feat: Optimize note encryption and decryption processes with parallel execution

lib/data/note_repository.dart

@@ -1,3 +1,8 @@
+import 'dart:async';
+import 'dart:isolate';
+import 'dart:math' as math;
+import 'dart:io' show Platform;
+
 import 'package:drift/drift.dart';
 import 'package:notas/data/app_database.dart';
 import 'package:notas/data/api_client.dart';
@@ -126,8 +131,7 @@ class NoteRepository {
       final int totalNotesToEncrypt = unsyncedNotes.length;
 
       // Build sync request (note: we send encrypted data, but locally we have plaintext)
-      // Encrypt all notes before sending
+      // Encrypt all notes before sending.
-      final List<SyncNotePayload> encryptedNotesPayload = [];
       if (totalNotesToEncrypt == 0) {
         onProgress?.call(
           SyncStatus.encrypting,
@@ -136,32 +140,21 @@ class NoteRepository {
         );
       }
 
-      for (var index = 0; index < unsyncedNotes.length; index += 1) {
+      final List<SyncNotePayload>
-        final DbNote dbNote = unsyncedNotes[index];
+      encryptedNotesPayload = await _encryptNotesInParallel(
-        final note = _fromDbNote(dbNote);
+        unsyncedNotes,
-        final encryptedTitle = await NoteEncryption.encryptNote(
+        masterKey: _masterKey,
-          note.title,
+        onProgress: (int encryptedCount) {
-          _masterKey,
+          onProgress?.call(
-        );
+            SyncStatus.encrypting,
-        final encryptedBody = await NoteEncryption.encryptNote(
+            progress: totalNotesToEncrypt == 0
-          note.body,
+                ? 1.0
-          _masterKey,
+                : encryptedCount / totalNotesToEncrypt,
-        );
+            message:
-        encryptedNotesPayload.add(
+                'Encriptando notas para subir: $encryptedCount de $totalNotesToEncrypt',
-          SyncNotePayload.fromNote(
+          );
-            note,
+        },
-            encryptedTitle: encryptedTitle,
+      );
-            encryptedBody: encryptedBody,
-          ),
-        );
-
-        onProgress?.call(
-          SyncStatus.encrypting,
-          progress: (index + 1) / totalNotesToEncrypt,
-          message:
-              'Encriptando notas para subir: ${index + 1} de $totalNotesToEncrypt',
-        );
-      }
 
       final List<SyncCategoryPayload> categoriesPayload = unsyncedCategories
           .map((cat) => SyncCategoryPayload.fromCategory(_fromDbCategory(cat)))
@@ -241,35 +234,33 @@ class NoteRepository {
 
     // Apply notes from server
     final int totalNotesToDecrypt = response.changes.notes.length;
-    for (var index = 0; index < response.changes.notes.length; index += 1) {
+    final List<Map<String, Object?>> decryptedNotes =
-      final SyncNoteResponse noteResponse = response.changes.notes[index];
+        await _decryptResponseNotesInParallel(
+          response.changes.notes,
+          masterKey: _masterKey,
+          onProgress: onDecryptProgress == null
+              ? null
+              : (processed) =>
+                    onDecryptProgress(processed, totalNotesToDecrypt),
+        );
+
+    for (var index = 0; index < decryptedNotes.length; index += 1) {
+      final Map<String, Object?> decryptedNote = decryptedNotes[index];
+      final String noteId = decryptedNote['id']! as String;
       final existingNote = await (_database.select(
         _database.notes,
-      )..where((n) => n.uuid.equals(noteResponse.id))).getSingleOrNull();
+      )..where((n) => n.uuid.equals(noteId))).getSingleOrNull();
 
-      // Decrypt note content
+      final String decryptedTitle = decryptedNote['title']! as String;
-      String decryptedTitle = 'Encrypted';
+      final String decryptedBody = decryptedNote['body']! as String;
-      String decryptedBody = 'Encrypted';
+      final SyncNoteResponse noteResponse = response.changes.notes[index];
-      try {
-        decryptedTitle = await NoteEncryption.decryptNote(
-          noteResponse.encryptedTitle,
-          _masterKey,
-        );
-        decryptedBody = await NoteEncryption.decryptNote(
-          noteResponse.encryptedBody,
-          _masterKey,
-        );
-      } catch (e) {
-        // If decryption fails, keep default encrypted placeholders
-        print('Failed to decrypt note ${noteResponse.id}: $e');
-      }
 
       if (existingNote != null) {
         // Update existing note
         await _database.updateNoteRow(
           DbNote(
             id: existingNote.id,
-            uuid: noteResponse.id,
+            uuid: noteId,
             title: decryptedTitle,
             body: decryptedBody,
             createdAt: existingNote.createdAt,
@@ -298,8 +289,6 @@ class NoteRepository {
               ),
             );
       }
-
-      onDecryptProgress?.call(index + 1, totalNotesToDecrypt);
     }
   }
 
