Cava back/front end transformation

include/modules/cava/cava_backend.hpp

@@ -0,0 +1,74 @@
+#pragma once
+
+#include <json/json.h>
+#include <sigc++/sigc++.h>
+
+#include "util/sleeper_thread.hpp"
+
+namespace cava {
+extern "C" {
+// Need sdl_glsl output feature to be enabled on libcava
+#ifndef SDL_GLSL
+#define SDL_GLSL
+#endif
+
+#include <cava/common.h>
+
+#ifdef SDL_GLSL
+#undef SDL_GLSL
+#endif
+}
+}  // namespace cava
+
+namespace waybar::modules::cava {
+using namespace std::literals::chrono_literals;
+
+class CavaBackend final {
+ public:
+  static std::shared_ptr<CavaBackend> inst(const Json::Value& config);
+
+  virtual ~CavaBackend();
+  // Methods
+  int getAsciiRange();
+  void doPauseResume();
+  void Update();
+  // Signal accessor
+  using type_signal_update = sigc::signal<void(const std::string&)>;
+  type_signal_update signal_update();
+  using type_signal_silence = sigc::signal<void()>;
+  type_signal_silence signal_silence();
+
+ private:
+  CavaBackend(const Json::Value& config);
+  util::SleeperThread thread_;
+  util::SleeperThread read_thread_;
+  // Cava API to read audio source
+  ::cava::ptr input_source_;
+
+  struct ::cava::error_s error_{};          // cava errors
+  struct ::cava::config_params prm_{};      // cava parameters
+  struct ::cava::audio_raw audio_raw_{};    // cava handled raw audio data(is based on audio_data)
+  struct ::cava::audio_data audio_data_{};  // cava audio data
+  struct ::cava::cava_plan* plan_;          //{new cava_plan{}};
+
+  std::chrono::seconds fetch_input_delay_{4};
+  // Delay to handle audio source
+  std::chrono::milliseconds frame_time_milsec_{1s};
+
+  int re_paint_{0};
+  bool silence_{false};
+  bool silence_prev_{false};
+  std::chrono::seconds suspend_silence_delay_{0};
+  int sleep_counter_{0};
+  std::string output_{};
+  // Methods
+  void invoke();
+  void execute();
+  bool isSilence();
+  void doUpdate(bool force = false);
+
+  // Signal
+  type_signal_update m_signal_update_;
+  type_signal_silence m_signal_silence_;
+};
+}  // namespace waybar::modules::cava