using Godot;
using System;

public partial class PhysicsManager : Node2D
{
    private const double TARGET_DT = 1.0 / 2000.0;
    private const double VALUE_SENSITIVITY = 5;

    private double _accumulator = 0.0;
    private double _simulationTime = 0.0;

    private double _rpmSmooth = 0, _powerSmooth = 0, _throttleSmooth = 0;

    private Label _rpmLabel, _powerLabel, _throttleLabel;

    private Engine _engine;

    [Export] public ProceduralEngine EngineAudio;

    public override void _Ready()
    {
        _rpmLabel = GetNode<Label>("UI/EngineRPM");
        _powerLabel = GetNode<Label>("UI/EnginePower");
        _throttleLabel = GetNode<Label>("UI/EngineThrottle");

        _engine = new Engine(inertia: 0.2, cylinders: 1, displacementCC: 1998, compressionRatio: 10.5);
        _engine.MomentOfInertia = 0.4;

        // --- Audio initialization ---
        if (EngineAudio != null)
        {
            EngineAudio.CylinderCount = _engine.CylinderCount;
            EngineAudio.EngineLayout = "v";
            EngineAudio.IsCrossplane = true;
            EngineAudio.BaseEngineVolume = 0.35f;
            EngineAudio.IntakeRoarAmount = 0.28f;
            EngineAudio.IntakeHissAmount = 0.12f;
            EngineAudio.ExhaustRumbleAmount = 0.32f;
            EngineAudio.ExhaustCrackleAmount = 0.08f;

            EngineAudio.ResetAudioState();

            EngineAudio.CurrentRPM = 750f;
            EngineAudio.CurrentThrottle = 0f;
            EngineAudio.CurrentCombustionPower = 0f;

            if (!EngineAudio.Playing)
                EngineAudio.Play();

            EngineAudio.PrewarmBuffer();
        }
    }

    public override void _Process(double dt)
    {
        bool wPressed = Input.IsKeyPressed(Key.W);

        double throttle = wPressed ? 1.0f : 0.0f;
        _engine.Ecu.Throttle = throttle;

        double safeDelta = Math.Min(dt, 0.025);
        _accumulator += safeDelta;
        while (_accumulator >= TARGET_DT)
        {
            SimulateStep(TARGET_DT);
            _simulationTime += TARGET_DT;
            _accumulator -= TARGET_DT;
        }

        _rpmSmooth = Util.Lerp(_rpmSmooth, _engine.RPM, VALUE_SENSITIVITY * dt);
        _powerSmooth = Util.Lerp(_powerSmooth, _engine.CurrentPower/1000, VALUE_SENSITIVITY * dt);
        _throttleSmooth = Util.Lerp(_throttleSmooth, _engine.ThrottlePosition * 100, VALUE_SENSITIVITY * dt);

        _rpmLabel.Text = $"RPM: {_rpmSmooth:F0}";
        _powerLabel.Text = $"Power: {_powerSmooth:F2} Kw";
        _throttleLabel.Text = $"Throttle: {_throttleSmooth:F1} %";
    }

    public override void _Draw()
    {
        base._Draw();
    }

    private void SimulateStep(double dt)
    {
        _engine.Update(dt); // Engine uses _engine.Throttle inside its Update

        if (EngineAudio != null)
        {
            EngineAudio.CurrentRPM = (float)_engine.RPM;
            EngineAudio.CurrentThrottle = (float)_engine.ThrottlePosition;
            EngineAudio.CurrentCombustionPower = (float)_engine.CombustionPower;
        }
    }
}