using System;
using FluidSim.Components;
using FluidSim.Utils;

namespace FluidSim.Core
{
    public static class Simulation
    {
        private static Pipe1D pipe;
        private static Connection leftConn, rightConn;   // dummy connections for orifice params
        private static double time;
        private static double dt;
        private static int stepCount;

        public static void Initialize(int sampleRate)
        {
            dt = 1.0 / sampleRate;

            double length = 150 * Units.mm;
            double diameter = 25 * Units.mm;
            double area = Units.AreaFromDiameter(25, Units.mm);
            int nCells = 10;

            pipe = new Pipe1D(length, area, nCells, sampleRate);
            pipe.SetUniformState(1.2, 0.0, 1.0 * Units.atm);   // start at 1 atm
            pipe.FrictionFactor = 0.02;

            // Dummy connections – only used for orifice parameters
            leftConn = new Connection(null, null) { Area = area, DischargeCoefficient = 1.0, Gamma = 1.4 };
            rightConn = new Connection(null, null) { Area = area, DischargeCoefficient = 1.0, Gamma = 1.4 };
        }

        public static float Process()
        {
            // Fixed boundary reservoirs
            double pLeft = 1.1 * Units.atm;
            double rhoLeft = 1.2;
            double uLeft = 0.0;

            double pRight = 1.0 * Units.atm;
            double rhoRight = 1.2;
            double uRight = 0.0;

            // Compute boundary fluxes via orifice model
            OrificeBoundary.PipeVolumeFlux(
                pipe.GetLeftPressure(), pipe.GetLeftDensity(), 0.0,
                pLeft, rhoLeft, uLeft,
                leftConn, pipe.Area, true,
                out double leftMassFlux, out double leftMomFlux, out double leftEnergyFlux);

            OrificeBoundary.PipeVolumeFlux(
                pipe.GetRightPressure(), pipe.GetRightDensity(), 0.0,
                pRight, rhoRight, uRight,
                rightConn, pipe.Area, false,
                out double rightMassFlux, out double rightMomFlux, out double rightEnergyFlux);

            pipe.SetLeftBoundaryFlux(leftMassFlux, leftMomFlux, leftEnergyFlux);
            pipe.SetRightBoundaryFlux(rightMassFlux, rightMomFlux, rightEnergyFlux);
            pipe.Simulate();

            time += dt;
            stepCount++;
            Log();
            return 0f;
        }

        public static void Log()
        {
            if (stepCount <= 20 || stepCount % 50 == 0)
            {
                Console.WriteLine($"Step {stepCount:D4}  t = {time * 1e3:F3} ms");
                for (int i = 0; i < pipe.GetCellCount(); i++)
                {
                    double rho = pipe.GetCellDensity(i);
                    double p = pipe.GetCellPressure(i);
                    double u = pipe.GetCellVelocity(i);
                    Console.WriteLine($"  Cell {i}: ρ={rho:F4} kg/m³  p={p / 1e5:F6} bar  u={u:F3} m/s");
                }
                double leftFlow = pipe.PortA.MassFlowRate;
                double rightFlow = pipe.PortB.MassFlowRate;
                Console.WriteLine($"  Left flow = {leftFlow * 1e3:F4} g/s   Right flow = {rightFlow * 1e3:F4} g/s");
                Console.WriteLine();
            }
        }
    }
}