MARKUS

using NetSparkleUpdater.Interfaces;

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.IO;

using System.Net;

using System.Net.Http;

using System.Text;

using System.Threading.Tasks;

namespace NetSparkleUpdater.Downloaders

{

    /// <summary>

    /// Class that downloads files from the internet and reports

    /// progress on those files being downloaded. Uses a WebClient

    /// object as its main method for downloading.

    /// </summary>

    public class WebClientFileDownloader : IUpdateDownloader, IDisposable

    {

        private WebClient _webClient;

        /// <summary>

        /// Default constructor for the web client file downloader.

        /// Uses default credentials and default proxy.

        /// </summary>

        public WebClientFileDownloader()

        {

            _webClient = new WebClient

            {

                UseDefaultCredentials = true,

                Proxy = { Credentials = CredentialCache.DefaultNetworkCredentials },

            };

            _webClient.DownloadProgressChanged += WebClient_DownloadProgressChanged;

            _webClient.DownloadFileCompleted += WebClient_DownloadFileCompleted;

        }

        private void WebClient_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)

        {

            DownloadProgressChanged?.Invoke(sender, 

                new Events.ItemDownloadProgressEventArgs(e.ProgressPercentage, e.UserState, e.BytesReceived, e.TotalBytesToReceive));

        }

        private void WebClient_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)

        {

            DownloadFileCompleted?.Invoke(sender, e);

        }

        /// <inheritdoc/>

        public bool IsDownloading

        {

            get => _webClient.IsBusy;

        }

        /// <inheritdoc/>

        public event DownloadProgressEvent DownloadProgressChanged;

        /// <inheritdoc/>

        public event AsyncCompletedEventHandler DownloadFileCompleted;

        /// <inheritdoc/>

        public void Dispose()

        {

            _webClient.Dispose();

        }

        /// <inheritdoc/>

        public void StartFileDownload(Uri uri, string downloadFilePath)

        {

            _webClient.DownloadFileAsync(uri, downloadFilePath);

        }

        /// <inheritdoc/>

        public void CancelDownload()

        {

            _webClient.CancelAsync();

        }

        /// <inheritdoc/>

        public async Task<string> RetrieveDestinationFileNameAsync(AppCastItem item)

        {

            var httpClient = new HttpClient { Timeout = TimeSpan.FromSeconds(30) };

            try

            {

                using (var response =

                    await httpClient.SendAsync(new HttpRequestMessage

                    {

                        Method = HttpMethod.Head,

                        RequestUri = new Uri(item.DownloadLink)

                    }).ConfigureAwait(false))

                {

                    if (response.IsSuccessStatusCode)

                    {

                        //var totalBytes = response.Content.Headers.ContentLength; // TODO: Use this value as well for a more accurate download %?

                        string destFilename = response.RequestMessage?.RequestUri?.LocalPath;

                        return Path.GetFileName(destFilename);

                    }

                    return null;

                }

            }

            catch

            {

            }

            return null;

        }

    }

}