using UnityEngine;


public class Boid : MonoBehaviour {
    public float speed = 0.2f;
    public int neighbourCount = 0;
    public float inertia = 0.2f;
    public float alignmentForce = 1.0f;
    public float cohesionForce = 1.0f;
    public float separationForce = 1.0f;
    public float separationDistance = 0.5f;
    public float bodyForce = 1;

    public SwarmControl sc;
    public Vector3 velocity = Vector3.zero;
    public Vector3 acceleration = Vector3.zero;

    private Bounds bounds;

    readonly Collider[] results = new Collider[10];

    public SensoryNeuroid[] neighbourSensor = new SensoryNeuroid[6];

    public NeuroidNetwork neuroidNet = new();
    public Neuroid bodyVector;
    public Neuroid cohesion;
    public Neuroid alignment;
    public Neuroid separation;
    public Neuroid target;
    public Neuroid boundary;

    public Neuroid totalForce;

    public int id;

    void Awake() {
        this.id = this.GetInstanceID();

        sc = FindFirstObjectByType<SwarmControl>();

        bounds = new(sc.transform.position, sc.spaceSize - 2 * sc.boundaryWidth);

        //neighbourSensor = new(neuroidNet) { name = "Neighbour", id = 879 };

        cohesion = new(neuroidNet) { name = "Cohesion", mode = Neuroid.Mode.Sum };
        //cohesion.GetInputFrom(neighbourSensor);
        alignment = new(neuroidNet) { name = "Alignment", mode = Neuroid.Mode.Average };
        separation = new(neuroidNet) { name = "Separation", mode = Neuroid.Mode.Sum };
        target = new(neuroidNet) { name = "Target", mode = Neuroid.Mode.Sum };
        boundary = new(neuroidNet) { name = "Boundary", mode = Neuroid.Mode.Sum };


        totalForce = new(neuroidNet) { name = "Total force", mode = Neuroid.Mode.Sum };
        totalForce.GetInputFrom(alignment, sc.alignmentForce);
        totalForce.GetInputFrom(cohesion, sc.cohesionForce);
        totalForce.GetInputFrom(separation, sc.separationForce);
        totalForce.GetInputFrom(target, sc.bodyForce);
        totalForce.GetInputFrom(boundary, sc.boundaryForce);
    }

    void Update() {
        Physics.OverlapSphereNonAlloc(this.transform.position, 10, results);
        neighbourCount = 0;

        cohesion.ResetWeights();
        alignment.ResetWeights();
        separation.ResetWeights();

        foreach (Collider c in results) {
            if (c == null)
                continue;

            if (c as CapsuleCollider != null) {
                Boid neighbour = c.GetComponentInParent<Boid>();
                if (neighbour == null || neighbour == this)
                    continue;

                Vector3 localPosition = neighbour.transform.position - this.transform.position;
                Vector3 relativeVelocity = neighbour.velocity - this.velocity;

                int id = neighbour.GetInstanceID();
                Receptor receptor = GetReceptor(id);
                if (receptor != null) {
                    receptor.SetValue(localPosition);
                }
                Vector3 separationForce = -localPosition / localPosition.sqrMagnitude;
                // which is equivalent to -(localPosition.normalized / localPosition.magnitude)

                separation.SetInput(id, separationForce, sc.separationDistance);
                //cohesion.SetInput(id, localPosition, sc.cohesionForce);
                alignment.SetInput(id, relativeVelocity, sc.alignmentForce);

                neighbourCount++;
            }
        }

        //Vector3 spaceLocalPosition = sc.transform.InverseTransformPoint(this.transform.position);
        if (!bounds.Contains(this.transform.position)) {
            Vector3 point = this.transform.position;
            // Vector3 distanceOutside = Vector3.Max(bounds.min - this.transform.position, this.transform.position - bounds.max);
            // // Ensure value is > 0 (but isn't this already)
            // Vector3 outside = distanceOutside; // Vector3.Max(Vector3.zero, distanceOutside);

            Vector3 below = bounds.min - point;    // positive where point < min
            Vector3 above = point - bounds.max;    // positive where point > max

            // outside distances per axis (0 if inside on that axis)
            Vector3 outside = Vector3.Max(Vector3.zero, Vector3.Max(below, above));
            float magnitude = outside.magnitude;
            Vector3 direction = (sc.transform.position - this.transform.position).normalized;
            outside = direction * magnitude;

            boundary.SetInput(id, outside, sc.boundaryForce);
            // Debug.Log($"boundary {this.transform.position} {outside} force = {outside * sc.boundaryForce}");
        }

        Vector3 totalForceVector = totalForce.outputValue;
        //Debug.DrawRay(this.transform.position, totalForceVector, Color.magenta);

        this.velocity = (1 - sc.inertia) * (totalForceVector * Time.deltaTime) + sc.inertia * velocity + (sc.speed * transform.forward);
        //this.velocity = Vector3.ClampMagnitude(this.velocity, sc.speed);

        this.transform.position += this.velocity * Time.deltaTime;

        if (this.velocity != Vector3.zero) {
            Quaternion targetRotation = Quaternion.LookRotation(this.velocity);
            transform.rotation = Quaternion.Slerp(transform.rotation, targetRotation, Time.deltaTime * 2f); // Adjust the speed of rotation        
        }
    }

    Receptor GetReceptor(int id) {
        int availableIx = -1;
        for (int i = 0; i < neighbourSensor.Length; i++) {
            if (neighbourSensor[i] == null)
                availableIx = i;
            else if (neighbourSensor[i].id == id)
                return neighbourSensor[i].receptor;
        }
        if (availableIx != -1) {
            Debug.Log($"new receptor for {id}");
            SensoryNeuroid neuroid = new(neuroidNet, id);
            cohesion.GetInputFrom(neuroid);
            neighbourSensor[availableIx] = neuroid;
            return neuroid.receptor;
        }
        return null;
    }

}