using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Runtime.Caching;

namespace LJProxy
{
    public static class Cache
    {
        public static MemoryCache DefaultCache
        {
            get
            {
                return MemoryCache.Default;
            }
        }

        private static MemoryCache _fileCache = new MemoryCache("FileCache");
        public static MemoryCache FileCache
        {
            get
            {
                return _fileCache;
            }
        }

        public static CacheItemPolicy CreateCacheItemPolicy(TimeSpan? slidingExpiration = null, DateTime? absoluteExpiration = null
            , List<string> dependencyKeys = null, CacheItemPriority? priority = null)
        {
            var cachePolicy = new CacheItemPolicy();
            if (slidingExpiration != null)
                cachePolicy.SlidingExpiration = slidingExpiration.Value;
            if (absoluteExpiration != null)
                cachePolicy.AbsoluteExpiration = absoluteExpiration.Value;
            if (dependencyKeys !=null && dependencyKeys.Count>0 )
            {
                cachePolicy.ChangeMonitors.Add(new HostFileChangeMonitor(dependencyKeys));
            }

            if (priority != null)
                cachePolicy.Priority = priority.Value;
            else
                cachePolicy.Priority = CacheItemPriority.Default;
            return cachePolicy;
        }
    }
}