GameJamDungeon/Zennysoft.Game.Ma/src/enemy/behaviors/PatrolBehavior.cs

using Chickensoft.AutoInject;
using Chickensoft.Introspection;
using Godot;
using Godot.Collections;
using System.Linq;
using Zennysoft.Game.Abstractions.Entity;

namespace Zennysoft.Game.Ma;

[Meta(typeof(IAutoNode))]
public partial class PatrolBehavior : Node3D, IBehavior
{
  public override void _Notification(int what) => this.Notify(what);

  [Export] private double _patrolSpeed { get; set; } = 100f;

  [Export] private double _thinkTime { get; set; } = 0.8f;

  [Export] private float _patrolRange { get; set; } = 5f;

  [Export] private float _patrolTime { get; set; } = 10f;

  private Timer _patrolTimer { get; set; } = default!;
  private NavigationAgent3D _navigationAgent;

  private Vector3 _homePosition;

  public Vector3 HomePosition
  {
    get => _homePosition;
    set
    {
      _homePosition = value;
      _navigationAgent.TargetPosition = value;
    }
  }

  [Signal] public delegate void OnVelocityComputedEventHandler(Vector3 safeVelocity);

  public void OnReady()
  {
    _patrolTimer = new Timer() { WaitTime = _patrolTime };
    _patrolTimer.Timeout += PatrolTimer_Timeout;
    AddChild(_patrolTimer);
    SetPhysicsProcess(false);
  }

  public void Init(NavigationAgent3D navigationAgent)
  {
    _navigationAgent = navigationAgent;
    _navigationAgent.WaypointReached += NavigationAgent_WaypointReached;
  }

  private async void NavigationAgent_WaypointReached(Dictionary details)
  {
    await ToSignal(GetTree().CreateTimer(_thinkTime), "timeout");
  }

  public void StartPatrol()
  {
    SetPhysicsProcess(true);
    _patrolTimer?.Start();
  }

  public void StopPatrol()
  {
    SetPhysicsProcess(false);
    _patrolTimer?.Stop();
  }

  public void OnPhysicsProcess(double delta)
  {
    var nextVelocity = _navigationAgent.GetNextPathPosition();
    var parent = GetParent() as Node3D;
    var velocity = parent.GlobalPosition.DirectionTo(nextVelocity) * (float)_patrolSpeed * (float)delta;
    EmitSignal(SignalName.OnVelocityComputed, velocity);
  }

  public void SetPatrolTarget()
  {
    var rng = new RandomNumberGenerator();
    rng.Randomize();
    var randomPointX = rng.RandfRange(-_patrolRange, _patrolRange);
    var randomPointZ = rng.RandfRange(-_patrolRange, _patrolRange);
    var patrolPoint = HomePosition + new Vector3(randomPointX, 0, randomPointZ);
    var rid = NavigationServer3D.GetMaps().Single();
    _navigationAgent.TargetPosition = NavigationServer3D.MapGetClosestPoint(rid, patrolPoint);
  }

  private void PatrolTimer_Timeout() => SetPatrolTarget();

  public void OnExitTree()
  {
    _patrolTimer.Stop();
    _patrolTimer.Timeout -= PatrolTimer_Timeout;
    _navigationAgent.WaypointReached -= NavigationAgent_WaypointReached;
  }
}