filter.h

#pragma once

#include "frequency_domain/buffer.h"

#include <complex>
#include <functional>
#include <stdexcept>

namespace frequency_domain {

class filter final {
public:
    explicit filter(size_t signal_length);

    filter(const filter&) = delete;
    filter& operator=(const filter&) = delete;
    filter(filter&&) = delete;
    filter& operator=(filter&&) = delete;

    ~filter() noexcept;

    using callback =
            std::function<std::complex<float>(std::complex<float>, float)>;

    template <typename In, typename Out>
    void run(In begin, In end, Out output_it, const callback& callback) {
        const auto dist = std::distance(begin, end);

        if (dist > 0) {
            if (dist > rbuf_.size()) {
                throw std::runtime_error{"Filter input signal is too long."};
            }

            rbuf_.zero();
            std::copy(begin, end, rbuf_.begin());
            filter_impl(callback);
            std::copy(rbuf_.begin(), rbuf_.begin() + dist, output_it);
        }
    }

private:
    void filter_impl(const callback& callback);

    rbuf rbuf_;

    class impl;
    std::unique_ptr<impl> pimpl_;
};

}  // namespace frequency_domain