/*
 * 由SharpDevelop创建。
 * 用户： Acer
 * 日期: 6月10 星期二
 * 时间: 9:58
 * 
 */
using System.IO;
using System.Net;
using System.Text;

namespace DataEditorX.Common
{
	/// <summary>
	/// 检查更新
	/// </summary>
	public static class CheckUpdate
	{
		static CheckUpdate()
		{
			//连接数
			ServicePointManager.DefaultConnectionLimit = 255;
		}
		/// <summary>
		/// 下载URL
		/// </summary>
		public static string URL = "";
		/// <summary>
		/// 从HEAD获取版本号
		/// </summary>
		const string HEAD = "[DataEditorX]";
		const string HEAD2 = "[URL]";
		public const string DEFALUT = "0.0.0.0";

		#region 检查版本
		/// <summary>
		/// 获取新版本
		/// </summary>
		/// <param name="VERURL">链接</param>
		/// <returns>版本号</returns>
		public static string GetNewVersion(string VERURL)
		{
			string urlver = DEFALUT;
			string html = GetHtmlContentByUrl(VERURL);
			if (!string.IsNullOrEmpty(html))
			{
				int t, w;
				t = html.IndexOf(HEAD);
				w = (t > 0) ? html.IndexOf(HEAD, t + HEAD.Length) : 0;
				if (w > 0)
				{
					//获取版本
					urlver = html.Substring(t + HEAD.Length, w - t - HEAD.Length);
				}
				t = html.IndexOf(HEAD2);
				w = (t > 0) ? html.IndexOf(HEAD2, t + HEAD2.Length) : 0;
				if (w > 0)
				{
					//获取下载地址
					URL = html.Substring(t + HEAD2.Length, w - t - HEAD2.Length);
				}
			}
			return urlver;
		}
		/// <summary>
		/// 检查版本号，格式0.0.0.0
		/// </summary>
		/// <param name="ver">0.0.0.0</param>
		/// <param name="oldver">0.0.0.0</param>
		/// <returns>是否有新版本</returns>
		public static bool CheckVersion(string ver, string oldver)
		{
			bool hasNew = false;
			#if DEBUG
			System.Windows.Forms.MessageBox.Show(oldver+"=>"+ver);
			#endif
			string[] vers = ver.Split('.');
			string[] oldvers = oldver.Split('.');
			if (vers.Length == oldvers.Length)
			{
                //从左到右比较数字
                for (int i = 0; i < oldvers.Length; i++)
                {
                    int.TryParse(vers[i], out int j);
                    int.TryParse(oldvers[i], out int k);
                    if (j > k)//新的版本号大于旧的
                    {
                        hasNew = true;
                        break;
                    }
                    else if (j < k)
                    {
                        hasNew = false;
                        break;
                    }
                }
            }
			return hasNew;
		}
		#endregion

		#region 获取网址内容
		/// <summary>
		/// 获取网址内容
		/// </summary>
		/// <param name="url">网址</param>
		/// <returns>内容</returns>
		public static string GetHtmlContentByUrl(string url)
		{
			string htmlContent = string.Empty;
			try
			{
				HttpWebRequest httpWebRequest =
					(HttpWebRequest)WebRequest.Create(url);
				httpWebRequest.Timeout = 15000;
				using (HttpWebResponse httpWebResponse =
				       (HttpWebResponse)httpWebRequest.GetResponse())
				{
					using (Stream stream = httpWebResponse.GetResponseStream())
					{
						using (StreamReader streamReader =
						       new StreamReader(stream, Encoding.UTF8))
						{
							htmlContent = streamReader.ReadToEnd();
							streamReader.Close();
						}
						stream.Close();
					}
					httpWebResponse.Close();
				}
				return htmlContent;
			}
			catch
			{

			}
			return "";
		}
		#endregion

		#region 下载文件
		/// <summary>
		/// 下载文件
		/// </summary>
		/// <param name="filename">保存文件路径</param>
		/// <returns>是否下载成功</returns>
		public static bool DownLoad(string filename)
		{
			try
			{
				if (File.Exists(filename))
                {
                    File.Delete(filename);
                }

                HttpWebRequest Myrq = (HttpWebRequest)System.Net.HttpWebRequest.Create(URL);
				HttpWebResponse myrp = (HttpWebResponse)Myrq.GetResponse();
				long totalBytes = myrp.ContentLength;

				Stream st = myrp.GetResponseStream();
				Stream so = new System.IO.FileStream(filename + ".tmp", FileMode.Create);
				long totalDownloadedByte = 0;
				byte[] by = new byte[2048];
				int osize = st.Read(by, 0, (int)by.Length);
				while (osize > 0)
				{
					totalDownloadedByte = osize + totalDownloadedByte;
					System.Windows.Forms.Application.DoEvents();
					so.Write(by, 0, osize);
					osize = st.Read(by, 0, (int)by.Length);
				}
				so.Close();
				st.Close();
				File.Move(filename + ".tmp", filename);
			}
			catch (System.Exception)
			{
				return false;
			}
			return true;
		}
		#endregion
	}
}
