#pragma once

#include "FluidSim/Component.hpp"
#include "FluidSim/Constants.hpp"
#include <array>
#include <cstddef>
#include <random>

namespace fluidsim::port {

class Ecu;

class Crankshaft {
public:
    float omega{400.0f * 2.0f * pi / 60.0f};
    float angle{}, previous_angle{}, inertia{0.2f};
    float friction_constant{}, friction_viscous{};
    float friction_quadratic{}; // Nm / (rad/s)^2, dissipative windage term
    float load_torque{}, drivetrain_torque{};
    float average_power{}, average_torque{};

    void add_torque(float torque);
    void step(float dt);
private:
    float external_torque_{};
    std::array<float, 16384> power_buffer_{}, torque_buffer_{};
    std::size_t power_index_{}, power_count_{}, torque_index_{}, torque_count_{};
    float power_sum_{}, torque_sum_{};
};

class EngineCylinder : public Component {
public:
    Ecu* ecu{}; // Optional ideal electronic fuel/ignition controller.
    float bore{0.075f}, stroke{0.068f}, rod{0.112f}, compression{11.5f};
    float intake_valve_diameter{0.030f}, exhaust_valve_diameter{0.028f};
    int intake_valve_count{1}, exhaust_valve_count{1};
    float intake_valve_lift{0.005f}, exhaust_valve_lift{0.005f};
    float phase{};
    float spark_advance{20.0f}, wiebe_a{5.0f}, wiebe_m{2.0f}, burn_duration{60.0f}, burn_start{5.0f};
    float afr{14.7f}, fuel_lhv{44.0e6f}, energy_variation{0.05f}, misfire_probability{};
    float wall_area{0.02f}, heat_transfer{100.0f}, ambient_temperature{300.0f};
    bool rev_limit_enabled{};
    float rev_limit_rpm{7500.0f}, rev_limit_cut_time{0.05f}, rev_limit_hysteresis{200.0f};
    float air_mass{}, exhaust_mass{}, energy{}, volume{}, pressure{101325.0f};
    float fuel_mass{}, burn_fraction{};
    bool combustion_active{}, fuel_injected{}, rev_limit_active{};
    Port intake{}, exhaust{};

    std::vector<Port*> ports() override { return {&intake, &exhaust}; }
    float swept_volume() const;
    float clearance_volume() const;
    float total_mass() const;
    float temperature() const;
    float air_fraction() const;
    float compute_volume(float theta) const;
    void initialize(const Crankshaft& crank);
    virtual float valve_area(float cycle_degrees, bool inlet) const = 0;
    virtual void pre_step(Crankshaft& crank, float dt, float throttle) = 0;
    void update_state(float dt) override;

protected:
    float energy_factor_{1.0f};
    float rev_limit_timer_{};
    std::mt19937 random_{0xF17D51u};
    std::uniform_real_distribution<float> unit_{0.0f, 1.0f};

    float random_unit();
    static float wrap_degrees(float value, float cycle_degrees = 720.0f);
    static bool crossed_angle(float previous, float current, float event) {
        return current >= previous ? previous < event && current >= event : event > previous || event <= current;
    }
    static bool crossed_window_close(float previous, float current, float open, float close);
    void update_rev_limiter(float rpm, float dt);
    void sync_ports();
};

class FourStrokeCylinder final : public EngineCylinder {
public:
    float intake_open{340.0f}, intake_close{590.0f}, exhaust_open{130.0f}, exhaust_close{390.0f};
    float valve_area(float cycle_degrees, bool inlet) const override;
    void pre_step(Crankshaft& crank, float dt, float throttle) override;
};
} // namespace fluidsim::port