Handle one TopsyTurvy key / cycle

To avoid duplicating keys, handle only one TopsyTurvy key / cycle. We handle the
one with the highest index for the time being.

Fixes #4.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>

src/Kaleidoscope/TopsyTurvy.cpp

@@ -23,12 +23,14 @@
 namespace kaleidoscope {
 
 uint8_t TopsyTurvy::mod_state_;
+bool TopsyTurvy::is_active_;
 
 TopsyTurvy::TopsyTurvy(void) {
 }
 
 void TopsyTurvy::begin(void) {
   event_handler_hook_use(eventHandlerHook);
+  loop_hook_use(loopHook);
 }
 
 Key TopsyTurvy::eventHandlerHook(Key mapped_key, byte row, byte col, uint8_t key_state) {
@@ -46,6 +48,11 @@ Key TopsyTurvy::eventHandlerHook(Key mapped_key, byte row, byte col, uint8_t key
   if (mapped_key < ranges::TT_FIRST || mapped_key > ranges::TT_LAST)
     return mapped_key;
 
+  if (is_active_)
+    return Key_NoKey;
+
+  is_active_ = true;
+
   Key new_key = {.raw = mapped_key.raw - ranges::TT_FIRST};
   if (new_key.raw == Key_NoKey.raw)
     return mapped_key;
@@ -75,6 +82,10 @@ Key TopsyTurvy::eventHandlerHook(Key mapped_key, byte row, byte col, uint8_t key
   return Key_NoKey;
 }
 
+void TopsyTurvy::loopHook(bool is_post_clear) {
+  is_active_ = false;
+}
+
 }
 
 kaleidoscope::TopsyTurvy TopsyTurvy;

src/Kaleidoscope/TopsyTurvy.h

@@ -32,8 +32,10 @@ class TopsyTurvy: public KaleidoscopePlugin {
   void begin(void) final;
  private:
   static uint8_t mod_state_;
+  static bool is_active_;
 
   static Key eventHandlerHook(Key mapped_key, byte row, byte col, uint8_t key_state);
+  static void loopHook(bool is_post_clear);
 };
 
 }