using System;
using System.Threading.Tasks;
using UnityEngine;

namespace AibisDream.Utility
{
    public static class CommonUtil
    {
        private const float Epsilon = 1e-5f;

        private static Camera _mainCam;

        /// <summary>
        /// 判断为0
        /// </summary>
        /// <param name="value">浮点数</param>
        /// <returns>是否为0</returns>
        public static bool IsZero(float value)
        {
            // 如果value小于epsilon，则认为它等于0
            return Mathf.Abs(value) < Epsilon;
        }

        /// <summary>
        /// 判断浮点数是否相等
        /// </summary>
        /// <param name="value1">value1</param>
        /// <param name="value2">value2</param>
        /// <returns>是否相等</returns>
        public static bool IsEqual(float value1, float value2)
        {
            return Mathf.Abs(value1 - value2) < Epsilon;
        }

        /// <summary>
        /// 简单延时实现
        /// </summary>
        /// <param name="delayTime">延时</param>
        /// <param name="action">函数</param>
        public static async Task Delay(int delayTime, Action action)
        {
            await Task.Delay(delayTime);
            action?.Invoke();
        }

        /// <summary>
        /// 受限数值
        /// </summary>
        /// <param name="target">目标数</param>
        /// <param name="max">上限</param>
        /// <param name="min">下限</param>
        /// <returns>结果</returns>
        public static float Limit(float target, float max, float min)
        {
            if (target <= min)
            {
                return min;
            }

            if (target >= max)
            {
                return max;
            }

            return target;
        }

        /// <summary>
        /// 获取鼠标在世界中的位置
        /// </summary>
        /// <param name="mousePoint">鼠标界面位置</param>
        /// <param name="transform">物体形状</param>
        /// <returns>世界位置</returns>
        public static Vector3 GetMouseWorldPos(Vector3 mousePoint, Transform transform)
        {
            if (!_mainCam) _mainCam = Camera.main;
            
            mousePoint.z = _mainCam.WorldToScreenPoint(transform.position).z;
            return _mainCam.ScreenToWorldPoint(mousePoint);
        }
    }
}