feat(ui): Show errors

lib/shared/error_types.dart

@@ -1,6 +1,8 @@
 import 'package:moxxmpp/moxxmpp.dart';
+import 'package:moxxyv2/i18n/strings.g.dart';
 import 'package:omemo_dart/omemo_dart.dart';
 
+const unspecifiedError = -1;
 const noError = 0;
 const fileUploadFailedError = 1;
 const messageNotEncryptedForDevice = 2;
@@ -14,6 +16,9 @@ const messageContactDoesNotSupportOmemo = 9;
 const messageChatEncryptedButFileNot = 10;
 const messageFailedToEncryptFile = 11;
 const fileDownloadFailedError = 12;
+const messageServiceUnavailable = 13;
+const messageRemoteServerTimeout = 14;
+const messageRemoteServerNotFound = 15;
 
 int errorTypeFromException(dynamic exception) {
   if (exception is NoDecryptionKeyException) {
@@ -32,3 +37,24 @@ int errorTypeFromException(dynamic exception) {
 
   return noError;
 }
+
+String errorToTranslatableString(int error) {
+  assert(error != noError, 'Calling errorToTranslatableString with noError makes no sense');
+
+  switch (error) {
+    case fileUploadFailedError: return t.errors.message.fileUploadFailed;
+    case messageContactDoesNotSupportOmemo: return t.errors.message.contactDoesntSupportOmemo;
+    case fileDownloadFailedError: return t.errors.message.fileDownloadFailed;
+    case messageServiceUnavailable: return t.errors.message.serviceUnavailable;
+    case messageRemoteServerTimeout: return t.errors.message.remoteServerTimeout;
+    case messageRemoteServerNotFound: return t.errors.message.remoteServerNotFound;
+    case messageFailedToEncrypt: return t.errors.message.failedToEncrypt;
+    case messageFailedToDecryptFile: return t.errors.message.failedToDecryptFile;
+    case messageChatEncryptedButFileNot: return t.errors.message.fileNotEncrypted;
+    case messageFailedToEncryptFile: return t.errors.message.failedToEncryptFile;
+    case unspecifiedError: return t.errors.message.unspecified;
+  }
+
+  assert(false, 'Invalid error code $error used');
+  return '';
+}

lib/shared/models/message.dart

@@ -142,4 +142,13 @@ class Message with _$Message {
   /// Returns true if the message can open the selection menu by longpressing. False if
   /// not.
   bool get isLongpressable => !isRetracted;
+
+  /// Returns true if the menu item to show the error should be shown in the
+  /// longpress menu.
+  bool get errorMenuVisible {
+    return isError() && (
+      errorType! < messageNotEncryptedForDevice ||
+      errorType! > messageInvalidNumber
+    );
+  }
 }

lib/ui/widgets/chat/chatbubble.dart

@@ -4,7 +4,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:flutter_vibrate/flutter_vibrate.dart';
 import 'package:moxxyv2/i18n/strings.g.dart';
-//import 'package:moxxyv2/shared/error_types.dart';
+import 'package:moxxyv2/shared/error_types.dart';
 import 'package:moxxyv2/shared/helpers.dart';
 import 'package:moxxyv2/shared/models/message.dart';
 import 'package:moxxyv2/shared/warning_types.dart';
@@ -323,6 +323,19 @@ class ChatBubbleState extends State<ChatBubble>
                                             },
                                           ),
                                         ] : [],
+                                        ...widget.message.errorMenuVisible ? [
+                                          _buildMessageOption(
+                                            Icons.info_outline,
+                                            'Show Error',
+                                            () {
+                                              showInfoDialog(
+                                                'Error',
+                                                errorToTranslatableString(widget.message.errorType!),
+                                                context,
+                                              );
+                                            },
+                                          ),
+                                        ] : [],
                                         ...widget.message.isWarning() ? [
                                           _buildMessageOption(
                                             Icons.warning,