Option to lock reader screen rotation

app/src/main/kotlin/org/koitharu/kotatsu/core/util/ScreenOrientationHelper.kt

@@ -6,13 +6,16 @@ import android.content.res.Configuration
 import android.database.ContentObserver
 import android.os.Handler
 import android.provider.Settings
+import dagger.hilt.android.scopes.ActivityScoped
 import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.channels.trySendBlocking
 import kotlinx.coroutines.flow.callbackFlow
 import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.onStart
+import javax.inject.Inject
 
-class ScreenOrientationHelper(private val activity: Activity) {
+@ActivityScoped
+class ScreenOrientationHelper @Inject constructor(private val activity: Activity) {
 
 	val isAutoRotationEnabled: Boolean
 		get() = Settings.System.getInt(
@@ -31,9 +34,15 @@ class ScreenOrientationHelper(private val activity: Activity) {
 			}
 		}
 
-	fun toggleOrientation() {
-		isLandscape = !isLandscape
-	}
+	var isLocked: Boolean
+		get() = activity.requestedOrientation == ActivityInfo.SCREEN_ORIENTATION_LOCKED
+		set(value) {
+			activity.requestedOrientation = if (value) {
+				ActivityInfo.SCREEN_ORIENTATION_LOCKED
+			} else {
+				ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED
+			}
+		}
 
 	fun observeAutoOrientation() = callbackFlow {
 		val observer = object : ContentObserver(Handler(activity.mainLooper)) {

app/src/main/kotlin/org/koitharu/kotatsu/reader/ui/config/ReaderConfigSheet.kt

@@ -47,7 +47,10 @@ class ReaderConfigSheet :
 
 	private val viewModel by activityViewModels<ReaderViewModel>()
 	private val savePageRequest = registerForActivityResult(PageSaveContract(), this)
-	private var orientationHelper: ScreenOrientationHelper? = null
+
+	@Inject
+	lateinit var orientationHelper: ScreenOrientationHelper
+
 	private lateinit var mode: ReaderMode
 
 	@Inject
@@ -113,7 +116,7 @@ class ReaderConfigSheet :
 			}
 
 			R.id.button_screen_rotate -> {
-				orientationHelper?.toggleOrientation()
+				orientationHelper.isLandscape = !orientationHelper.isLandscape
 			}
 
 			R.id.button_color_filter -> {
@@ -131,6 +134,10 @@ class ReaderConfigSheet :
 				requireViewBinding().layoutTimer.isVisible = isChecked
 				requireViewBinding().sliderTimer.isVisible = isChecked
 			}
+
+			R.id.switch_screen_lock_rotation -> {
+				orientationHelper.isLocked = isChecked
+			}
 		}
 	}
 
@@ -168,14 +175,23 @@ class ReaderConfigSheet :
 	}
 
 	private fun observeScreenOrientation() {
-		val helper = ScreenOrientationHelper(requireActivity())
-		orientationHelper = helper
-		helper.observeAutoOrientation()
+		orientationHelper.observeAutoOrientation()
 			.onEach {
-				requireViewBinding().buttonScreenRotate.isGone = it
+				with(requireViewBinding()) {
+					buttonScreenRotate.isGone = it
+					switchScreenLockRotation.isVisible = it
+					updateOrientationLockSwitch()
+				}
 			}.launchIn(viewLifecycleScope)
 	}
 
+	private fun updateOrientationLockSwitch() {
+		val switch = viewBinding?.switchScreenLockRotation ?: return
+		switch.setOnCheckedChangeListener(null)
+		switch.isChecked = orientationHelper.isLocked
+		switch.setOnCheckedChangeListener(this)
+	}
+
 	private fun findCallback(): Callback? {
 		return (parentFragment as? Callback) ?: (activity as? Callback)
 	}