#include "FluidSim/Scenario.hpp"
#include "FluidSim/TwoStrokeScenario.hpp"
#include "FluidSim/HelmholtzScenario.hpp"
#include "FluidSim/PulseTestScenario.hpp"
#include <algorithm>
#include <chrono>
#include <cmath>
#include <iostream>
#include <limits>
#include <memory>
#include <numeric>
#include <stdexcept>
#include <string>
#include <vector>
using namespace fluidsim::port;
static void set_uniform_pipe_resolution(std::vector<Pipe1D>& pipes, int cells_per_meter) {
    if (cells_per_meter <= 0) throw std::invalid_argument("cells per meter must be positive");
    for (auto& pipe : pipes) {
        const float length = std::accumulate(pipe.cell_lengths.begin(), pipe.cell_lengths.end(), 0.0f);
        const float damping = pipe.damping_multiplier;
        const float relaxation = pipe.energy_relaxation_rate;
        const float ambient = pipe.ambient_pressure;
        const int count = std::max(1, static_cast<int>(std::ceil(length * cells_per_meter)));
        pipe = Pipe1D(pipe.area, length, count);
        pipe.damping_multiplier = damping;
        pipe.energy_relaxation_rate = relaxation;
        pipe.ambient_pressure = ambient;
    }
}
template<class S, class Control> void run(const char* name, S& s, int seconds, Control control) {
    double checksum = 0;
    std::uint64_t previous_iterations = 0;
    std::uint64_t previous_substeps = 0;
    for (int second = 0; second < seconds; ++second) {
        float peak = 0;
        const auto begin = std::chrono::steady_clock::now();
        for (int i = 0; i < 44100; ++i) {
            control(second);
            auto value = s.process();
            if constexpr (requires { value.left; }) {
                if (!std::isfinite(value.left) || !std::isfinite(value.right))
                    throw std::runtime_error("Nonfinite benchmark audio");
                checksum += value.left;
                peak = std::max({peak, std::abs(value.left), std::abs(value.right)});
            }
            else checksum += value;
        }
        const double elapsed = std::chrono::duration<double>(std::chrono::steady_clock::now()-begin).count();
        std::cout << name << ',' << second+1 << ',' << elapsed << ',' << checksum << std::endl;
        if constexpr (requires { s.pipes; }) {
            unsigned tiny = 0;
            std::uint64_t repairs=0, fallbacks=0;
            for(const auto& pipe:s.pipes) { repairs+=pipe.positivity_repairs; fallbacks+=pipe.hllc_fallbacks; }
            if(repairs) throw std::runtime_error("benchmark required pipe positivity repairs");
            std::cerr<<name<<" repairs="<<repairs<<" hllc_fallbacks="<<fallbacks<<" peak="<<peak<<"\n";
            for (const auto& pipe : s.pipes)
                for (const auto& cell : pipe.cells)
                    for (float value : {cell.rho, cell.momentum, cell.energy, cell.air})
                        tiny += std::fpclassify(value) == FP_SUBNORMAL;
            std::cerr << name << " second=" << second+1 << " subnormal_cell_fields=" << tiny << '\n';
        }
        if constexpr (requires { s.snapshot().boundary_iterations; }) {
            const auto state = s.snapshot();
            std::cerr << name << " iterations_per_frame="
                      << (state.boundary_iterations-previous_iterations)/44100.0 << '\n';
            std::size_t limiting_pipe = 0;
            float stable_dt = std::numeric_limits<float>::max();
            for (std::size_t p = 0; p < s.pipes.size(); ++p) {
                const float candidate = s.pipes[p].stable_timestep();
                if (candidate < stable_dt) { stable_dt = candidate; limiting_pipe = p; }
            }
            std::cerr << name << " substeps_per_frame=" << (state.solver_substeps-previous_substeps)/44100.0
                      << " limiting_pipe=" << limiting_pipe << " cfl_us=" << stable_dt*1e6f << '\n';
            previous_substeps = state.solver_substeps;
            unsigned long long repairs = 0, fallbacks = 0;
            for (const auto& pipe : s.pipes) { repairs += pipe.positivity_repairs; fallbacks += pipe.hllc_fallbacks; }
            std::cerr << name << " rpm=" << state.rpm << " power_kW=" << state.average_power/1000
                      << " peak=" << peak << " hllc_fallbacks=" << fallbacks << " pipe_repairs=" << repairs << '\n';
            previous_iterations = state.boundary_iterations;
        }
    }
}
int main(int argc, char** argv) {
    const int seconds = argc > 1 ? std::stoi(argv[1]) : 6;
    const std::string mode = argc > 2 ? argv[2] : "pedal";
    const std::string only = argc > 3 ? argv[3] : "all";
    const int uniform_v8_cells_per_meter = argc > 4 ? std::stoi(argv[4]) : 0;
    const auto selected_solver=argc>5 ? parse_pipe_solver(argv[5]) : PipeSolver::Rusanov;
    std::cerr << "solver=" << pipe_solver_name(selected_solver) << "\n";
    auto pedal = [&](int second) {
        return mode == "idle" ? 0.0f : mode == "coast" ? (second >= 1 && second < 5 ? .7f : 0.f) :
               mode == "transient" && (second == 0 || second >= seconds-2) ? 0.0f : .7f;
    };
    std::cout << "scenario,second,wall_seconds,checksum\n";
    for (auto name : {"twin", "b205", "v8"}) {
        if (only != "all" && only != name) continue;
        auto s = std::make_unique<FourStrokeScenario>(44100,
            std::string(name)=="v8" ? FourStrokePreset::AmericanV8 : std::string(name)=="b205" ? FourStrokePreset::SaabB205 : FourStrokePreset::Twin);
        if (std::string(name) == "v8" && uniform_v8_cells_per_meter > 0) {
            set_uniform_pipe_resolution(s->pipes, uniform_v8_cells_per_meter);
            std::cerr << "v8 uniform_cells_per_meter=" << uniform_v8_cells_per_meter << '\n';
        }
        s->set_pipe_solver(selected_solver);
        s->throttle = .7f;
        run(name, *s, seconds, [&](int second) {
            s->throttle = pedal(second);
            if (mode == "loaded") s->crankshaft.omega = (std::string(name)=="v8" ? 4500 : 7000) * 2*pi/60;
        });
    }
    for (bool racing : {true, false}) {
        if (only != "all" && only != (racing ? "two-stroke-racing" : "two-stroke-straight")) continue;
        TwoStrokeConfig config;
        config.exhaust = racing ? TwoStrokeExhaust::Racing : TwoStrokeExhaust::Straight;
        TwoStrokeScenario s(44100, config);
        s.set_pipe_solver(selected_solver);
        s.set_throttle(.7f);
        run(racing ? "two-stroke-racing" : "two-stroke-straight", s, seconds, [&](int second) {
            s.set_throttle(pedal(second));
            if (mode == "loaded") s.crankshaft.omega = 10000 * 2*pi/60;
        });
    }
    if (only == "all" || only == "helmholtz") {
        HelmholtzScenario helmholtz; run("helmholtz", helmholtz, seconds, [](int){});
    }
    if (only == "all" || only == "pulse") {
        PulseTestScenario pulse; run("pulse", pulse, seconds, [](int){});
    }
}