using System;
using System.Web;
using System.Configuration;
using System.Runtime.Serialization.Formatters.Binary;
using System.IO;
using System.Web.Script.Serialization;
using System.Xml.Linq;
using System.Text;
using System.Xml.Serialization;
using StackExchange.Redis;

namespace Neo.Afx.Common
{
    /// <summary>
    /// Cache provider for Azure Redis cache service
    /// </summary>
    public class CacheContextRedis : ICacheContext
    {
        private ConnectionMultiplexer _connection;
        private IDatabase _cache;
        
        readonly static JavaScriptSerializer Serializer = new JavaScriptSerializer()
        {
            MaxJsonLength = Int32.MaxValue,
            RecursionLimit = 100
        };

        /// <summary>
        /// Default constructor
        /// </summary>
        public CacheContextRedis()
        {
            if (_connection == null)
            {
                Connect();
            }                       
        }

        private void Connect()
        {
            _connection = ConnectionMultiplexer.Connect(ConfigurationManager.AppSettings["RedisConnection"].ToString());
            _cache = _connection.GetDatabase();
        }

        /// <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)
        {
            if (_connection == null || _connection.IsConnected == false)
            {
                Connect();
            }

            if (_cache == null)
            {
                return default(T);
            }
            else
            {
                if (_cache.KeyExists(key))
                {
                    var value = _cache.StringGet(key);

                    if (!value.HasValue)
                    {
                        return default(T);
                    }
                    else
                    {
                        return (T)SerializationUtilities.Deserialize<T>(value);
                    }
                }
                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)
        {
            if (_connection == null || _connection.IsConnected == false)
            {
                Connect();
            }

            if (_cache != null)
            {
                if (value != null)
                {
                    try
                    {
                        _cache.StringSet(key, SerializationUtilities.Serialize(value), TimeSpan.FromMinutes(cacheExpirationMinutes));
                    }
                    catch { }                    
                }
            }
        }

        /// <summary>
        /// Remove a cached value 
        /// </summary>
        /// <param name="key"></param>
        public void Remove(string key)
        {
            if (_connection == null || _connection.IsConnected == false)
            {
                Connect();
            }

            if (_cache != null)
            {
                _cache.KeyDelete(key);
            }
        }

        /// <summary>
        /// Clear the cache
        /// </summary>
        public void Clear()
        {
            if (_connection == null || _connection.IsConnected == false)
            {
                Connect();
            }

            var endPoints = _connection.GetEndPoints();

            if (endPoints.Length > 0)
            {
                var server = _connection.GetServer(endPoints[0]);

                if (server != null)
                {
                    try
                    {
                        server.FlushDatabase();
                        server.FlushAllDatabases();
                    }
                    catch { } //silent fall through
                }                
            }            
        }
    }
}