//
// Created by david on 17.05.2026.
//

#ifndef PASADASUPERPROJECT_PD_RESAMP_H
#define PASADASUPERPROJECT_PD_RESAMP_H

#include "iir_filter.h"

/** Filter that changes sampling rate between input and output. */
class ResamplingFilter {
public:
    ResamplingFilter() {}
    virtual ~ResamplingFilter() {}
    virtual void push(double ts, double val) = 0;
    virtual bool peek() = 0;
    virtual double get() = 0;
};

/** Normalizes incoming Android sensor sampling rate. */
class Resampler : public ResamplingFilter {
protected:
    const size_t INITIAL_SAMPLES = 100;
    std::vector<double> times;
    std::vector<double> data;
    /** circular buffer size */
    size_t N;
    /** write index */
    size_t n;
    /** read index */
    size_t m;
    bool initialized;
    bool read_valid;
    /** computed sampling frequency, this will be the output rate */
    double fs;
    void compute_fs();
public:
    Resampler();
    /**
     * Push a value into the buffer.
     * Caller is responsible for polling via peek() and get() afterward.
     * @param ts  timestamp in nanoseconds
     * @param val signal sample
     */
    void push(double ts, double val) override;
    bool peek() override;
    double get() override;
    double get_fs() const;
};

#endif //PASADASUPERPROJECT_PD_RESAMP_H