feat: работа с шифрованным текстом/фото

2026-07-26 16:23:05 +07:00
parent ba1f63ad05
commit ac951ea80a
90 changed files with 7248 additions and 64 deletions
@@ -0,0 +1,111 @@
+import 'dart:async';
+import 'dart:collection';
+
+import 'package:flutter/foundation.dart';
+
+import '../storage/chat_encryption_store.dart';
+import 'chat_crypto_service.dart';
+
+enum MessageDecryptionState { decrypted, wrongKey }
+
+@immutable
+class MessageDecryption {
+  final String? plaintext;
+  final MessageDecryptionState state;
+
+  const MessageDecryption.decrypted(String this.plaintext)
+    : state = MessageDecryptionState.decrypted;
+
+  const MessageDecryption.wrongKey()
+    : plaintext = null,
+      state = MessageDecryptionState.wrongKey;
+
+  bool get isDecrypted => state == MessageDecryptionState.decrypted;
+}
+
+class MessageDecryptionCache {
+  MessageDecryptionCache._() {
+    ChatEncryptionStore.instance.revision.addListener(clear);
+  }
+
+  static final MessageDecryptionCache instance = MessageDecryptionCache._();
+
+  static const int _maxEntries = 1000;
+
+  final LinkedHashMap<String, ValueNotifier<MessageDecryption?>> _entries =
+      LinkedHashMap();
+  final Set<String> _inFlight = {};
+
+  ValueListenable<MessageDecryption?> listenableFor(String messageId) =>
+      _entryFor(messageId);
+
+  ValueNotifier<MessageDecryption?> _entryFor(String messageId) =>
+      _entries[messageId] ??= ValueNotifier<MessageDecryption?>(null);
+
+  void _evictStale(String keep) {
+    while (_entries.length > _maxEntries) {
+      final oldest = _entries.keys.first;
+      if (oldest == keep) break;
+      _entries.remove(oldest);
+    }
+  }
+
+  void seed(String messageId, String plaintext) {
+    _entryFor(messageId).value = MessageDecryption.decrypted(plaintext);
+  }
+
+  void adopt(String fromMessageId, String toMessageId) {
+    final value = _entries[fromMessageId]?.value;
+    if (value != null) _entryFor(toMessageId).value = value;
+  }
+
+  void request({
+    required int accountId,
+    required int chatId,
+    required String messageId,
+    required String cipherText,
+  }) {
+    if (cipherText.isEmpty) return;
+    if (!ChatCryptoService.instance.isEnabled(accountId, chatId)) return;
+    if (_entryFor(messageId).value != null) return;
+    if (!_inFlight.add(messageId)) return;
+    _evictStale(messageId);
+    unawaited(_resolve(accountId, chatId, messageId, cipherText));
+  }
+
+  Future<void> _resolve(
+    int accountId,
+    int chatId,
+    String messageId,
+    String cipherText,
+  ) async {
+    try {
+      final crypto = ChatCryptoService.instance;
+      final result = await crypto.decrypt(accountId, chatId, cipherText);
+      if (result.isOk) {
+        _entryFor(messageId).value = MessageDecryption.decrypted(result.text!);
+        return;
+      }
+      switch (result.failure) {
+        case CryptoFailure.wrongKey:
+          _entryFor(messageId).value = const MessageDecryption.wrongKey();
+        case CryptoFailure.noKey:
+          if (await crypto.looksEncrypted(cipherText)) {
+            _entryFor(messageId).value = const MessageDecryption.wrongKey();
+          }
+        case CryptoFailure.notEncrypted:
+        case CryptoFailure.malformed:
+        case CryptoFailure.unavailable:
+        case null:
+          break;
+      }
+    } finally {
+      _inFlight.remove(messageId);
+    }
+  }
+
+  void clear() {
+    _entries.clear();
+    _inFlight.clear();
+  }
+}