using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;


namespace Shared.Net
{
	/// <summary>
	/// 异步下载图片
	/// </summary>
	public class DownLoadImageAsync
	{
		/// <summary>
		/// 当前的webClient对象
		/// </summary>
		private System.Net.WebClient webClient = new WebClient();
		/// <summary>
		/// 用户名
		/// </summary>
		public string Name;
		/// <summary>
		/// 密码
		/// </summary>
		public string Password;
		/// <summary>
		/// 地址
		/// </summary>
		private Uri uri;
		/// <summary>
		/// 异步下载图片
		/// </summary>
		/// <param name="uri">链接地址</param>
		/// <param name="name">登记用户名</param>
		/// <param name="password">密码</param>
		public DownLoadImageAsync(Uri uri,string name,string password)
		{
			this.uri = uri;
			this.Name = name;
			this.Password = password;
		}
		/// <summary>
		/// 下载进度变化事件
		/// </summary>
		public  event  DownloadProgressChangedEventHandler  DownloadProgressChanged;

		/// <summary>
		/// 下载完成
		/// </summary>
		public event DownloadDataCompletedEventHandler DownloadDataCompleted;

		/// <summary>
		/// 开始异步下载
		/// </summary>
		public async  void StartDownloadImageAsync()
		{
			// var url = new Uri("http://192.168.2.210/tmpfs/auto.jpg");

			webClient.DownloadProgressChanged += HandleDownloadProgressChanged;
			webClient.DownloadDataCompleted += webClient_DownloadDataCompleted;

			try
			{
				string newValue = Convert.ToBase64String(System.Text.Encoding.ASCII.GetBytes(Name + ":" + Password));

				webClient.Headers.Add("Content-Type", "image/webp,*/*;q=0.8");
				webClient.Headers.Add("Accept-Encoding", "gzip,deflate,sdch");
				webClient.Headers.Add("Authorization", "Basic " + newValue);
				await webClient.DownloadDataTaskAsync(this.uri);
			}
			catch 
			{
				DownloadDataCompleted("异步完成", null);
			}

		}


		/// <summary>
		/// 下载图片完成
		/// </summary>
		/// <param name="sender"></param>
		/// <param name="e"></param>
		void webClient_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e)
		{
			if (DownloadDataCompleted != null)
			{
				DownloadDataCompleted(sender, e);
			}
		}

		/// <summary>
		/// 下载进度变化
		/// </summary>
		/// <param name="sender"></param>
		/// <param name="e"></param>
		void HandleDownloadProgressChanged (object sender, DownloadProgressChangedEventArgs e)
		{
			if (DownloadProgressChanged != null)
			{
				DownloadProgressChanged(sender, e);
			}
		}

		/// <summary>
		/// 取消下载
		/// </summary>
		public void CancelDownload()
		{
			webClient.CancelAsync();
			webClient.DownloadProgressChanged -= HandleDownloadProgressChanged;
		}


	}
}