using System;
using System.Web;
using System.Web.Caching;

namespace Neo.Afx.Common
{
    /// <summary>
    /// Cache provider for HttpContext
    /// </summary>
    public class CacheContextWeb : ICacheContext
    {
        /// <summary>
        /// Get the cached value based on a specified key
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="key"></param>
        /// <returns></returns>
        public T Get<T>(string key)
        {                        
            var current = HttpContext.Current;

            if (current == null)
            {
                return default(T);
            }
            else
            {                
                var v = (byte[])current.Cache.Get(key);

                if (v != null)
                {
                    return (T)SerializationUtilities.Deserialize<T>(v);
                }
                else
                {
                    return default(T);
                }
            }                        
        }

        /// <summary>
        /// Set the cached value
        /// </summary>
        /// <param name="key"></param>
        /// <param name="value"></param>
        /// <param name="cacheExpirationMinutes"></param>
        public void Set(string key, object value, int cacheExpirationMinutes)
        {
            var current = HttpContext.Current;
            if (current != null)
            {
                current.Cache.Insert(key, SerializationUtilities.Serialize(value), null, DateTime.Now.AddMinutes(cacheExpirationMinutes), System.Web.Caching.Cache.NoSlidingExpiration);
            }
        }

        /// <summary>
        /// Remove a cached value 
        /// </summary>
        /// <param name="key"></param>
        public void Remove(string key)
        {
            var current = HttpContext.Current;
            if (current != null)
            {
                current.Cache.Remove(key);
            }
        }

        /// <summary>
        /// Clear the cache
        /// </summary>
        public void Clear()
        {
            var current = HttpContext.Current;
            if (current != null)
            {
                // Note: not thread safe
                var d = current.Cache.GetEnumerator();
                while (d.MoveNext())
                {
                    current.Cache.Remove(d.Key.ToString());
                }
            }
        }
    }
}