using Godot;
using System;

[Tool]
public class TrainCar : Spatial
{
    public float Length => Box.Depth;

    [Export]
    private NodePath _boxNode;

    [Export]
    private NodePath[] _bogiePaths;

    [Export]
    public float Wheelbase
    {
        get => _wheelbase;
        set
        {
            _wheelbase = value;

            // don't set the wheelbase except from the editor
            if (!Engine.EditorHint) return;

            SetBogeyPositions();
        }
    }
    private float _wheelbase;

    public Spatial[] Bogies
    {
        get
        {
            if (_bogies == null)
            {
                _bogies = new Spatial[2];
                for (int i = 0; i < _bogiePaths.Length; i++)
                {
                    _bogies[i] = GetNode<Spatial>(_bogiePaths[i]);
                }
            }
            return _bogies;
        }
    }
    private Spatial[] _bogies = null;

    private CSGBox _box;
    private CSGBox Box
    {
        get
        {
            if (_box == null)
            {
                _box = GetNode<CSGBox>(_boxNode);
            }
            return _box;
        }
    }

    public Railway Railway { get; set; }

    public override void _Ready()
    {

    }

    public override void _Process(float delta)
    {
    }

    private void SetBogeyPositions()
    {

        if (Wheelbase > Length)
            throw new Exception("wheelbase cannot be longer than car length");

        if (_bogiePaths.Length != 2)
            throw new Exception("_bogeyPaths should be of length 2");

        for (int i = 0; i < 2; i++)
        {
            _bogies[i] = GetNode<Spatial>(_bogiePaths[i]);
        }

        var axis = Vector3.Forward * Wheelbase;
        _bogies[0].Translation = axis * 0.5f;
        _bogies[1].Translation = axis * -0.5f;
    }
}