using UnityEngine;
using System.Collections.Generic;

namespace YKMoon
{
    /// <summary>
    /// ID生成器，可以生成一定个数的唯一ID，用来做循环可回收的ID用
    /// </summary>
    public class IDGenerator
    {
        const int DEFAULT_MAX = 10000;
        public IDGenerator(int max = DEFAULT_MAX)
        {
            idMax = max;
        }
        private HashSet<int> idList = new HashSet<int>();
        private int idIndex = 0;
        private int idMax = DEFAULT_MAX;
        /// <summary>
        /// 生成ID
        /// </summary>
        public int GetNextUIId()
        {
            if (idList.Count >= idMax) {
                Debug.LogError("IDGenerator:too many ID, it must be an error!!");
                return -1;
            }
            int whileCount = 0;
            do {
                idIndex = (idIndex + 1) % idMax;
                whileCount += 1;
                if (whileCount >= idMax) {
                    Debug.LogError("IDGenerator:too many ID, it must be an error!!");
                    return -1;
                }
            } while (idList.Contains(idIndex));
            idList.Add(idIndex);
            return idIndex;
        }
        /// <summary>
        /// 回收ID
        /// </summary>
        /// <param name="id"></param>
        public void RemoveId(int id)
        {
            if (idList.Contains(id)) {
                idList.Remove(id);
            }
        }

        public int GetCount()
        {
            return idList.Count;
        }

        public void Clear()
        {
            idIndex = 0;
            idList.Clear();
        }
    }
}