keybinds: better follow xkb translation state

fixes #4908

src/helpers/WLClasses.cpp

@@ -242,3 +242,67 @@ Vector2D SConstraint::getLogicConstraintSize() {
 
     return SIZE;
 }
+
+void SKeyboard::updateXKBTranslationState(xkb_keymap* const keymap) {
+    xkb_state_unref(xkbTranslationState);
+
+    if (keymap) {
+        Debug::log(LOG, "Updating keyboard {:x}'s translation state from a provided keymap", (uintptr_t)this);
+        xkbTranslationState = xkb_state_new(keymap);
+        return;
+    }
+
+    const auto WLRKB      = wlr_keyboard_from_input_device(keyboard);
+    const auto KEYMAP     = WLRKB->keymap;
+    const auto STATE      = WLRKB->xkb_state;
+    const auto LAYOUTSNUM = xkb_keymap_num_layouts(KEYMAP);
+
+    const auto PCONTEXT = xkb_context_new(XKB_CONTEXT_NO_FLAGS);
+
+    for (uint32_t i = 0; i < LAYOUTSNUM; ++i) {
+        if (xkb_state_layout_index_is_active(STATE, i, XKB_STATE_LAYOUT_EFFECTIVE)) {
+            Debug::log(LOG, "Updating keyboard {:x}'s translation state from an active index {}", (uintptr_t)this, i);
+
+            CVarList       keyboardLayouts(currentRules.layout, 0, ',');
+            CVarList       keyboardModels(currentRules.model, 0, ',');
+            CVarList       keyboardVariants(currentRules.variant, 0, ',');
+
+            xkb_rule_names rules = {.rules = "", .model = "", .layout = "", .variant = "", .options = ""};
+
+            std::string    layout, model, variant;
+            layout  = keyboardLayouts[i % keyboardLayouts.size()];
+            model   = keyboardModels[i % keyboardLayouts.size()];
+            variant = keyboardVariants[i % keyboardLayouts.size()];
+
+            rules.layout  = layout.c_str();
+            rules.model   = model.c_str();
+            rules.variant = variant.c_str();
+
+            const auto KEYMAP = xkb_keymap_new_from_names(PCONTEXT, &rules, XKB_KEYMAP_COMPILE_NO_FLAGS);
+
+            xkbTranslationState = xkb_state_new(KEYMAP);
+
+            xkb_keymap_unref(KEYMAP);
+            xkb_context_unref(PCONTEXT);
+
+            return;
+        }
+    }
+
+    Debug::log(LOG, "Updating keyboard {:x}'s translation state from an unknown index", (uintptr_t)this);
+
+    xkb_rule_names rules = {
+        .rules   = currentRules.rules.c_str(),
+        .model   = currentRules.model.c_str(),
+        .layout  = currentRules.layout.c_str(),
+        .variant = currentRules.variant.c_str(),
+        .options = currentRules.options.c_str(),
+    };
+
+    const auto NEWKEYMAP = xkb_keymap_new_from_names(PCONTEXT, &rules, XKB_KEYMAP_COMPILE_NO_FLAGS);
+
+    xkbTranslationState = xkb_state_new(NEWKEYMAP);
+
+    xkb_keymap_unref(NEWKEYMAP);
+    xkb_context_unref(PCONTEXT);
+}

src/helpers/WLClasses.hpp

@@ -148,6 +148,8 @@ struct SKeyboard {
     int                numlockOn         = -1;
     bool               resolveBindsBySym = false;
 
+    void               updateXKBTranslationState(xkb_keymap* const keymap = nullptr);
+
     // For the list lookup
     bool operator==(const SKeyboard& rhs) const {
         return keyboard == rhs.keyboard;

src/managers/input/InputManager.cpp

@@ -908,11 +908,10 @@ void CInputManager::applyConfigToKeyboard(SKeyboard* pKeyboard) {
         KEYMAP = xkb_keymap_new_from_names(CONTEXT, &rules, XKB_KEYMAP_COMPILE_NO_FLAGS);
     }
 
-    xkb_state_unref(pKeyboard->xkbTranslationState);
-    pKeyboard->xkbTranslationState = xkb_state_new(KEYMAP);
-
     wlr_keyboard_set_keymap(wlr_keyboard_from_input_device(pKeyboard->keyboard), KEYMAP);
 
+    pKeyboard->updateXKBTranslationState();
+
     wlr_keyboard_modifiers wlrMods = {0};
 
     if (NUMLOCKON == 1) {
@@ -1246,6 +1245,8 @@ void CInputManager::onKeyboardMod(void* data, SKeyboard* pKeyboard) {
 
         const auto LAYOUT = getActiveLayoutForKeyboard(pKeyboard);
 
+        pKeyboard->updateXKBTranslationState();
+
         g_pEventManager->postEvent(SHyprIPCEvent{"activelayout", pKeyboard->name + "," + LAYOUT});
         EMIT_HOOK_EVENT("activeLayout", (std::vector<void*>{pKeyboard, (void*)&LAYOUT}));
     }