Consolidate Magisk download subject

app/src/main/java/com/topjohnwu/magisk/model/download/DownloadService.kt

@@ -50,7 +50,6 @@ open class DownloadService : RemoteFileService() {
         Uninstall -> FlashActivity.uninstall(this, file)
         is Patch -> FlashActivity.patch(this, file, conf.fileUri)
         is Flash -> FlashActivity.flash(this, file, conf is Secondary)
-        else -> Unit
     }
 
     private fun onFinishedInternal(

app/src/main/java/com/topjohnwu/magisk/model/entity/internal/DownloadSubject.kt

@@ -16,24 +16,36 @@ sealed class DownloadSubject : Parcelable {
         val module: Repo,
         val configuration: Configuration
     ) : DownloadSubject() {
-
         override val url: String get() = module.zipUrl
         override val fileName: String get() = "${module.name}-v${module.version}(${module.versionCode}).zip"
+    }
 
+    sealed class Magisk : DownloadSubject() {
+
+        abstract val configuration: Configuration
+        val magisk: MagiskJson = Info.remote.magisk
+
+        @Parcelize
+        protected data class Flash(
+            override val configuration: Configuration
+        ) : Magisk() {
+            override val url: String get() = magisk.link
+            override val fileName get() = "magisk.zip"
         }
 
         @Parcelize
-    data class Magisk(
-        val configuration: Configuration,
-        val magisk: MagiskJson = Info.remote.magisk
-    ) : DownloadSubject() {
-
+        protected object Download : Magisk() {
+            override val configuration: Configuration get() = Configuration.Download
             override val url: String get() = magisk.link
-        override val fileName get() =
-            if (configuration is Configuration.Flash)
-                "magisk.zip"
-            else
-                "Magisk-v${magisk.version}(${magisk.versionCode}).zip"
+            override val fileName get() = "Magisk-v${magisk.version}(${magisk.versionCode}).zip"
+        }
+
+        companion object {
+            operator fun invoke(configuration: Configuration) = when (configuration) {
+                Configuration.Download -> Download
+                else -> Flash(configuration)
+            }
+        }
 
     }