Artist secondary section fetch failed for %s", artistId)
+            emptyList()
+        }
+
     /**
      * Pull every track across the artist's albums, shuffle, and start
      * playing. Mirrors Flutter's artist Play button — pressing Play on
@@ -118,4 +150,20 @@ class ArtistDetailViewModel @Inject constructor(
             }
         }
     }
+
+    /**
+     * Plays the loaded "Top tracks" list starting at [index] — the top
+     * tracks are themselves the playable queue (mirrors the web client's
+     * sectionTracks = top-tracks behaviour). No network round-trip; the
+     * list is already in the Success state.
+     */
+    fun playTopTracks(index: Int) {
+        val tracks = (internal.value as? ArtistDetailUiState.Success)?.topTracks.orEmpty()
+        if (tracks.isEmpty()) return
+        player.setQueue(
+            tracks = tracks,
+            initialIndex = index.coerceIn(0, tracks.lastIndex),
+            source = "artist-top:$artistId",
+        )
+    }
 }