@@ -333,3 +322,234 @@ class NoteRepository {
     );
   }
 }
+
+List<Future<List<Map<String, Object?>>>> _encryptNoteBatches(
+  List<DbNote> notes, {
+  required String masterKey,
+}) {
+  if (notes.isEmpty) {
+    return <Future<List<Map<String, Object?>>>>[];
+  }
+
+  final int workerCount = _parallelWorkerCount(notes.length);
+  final int batchSize = (notes.length / workerCount).ceil();
+
+  final List<Future<List<Map<String, Object?>>>> batchFutures = [];
+  for (var start = 0; start < notes.length; start += batchSize) {
+    final int end = math.min(start + batchSize, notes.length);
+    final List<Map<String, Object?>> batchNotes = [];
+    for (var index = start; index < end; index += 1) {
+      batchNotes.add(_dbNoteToEncryptionInput(notes[index], index));
+    }
+
+    batchFutures.add(
+      Isolate.run(
+        () => _encryptNoteBatch({'masterKey': masterKey, 'notes': batchNotes}),
+      ),
+    );
+  }
+
+  return batchFutures;
+}
+
+Future<List<SyncNotePayload>> _encryptNotesInParallel(
+  List<DbNote> notes, {
+  required String masterKey,
+  void Function(int encryptedCount)? onProgress,
+}) async {
+  final List<Future<List<Map<String, Object?>>>> batchFutures =
+      _encryptNoteBatches(notes, masterKey: masterKey);
+  final List<SyncNotePayload?> orderedPayloads = List<SyncNotePayload?>.filled(
+    notes.length,
+    null,
+  );
+  var encryptedCount = 0;
+
+  await for (final List<Map<String, Object?>> batchResult in Stream.fromFutures(
+    batchFutures,
+  )) {
+    for (final Map<String, Object?> row in batchResult) {
+      final int index = row['index']! as int;
+      orderedPayloads[index] = _syncNotePayloadFromEncryptionResult(row);
+    }
+
+    encryptedCount += batchResult.length;
+    onProgress?.call(encryptedCount);
+  }
+
+  return orderedPayloads.cast<SyncNotePayload>();
+}
+
+List<Future<List<Map<String, Object?>>>> _decryptNoteBatches(
+  List<SyncNoteResponse> notes, {
+  required String masterKey,
+}) {
+  if (notes.isEmpty) {
+    return <Future<List<Map<String, Object?>>>>[];
+  }
+
+  final int workerCount = _parallelWorkerCount(notes.length);
+  final int batchSize = (notes.length / workerCount).ceil();
+
+  final List<Future<List<Map<String, Object?>>>> batchFutures = [];
+  for (var start = 0; start < notes.length; start += batchSize) {
+    final int end = math.min(start + batchSize, notes.length);
+    final List<Map<String, Object?>> batchNotes = [];
+    for (var index = start; index < end; index += 1) {
+      batchNotes.add(_syncNoteToDecryptionInput(notes[index], index));
+    }
+
+    batchFutures.add(
+      Isolate.run(
+        () => _decryptNoteBatch({'masterKey': masterKey, 'notes': batchNotes}),
+      ),
+    );
+  }
+
+  return batchFutures;
+}
+
+Future<List<Map<String, Object?>>> _decryptResponseNotesInParallel(
+  List<SyncNoteResponse> notes, {
+  required String masterKey,
+  void Function(int processed)? onProgress,
+}) async {
+  final List<Future<List<Map<String, Object?>>>> batchFutures =
+      _decryptNoteBatches(notes, masterKey: masterKey);
+  final List<Map<String, Object?>?> decryptedNotes =
+      List<Map<String, Object?>?>.filled(notes.length, null);
+  var processed = 0;
+
+  await for (final List<Map<String, Object?>> batchResult in Stream.fromFutures(
+    batchFutures,
+  )) {
+    for (final Map<String, Object?> row in batchResult) {
+      final int index = row['index']! as int;
+      decryptedNotes[index] = row;
+    }
+    processed += batchResult.length;
+    onProgress?.call(processed);
+  }
+
+  return decryptedNotes.cast<Map<String, Object?>>();
+}
+
