Show will send immediately warning if scheduled send is in the past.

app/src/main/java/org/thoughtcrime/securesms/conversation/ScheduleMessageTimePickerBottomSheet.kt

@@ -9,6 +9,7 @@ import androidx.fragment.app.FragmentManager
 import com.google.android.material.datepicker.CalendarConstraints
 import com.google.android.material.datepicker.DateValidatorPointForward
 import com.google.android.material.datepicker.MaterialDatePicker
+import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.android.material.timepicker.MaterialTimePicker
 import com.google.android.material.timepicker.TimeFormat
 import org.thoughtcrime.securesms.R
@@ -64,15 +65,14 @@ class ScheduleMessageTimePickerBottomSheet : FixedRoundedCornerBottomSheetDialog
     scheduledMinute = scheduledLocalDateTime.minute
 
     binding.scheduleSend.setOnClickListener {
-      dismiss()
-      val messageId = arguments?.getLong(KEY_MESSAGE_ID)
-      if (messageId == null) {
-        findListener<ScheduleCallback>()?.onScheduleSend(getSelectedTimestamp())
+      if (getSelectedTimestamp() < System.currentTimeMillis()) {
+        MaterialAlertDialogBuilder(requireContext())
+          .setMessage(R.string.ScheduleMessageTimePickerBottomSheet__select_time_in_past_dialog_warning)
+          .setPositiveButton(R.string.ScheduleMessageTimePickerBottomSheet__select_time_in_past_dialog_positive_button) { _, _ -> scheduleMessageSend() }
+          .setNegativeButton(android.R.string.cancel, null)
+          .show()
       } else {
-        val selectedTime = getSelectedTimestamp()
-        if (selectedTime != arguments?.getLong(KEY_INITIAL_TIME)) {
-          findListener<RescheduleCallback>()?.onReschedule(selectedTime, messageId)
-        }
+        scheduleMessageSend()
       }
     }
 
@@ -166,6 +166,19 @@ class ScheduleMessageTimePickerBottomSheet : FixedRoundedCornerBottomSheetDialog
     binding.timeText.text = scheduledTime.formatHours(requireContext())
   }
 
+  private fun scheduleMessageSend() {
+    dismissAllowingStateLoss()
+    val messageId = arguments?.getLong(KEY_MESSAGE_ID)
+    if (messageId == null) {
+      findListener<ScheduleCallback>()?.onScheduleSend(getSelectedTimestamp())
+    } else {
+      val selectedTime = getSelectedTimestamp()
+      if (selectedTime != arguments?.getLong(KEY_INITIAL_TIME)) {
+        findListener<RescheduleCallback>()?.onReschedule(selectedTime, messageId)
+      }
+    }
+  }
+
   interface ScheduleCallback {
     fun onScheduleSend(scheduledTime: Long)
   }

app/src/main/res/values/strings.xml

@@ -660,9 +660,12 @@
     <string name="ScheduleMessageTimePickerBottomSheet__dialog_title">Schedule message</string>
     <!-- Text for confirmation button when scheduling messages that allows the user to confirm and schedule the sending time -->
     <string name="ScheduleMessageTimePickerBottomSheet__schedule_send">Schedule send</string>
-
     <!-- Disclaimer in message scheduling dialog. %1$s replaced with a GMT offset (e.g. GMT-05:00), and %2$s is replaced with the time zone name (e.g. Eastern Standard Time) -->
     <string name="ScheduleMessageTimePickerBottomSheet__timezone_disclaimer">All times in (%1$s) %2$s</string>
+    <!-- Warning dialog message text shown when select time for scheduled send is in the past resulting in an immediate send if scheduled. -->
+    <string name="ScheduleMessageTimePickerBottomSheet__select_time_in_past_dialog_warning">Selected time is in the past. This will send the message immediately.</string>
+    <!-- Positive button text for warning dialog shown when scheduled send is in the past -->
+    <string name="ScheduleMessageTimePickerBottomSheet__select_time_in_past_dialog_positive_button">Send immediately</string>
 
     <!-- Context menu option to send a scheduled message now -->
     <string name="ScheduledMessagesBottomSheet_menu_send_now">Send now</string>