feat: scan media store for pairing

app/src/main/java/at/lockstep/player/util/AudioReadPermission.kt

@@ -0,0 +1,13 @@
+package at.lockstep.player.util
+
+import android.Manifest
+import android.os.Build
+
+object AudioReadPermission {
+    fun permissionName(): String =
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+            Manifest.permission.READ_MEDIA_AUDIO
+        } else {
+            Manifest.permission.READ_EXTERNAL_STORAGE
+        }
+}

app/src/main/java/at/lockstep/player/util/MediaStoreMp3Scanner.kt

@@ -0,0 +1,60 @@
+package at.lockstep.player.util
+
+import android.content.ContentUris
+import android.content.Context
+import android.os.Build
+import android.provider.MediaStore
+import android.util.Log
+
+object MediaStoreMp3Scanner {
+    private const val TAG = "LockstepPairing"
+
+    fun listMp3Candidates(context: Context): List<Mp3FolderCandidate> {
+        val resolver = context.applicationContext.contentResolver
+        val collection =
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+                MediaStore.Audio.Media.getContentUri(MediaStore.VOLUME_EXTERNAL)
+            } else {
+                @Suppress("DEPRECATION")
+                MediaStore.Audio.Media.EXTERNAL_CONTENT_URI
+            }
+
+        val projection =
+            arrayOf(
+                MediaStore.Audio.Media._ID,
+                MediaStore.Audio.Media.DISPLAY_NAME,
+                MediaStore.Audio.Media.TITLE,
+                MediaStore.Audio.Media.ARTIST,
+            )
+
+        val selection =
+            "(${MediaStore.Audio.Media.MIME_TYPE} = ? OR " +
+                "${MediaStore.Audio.Media.DISPLAY_NAME} LIKE ?)"
+        val selectionArgs = arrayOf("audio/mpeg", "%.mp3")
+
+        val out = mutableListOf<Mp3FolderCandidate>()
+        resolver.query(collection, projection, selection, selectionArgs, null)?.use { cursor ->
+            val idCol = cursor.getColumnIndexOrThrow(MediaStore.Audio.Media._ID)
+            val nameCol = cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME)
+            val titleCol = cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.TITLE)
+            val artistCol = cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.ARTIST)
+            while (cursor.moveToNext()) {
+                val id = cursor.getLong(idCol)
+                val displayName = cursor.getString(nameCol).orEmpty()
+                val title = cursor.getString(titleCol)?.trim()?.takeIf { it.isNotEmpty() }
+                val artist = cursor.getString(artistCol)?.trim()?.takeIf { it.isNotEmpty() }
+                out.add(
+                    Mp3FolderCandidate(
+                        uri = ContentUris.withAppendedId(collection, id),
+                        fileBaseName = displayName.substringBeforeLast('.'),
+                        id3Title = title,
+                        id3Artist = artist,
+                    ),
+                )
+            }
+        } ?: Log.w(TAG, "MediaStore audio query returned null")
+
+        Log.d(TAG, "MediaStoreMp3Scanner found mp3Count=${out.size}")
+        return out.distinctBy { it.uri }.sortedBy { it.fileBaseName.lowercase() }
+    }
+}

app/src/main/java/at/lockstep/player/util/SafInitialUris.kt

@@ -1,15 +1,41 @@
 package at.lockstep.player.util
 
+import android.content.Context
 import android.net.Uri
+import android.os.Build
+import android.os.storage.StorageManager
 import android.provider.DocumentsContract
 
 object SafInitialUris {
     private const val EXTERNAL_STORAGE_AUTHORITY = "com.android.externalstorage.documents"
+    private const val INITIAL_URI_EXTRA = "android.provider.extra.INITIAL_URI"
 
-    /** Internal-storage Documents — avoids the blocked volume root shown on Pixel devices. */
-    fun internalDocuments(): Uri =
-        DocumentsContract.buildDocumentUri(
+    /**
+     * Internal-storage Documents. Uses [StorageManager] on Android 10+ so the system picker
+     * lands in a choosable folder instead of the blocked volume root on Pixel devices.
+     */
+    fun internalDocuments(context: Context): Uri {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+            val storageManager = context.getSystemService(StorageManager::class.java)
+            val intent = storageManager.primaryStorageVolume.createOpenDocumentTreeIntent()
+            val root =
+                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+                    intent.getParcelableExtra(INITIAL_URI_EXTRA, Uri::class.java)
+                } else {
+                    @Suppress("DEPRECATION")
+                    intent.getParcelableExtra(INITIAL_URI_EXTRA)
+                }
+            if (root != null) {
+                val scheme =
+                    root
+                        .toString()
+                        .replace("/root/", "/document/") + "%3A" + "Documents"
+                return Uri.parse(scheme)
+            }
+        }
+        return DocumentsContract.buildDocumentUri(
             EXTERNAL_STORAGE_AUTHORITY,
             "primary:Documents",
         )
+    }
 }