+Map<String, Object?> _syncNoteToDecryptionInput(
+  SyncNoteResponse row,
+  int index,
+) {
+  return <String, Object?>{
+    'index': index,
+    'id': row.id,
+    'encryptedTitle': row.encryptedTitle,
+    'encryptedBody': row.encryptedBody,
+  };
+}
+
+Map<String, Object?> _dbNoteToEncryptionInput(DbNote row, int index) {
+  return <String, Object?>{
+    'index': index,
+    'uuid': row.uuid,
+    'title': row.title,
+    'body': row.body,
+    'createdAt': row.createdAt.toIso8601String(),
+    'updatedAt': row.updatedAt.toIso8601String(),
+    'categoryId': row.categoryId,
+    'serverVersion': row.serverVersion,
+    'position': row.sortIndex,
+    'isDeleted': row.isDeleted,
+  };
+}
+
+SyncNotePayload _syncNotePayloadFromEncryptionResult(Map<String, Object?> row) {
+  return SyncNotePayload(
+    id: row['id']! as String,
+    categoryId: row['categoryId'] as String?,
+    encryptedTitle: row['encryptedTitle']! as String,
+    encryptedBody: row['encryptedBody']! as String,
+    serverVersion: row['serverVersion']! as int,
+    position: row['position']! as int,
+    isDeleted: row['isDeleted']! as bool,
+    updatedAt: DateTime.parse(row['updatedAt']! as String),
+  );
+}
+
+Future<List<Map<String, Object?>>> _encryptNoteBatch(
+  Map<String, Object?> request,
+) async {
+  final String masterKey = request['masterKey']! as String;
+  final List<Map<String, Object?>> notes = (request['notes']! as List)
+      .cast<Map<String, Object?>>();
+
+  final List<Map<String, Object?>> encryptedNotes = [];
+  for (final Map<String, Object?> note in notes) {
+    final String title = note['title']! as String;
+    final String body = note['body']! as String;
+
+    final String encryptedTitle = await NoteEncryption.encryptNote(
+      title,
+      masterKey,
+    );
+    final String encryptedBody = await NoteEncryption.encryptNote(
+      body,
+      masterKey,
+    );
+
+    encryptedNotes.add(<String, Object?>{
+      'index': note['index'] as int,
+      'id': note['uuid'] as String,
+      'categoryId': note['categoryId'] as String?,
+      'encryptedTitle': encryptedTitle,
+      'encryptedBody': encryptedBody,
+      'serverVersion': note['serverVersion']! as int,
+      'position': note['position']! as int,
+      'isDeleted': note['isDeleted']! as bool,
+      'updatedAt': note['updatedAt']! as String,
+    });
+  }
+
+  return encryptedNotes;
+}
+
+Future<List<Map<String, Object?>>> _decryptNoteBatch(
+  Map<String, Object?> request,
+) async {
+  final String masterKey = request['masterKey']! as String;
+  final List<Map<String, Object?>> notes = (request['notes']! as List)
+      .cast<Map<String, Object?>>();
+
+  final List<Map<String, Object?>> decryptedNotes = [];
+  for (final Map<String, Object?> note in notes) {
+    String decryptedTitle = 'Encrypted';
+    String decryptedBody = 'Encrypted';
+    try {
+      decryptedTitle = await NoteEncryption.decryptNote(
+        note['encryptedTitle']! as String,
+        masterKey,
+      );
+      decryptedBody = await NoteEncryption.decryptNote(
+        note['encryptedBody']! as String,
+        masterKey,
+      );
+    } catch (e) {
+      print('Failed to decrypt note ${note['id']}: $e');
+    }
+
+    decryptedNotes.add(<String, Object?>{
+      'index': note['index'] as int,
+      'id': note['id'] as String,
+      'title': decryptedTitle,
+      'body': decryptedBody,
+    });
+  }
+
+  return decryptedNotes;
+}
+
+int _parallelWorkerCount(int itemCount) {
+  final int cappedByCpu = math.max(
+    1,
+    (Platform.numberOfProcessors * 0.6).floor(),
+  );
+  return math.max(1, math.min(itemCount, cappedByCpu));
+}

