Prevent issue on queue item deletion. Should close #48.

app/src/main/java/com/github/apognu/otter/activities/MainActivity.kt

@@ -45,7 +45,6 @@ import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
-import kotlin.random.Random
 
 class MainActivity : AppCompatActivity() {
   enum class ResultCode(val code: Int) {

app/src/main/java/com/github/apognu/otter/playback/PlayerService.kt

@@ -253,8 +253,6 @@ class PlayerService : Service() {
     state(false)
     player.release()
 
-    Otter.get().exoCache.release()
-
     stopForeground(true)
     stopSelf()
 

app/src/main/java/com/github/apognu/otter/playback/QueueManager.kt

@@ -127,8 +127,24 @@ class QueueManager(val context: Context) {
 
   fun remove(track: Track) {
     metadata.indexOf(track).let {
+      if (it < 0) {
+        return
+      }
+
       datasources.removeMediaSource(it)
       metadata.removeAt(it)
+
+      if (it == current) {
+        CommandBus.send(Command.NextTrack)
+      }
+
+      if (it < current) {
+        current--
+      }
+    }
+
+    if (metadata.isEmpty()) {
+      current = -1
     }
 
     persist()