using FluidSim.Audio;
using FluidSim.Components;
using FluidSim.Interfaces;

namespace FluidSim.Core
{
    public class Solver
    {
        private readonly List<Volume0D> _volumes = new();
        private readonly List<Pipe1D> _pipes = new();
        private readonly List<Connection> _connections = new();

        public float LastSample { get; private set; }

        public void AddVolume(Volume0D v) => _volumes.Add(v);
        public void AddPipe(Pipe1D p) => _pipes.Add(p);
        public void AddConnection(Connection c) => _connections.Add(c);

        public void Step()
        {
            // 1. Publish volume states to their own ports
            foreach (var v in _volumes)
                v.PushStateToPort();

            // 2. Handle direct volume‑to‑volume connections
            foreach (var conn in _connections)
            {
                if (IsVolumePort(conn.PortA) && IsVolumePort(conn.PortB))
                {
                    Volume0D volA = _volumes.Find(v => v.Port == conn.PortA);
                    Volume0D volB = _volumes.Find(v => v.Port == conn.PortB);

                    if (volA == null || volB == null) continue;

                    double pA = volA.Pressure, rhoA = volA.Density;
                    double pB = volB.Pressure, rhoB = volB.Density;

                    double mdot = OrificeBoundary.MassFlow(pA, rhoA, pB, rhoB, conn);

                    if (mdot > 0) // A → B
                    {
                        volA.Port.MassFlowRate = -mdot;
                        volB.Port.MassFlowRate = mdot;
                        volB.Port.SpecificEnthalpy = volA.SpecificEnthalpy; // fluid from A
                        volA.Port.SpecificEnthalpy = volA.SpecificEnthalpy; // outflow carries its own enthalpy
                    }
                    else // B → A (mdot negative)
                    {
                        volA.Port.MassFlowRate = -mdot;  // positive
                        volB.Port.MassFlowRate = mdot;  // negative
                        volA.Port.SpecificEnthalpy = volB.SpecificEnthalpy; // fluid from B
                        volB.Port.SpecificEnthalpy = volB.SpecificEnthalpy; // outflow carries its own
                    }
                }
            }

            // 3. Pipe‑volume boundary conditions – unchanged
            foreach (var conn in _connections)
            {
                if (IsPipePort(conn.PortA) && IsVolumePort(conn.PortB))
                    SetVolumeBC(conn.PortA, conn.PortB);
                else if (IsVolumePort(conn.PortA) && IsPipePort(conn.PortB))
                    SetVolumeBC(conn.PortB, conn.PortA);
            }

            // 4. Run pipe simulations
            foreach (var p in _pipes)
                p.Simulate();

            // 5. Transfer pipe‑to‑volume flows – unchanged
            foreach (var conn in _connections)
            {
                if (IsPipePort(conn.PortA) && IsVolumePort(conn.PortB))
                    TransferPipeToVolume(conn.PortA, conn.PortB);
                else if (IsVolumePort(conn.PortA) && IsPipePort(conn.PortB))
                    TransferPipeToVolume(conn.PortB, conn.PortA);
            }

            // 6. Integrate volumes
            foreach (var v in _volumes)
                v.Integrate();

            // 7. COMPUTE AUDIO SAMPLE from all sound connections
            double sample = 0f;
            foreach (var conn in _connections)
            {
                if (conn is SoundConnection)
                {
                    // Both ports have the same absolute mass flow; either works.
                    sample += SoundProcessor.ComputeSample(conn);
                }
            }
            LastSample = (float)Math.Tanh(sample);
        }

        bool IsVolumePort(Port p) => _volumes.Exists(v => v.Port == p);
        bool IsPipePort(Port p) => _pipes.Exists(pp => pp.PortA == p || pp.PortB == p);
        Pipe1D GetPipe(Port p) => _pipes.Find(pp => pp.PortA == p || pp.PortB == p);

        void SetVolumeBC(Port pipePort, Port volPort)
        {
            Pipe1D pipe = GetPipe(pipePort);
            if (pipe == null) return;
            bool isLeft = pipe.PortA == pipePort;

            if (isLeft)
                pipe.SetLeftVolumeState(volPort.Density, volPort.Pressure);
            else
                pipe.SetRightVolumeState(volPort.Density, volPort.Pressure);
        }

        void TransferPipeToVolume(Port pipePort, Port volPort)
        {
            double mdot = pipePort.MassFlowRate;
            volPort.MassFlowRate = -mdot;

            if (mdot < 0)  // pipe → volume
            {
                // pipePort.SpecificEnthalpy is already total (h + ½u²)
                volPort.SpecificEnthalpy = pipePort.SpecificEnthalpy;
            }
            // else: volume → pipe, volume’s own static enthalpy is used (already set)
        }
    }
}