using Godot;
using System.Diagnostics.CodeAnalysis;

public partial class CryingGhost : CharacterBase
{
    private AnimatedSprite2D _animatedSprite = default!;
    private NavigationAgent2D _navigationAgent = default!;
    private Area2D _detectionArea = default!;
    private Timer _targetTimer = default!;

    protected Node2D? Target { get; private set; }
    [MemberNotNullWhen(true, nameof(Target))]
    protected bool HasTarget => Target is not null;

    public override void _Ready()
    {
        _animatedSprite = GetNode<AnimatedSprite2D>("AnimatedSprite2D");
        _navigationAgent = GetNode<NavigationAgent2D>("NavigationAgent2D");
        _detectionArea = GetNode<Area2D>("DetectionArea");
        _targetTimer = GetNode<Timer>("TargetTimer");

        _animatedSprite?.Play("idle");
        _detectionArea.BodyEntered += OnBodyEntered;
        _detectionArea.BodyExited += OnBodyExited;
        _targetTimer.Timeout += OnTimeout;
        _navigationAgent.VelocityComputed += OnVelocityComputed;
    }

    public override void _PhysicsProcess(double delta)
    {
        if (!HasTarget)
        {
            Velocity = Vector2.Zero;
        }
        else
        {
            var nextPosition = _navigationAgent.GetNextPathPosition();
            var direction = (nextPosition - GlobalPosition).Normalized();

            _navigationAgent.Velocity = direction * Speed;
        }

        MoveAndSlide();
    }

    void OnBodyEntered(Node2D body)
    {
        if (body.IsInGroup("Player"))
        {
            Target = body;
            _navigationAgent.TargetPosition = Target.GlobalPosition;
            _targetTimer.Start();
        }
    }

    void OnBodyExited(Node2D body)
    {
        if (body == Target)
        {
            Target = null;
            _navigationAgent.TargetPosition = GlobalPosition;
            _targetTimer.Stop();
        }
    }

    void OnTimeout()
    {
        if (HasTarget)
        {
            _navigationAgent.TargetPosition = Target.GlobalPosition;
        }
    }

    void OnVelocityComputed(Vector2 safeVelocity)
    {
        Velocity = safeVelocity;
    }
}