Hotkeys: Display reason why rewind is unavailable

src/core/achievements.cpp

@@ -2299,7 +2299,8 @@ void Achievements::ConfirmHardcoreModeDisableAsync(std::string_view trigger, std
       Host::RunOnCoreThread([callback = std::move(callback), res]() {
         if (res)
           DisableHardcoreMode(true, true);
-        callback(res);
+        if (callback)
+          callback(res);
       });
     });
 }

src/core/hotkeys.cpp

@@ -85,6 +85,45 @@ static void HotkeyToggleOSD()
   VideoThread::UpdateSettings(true, false, false);
 }
 
+static bool HotkeyCheckRewindAvailability(bool enabled)
+{
+  if (g_settings.rewind_enable)
+    return true;
+
+  // don't do anything on key release
+  if (!enabled)
+    return false;
+
+  // figure out why it's disabled...
+  std::string summary;
+  const bool rewind_actually_enabled = Core::GetBoolSettingValue("Main", "RewindEnable", false);
+  if (rewind_actually_enabled)
+  {
+    if (g_settings.IsRunaheadEnabled())
+    {
+      summary = TRANSLATE_STR("OSDMessage", "Rewinding is disabled while runahead is enabled.");
+    }
+    else if (g_settings.disable_all_enhancements)
+    {
+      summary = TRANSLATE_STR("OSDMessage", "Rewinding is disabled while safe mode is enabled.");
+    }
+    else if (Achievements::IsHardcoreModeActive())
+    {
+      // because this is keypress-based, don't enable it on accept
+      Achievements::ConfirmHardcoreModeDisableAsync("Rewinding", {});
+      return false;
+    }
+  }
+  else
+  {
+    summary = TRANSLATE_STR("OSDMessage", "Rewinding is not enabled.");
+  }
+
+  Host::AddIconOSDMessage(OSDMessageType::Warning, "SetRewindState", ICON_EMOJI_WARNING,
+                          TRANSLATE_STR("OSDMessage", "Rewinding unavailable."), std::move(summary));
+  return false;
+}
+
 static constexpr const HotkeyInfo s_hotkey_list[] = {
 
 #ifndef __ANDROID__
@@ -197,7 +236,10 @@ static constexpr const HotkeyInfo s_hotkey_list[] = {
    [](s32 pressed) {
      if (pressed < 0)
        return;
-     System::SetRewindState(pressed > 0);
+
+     const bool enabled = (pressed > 0);
+     if (HotkeyCheckRewindAvailability(enabled))
+       System::SetRewindState(enabled);
    }},
 
 #ifndef __ANDROID__

src/core/system.cpp

@@ -209,7 +209,6 @@ static void DoMemoryState(StateWrapper& sw, MemorySaveState& mss, bool update_di
 static bool IsExecutionInterrupted();
 static void CheckForAndExitExecution();
 
-static void SetRewinding(bool enabled);
 static void DoRewind();
 
 static bool DoRunahead();
@@ -3699,35 +3698,6 @@ void System::SetTurboEnabled(bool enabled)
   UpdateSpeedLimiterState();
 }
 
-void System::SetRewindState(bool enabled)
-{
-  if (!System::IsValid())
-    return;
-
-  if (!g_settings.rewind_enable)
-  {
-    if (enabled)
-    {
-      Host::AddKeyedOSDMessage(OSDMessageType::Info, "SetRewindState",
-                               TRANSLATE_STR("OSDMessage", "Rewinding is not enabled."));
-    }
-
-    return;
-  }
-
-  if (Achievements::IsHardcoreModeActive() && enabled)
-  {
-    Achievements::ConfirmHardcoreModeDisableAsync("Rewinding", [](bool approved) {
-      if (approved)
-        SetRewindState(true);
-    });
-    return;
-  }
-
-  System::SetRewinding(enabled);
-  UpdateSpeedLimiterState();
-}
-
 void System::FrameStep()
 {
   if (!IsValid())
@@ -5072,9 +5042,14 @@ bool System::IsRewinding()
   return (s_state.rewind_load_frequency >= 0);
 }
 
-void System::SetRewinding(bool enabled)
+void System::SetRewindState(bool enabled)
 {
+  if (!System::IsValid() || !g_settings.rewind_enable)
+    return;
+
   const bool was_enabled = IsRewinding();
+  if (enabled == was_enabled)
+    return;
 
   if (enabled)
   {
@@ -5106,6 +5081,8 @@ void System::SetRewinding(bool enabled)
       s_state.rewind_save_counter = s_state.rewind_save_frequency;
     }
   }
+
+  UpdateSpeedLimiterState();
 }
 
 void System::DoRewind()