#pragma once

#include "FluidSim/Engine.hpp"
#include <random>

namespace fluidsim::port {

// Synthetic valve, piston, combustion, chain, and gear sounds driven by live
// engine state; direct port of Core/MechanicalSoundProcessor.cs.
class MechanicalSoundProcessor {
public:
    float master_gain{0.6f}, valve_tick_gain{0.9f}, piston_slap_gain{1.2f};
    float combustion_gain{0.5f}, gear_whine_gain{0.12f}, cam_chain_gain{0.25f};

    explicit MechanicalSoundProcessor(int sample_rate = 44100);
    float process(const Crankshaft& crank, const EngineCylinder& cylinder, float load);

private:
    class Resonator {
    public:
        Resonator(float frequency_hz, float q, float sample_rate);
        float process(float input);
    private:
        float b1_{}, b2_{}, gain_{}, y1_{}, y2_{};
    };
    class OnePoleLowPass {
    public:
        OnePoleLowPass(float cutoff_hz, float sample_rate);
        float process(float input);
    private:
        float alpha_{}, state_{};
    };

    float dt_{};
    Resonator intake_tick_, exhaust_tick_;
    OnePoleLowPass slap_filter_, combustion_filter_, chain_filter_;
    float slap_envelope_{}, combustion_envelope_{}, chain_envelope_{};
    float slap_decay_{}, combustion_decay_{}, chain_decay_{};
    float gear_phase1_{}, gear_phase2_{}, gear_phase3_{};
    float previous_intake_area_{}, previous_exhaust_area_{}, previous_pressure_{};
    float previous_cycle_position_{-1.0f}, previous_crank_fraction_{-1.0f};
    std::mt19937 random_{0x5EEDu};
    std::uniform_real_distribution<float> unit_{-1.0f, 1.0f};

    float random_sample();
    static bool crossed_fraction(float previous, float current, float target);
};

} // namespace fluidsim::port