/** inc/complex_frames.h
 
  Defines the interface for the `RealtimeHilbert` class.
 
    This is a stateful processor designed for continuous, low-latency, real-time
    audio streaming. It uses an internal history buffer and an overlap-add to prevent
    artifacts that would occur with block-based processing of the same chunk-sizes.

    The point of this is to provide a complex stream alongside the raw real stream simultaneously.
    It's kind of the core of this whole engine. This is what allowed the spiral visualizer idea to work in real-time.
    
**/

#ifndef COMPLEX_FRAMES_H
#define COMPLEX_FRAMES_H

#include <vector>
#include <complex>
#include <utility>
#include <fftw3.h>

class RealtimeHilbert {
public:
    RealtimeHilbert();
    ~RealtimeHilbert();

    void reinit(size_t fft_size);
    std::pair<std::vector<std::complex<double>>, std::vector<std::complex<double>>> 
    process(const std::vector<double>& left_input_block, const std::vector<double>& right_input_block);

private:
    void cleanup();

    size_t m_fft_size;
    size_t m_hop_size;
    std::vector<double> m_history_buffer_L;
    std::vector<double> m_history_buffer_R;

    // --- Left Channel Resources ---
    fftw_plan m_plan_forward_L;
    fftw_plan m_plan_backward_L;
    double*       m_fft_input_real_L;
    fftw_complex* m_fft_output_spectrum_L;
    fftw_complex* m_ifft_input_spectrum_L;
    fftw_complex* m_ifft_output_complex_L;

    // --- Right Channel Resources ---
    fftw_plan m_plan_forward_R;
    fftw_plan m_plan_backward_R;
    double*       m_fft_input_real_R;
    fftw_complex* m_fft_output_spectrum_R;
    fftw_complex* m_ifft_input_spectrum_R;
    fftw_complex* m_ifft_output_complex_R;
};

#endif // COMPLEX_FRAMES_H