juce_plugin.h

// SPDX-FileCopyrightText: © 2025-2026 Alexandros Theodotou <alex@zrythm.org>
// SPDX-License-Identifier: LicenseRef-ZrythmLicense
 
#pragma once
 
#include "plugins/plugin.h"
 
#include <juce_audio_processors_headless/juce_audio_processors_headless.h>
 
namespace zrythm::plugins
{

class JucePlugin : public Plugin
{
  Q_OBJECT
  QML_ELEMENT
  QML_UNCREATABLE ("")
 
public:
  using CreatePluginInstanceAsyncFunc = std::function<void (
    const juce::PluginDescription &,
    double,
    int,
    juce::AudioPluginFormat::AudioPluginFormat::PluginCreationCallback)>;

  JucePlugin (
    dsp::ProcessorBase::ProcessorBaseDependencies dependencies,
    CreatePluginInstanceAsyncFunc          create_plugin_instance_async_func,
    std::function<units::sample_rate_t ()> sample_rate_provider,
    std::function<units::sample_u32_t ()>  buffer_size_provider,
    PluginHostWindowFactory                top_level_window_provider,
    QObject *                              parent = nullptr);
 
  ~JucePlugin () override;
 
  // ============================================================================
  // Plugin Interface Implementation
  // ============================================================================
 
  units::sample_u32_t get_single_playback_latency () const override;
 
protected:
  void prepare_for_processing_impl (
    units::sample_rate_t sample_rate,
    units::sample_u32_t  max_block_length) override;
 
  void process_impl (dsp::graph::ProcessBlockInfo time_info) noexcept override;
 
  std::string save_state_impl () const override;
  void        load_state_impl (const std::string &base64_state) override;
 
private Q_SLOTS:
  void on_configuration_changed (
    PluginConfiguration * configuration,
    bool                  generateNewPluginPortsAndParams);

  void on_ui_visibility_changed ();
 
private:
  void initialize_juce_plugin_async (bool generateNewPluginPortsAndParams);

  void create_ports_from_juce_plugin ();

  void create_parameters_from_juce_plugin ();

  void sync_changed_params_to_juce () noexcept [[clang::nonblocking]];

  void show_editor ();

  void hide_editor ();
 
  static constexpr auto kStateKey = "state"sv;
  friend void           to_json (nlohmann::json &j, const JucePlugin &p);
  friend void           from_json (const nlohmann::json &j, JucePlugin &p);
 
private:
  // ============================================================================
  // JUCE-specific members
  // ============================================================================
 
  CreatePluginInstanceAsyncFunc create_plugin_instance_async_func_;
 
  std::unique_ptr<juce::AudioPluginInstance>  juce_plugin_;
  std::unique_ptr<juce::AudioProcessorEditor> editor_;
  std::unique_ptr<plugins::IPluginHostWindow> top_level_window_;
 
  std::function<units::sample_rate_t ()> sample_rate_provider_;
  std::function<units::sample_u32_t ()>  buffer_size_provider_;
 
  juce::AudioBuffer<float> juce_audio_buffer_;
  juce::MidiBuffer         juce_midi_buffer_;
 
  class JuceParamListener : public juce::AudioProcessorParameter::Listener
  {
  public:
    JuceParamListener (JucePlugin &parent) : parent_ (parent) { }
 
    void parameterValueChanged (int parameterIndex, float newValue)
      [[clang::blocking]] override;
    void parameterGestureChanged (int parameterIndex, bool gestureIsStarting)
      [[clang::blocking]] override;
 
  private:
    JucePlugin &parent_;
  };
 
  // Parameter mapping between JUCE and Zrythm
  struct ParameterMapping
  {
    juce::AudioProcessorParameter *    juce_param;
    dsp::ProcessorParameter *          zrythm_param;
    int                                juce_param_index;
    size_t                             zrythm_param_index;
    std::unique_ptr<JuceParamListener> juce_param_listener;
  };
 
  std::vector<ParameterMapping> parameter_mappings_;

  std::unordered_map<int, size_t> juce_param_index_to_mapping_;

  std::unordered_map<size_t, size_t> zrythm_param_index_to_mapping_;
 
  // Audio/MIDI buffer management
  std::vector<float *> input_channels_;
  std::vector<float *> output_channels_;
 
  bool juce_initialized_ = false;
  bool editor_visible_ = false;
  bool plugin_loading_ = false;
 
  // Optional state to apply on instantiation (this is mainly used as a
  // temporary space to store the restored state temporarily until the plugin is
  // instantiated).
  std::optional<juce::MemoryBlock> state_to_apply_;
 
  PluginHostWindowFactory top_level_window_provider_;
};
 
} // namespace zrythm::plugins