#pragma once

#include "AudioBuffer.h"
#include <array>

namespace engine {

class EqProcessor {
public:
    static constexpr int BANDS = 10;
    static constexpr float FREQS[BANDS] = {
        32, 64, 125, 250, 500, 1000, 2000, 4000, 8000, 16000
    };

    EqProcessor();

    void  setBand(int band, float dB);
    float band(int band) const;
    void  process(AudioBuffer &buf);
    void  reset();
    void  setSampleRate(int sr);

private:
    void recomputeBiquad(int band);

    int   m_sampleRate { 44100 };
    float m_gainDb[BANDS] {};

    struct BiquadCoefficients {
        float b0 { 1.0f };
        float b1 { 0.0f };
        float b2 { 0.0f };
        float a1 { 0.0f };
        float a2 { 0.0f };
    };
    BiquadCoefficients m_coeff[BANDS];

    struct BiquadState {
        float z1 { 0.0f };
        float z2 { 0.0f };
    };
    
    static constexpr int MAX_CH = 8;
    BiquadState m_state[BANDS][MAX_CH] {}; 
};

} // namespace engine