#pragma once

#include <JuceHeader.h>
#include "Params.h"

namespace serum
{

// ===========================================================================
// Mono filter with 7 models (Ladder LP/HP/BP, Diode, Comb, Formant, Screamer),
// 6/12/24 dB slopes (ladder family) and per-sample drive + keytrack. All state
// is clamped to prevent NaN/inf at extreme settings.
// ===========================================================================
class Filter
{
public:
    void prepare (double sampleRate, int maxBlockSize);
    void reset();

    // Process a mono buffer in-place. cutoffNorm is 0..1 (mapped to 20Hz..20kHz).
    void process (float* samples, int numSamples, float cutoffNorm, float res,
                  float drive, float keytrack, float noteHz, int type, int slope) noexcept;

    // Single-sample version (used by the comb/naive paths where convenient).
    float processSample (float in, float cutoffHz, float res, float drive, int type, int slope) noexcept;

private:
    double sr = 44100.0;

    // TPT SVF state (also reused by formant/screamer).
    double ic1eq = 0.0, ic2eq = 0.0;
    double lastG = 0.0, lastK = 0.0;
    double a1 = 0.0, a2 = 0.0, a3 = 0.0;

    // Ladder stage state.
    std::array<double, 4> stage { { 0.0, 0.0, 0.0, 0.0 } };

    // Comb delay line.
    std::vector<float> combLine;
    int    combWrite = 0;
    double combDamp  = 0.0;

    // Formant: three parallel bandpass SVFs (state pairs).
    std::array<std::array<double, 2>, 3> formantState { { { { 0.0, 0.0 } }, { { 0.0, 0.0 } }, { { 0.0, 0.0 } } } };

    void   updateSvf (double g, double k) noexcept;
    double svfLow   (double in, double g, double k) noexcept;
    double svfBand  (double in, double g, double k) noexcept;
    double svfHigh  (double in, double g, double k) noexcept;
    double ladder   (double in, double g, double res, double drive, int stages, bool diode) noexcept;
    double comb     (double in, double freqHz, double res, double drive) noexcept;
    double formant  (double in, double morph, double res) noexcept;
    double screamer (double in, double cutoffHz, double res, double drive) noexcept;
};

} // namespace serum