Allow mod swapping for mod tap (MT) (#1202)

* allow mod swapping for mod tap

* quick include

* fix the mod swapping

* make changes consistent with action code

* fix bug

* re-enable no gui, etc

* fix binary comps

* solid logic

quantum/keycode_config.c

@@ -88,3 +88,31 @@ uint16_t keycode_config(uint16_t keycode) {
             return keycode;
     }
 }
+
+uint8_t mod_config(uint8_t mod) {
+    keymap_config.raw = eeconfig_read_keymap();
+    if (keymap_config.swap_lalt_lgui) {
+        if ((mod & MOD_RGUI) == MOD_LGUI) {
+            mod &= ~MOD_LGUI;
+            mod |= MOD_LALT;
+        } else if ((mod & MOD_RALT) == MOD_LALT) {
+            mod &= ~MOD_LALT;
+            mod |= MOD_LGUI;
+        }
+    }
+    if (keymap_config.swap_ralt_rgui) {
+        if ((mod & MOD_RGUI) == MOD_RGUI) {
+            mod &= ~MOD_RGUI;
+            mod |= MOD_RALT;
+        } else if ((mod & MOD_RALT) == MOD_RALT) {
+            mod &= ~MOD_RALT;
+            mod |= MOD_RGUI;
+        }
+    }
+    if (keymap_config.no_gui) {
+        mod &= ~MOD_LGUI;
+        mod &= ~MOD_RGUI;
+    }
+
+    return mod;
+}

quantum/keycode_config.h

@@ -16,11 +16,13 @@
 
 #include "eeconfig.h"
 #include "keycode.h"
+#include "action_code.h"
 
 #ifndef KEYCODE_CONFIG_H
 #define KEYCODE_CONFIG_H
 
 uint16_t keycode_config(uint16_t keycode);
+uint8_t mod_config(uint8_t mod);
 
 /* NOTE: Not portable. Bit field order depends on implementation */
 typedef union {

quantum/keymap_common.c

@@ -123,7 +123,8 @@ action_t action_for_key(uint8_t layer, keypos_t key)
             action.code = ACTION_LAYER_TAP_TOGGLE(keycode & 0xFF);
             break;
         case QK_MOD_TAP ... QK_MOD_TAP_MAX:
-            action.code = ACTION_MODS_TAP_KEY((keycode >> 0x8) & 0x1F, keycode & 0xFF);
+            mod = mod_config((keycode >> 0x8) & 0x1F);
+            action.code = ACTION_MODS_TAP_KEY(mod, keycode & 0xFF);
             break;
     #ifdef BACKLIGHT_ENABLE
         case BL_0 ... BL_15: