using System;
using System.Collections.Generic;
using System.Runtime.Caching;

namespace IStation
{
    /// <summary>
    /// 内存缓存辅助类
    /// </summary>
    public class MemoryCacheHelper
    {
        //缓存对象
        private static SharedMemoryCache MemoryCache
        {
            get
            {
                return SharedMemoryCache.Instance;
            }
        }

        /// <summary>
        /// 设置缓存
        /// </summary>
        /// <param name="key"></param>
        /// <param name="obj"></param>
        /// <param name="second">多少秒后移除缓存项</param>
        public static void Set(string key, object obj, int second = 300)
        {
            var policy = new CacheItemPolicy();
            policy.AbsoluteExpiration = new DateTimeOffset(DateTime.Now.AddSeconds(second));
            MemoryCache.Set(key, obj, policy);
        }

        /// <summary>
        /// 获取缓存
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="key"></param>
        /// <returns></returns>
        public static T Get<T>(string key)
        {
            return MemoryCache.Get<T>(key);
        }

        /// <summary>
        /// 获取和设置
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="key"></param>
        /// <param name="func"></param>
        /// <returns></returns>
        public static T GetSet<T>(string key, Func<T> func, int second = 300)
        {
            var policy = new CacheItemPolicy();
            policy.AbsoluteExpiration = new DateTimeOffset(DateTime.Now.AddSeconds(second));
            return MemoryCache.GetSet<T>(key, func, policy);
        }

        /// <summary>
        /// 移除缓存
        /// </summary>
        /// <param name="key"></param>
        public static void Remove(string key)
        {
            MemoryCache.Remove(key);
        }

        /// <summary>
        /// 移除符合条件的缓存
        /// </summary>
        /// <param name="keyFunction"></param>
        public static void Remove(Func<string, bool> keyFunction)
        {
            MemoryCache.Remove(keyFunction);
        }
        /// <summary>
        /// 移除符合条件的缓存
        /// </summary>
        /// <param name="keyFunction"></param>
        public static int Remove(IEnumerable<string> keys)
        {
            return MemoryCache.Remove(keys);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="key"></param>
        /// <returns></returns>
        public static int Remove_StartWith(string key)
        {
            return MemoryCache.Remove_StartWith(key);
        }
    }
}