using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Slicer2DAnchor : MonoBehaviour {
    public enum AnchorType {AttachRigidbody, CancelSlice};
    public Collider2D[] anchorColliders = new Collider2D[1];
    public AnchorType anchorType = AnchorType.AttachRigidbody;

    private List<Polygon> polygons = new List<Polygon>();
    private List<Collider2D> colliders = new List<Collider2D>();

    void Start () {
        bool addEvents = false;

        foreach(Collider2D collider in anchorColliders) {
            addEvents = true;
        }

        if (addEvents == false) {
            return;
        }

        Slicer2D slicer = GetComponent<Slicer2D> ();
        if (slicer != null) {
            slicer.AddResultEvent (OnSliceResult);
            slicer.AddEvent (OnSlice);
        }

        foreach(Collider2D collider in anchorColliders) {
            polygons.Add(Polygon.CreateFromCollider (collider.gameObject));
            colliders.Add(collider);
        }
    }

    Polygon GetPolygonInWorldSpace(Polygon poly) {
        return(poly.ToWorldSpace(colliders[polygons.IndexOf(poly)].transform));
    }

    bool OnSlice(Slice2D sliceResult)
    {
        switch (anchorType) {
            case AnchorType.CancelSlice:
                foreach (Polygon polyA in new List<Polygon>(sliceResult.polygons)) {
                    bool perform = true;
                    foreach(Polygon polyB in polygons) {
                        if (MathHelper.PolyCollidePoly (polyA.pointsList, GetPolygonInWorldSpace(polyB).pointsList) ) {
                            perform = false;
                        }
                    }
                    if (perform) {
                        return(false);
                    }
                }
                break;

            default:
                break;
        }
        return(true);
    }

    void OnSliceResult(Slice2D sliceResult)
    {
        if (polygons.Count < 1)
            return;

        foreach (GameObject p in sliceResult.gameObjects) {
            Polygon polyA = Polygon.CreateFromCollider (p).ToWorldSpace (p.transform);
            bool perform = true;

            foreach(Polygon polyB in polygons) {
                if (MathHelper.PolyCollidePoly (polyA.pointsList, GetPolygonInWorldSpace(polyB).pointsList)) {
                    perform = false;
                }
            }

            if (perform) {
                switch (anchorType) {
                    case AnchorType.AttachRigidbody:
                        if (p.GetComponent<Rigidbody2D> () == null) {
                            p.AddComponent<Rigidbody2D> ();
                        }

                        p.GetComponent<Rigidbody2D> ().isKinematic = false;
                        break;
                    default:
                        break;
                }
            }
        }
    }
}