lib/data/sync_models.dart

@@ -1,13 +1,12 @@
 import 'package:notas/models/note.dart';
 import 'package:notas/models/category.dart';
+import 'dart:convert';
 
 // DTOs para sincronización con el servidor
 
 class SyncRequest {
-  SyncRequest({
+  SyncRequest({DateTime? lastSyncAt, required this.changes})
-    DateTime? lastSyncAt,
+    : lastSyncAt = lastSyncAt ?? DateTime.utc(1970, 1, 1);
-    required this.changes,
-  }) : lastSyncAt = lastSyncAt ?? DateTime.utc(1970, 1, 1);
 
   final DateTime lastSyncAt;
   final SyncChanges changes;
@@ -21,10 +20,7 @@ class SyncRequest {
 }
 
 class SyncChanges {
-  const SyncChanges({
+  const SyncChanges({this.categories = const [], this.notes = const []});
-    this.categories = const [],
-    this.notes = const [],
-  });
 
   final List<SyncCategoryPayload> categories;
   final List<SyncNotePayload> notes;
@@ -33,8 +29,7 @@ class SyncChanges {
     return {
       if (categories.isNotEmpty)
         'categories': categories.map((c) => c.toJson()).toList(),
-      if (notes.isNotEmpty)
+      if (notes.isNotEmpty) 'notes': notes.map((n) => n.toJson()).toList(),
-        'notes': notes.map((n) => n.toJson()).toList(),
     };
   }
 }
@@ -49,7 +44,8 @@ class SyncChangesResponse {
   final List<SyncNoteResponse> notes;
 
   factory SyncChangesResponse.fromJson(Map<String, dynamic> json) {
-    final List<dynamic> categoriesJson = json['categories'] as List<dynamic>? ?? [];
+    final List<dynamic> categoriesJson =
+        json['categories'] as List<dynamic>? ?? [];
     final List<dynamic> notesJson = json['notes'] as List<dynamic>? ?? [];
 
     return SyncChangesResponse(
@@ -62,6 +58,30 @@ class SyncChangesResponse {
     );
   }
 }
+
+String _readStringValue(dynamic value) {
+  if (value is String) {
+    return value;
+  }
+  if (value == null) {
+    throw FormatException('Expected String value but found null');
+  }
+  return jsonEncode(value);
+}
+
+int _readIntValue(dynamic value) {
+  if (value is int) {
+    return value;
+  }
+  if (value is String) {
+    final int? parsed = int.tryParse(value);
+    if (parsed != null) {
+      return parsed;
+    }
+  }
+  throw FormatException('Expected int value but found $value');
+}
+
 class SyncCategoryPayload {
   const SyncCategoryPayload({
     required this.id,
@@ -163,11 +183,11 @@ class SyncResponse {
 
   factory SyncResponse.fromJson(Map<String, dynamic> json) {
     return SyncResponse(
-      serverTimestamp:
+      serverTimestamp: DateTime.parse(json['serverTimestamp'] as String),
-          DateTime.parse(json['serverTimestamp'] as String),
       synced: json['synced'] as bool? ?? false,
-        changes: SyncChangesResponse.fromJson(
+      changes: SyncChangesResponse.fromJson(
-          json['changes'] as Map<String, dynamic>? ?? {}),
+        json['changes'] as Map<String, dynamic>? ?? {},
+      ),
     );
   }
 }
@@ -189,9 +209,9 @@ class SyncCategoryResponse {
 
   factory SyncCategoryResponse.fromJson(Map<String, dynamic> json) {
     return SyncCategoryResponse(
-      id: json['id'] as String,
+      id: _readStringValue(json['id']),
-      encryptedName: json['encrypted_name'] as String,
+      encryptedName: _readStringValue(json['encrypted_name']),
-      serverVersion: json['serverVersion'] as int,
+      serverVersion: _readIntValue(json['serverVersion']),
       isDeleted: json['isDeleted'] as bool? ?? false,
       updatedAt: DateTime.parse(json['updatedAt'] as String),
     );
@@ -231,11 +251,13 @@ class SyncNoteResponse {
 
   factory SyncNoteResponse.fromJson(Map<String, dynamic> json) {
     return SyncNoteResponse(
-      id: json['id'] as String,
+      id: _readStringValue(json['id']),
-      categoryId: json['categoryId'] as String?,
+      categoryId: json['categoryId'] == null
-      encryptedTitle: json['encrypted_title'] as String,
+          ? null
-      encryptedBody: json['encrypted_body'] as String,
+          : _readStringValue(json['categoryId']),
-      serverVersion: json['serverVersion'] as int,
+      encryptedTitle: _readStringValue(json['encrypted_title']),
+      encryptedBody: _readStringValue(json['encrypted_body']),
+      serverVersion: _readIntValue(json['serverVersion']),
       position: json['position'] as int? ?? 0,
       isDeleted: json['isDeleted'] as bool? ?? false,
       updatedAt: DateTime.parse(json['updatedAt'] as String),

lib/widgets/sync_status_indicator.dart

@@ -150,7 +150,7 @@ class SyncStatusIndicator extends StatelessWidget {
             _buildStatusBadge(
               icon: Icons.cloud_download_outlined,
               color: const Color.fromARGB(255, 154, 194, 112),
-              determinate: false,
+              determinate: true,
             ),
           ),
         );