using System;
using System.ComponentModel;
using System.IO;
using System.Net;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    class Installer
    {
        Button saveButton;
        ProgressBar progressBar;
        Label statusLabel;
        Boolean downloadDone;

        public Installer(Button _saveButton, ProgressBar _progressBar, Label _statusLabel)
        {
            saveButton = _saveButton;
            progressBar = _progressBar;
            statusLabel = _statusLabel;
        }

        public async void Start(string fileUrl)
        {
            saveButton.BeginInvoke((Action)(() => {
                saveButton.Enabled = false;
            }));

            Task<bool> downloadArchiveTask = DownloadArchiveAsync(fileUrl);

            bool downloadArchiveDone = await downloadArchiveTask;

            if (downloadArchiveDone)
                statusLabel.BeginInvoke((Action)(() => {
                    statusLabel.Text = "Download Completed";
                }));
        }

        async Task<bool> DownloadArchiveAsync(string fileUrl)
        {
            var downloadLink = new Uri(fileUrl);
            var saveFilename = Path.GetFileName(downloadLink.AbsolutePath);

            DownloadProgressChangedEventHandler DownloadProgressChangedEvent = (s, e) =>
            {
                progressBar.BeginInvoke((Action)(() => {
                    progressBar.Value = e.ProgressPercentage;
                }));

                var downloadProgress = string.Format("{0} MB / {1} MB",
                        (e.BytesReceived / 1024d / 1024d).ToString("0.00"),
                        (e.TotalBytesToReceive / 1024d / 1024d).ToString("0.00"));

                statusLabel.BeginInvoke((Action)(() => {
                    statusLabel.Text = "Downloading " + downloadProgress + " ...";
                }));
            };

            AsyncCompletedEventHandler AsyncCompletedEvent = (s, e) =>
            {
                // Todo: Extract
                downloadDone = true;
            };

            using (WebClient webClient = new WebClient())
            {
                webClient.DownloadProgressChanged += DownloadProgressChangedEvent;
                webClient.DownloadFileCompleted += AsyncCompletedEvent;
                webClient.DownloadFileAsync(downloadLink, saveFilename);
            }

            await IsDownloadDone();

            return true;
        }

        async Task IsDownloadDone()
        {
            await Task.Run(() =>
            {
                while (!downloadDone) ;
            });
        }
    }
}