#pragma once
#include "FluidSim/PipeProfile.hpp"
#include <array>

namespace fluidsim::port {
enum class TwoStrokeExhaust { Racing, Straight };

// YZ125-sized baseline. Port/chamber/combustion dimensions are explicit design
// estimates, not a measured Yamaha cylinder or factory exhaust/ignition map.
struct TwoStrokeConfig {
    TwoStrokeExhaust exhaust{TwoStrokeExhaust::Racing};
    float bore{.054f}, stroke{.0545f}, rod{.110f};
    float trapped_compression{8.2f}; // exhaust-closure volume / clearance volume
    float transfer_duration{130}, exhaust_duration{190};
    float transfer_width{.050f}, exhaust_width{.036f}; // summed effective window widths
    float jet_scale{1.f}; // multiplier on effective jet diameters
    float crankcase_clearance{150e-6f};
    float carburetor_diameter{.0381f};
    float idle_slide_opening{.045f}; // fixed mechanical stop, normalized 0..1 (4.5%)
    float minimum_burn_seconds{.0008f};
    // Empirical mechanical FMEP = A + B*mean_piston_speed + C*speed^2.
    // Generic correlation estimates, not a measured YZ125 coast-down fit.
    float friction_bar{.4f}, friction_bar_per_mps{.09f}, friction_bar_per_mps2{.0009f};
    float exhaust_cell_length{.01f};
    std::array<PipeSection, 6> racing_pipe{{
        {.160f, .036f, .036f}, // header
        {.180f, .036f, .060f}, // shallow first diffuser
        {.190f, .060f, .105f}, // second diffuser
        {.130f, .105f, .105f}, // belly
        {.210f, .105f, .022f}, // convergent / baffle cone
        {.240f, .022f, .022f}  // stinger
    }};
    float geometric_compression() const {
        const float theta = (180 + exhaust_duration * .5f) * pi / 180;
        const float radius = stroke * .5f, sine = std::sin(theta);
        const float travel = radius * (1 - std::cos(theta)) + rod -
                             std::sqrt(rod*rod - radius*radius*sine*sine);
        return 1 + (trapped_compression - 1) * stroke / travel;
    }
};
} // namespace fluidsim::port