refactor: Add json parsing for encryption and encrypted content

lib/encryption/encryption.dart

@@ -149,16 +149,19 @@ class Encryption {
   }
 
   Event decryptRoomEventSync(String roomId, Event event) {
+    final content = event.parsedRoomEncryptedContent;
     if (event.type != EventTypes.Encrypted ||
-        event.content['ciphertext'] == null) return event;
+        content.ciphertextMegolm == null) {
+      return event;
+    }
     Map<String, dynamic> decryptedPayload;
     var canRequestSession = false;
     try {
-      if (event.content['algorithm'] != AlgorithmTypes.megolmV1AesSha2) {
+      if (content.algorithm != AlgorithmTypes.megolmV1AesSha2) {
         throw DecryptException(DecryptException.unknownAlgorithm);
       }
-      final String sessionId = event.content['session_id'];
+      final sessionId = content.sessionId;
-      final String senderKey = event.content['sender_key'];
+      final senderKey = content.senderKey;
       final inboundGroupSession =
           keyManager.getInboundGroupSession(roomId, sessionId, senderKey);
       if (inboundGroupSession == null) {
@@ -169,7 +172,7 @@ class Encryption {
       canRequestSession = true;
 
       final decryptResult = inboundGroupSession.inboundGroupSession
-          .decrypt(event.content['ciphertext']);
+          .decrypt(content.ciphertextMegolm);
       canRequestSession = false;
       // we can't have the key be an int, else json-serializing will fail, thus we need it to be a string
       final messageIndexKey = 'key-' + decryptResult.message_index.toString();
@@ -204,7 +207,7 @@ class Encryption {
                       ?.outboundGroupSession
                       ?.session_id() ??
                   '') ==
-              event.content['session_id']) {
+              content.sessionId) {
         runInRoot(() =>
             keyManager.clearOrUseOutboundGroupSession(roomId, wipe: true));
       }

lib/encryption/key_manager.dart

@@ -275,15 +275,11 @@ class KeyManager {
     }
     if (!wipe) {
       // first check if it needs to be rotated
-      final encryptionContent = room.getState(EventTypes.Encryption)?.content;
+      final encryptionContent =
-      final maxMessages = encryptionContent != null &&
+          room.getState(EventTypes.Encryption)?.parsedRoomEncryptionContent;
-              encryptionContent['rotation_period_msgs'] is int
+      final maxMessages = encryptionContent?.rotationPeriodMsgs ?? 100;
-          ? encryptionContent['rotation_period_msgs']
+      final maxAge = encryptionContent?.rotationPeriodMs ??
-          : 100;
+          604800000; // default of one week
-      final maxAge = encryptionContent != null &&
-              encryptionContent['rotation_period_ms'] is int
-          ? encryptionContent['rotation_period_ms']
-          : 604800000; // default of one week
       if (sess.sentMessages >= maxMessages ||
           sess.creationTime
               .add(Duration(milliseconds: maxAge))

lib/encryption/olm_manager.dart

@@ -247,16 +247,17 @@ class OlmManager {
     if (event.type != EventTypes.Encrypted) {
       return event;
     }
-    if (event.content['algorithm'] != AlgorithmTypes.olmV1Curve25519AesSha2) {
+    final content = event.parsedRoomEncryptedContent;
+    if (content.algorithm != AlgorithmTypes.olmV1Curve25519AesSha2) {
       throw DecryptException(DecryptException.unknownAlgorithm);
     }
-    if (!event.content['ciphertext'].containsKey(identityKey)) {
+    if (!content.ciphertextOlm.containsKey(identityKey)) {
       throw DecryptException(DecryptException.isntSentForThisDevice);
     }
     String plaintext;
-    final String senderKey = event.content['sender_key'];
+    final senderKey = content.senderKey;
-    final String body = event.content['ciphertext'][identityKey]['body'];
+    final body = content.ciphertextOlm[identityKey].body;
-    final int type = event.content['ciphertext'][identityKey]['type'];
+    final type = content.ciphertextOlm[identityKey].type;
     if (type != 0 && type != 1) {
       throw DecryptException(DecryptException.unknownMessageType);
     }
@@ -429,7 +430,7 @@ class OlmManager {
     if (event.type != EventTypes.Encrypted) {
       return event;
     }
-    final senderKey = event.content['sender_key'];
+    final senderKey = event.parsedRoomEncryptedContent.senderKey;
     final loadFromDb = () async {
       final sessions = await getOlmSessions(senderKey);
       return sessions.isNotEmpty;

lib/src/room.dart

@@ -1670,9 +1670,8 @@ class Room {
 
   /// Returns the encryption algorithm. Currently only `m.megolm.v1.aes-sha2` is supported.
   /// Returns null if there is no encryption algorithm.
-  String get encryptionAlgorithm => getState(EventTypes.Encryption) != null
+  String get encryptionAlgorithm =>
-      ? getState(EventTypes.Encryption).content['algorithm'].toString()
+      getState(EventTypes.Encryption)?.parsedRoomEncryptionContent?.algorithm;
-      : null;
 
   /// Checks if this room is encrypted.
   bool get encrypted => encryptionAlgorithm != null;

pubspec.yaml

@@ -23,9 +23,7 @@ dependencies:
   matrix_file_e2ee: ^1.0.5
   isolate: ^2.0.3
   logger: ^0.9.4
-  matrix_api_lite:
+  matrix_api_lite: ^0.1.4
-    git:
-      url: https://gitlab.com/famedly/libraries/matrix_api_lite.git
 
 dev_dependencies:
   test: ^1.15.7