ios: group welcome message byte limit (#3751)

* ios: group welcome message character limit

* confirmation dialogue key

* use chatJsonLength

* text

* change footer

---------

Co-authored-by: Evgeny Poberezkin <evgeny@poberezkin.com>

apps/ios/Shared/Views/Chat/Group/GroupWelcomeView.swift

@@ -18,6 +18,8 @@ struct GroupWelcomeView: View {
     @FocusState private var keyboardVisible: Bool
     @State private var showSaveDialog = false
 
+    let maxByteCount = 1200
+
     var body: some View {
         VStack {
             if groupInfo.canEdit {
@@ -29,9 +31,12 @@ struct GroupWelcomeView: View {
                             showSaveDialog = true
                         }
                     })
-                    .confirmationDialog("Save welcome message?", isPresented: $showSaveDialog) {
-                        Button("Save and update group profile") {
-                            save()
+                    .confirmationDialog(
+                        welcomeTextFitsLimit() ? "Save welcome message?" : "Welcome message is too long",
+                        isPresented: $showSaveDialog
+                    ) {
+                        if welcomeTextFitsLimit() {
+                            Button("Save and update group profile") { save() }
                         }
                         Button("Exit without saving") { dismiss() }
                     }
@@ -53,7 +58,7 @@ struct GroupWelcomeView: View {
 
     private func textPreview() -> some View {
         messageText(welcomeText, parseSimpleXMarkdown(welcomeText), nil, showSecrets: false)
-            .frame(minHeight: 140, alignment: .topLeading)
+            .frame(minHeight: 130, alignment: .topLeading)
             .frame(maxWidth: .infinity, alignment: .leading)
     }
 
@@ -73,7 +78,7 @@ struct GroupWelcomeView: View {
                         }
                         .padding(.horizontal, -5)
                         .padding(.top, -8)
-                        .frame(height: 140, alignment: .topLeading)
+                        .frame(height: 130, alignment: .topLeading)
                         .frame(maxWidth: .infinity, alignment: .leading)
                     }
                 } else {
@@ -92,6 +97,9 @@ struct GroupWelcomeView: View {
                 }
                 .disabled(welcomeText.isEmpty)
                 copyButton()
+            } footer: {
+                Text(!welcomeTextFitsLimit() ? "Message too large" : "")
+                    .foregroundColor(.red)
             }
 
             Section {
@@ -112,13 +120,17 @@ struct GroupWelcomeView: View {
         Button("Save and update group profile") {
             save()
         }
-        .disabled(welcomeTextUnchanged())
+        .disabled(welcomeTextUnchanged() || !welcomeTextFitsLimit())
     }
 
     private func welcomeTextUnchanged() -> Bool {
         welcomeText == groupInfo.groupProfile.description || (welcomeText == "" && groupInfo.groupProfile.description == nil)
     }
 
+    private func welcomeTextFitsLimit() -> Bool {
+        chatJsonLength(welcomeText) <= maxByteCount
+    }
+
     private func save() {
         Task {
             do {

apps/ios/SimpleXChat/API.swift

@@ -105,6 +105,11 @@ public func parseSimpleXMarkdown(_ s: String) -> [FormattedText]? {
     return nil
 }
 
+public func chatJsonLength(_ s: String) -> Int {
+    var c = s.cString(using: .utf8)!
+    return Int(chat_json_length(&c))
+}
+
 struct ParsedMarkdown: Decodable {
     var formattedText: [FormattedText]?
 }

apps/ios/SimpleXChat/SimpleX.h

@@ -25,6 +25,7 @@ extern char *chat_parse_markdown(char *str);
 extern char *chat_parse_server(char *str);
 extern char *chat_password_hash(char *pwd, char *salt);
 extern char *chat_valid_name(char *name);
+extern int chat_json_length(char *str);
 extern char *chat_encrypt_media(chat_ctrl ctl, char *key, char *frame, int len);
 extern char *chat_decrypt_media(char *key, char *frame, int len);