using System;
using System.Collections.Generic;
using System.IO;
//using System.Linq;
using System.Web;
 
// <summary>
// IP訪問頻率控制
// </summary> 
public static class IPCacheManager
{
 
  /// <summary>
  /// IP快取集合 
  /// </summary> 
  private static List<IPCacheInfo> dataList = new List<IPCacheInfo>();
  private static object lockObj = new object();
 
  /// <summary> 
  /// 一段時間內，最大請求次數,必須大於等於1 
  /// </summary> 
  private static int maxTimes = 3;
 
  /// <summary> 
  /// 一段時間長度（單位秒)，必須大於等於1 
  /// </summary> 
  private static int partSecond = 30;
 
  /// <summary> 
  /// 請求被拒絕是否加入請求次數 
  /// </summary> 
  private static bool isFailAddIn = false;
 
  static IPCacheManager()
  {
  }
 
  /// <summary> 
  /// 設定時間，預設maxTimes=3, partSecond=30 
  /// </summary> 
  /// <param name="_maxTimes">最大請求次數</param> 
  /// <param name="_partSecond">請求單位時間</param> 
  public static void SetTime(int _maxTimes, int _partSecond)
  {
    maxTimes = _maxTimes;
    partSecond = _partSecond;
  }
 
  /// <summary> 
  /// 檢測一段時間內，IP的請求次數是否可以繼續請求 
  /// 和使用 
  /// </summary> 
  /// <param name="ip"></param> 
  /// <returns></returns> 
  public static bool CheckIsAble(string ip)
  {
    lock (lockObj)
    {
      var item = dataList.Find(p => p.IP == ip);
      if (item == null)
      {
        item = new IPCacheInfo();
        item.IP = ip;
        item.ReqTime.Add(DateTime.Now);
        dataList.Add(item);
 
        return true;
      }
      else
      {
        if (item.ReqTime.Count > maxTimes)
        {
          item.ReqTime.RemoveAt(0);
        }
 
        var nowTime = DateTime.Now;
        if (isFailAddIn)
        {
          #region 請求被拒絕也需要加入當次請求
          item.ReqTime.Add(nowTime);
          if (item.ReqTime.Count >= maxTimes)
          {
            if (item.ReqTime[0].AddSeconds(partSecond) > nowTime)
            {
              return false;
            }
            else
            {
              return true;
            }
          }
          else
          {
            return true;
          }
          #endregion
        }
        else
        {
          #region 請求被拒絕就不需要加入當次請求了
          if (item.ReqTime.Count >= maxTimes)
          {
            if (item.ReqTime[0].AddSeconds(partSecond) > nowTime)
            {
              return false;
            }
            else
            {
              item.ReqTime.Add(nowTime);
              return true;
            }
          }
          else
          {
            item.ReqTime.Add(nowTime);
            return true;
          }
          #endregion
        }
      }
    }
  }
}
 
public class IPCacheInfo
{
  public string IP { get; set; }
 
  private List<DateTime> reqTime = new List<DateTime>();
  public List<DateTime> ReqTime
  {
    get { return this.reqTime; }
    set { this.reqTime = value; }
  }
}