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

namespace BF
{
    [ExecuteInEditMode]
    [RequireComponent(typeof(RectTransform))]
    public class BFCircleLayout : MonoBehaviour
    {
        public float radius = 100;
        [Range(0, 360)]
        public float startAngle = 0;
        [Range(0, 360)]
        public float angle = 30;

        public int ActiveCount
        {
            get
            {
                var result = 0;
                for (var i = 0; i < rectTransform.childCount; i++)
                {
                    var t = rectTransform.GetChild(i);
                    if (t != null && t.gameObject.activeInHierarchy)
                    {
                        result++;
                    }
                }
                return result;
            }
        }

        RectTransform rectTransform;
        List<RectTransform> children = new List<RectTransform>(4);

        void Start()
        {
            rectTransform = GetComponent<RectTransform>();
            Relayout();
        }

        void OnValidate()
        {
            Relayout();
        }

        public void Relayout()
        {
#if UNITY_EDITOR
            if (rectTransform == null)
            {
                return;
            }
#endif

            children.Clear();
            for (var i = 0; i < rectTransform.childCount; i++)
            {
                var rect = (RectTransform)rectTransform.GetChild(i);
                if (rect != null && rect.gameObject.activeInHierarchy)
                {
                    children.Add(rect);
                }
            }

            var length = children.Count;
            for (int i = 0; i < length; i++)
            {
                var t = children[i];
                t.anchoredPosition = GetPosByIndex(i);
            }
        }

        public Vector2 GetPosByIndex(int index)
        {
            var a = Mathf.Deg2Rad * (index * angle + startAngle);
            var pos = new Vector2(radius * Mathf.Cos(a), Mathf.Sin(a) * radius);
            return pos;
        }
    }
}