Downloader.cs

using System.Security.Policy;

namespace Nexus
{
    public partial class Downloader : Form
    {
        private HttpClient? httpClient;
        private CancellationTokenSource? cts;
        public string DownloadUrl { get; set; } = string.Empty;
        public string SavePath { get; set; } = string.Empty;
        public Downloader()
        {
            InitializeComponent();
        }

        private async Task DownloadFiles(string downloadUrl, string savePath)
        {
            if (string.IsNullOrEmpty(downloadUrl))
            {
                MessageBox.Show("Por favor, insira a URL para download.", "Erro", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            cts = new CancellationTokenSource();
            httpClient = new HttpClient();

            try
            {
                using var response = await httpClient.GetAsync(downloadUrl, HttpCompletionOption.ResponseHeadersRead, cts.Token);
                response.EnsureSuccessStatusCode();

                long? totalBytes = response.Content.Headers.ContentLength;
                long downloadedBytes = 0;
                byte[] buffer = new byte[8192];
                bool isStreaming = true;

                using (var contentStream = await response.Content.ReadAsStreamAsync(cts.Token))
                using (var fileStream = new FileStream(savePath!, FileMode.Create, FileAccess.Write, FileShare.None))
                {
                    if (totalBytes.HasValue)
                    {
                        ProgressStatus.Maximum = (int)totalBytes.Value;
                    }
                    else
                    {
                        isStreaming = false;
                        ProgressStatus.Style = ProgressBarStyle.Marquee; // Indica progresso indeterminado
                    }

                    int bytesRead;
                    while ((bytesRead = await contentStream.ReadAsync(buffer, cts.Token)) > 0)
                    {
                        await fileStream.WriteAsync(buffer.AsMemory(0, bytesRead), cts.Token);
                        downloadedBytes += bytesRead;

                        if (totalBytes.HasValue)
                        {
                            ProgressStatus.Value = (int)downloadedBytes;
                            LabelStatus.Text = $"Baixando {(double)downloadedBytes / totalBytes.Value * 100:F2}% ({FormatBytes(downloadedBytes)} / {FormatBytes(totalBytes.Value)})";
                        }
                        else if (isStreaming)
                        {
                            LabelStatus.Text = $"Baixando {FormatBytes(downloadedBytes)}...";
                        }
                    }
                }

                ProgressStatus.Style = ProgressBarStyle.Continuous; // Restaura o estilo da barra de progresso
                LabelStatus.Text = $"Download concluído com sucesso! Salvo em: {savePath}";
            }
            catch (HttpRequestException ex)
            {
                MessageBox.Show($"Erro na requisição HTTP: {ex.Message}", "Erro", MessageBoxButtons.OK, MessageBoxIcon.Error);
                LabelStatus.Text = "Erro no download.";
                if (File.Exists(savePath))
                {
                    File.Delete(savePath);
                }
            }
            catch (TaskCanceledException)
            {
                LabelStatus.Text = "Download cancelado.";
                if (File.Exists(savePath))
                {
                    File.Delete(savePath);
                }
            }
            catch (UriFormatException)
            {
                MessageBox.Show("A URL inserida é inválida.", "Erro", MessageBoxButtons.OK, MessageBoxIcon.Error);
                LabelStatus.Text = "URL inválida.";
            }
            catch (Exception ex)
            {
                MessageBox.Show($"Ocorreu um erro durante o download: {ex.Message}", "Erro", MessageBoxButtons.OK, MessageBoxIcon.Error);
                LabelStatus.Text = "Erro no download.";
                if (File.Exists(savePath))
                {
                    File.Delete(savePath);
                }
            }
            finally
            {
                httpClient?.Dispose();
                httpClient = null!;
                cts?.Dispose();
                cts = null!;
            }
        }
        private static string FormatBytes(long bytes)
        {
            string[] suffixes = { "B", "KB", "MB", "GB", "TB" };
            int i;
            double dblSByte = bytes;
            for (i = 0; i < suffixes.Length && bytes >= 1024; i++, bytes /= 1024)
            {
                dblSByte = bytes / 1024.0;
            }
            return string.Format("{0:0.##} {1}", dblSByte, suffixes[i]);
        }

        private async void Downloader_Load(object sender, EventArgs e)
        {
            TextUrl.Text = DownloadUrl;
            await DownloadFiles(DownloadUrl, SavePath);
        }
    }
}