Insert time element global

assets/l10n/app_en.arb

@@ -870,5 +870,9 @@
   "zulipAppTitle": "Zulip",
   "@zulipAppTitle": {
     "description": "The name of Zulip. This should be either 'Zulip' or a transliteration."
+  },
+  "composeBoxAttachGlobalTimeTooltip": "Attach a global time",
+      "@composeBoxAttachGlobalTimeTooltip": {
+        "description": "Tooltip for the button to attach a global time to the compose box."
   }
 }

lib/generated/l10n/zulip_localizations.dart

@@ -1274,6 +1274,12 @@ abstract class ZulipLocalizations {
   /// In en, this message translates to:
   /// **'Zulip'**
   String get zulipAppTitle;
+
+  /// Tooltip for the button to attach a global time to the compose box.
+  ///
+  /// In en, this message translates to:
+  /// **'Attach a global time'**
+  String get composeBoxAttachGlobalTimeTooltip;
 }
 
 class _ZulipLocalizationsDelegate extends LocalizationsDelegate<ZulipLocalizations> {

lib/generated/l10n/zulip_localizations_ar.dart

@@ -678,4 +678,7 @@ class ZulipLocalizationsAr extends ZulipLocalizations {
 
   @override
   String get zulipAppTitle => 'Zulip';
+
+  @override
+  String get composeBoxAttachGlobalTimeTooltip => 'Attach a global time';
 }

lib/generated/l10n/zulip_localizations_en.dart

@@ -678,4 +678,7 @@ class ZulipLocalizationsEn extends ZulipLocalizations {
 
   @override
   String get zulipAppTitle => 'Zulip';
+
+  @override
+  String get composeBoxAttachGlobalTimeTooltip => 'Attach a global time';
 }

lib/generated/l10n/zulip_localizations_ja.dart

@@ -678,4 +678,7 @@ class ZulipLocalizationsJa extends ZulipLocalizations {
 
   @override
   String get zulipAppTitle => 'Zulip';
+
+  @override
+  String get composeBoxAttachGlobalTimeTooltip => 'Attach a global time';
 }

lib/generated/l10n/zulip_localizations_nb.dart

@@ -678,4 +678,7 @@ class ZulipLocalizationsNb extends ZulipLocalizations {
 
   @override
   String get zulipAppTitle => 'Zulip';
+
+  @override
+  String get composeBoxAttachGlobalTimeTooltip => 'Attach a global time';
 }

lib/generated/l10n/zulip_localizations_pl.dart

@@ -678,4 +678,7 @@ class ZulipLocalizationsPl extends ZulipLocalizations {
 
   @override
   String get zulipAppTitle => 'Zulip';
+
+  @override
+  String get composeBoxAttachGlobalTimeTooltip => 'Attach a global time';
 }

lib/generated/l10n/zulip_localizations_ru.dart

@@ -678,4 +678,7 @@ class ZulipLocalizationsRu extends ZulipLocalizations {
 
   @override
   String get zulipAppTitle => 'Zulip';
+
+  @override
+  String get composeBoxAttachGlobalTimeTooltip => 'Attach a global time';
 }

lib/generated/l10n/zulip_localizations_sk.dart

@@ -678,4 +678,7 @@ class ZulipLocalizationsSk extends ZulipLocalizations {
 
   @override
   String get zulipAppTitle => 'Zulip';
+
+  @override
+  String get composeBoxAttachGlobalTimeTooltip => 'Attach a global time';
 }

lib/widgets/compose_box.dart

@@ -4,7 +4,7 @@ import 'package:app_settings/app_settings.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:mime/mime.dart';
-
+import 'package:intl/intl.dart';
 import '../api/exception.dart';
 import '../api/model/model.dart';
 import '../api/route/messages.dart';
@@ -1034,6 +1034,68 @@ class _AttachFromCameraButton extends _AttachUploadsButton {
   }
 }
 
+class _AttachGlobalTimeButton extends _AttachUploadsButton {
+  const _AttachGlobalTimeButton({required super.controller});
+
+  @override
+  IconData get icon => ZulipIcons.clock;
+
+  @override
+  String tooltip(ZulipLocalizations zulipLocalizations) =>
+      zulipLocalizations.composeBoxAttachGlobalTimeTooltip;
+
+  @override
+  Future<Iterable<_File>> getFiles(BuildContext context) async {
+    // Ensure the context is still valid
+    if (!context.mounted) return [];
+
+    // Request a date and time from the user.
+    final DateTime? pickedDate = await showDatePicker(
+      context: context,
+      initialDate: DateTime.now(),
+      firstDate: DateTime(2000),
+      lastDate: DateTime(2100),
+    );
+
+    // Recheck context after async operation
+    if (!context.mounted) return [];
+
+    if (pickedDate == null) {
+      return []; // User canceled, no action needed.
+    }
+
+    final TimeOfDay? pickedTime = await showTimePicker(
+      context: context,
+      initialTime: TimeOfDay.now(),
+    );
+
+    // Recheck context after async operation
+    if (!context.mounted) return [];
+
+    if (pickedTime == null) {
+      return [];
+    }
+
+    // Combine the picked date and time.
+    final DateTime fullDateTime = DateTime(
+      pickedDate.year,
+      pickedDate.month,
+      pickedDate.day,
+      pickedTime.hour,
+      pickedTime.minute,
+    );
+
+    // Format the date-time for the new markup.
+    final String timeMarkup =
+        "<time:${DateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'").format(fullDateTime.toUtc())}>";
+
+    // Safely update the content controller
+    controller.content.text += timeMarkup;
+
+    return [];
+  }
+}
+
 class _SendButton extends StatefulWidget {
   const _SendButton({required this.controller, required this.getDestination});
 
@@ -1270,6 +1332,7 @@ abstract class _ComposeBoxBody extends StatelessWidget {
       _AttachFileButton(controller: controller),
       _AttachMediaButton(controller: controller),
       _AttachFromCameraButton(controller: controller),
+      _AttachGlobalTimeButton(controller: controller),
     ];
 
     final topicInput = buildTopicInput();