Add synchronized lyrics (#126)

app/src/main/kotlin/it/vfsfitvnm/vimusic/utils/Preferences.kt

@@ -26,6 +26,7 @@ const val repeatModeKey = "repeatMode"
 const val skipSilenceKey = "skipSilence"
 const val volumeNormalizationKey = "volumeNormalization"
 const val persistentQueueKey = "persistentQueue"
+const val isShowingSynchronizedLyricsKey = "isShowingSynchronizedLyrics"
 
 inline fun <reified T : Enum<T>> SharedPreferences.getEnum(
     key: String,

app/src/main/kotlin/it/vfsfitvnm/vimusic/utils/RelaunchableEffect.kt

@@ -7,6 +7,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.InternalComposeApi
 import androidx.compose.runtime.LaunchedEffectImpl
 import androidx.compose.runtime.NonRestartableComposable
+import androidx.compose.runtime.RememberObserver
 import androidx.compose.runtime.currentComposer
 import androidx.compose.runtime.remember
 import kotlinx.coroutines.CoroutineScope
@@ -21,3 +22,13 @@ fun relaunchableEffect(
     val launchedEffect = remember(key1) { LaunchedEffectImpl(applyContext, block) }
     return launchedEffect::onRemembered
 }
+
+@Composable
+@NonRestartableComposable
+fun relaunchableEffect2(
+    key1: Any?,
+    block: suspend CoroutineScope.() -> Unit
+): RememberObserver {
+    val applyContext = currentComposer.applyCoroutineContext
+    return remember(key1) { LaunchedEffectImpl(applyContext, block) }
+}

app/src/main/kotlin/it/vfsfitvnm/vimusic/utils/SynchronizedLyrics.kt

@@ -0,0 +1,33 @@
+package it.vfsfitvnm.vimusic.utils
+
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import it.vfsfitvnm.synchronizedlyrics.parseSentences
+
+class SynchronizedLyrics(text: String, private val positionProvider: () -> Long) {
+    val sentences = parseSentences(text)
+
+    var index by mutableStateOf(currentIndex)
+        private set
+
+    private val currentIndex: Int
+        get() {
+            var index = -1
+            for (item in sentences) {
+                if (item.first >= positionProvider()) break
+                index++
+            }
+            return index
+        }
+
+    fun update(): Boolean {
+        val newIndex = currentIndex
+        return if (newIndex != index) {
+            index = newIndex
+            true
+        } else {
+            false
+        }
+    }
+}