starfighter/MB_FYP/script/ai_fighter.cs

using Godot;
using System;


public partial class ai_fighter : ship
{
    [Export]
    public float AggroRange = 500f;
    [Export]
    public float FireCooldown = 2f;
    [Export]
    public int ScorePayout = 50;
    [Export]
    public float EngageDistance = 300f;

    //retreat logic
    private float previousDistance = 0f;
    private float stuckTime = 0f;
    private const float stuckThreshold = 0.5f; // how many seconds to count as “stuck”
    private const float distanceTolerance = 5f; // how little the distance must change


    private Node2D currentTarget;
    private float fireTimer = 0f;

    public override void _Ready()
    {
        SetShipStats();
        SetupVisual();
        Sprite.Texture = GD.Load<Texture2D>(spritePath);

        LaserSpawn = GetNode<Node2D>("LaserSpawn");
    }

    public override void _PhysicsProcess(double delta)
    {
        UpdateMovement(delta);
        GD.Print(Name, ": MainSpeed = ", MainSpeed, "  Velocity = ", Velocity.Length());
    }

    // SETUP

    private void SetupAI()
    {

    }

    // COMBAT
    private void FireWeapons()
    {
        

    }

    // TARGETING
    private Node2D FindClosestTarget()
    {
        Node2D closest = null;
        float closestDistance = Mathf.Inf;

        Node shipParent = null;
        if (faction == ShipFaction.FRIENDLY)
        {
            shipParent = GetTree().Root.GetNode("Game/Ships/Enemy");
        }
        else if (faction == ShipFaction.ENEMY || faction == ShipFaction.ACE)
        {
            shipParent = GetTree().Root.GetNode("Game/Ships/Friendly");
        }
        if (shipParent == null)
        {
            GD.Print("No shipParent found");
            return null;
        }

        foreach (Node node in shipParent.GetChildren())
        {
            if (node is ship target &&  target.Health > 0)
            {
                float dist = GlobalPosition.DistanceTo(target.GlobalPosition);
                if (dist < closestDistance)
                {
                    closest = target;
                    closestDistance = dist;
                }
            }
        }

        return closest;
    }

    private bool EnsureTarget()
    {
        if (currentTarget == null || !IsInstanceValid(currentTarget))
        {
            currentTarget = FindClosestTarget();
            return false;
        }
        return true;
    }

    private void UpdateDistanceTracking(float distance)
    {
        if (MathF.Abs(distance - previousDistance) < distanceTolerance)
        {
            stuckTime += (float)GetProcessDeltaTime();
        }
        else
        {
            stuckTime = 0f;
        }
        previousDistance = distance;
    }

    private void HandleThrust(Vector2 direction, float angleDiff, float distance)
    {
        float retreatThreshold = EngageDistance * 0.75f;

        if (Mathf.Abs(angleDiff) < 1f && Velocity.Length() < MaxSpeed - MainSpeed)
        {
            if (distance > EngageDistance)
            {
                Velocity += -Transform.Y * MainSpeed;
            }
            else if (distance < retreatThreshold)
            {
                if (stuckTime > stuckThreshold)
                {
                    Vector2 away = (GlobalPosition - currentTarget.GlobalPosition).Normalized();
                    Velocity += away * MainSpeed;
                }
                else
                {
                    Velocity += Transform.X * StrafeSpeed;
                }
            }
        }
    }

    private void RotateToTarget(Vector2 direction, double delta)
    {
        float targetAngle = direction.Angle() + Mathf.Pi / 2;
        float angleDiff = Mathf.AngleDifference(Rotation, targetAngle);
        Rotation += Mathf.Clamp(angleDiff, -RotationSpeed * (float)delta, RotationSpeed * (float)delta);
    }

    
    private void UpdateMovement(double delta)
    {
        if (!EnsureTarget())
        {
            return;
        }

        Vector2 direction = (currentTarget.GlobalPosition - GlobalPosition).Normalized();
        float angleToTarget = direction.Angle() + MathF.PI / 2;
        float angleDiff = Mathf.AngleDifference(Rotation, angleToTarget);
        float distance = GlobalPosition.DistanceTo(currentTarget.GlobalPosition);

        UpdateDistanceTracking(distance);
        HandleThrust(direction, angleDiff, distance);
        RotateToTarget(direction, delta);

        Velocity = Velocity.MoveToward(Vector2.Zero, 2.5f); //2.5f FA value (on for AI)
        Velocity = Velocity.LimitLength(MaxSpeed);
        
        MoveAndSlide();
    }
    
    /*private void UpdateMovement(double delta)
    {
        if (currentTarget == null || !IsInstanceValid(currentTarget))
        {
            currentTarget = FindClosestTarget();
            return;
        }

        Vector2 direction = (currentTarget.GlobalPosition - GlobalPosition).Normalized();
        float distance = GlobalPosition.DistanceTo(currentTarget.GlobalPosition);
        float retreatThreshold = EngageDistance * 0.75f;
        //Velocity += direction * MainSpeed;
        float angleToTarget = direction.Angle() + Mathf.Pi / 2;
        float angleDiff = Mathf.AngleDifference(Rotation, angleToTarget);




        float currentDistance = GlobalPosition.DistanceTo(currentTarget.GlobalPosition);

        if (Mathf.Abs(currentDistance - previousDistance) < distanceTolerance)
            stuckTime += (float)delta;
        else
            stuckTime = 0f;

        previousDistance = currentDistance;
        
        
        //GD.Print("angleDiff: ", Mathf.RadToDeg(angleDiff));
        //GD.Print("rotation: ", Mathf.RadToDeg(Rotation), "  target: ", Mathf.RadToDeg(angleToTarget));



        if (Mathf.Abs(angleDiff) < 1f && Velocity.Length() < MaxSpeed - MainSpeed)
        {
            if (distance > EngageDistance)
            {
                Velocity += -Transform.Y * MainSpeed;
            }
            else if (distance < retreatThreshold)
            {
                if (stuckTime > stuckThreshold){
                    Velocity += Transform.Y * MainSpeed;
                }
                else
                {
                    Velocity += Transform.X * StrafeSpeed;
                }
                
                //Velocity += Transform.Y * MainSpeed;
                //Velocity += Transform.X * StrafeSpeed;
            }

        }

        Velocity = Velocity.MoveToward(Vector2.Zero, 2.5f);


        //GD.Print(MainSpeed);
        //GD.Print(Velocity);
        //Rotation = direction.Angle() + Mathf.Pi / 2; // Keeps ship pointing right way

        angleDiff = Mathf.AngleDifference(Rotation, direction.Angle() + Mathf.Pi / 2);
        Rotation += Mathf.Clamp(angleDiff, -RotationSpeed * (float)delta, RotationSpeed * (float)delta);

        Velocity.LimitLength(MaxSpeed);

        MoveAndSlide();
    }*/


}