implement /current endpoint

Author: lolcatjpg

src/main/kotlin/gent/zeus/guitar/PlayerState.kt

@@ -21,3 +21,5 @@ object PlayerState {
 
     val mutex = Mutex()
 }
+
+class EmptyPlayerStateError : ServerError("no tracks have played yet since last restart", null)

src/main/kotlin/gent/zeus/guitar/api/MusicControllers.kt

@@ -37,24 +37,18 @@ class ArtistController {
     private fun artistDetails(@PathVariable id: String) = getApiResponse(Preset.Artist.details, id)
 }
 
-/*
-
-// coroutines make spring boot crash
 
 @RestController
 @RequestMapping("/current")
 class CurrentController {
 
-    @GetMapping("/")
-    private suspend fun currentTrack() = coroutineScope {
-        runBlocking {
-            val id = PlayerState.mutex.withLock { PlayerState.currentTrackId }
+    @GetMapping("")
+    private fun currentTrack() = runBlocking {
+        val id = PlayerState.mutex.withLock { PlayerState.currentTrackId }
 
-            if (id != null)
-                getApiResponse(Preset.Track.details, id)
-            else
-                ResponseEntity.status(200).body(null)
-        }
+        if (id != null)
+            getApiResponse(Preset.Track.detailsWithState, id)
+        else
+            ResponseEntity.status(200).body(null)
     }
 }
-*/

src/main/kotlin/gent/zeus/guitar/data/MusicModels.kt

@@ -12,6 +12,8 @@ data class Track(
     val album: Album? = null,
     val artists: List<Artist>? = null,
     val durationInMs: Int? = null,
+    val startedAtMs: Long? = null,
+    val endsAtMs: Long? = null,
     val imageUrl: String? = null,
     val spotifyUrl: String? = null,
     val votesFor: Int? = null,

src/main/kotlin/gent/zeus/guitar/data/Preset.kt

@@ -1,5 +1,7 @@
 package gent.zeus.guitar.data
 
+import gent.zeus.guitar.data.Preset.Track
+import gent.zeus.guitar.ext.playerstate.PlayerStateFetcher
 import gent.zeus.guitar.ext.spotify.AlbumFetcher
 import gent.zeus.guitar.ext.spotify.ArtistFetcher
 import gent.zeus.guitar.ext.spotify.TrackFetcher
@@ -9,6 +11,7 @@ object Preset {
     object Track {
         val details get() = MusicModelMaker(::Track, TrackFetcher(), VoteFetcher())
         val voteless get() = MusicModelMaker(::Track, TrackFetcher())
+        val detailsWithState get() = MusicModelMaker(::Track, TrackFetcher(), VoteFetcher(), PlayerStateFetcher())
     }
 
     object Album {

src/main/kotlin/gent/zeus/guitar/ext/Errors.kt

@@ -0,0 +1,8 @@
+package gent.zeus.guitar.ext
+
+import gent.zeus.guitar.ServerError
+
+class OrderingError(missingValueName: String) : ServerError(
+    "model fillers are in wrong order (value `$missingValueName` is still missing)",
+    null,
+)

src/main/kotlin/gent/zeus/guitar/ext/playerstate/PlayerStateFetcher.kt

@@ -0,0 +1,40 @@
+package gent.zeus.guitar.ext.playerstate
+
+import gent.zeus.guitar.DataResult
+import gent.zeus.guitar.EmptyPlayerStateError
+import gent.zeus.guitar.PlayerState
+import gent.zeus.guitar.ServerError
+import gent.zeus.guitar.UserError
+import gent.zeus.guitar.data.Track
+import gent.zeus.guitar.ext.ModelFiller
+import gent.zeus.guitar.ext.OrderingError
+import kotlinx.coroutines.runBlocking
+import kotlinx.coroutines.sync.withLock
+import org.apache.catalina.Server
+
+class PlayerStateFetcher : ModelFiller<Track> {
+    override fun fetchInto(musicModel: Track): DataResult<Track> = runBlocking {
+        musicModel.durationInMs
+            ?: return@runBlocking DataResult.Error(OrderingError("durationInMs"))
+
+        val id = PlayerState.mutex.withLock { PlayerState.currentTrackId }
+            ?: return@runBlocking DataResult.Error(EmptyPlayerStateError())
+
+        if (id != musicModel.spotifyId) DataResult.Error(NotCurrentTrackError())
+
+        val startedAt = PlayerState.mutex.withLock { PlayerState.currentStartTime }
+            ?: return@runBlocking DataResult.Error(EmptyPlayerStateError())
+
+        DataResult.Ok(
+            musicModel.copy(
+                startedAtMs = startedAt,
+                endsAtMs = startedAt + musicModel.durationInMs
+            )
+        )
+    }
+}
+
+class NotCurrentTrackError : ServerError(
+    "this is not the current track",
+    null,
+)