Revert "Remove the LayerBasedTheme plugin"

This reverts commit 48ceca0dd2.

LayerBasedTheme.cpp

@@ -0,0 +1,32 @@
+#include "LayerBasedTheme.h"
+
+#include "kaleidoscope/layers.h"
+#include "kaleidoscope/plugin/LEDControl.h"
+
+namespace kaleidoscope {
+namespace plugin {
+EventHandlerResult LayerBasedTheme::onLayerChange() {
+  uint8_t current_layer = Layer.mostRecent();
+  uint8_t current_mode = ::LEDControl.get_mode_index();
+  uint8_t new_mode;
+
+  if (current_layer <= 3) {
+    new_mode = 2;
+  } else {
+    new_mode = 3;
+  }
+
+  if (new_mode != current_mode) {
+    ::LEDControl.set_mode(new_mode);
+  }
+
+  return EventHandlerResult::OK;
+}
+
+LayerBasedTheme::TransientLEDMode::TransientLEDMode(
+    const LayerBasedTheme *parent)
+    : parent_(parent){};
+} // namespace plugin
+} // namespace kaleidoscope
+
+kaleidoscope::plugin::LayerBasedTheme LayerBasedTheme;

LayerBasedTheme.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include "kaleidoscope/event_handler_result.h"
+#include "kaleidoscope/plugin.h"
+#include "kaleidoscope/plugin/AccessTransientLEDMode.h"
+#include "kaleidoscope/plugin/LEDMode.h"
+#include "kaleidoscope/plugin/LEDModeInterface.h"
+
+namespace kaleidoscope {
+namespace plugin {
+class LayerBasedTheme : public Plugin,
+                        public LEDModeInterface,
+                        public AccessTransientLEDMode {
+public:
+  LayerBasedTheme(void) {}
+
+  EventHandlerResult onLayerChange();
+
+  class TransientLEDMode : public LEDMode {
+  public:
+    explicit TransientLEDMode(const LayerBasedTheme *parent);
+
+  private:
+    const LayerBasedTheme *parent_;
+  };
+};
+} // namespace plugin
+} // namespace kaleidoscope
+
+extern kaleidoscope::plugin::LayerBasedTheme LayerBasedTheme;

Model100.ino

@@ -48,6 +48,8 @@
 
 #include "Kaleidoscope-Leader.h"
 
+#include "LayerBasedTheme.h"
+
 /** The Model 100's key layouts are defined as 'keymaps'.
  *
  * Each keymap is defined as a list using the 'KEYMAP_STACKED' macro, built
@@ -320,7 +322,8 @@ KALEIDOSCOPE_INIT_PLUGINS(
   EscapeOneShot,
   EscapeOneShotConfig,
   TapDance,
-  Leader
+  Leader,
+  LayerBasedTheme
 );
 
 void setup() {