#include "FluidSim/AudioOutputStream.hpp"

#include <algorithm>
#include <cmath>

namespace fluidsim::port {

AudioOutputStream::AudioOutputStream(SimulationRingBuffer& ring, unsigned int sample_rate)
    : ring_(ring) {
    initialize(2, sample_rate, {sf::SoundChannel::FrontLeft, sf::SoundChannel::FrontRight});
}

bool AudioOutputStream::onGetData(Chunk& data) {
    const std::size_t read = ring_.read_interpolated(temp_left_, temp_right_, speed());
    constexpr float dc_coefficient = 0.9995f;
    for (std::size_t i = 0; i < read; ++i) {
        const float left = temp_left_[i] - previous_input_left_ + dc_coefficient * previous_output_left_;
        const float right = temp_right_[i] - previous_input_right_ + dc_coefficient * previous_output_right_;
        previous_input_left_ = temp_left_[i];
        previous_input_right_ = temp_right_[i];
        previous_output_left_ = left;
        previous_output_right_ = right;
        const float finite_left = std::isfinite(left) ? std::clamp(left, -1.0f, 1.0f) : 0.0f;
        const float finite_right = std::isfinite(right) ? std::clamp(right, -1.0f, 1.0f) : 0.0f;
        output_[i * 2] = static_cast<std::int16_t>(finite_left * 32767.0f);
        output_[i * 2 + 1] = static_cast<std::int16_t>(finite_right * 32767.0f);
    }
    std::fill(output_.begin() + static_cast<std::ptrdiff_t>(read * 2), output_.end(), 0);
    data.samples = output_.data();
    data.sampleCount = output_.size();
    return true;
}

void AudioOutputStream::onSeek(sf::Time /*time_offset*/) {}

} // namespace fluidsim::port