/// <summary>
    /// 功能描述    ：衛星雲圖下載管理器  
    /// 創 建 者    ：Administrator
    /// 建立日期    ：2018/9/25 14:29:03 
    /// 最後修改者  ：Administrator
    /// 最後修改日期：2018/9/25 14:29:03 
    /// </summary>
    public class CloudImageManager
    {
        private string _ImagePath = System.Configuration.ConfigurationManager.AppSettings["Path"];
        private Timer _Timer = null;
        private double Interval = double.Parse(System.Configuration.ConfigurationManager.AppSettings["Minutes"]);
        public CloudImageManager()
        {
            _Timer = new Timer();
            _Timer.Interval = Interval * 60 * 1000;
            _Timer.Elapsed += _Timer_Elapsed;
        }
        void _Timer_Elapsed(object sender, ElapsedEventArgs e)
        {
            StartLoad();
        }
        /// <summary>
        /// 開始下載雲圖
        /// </summary>
        private void StartLoad()
        {
            LoadCloudImage();
        }
        public void Start()
        {
            StartLoad();
            _Timer.Start();
        }
        public void Stop()
        {
            _Timer.Stop();
        }
        /// <summary>
        /// 下載當天所有衛星雲圖
        /// </summary>
        private void LoadCloudImage()
        {
            CreateFilePath();//判斷資料夾是否存在，不存在則建立
            //獲取前一天日期
            string lastYear = DateTime.Now.AddDays(-1).Year.ToString();
            string lastMonth = DateTime.Now.AddDays(-1).Month.ToString();
            if (lastMonth.Length < 2) lastMonth = "0" + lastMonth;
            string lastDay = DateTime.Now.AddDays(-1).Day.ToString();
            if (lastDay.Length < 2) lastDay = "0" + lastDay;
            //獲取當天日期
            string year = DateTime.Now.Year.ToString();
            string month = DateTime.Now.Month.ToString();
            if (month.Length < 2) month = "0" + month;
            string day = DateTime.Now.Day.ToString();
            if (day.Length < 2) day = "0" + day;
            //設定所有檔名
            string[] dates0 = { lastYear + "/" + lastMonth + "/" + lastDay, year + "/" + month + "/" + day };
            string[] dates = { lastYear + lastMonth + lastDay, year + month + day };
            string[] hours = { "00", "01", "02", "03", "04", "05", "06", "07", "08", "09", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23" };
            string[] minutes = { "15", "45" };
            int hLength = hours.Count();
            //遍歷下載當天所有線上雲圖
            for (int i = 0; i < 2; i++)
            {
                string date = dates[i];
                string date0 = dates0[i];
                for (int j = 0; j < hLength; j++)
                {
                    string hour = hours[j];
                    for (int k = 0; k < 2; k++)
                    {
                        string minute = minutes[k];
                        string imageUrl = @"http://image.nmc.cn/product/" + date0 + @"/WXCL/SEVP_NSMC_WXCL_ASC_E99_ACHN_LNO_PY_" + date + hour + minute + "00000.JPG";
                        string[] s = imageUrl.Split('/');
                        string imageName = s[s.Count() - 1];

                        HttpWebRequest request = HttpWebRequest.Create(imageUrl) as HttpWebRequest;
                        HttpWebResponse response = null;
                        try
                        {
                            response = request.GetResponse() as HttpWebResponse;
                        }
                        catch (Exception)
                        {
                            continue;
                        }

                        if (response.StatusCode != HttpStatusCode.OK) continue;
                        Stream reader = response.GetResponseStream();
                        FileStream writer = new FileStream(_ImagePath + imageName, FileMode.OpenOrCreate, FileAccess.Write);
                        byte[] buff = new byte[512];
                        int c = 0; //實際讀取的位元組數
                        while ((c = reader.Read(buff, 0, buff.Length)) > 0)
                        {
                            writer.Write(buff, 0, c);
                        }
                        writer.Close();
                        writer.Dispose();
                        reader.Close();
                        reader.Dispose();
                        response.Close();
                    }
                }
            }
        }
        /// <summary>
        /// 判斷資料夾是否存在，不存在則建立
        /// </summary>
        private void CreateFilePath()
        {
            if (Directory.Exists(_ImagePath))
            {
                ClearImages();
                return;
            }
            else
            {
                Directory.CreateDirectory(_ImagePath);
            }
        }
        /// <summary>
        /// 清空資料夾下所有檔案
        /// </summary>
        private void ClearImages()
        {
            try
            {
                DirectoryInfo dir = new DirectoryInfo(_ImagePath);
                FileSystemInfo[] fileinfo = dir.GetFileSystemInfos();  //返回目錄中所有檔案和子目錄
                foreach (FileSystemInfo i in fileinfo)
                {
                    if (i is DirectoryInfo)            //判斷是否資料夾
                    {
                        DirectoryInfo subdir = new DirectoryInfo(i.FullName);
                        subdir.Delete(true);          //刪除子目錄和檔案
                    }
                    else
                    {
                        File.Delete(i.FullName);      //刪除指定檔案
                    }
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }
    }