Warn about missing sources before restoring backup

(cherry picked from commit a00d11701f)

app/src/main/java/eu/kanade/tachiyomi/data/backup/BackupRestoreService.kt

@@ -118,6 +118,11 @@ class BackupRestoreService : Service() {
 
     private var totalAmount = 0
 
+    /**
+     * Mapping of source ID to source name from backup data
+     */
+    private var sourceMapping: Map<Long, String> = emptyMap()
+
     /**
      * List containing errors
      */
@@ -235,6 +240,9 @@ class BackupRestoreService : Service() {
         // Restore categories
         restoreCategories(json.get(CATEGORIES))
 
+        // Store source mapping for error messages
+        sourceMapping = BackupRestoreValidator.getSourceMapping(json)
+
         // Restore individual manga
         mangasJson.forEach {
             if (job?.isActive != true) {
@@ -286,9 +294,20 @@ class BackupRestoreService : Service() {
         // <-- EXH
 
         try {
-            restoreMangaData(manga, chapters, categories, history, tracks)
+            val source = backupManager.sourceManager.get(manga.source)
+            if (source != null) {
+                restoreMangaData(manga, source, chapters, categories, history, tracks)
+            } else {
+                val message = if (manga.source in sourceMapping) {
+                    getString(R.string.source_not_found_name, sourceMapping[manga.source])
+                } else {
+                    getString(R.string.source_not_found)
+                }
+
+                errors.add(Date() to "${manga.title} - $message")
+            }
         } catch (e: Exception) {
-            errors.add(Date() to "${manga.title} - ${getString(R.string.source_not_found)}")
+            errors.add(Date() to "${manga.title} - ${e.message}")
         }
 
         restoreProgress += 1
@@ -299,6 +318,7 @@ class BackupRestoreService : Service() {
      * Returns a manga restore observable
      *
      * @param manga manga data from json
+     * @param source source to get manga data from
      * @param chapters chapters data from json
      * @param categories categories data from json
      * @param history history data from json
@@ -306,13 +326,12 @@ class BackupRestoreService : Service() {
      */
     private fun restoreMangaData(
         manga: Manga,
+        source: Source,
         chapters: List<Chapter>,
         categories: List<String>,
         history: List<DHistory>,
         tracks: List<Track>
     ) {
-        // Get source
-        val source = backupManager.sourceManager.getOrStub(manga.source)
         val dbManga = backupManager.getMangaFromDatabase(manga)
 
         db.inTransaction {

app/src/main/java/eu/kanade/tachiyomi/data/backup/BackupRestoreValidator.kt

@@ -0,0 +1,46 @@
+package eu.kanade.tachiyomi.data.backup
+
+import android.content.Context
+import android.net.Uri
+import com.google.gson.JsonObject
+import com.google.gson.JsonParser
+import com.google.gson.stream.JsonReader
+import eu.kanade.tachiyomi.R
+import eu.kanade.tachiyomi.data.backup.models.Backup
+
+object BackupRestoreValidator {
+
+    /**
+     * Checks for critical backup file data.
+     *
+     * @throws Exception if version or manga cannot be found.
+     * @return List of required sources.
+     */
+    fun validate(context: Context, uri: Uri): Map<Long, String> {
+        val reader = JsonReader(context.contentResolver.openInputStream(uri)!!.bufferedReader())
+        val json = JsonParser.parseReader(reader).asJsonObject
+
+        val version = json.get(Backup.VERSION)
+        val mangasJson = json.get(Backup.MANGAS)
+        if (version == null || mangasJson == null) {
+            throw Exception(context.getString(R.string.invalid_backup_file_missing_data))
+        }
+
+        if (mangasJson.asJsonArray.size() == 0) {
+            throw Exception(context.getString(R.string.invalid_backup_file_missing_manga))
+        }
+
+        return getSourceMapping(json)
+    }
+
+    fun getSourceMapping(json: JsonObject): Map<Long, String> {
+        val extensionsMapping = json.get(Backup.EXTENSIONS) ?: return emptyMap()
+
+        return extensionsMapping.asJsonArray
+            .map {
+                val items = it.asString.split(":")
+                items[0].toLong() to items[1]
+            }
+            .toMap()
+    }
+}

app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsBackupController.kt

@@ -16,9 +16,11 @@ import eu.kanade.tachiyomi.R
 import eu.kanade.tachiyomi.data.backup.BackupCreateService
 import eu.kanade.tachiyomi.data.backup.BackupCreatorJob
 import eu.kanade.tachiyomi.data.backup.BackupRestoreService
+import eu.kanade.tachiyomi.data.backup.BackupRestoreValidator
 import eu.kanade.tachiyomi.data.backup.models.Backup
 import eu.kanade.tachiyomi.data.preference.PreferenceKeys as Keys
 import eu.kanade.tachiyomi.data.preference.asImmediateFlow
+import eu.kanade.tachiyomi.source.SourceManager
 import eu.kanade.tachiyomi.ui.base.controller.DialogController
 import eu.kanade.tachiyomi.ui.base.controller.requestPermissionsSafe
 import eu.kanade.tachiyomi.util.preference.defaultValue
@@ -34,6 +36,8 @@ import eu.kanade.tachiyomi.util.system.getFilePicker
 import eu.kanade.tachiyomi.util.system.toast
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
+import uy.kohesive.injekt.Injekt
+import uy.kohesive.injekt.api.get
 
 class SettingsBackupController : SettingsController() {
 
@@ -247,15 +251,36 @@ class SettingsBackupController : SettingsController() {
         )
 
         override fun onCreateDialog(savedViewState: Bundle?): Dialog {
-            return MaterialDialog(activity!!)
-                .title(R.string.pref_restore_backup)
-                .message(R.string.backup_restore_content)
-                .positiveButton(R.string.action_restore) {
-                    val context = applicationContext
-                    if (context != null) {
-                        BackupRestoreService.start(context, args.getParcelable(KEY_URI)!!)
+            val activity = activity!!
+            val uri: Uri = args.getParcelable(KEY_URI)!!
+
+            return try {
+                var message = activity.getString(R.string.backup_restore_content)
+
+                val sources = BackupRestoreValidator.validate(activity, uri)
+                if (sources.isNotEmpty()) {
+                    val sourceManager = Injekt.get<SourceManager>()
+                    val missingSources = sources
+                        .filter { sourceManager.get(it.key) == null }
+                        .values
+                        .sorted()
+                    if (missingSources.isNotEmpty()) {
+                        message += "\n\n${activity.getString(R.string.backup_restore_missing_sources)}\n${missingSources.joinToString("\n") { "- $it" }}"
                     }
                 }
+
+                MaterialDialog(activity)
+                    .title(R.string.pref_restore_backup)
+                    .message(text = message)
+                    .positiveButton(R.string.action_restore) {
+                        BackupRestoreService.start(activity, uri)
+                    }
+            } catch (e: Exception) {
+                MaterialDialog(activity)
+                    .title(R.string.invalid_backup_file)
+                    .message(text = e.message)
+                    .positiveButton(android.R.string.cancel)
+            }
         }
 
         private companion object {