[Dúvida] Download + ProgressBar

unit Unit1;

interface

uses
  SysUtils, Types, Classes, Variants, QTypes, QGraphics, QControls, QForms, 
  QDialogs, QStdCtrls, IdBaseComponent, IdComponent, IdTCPConnection,
  IdTCPClient, IdHTTP, QComCtrls;

type
  TForm1 = class(TForm)
    btnDownload: TButton;
    ProgressBar1: TProgressBar;
    Label1: TLabel;
    IdHTTP1: TIdHTTP;
    memoLog: TMemo;
    procedure UpdateProgressWork(Sender: TObject; AWorkMode: TWorkMode; const AWorkCount: Integer);
    procedure btnDownloadClick(Sender: TObject);
    procedure IdHTTP1Work(Sender: TObject; AWorkMode: TWorkMode;
      const AWorkCount: Integer);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
    FDownloaded: Int64;
    FFileSize: Int64;
    procedure AddLog(const AMessage: string);
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.xfm}

{ TForm1 }

procedure TForm1.FormCreate(Sender: TObject);
begin
  memoLog.Clear;
  AddLog('Aplicativo iniciado.');
end;

procedure TForm1.AddLog(const AMessage: string);
begin
  memoLog.Lines.Add(FormatDateTime('[dd/mm/yyyy hh:nn:ss] ', Now) + AMessage);

  memoLog.SelStart := Length(memoLog.Text);
  memoLog.SelLength := 0;

  memoLog.SetFocus;
end;

procedure TForm1.UpdateProgressWork(Sender: TObject; AWorkMode: TWorkMode; const AWorkCount: Integer);
var
  ProgressPercent: Double;
  LastProgress: Integer;
begin
  if AWorkMode = wmRead then
  begin
    FDownloaded := FDownloaded + AWorkCount;
    
    // Limitar o progresso para evitar que ultrapasse 100%
    if FDownloaded > FFileSize then
      FDownloaded := FFileSize;

    if FFileSize <= MaxInt then
    begin
      if FDownloaded <= MaxInt then
        ProgressBar1.Position := FDownloaded
      else
        ProgressBar1.Position := MaxInt;
    end;

    if FFileSize > 0 then
    begin
      ProgressPercent := (FDownloaded * 100.0) / FFileSize;
      if ProgressPercent > 100 then ProgressPercent := 100;
      
      Label1.Caption := Format('Baixando... %.2f%%', [ProgressPercent]);
      
      // Adicionar log a cada 10% do progresso (usando variável estática)
      LastProgress := Trunc(ProgressPercent);
      if (LastProgress mod 10 = 0) and (LastProgress > 0) and (LastProgress <= 100) then
      begin
        // Usar Tag para guardar o último valor de progresso registrado
        if LastProgress <> ProgressBar1.Tag then
        begin
          ProgressBar1.Tag := LastProgress;
          AddLog(Format('Progresso: %.2f%% (%d de %d bytes)', 
                 [ProgressPercent, FDownloaded, FFileSize]));
        end;
      end;
    end
    else
      Label1.Caption := 'Baixando...';
  end;
end;


procedure TForm1.btnDownloadClick(Sender: TObject);
var
  FileStream: TFileStream;
  URL, Destino: string;
begin
  memoLog.Clear;
  
  // URL HTTP em vez de HTTPS
  URL := 'http://speedtest.tele2.net/10MB.zip'; 
  Destino := ExtractFilePath(Application.ExeName) + 'download_test.zip';

  AddLog('Iniciando download de: ' + URL);
  AddLog('Destino: ' + Destino);

  IdHTTP1.OnWork := UpdateProgressWork;
  ProgressBar1.Tag := -1; // Reseta o valor do último progresso

  FileStream := TFileStream.Create(Destino, fmCreate);
  try
    try
      AddLog('Verificando tamanho do arquivo...');
      IdHTTP1.Head(URL);
      FFileSize := IdHTTP1.Response.ContentLength;
      AddLog(Format('Tamanho do arquivo: %d bytes (%.2f MB)', 
             [FFileSize, FFileSize / 1024 / 1024]));
      
      FDownloaded := 0;

      if FFileSize <= MaxInt then
        ProgressBar1.Max := FFileSize
      else
        ProgressBar1.Max := MaxInt;

      ProgressBar1.Position := 0;
      Label1.Caption := 'Baixando... 0%';
      
      AddLog('Iniciando download do arquivo...');
      IdHTTP1.Get(URL, FileStream);
      AddLog('Download concluído com sucesso!');
      ShowMessage('Download concluído com sucesso!');
    except
      on E: Exception do
      begin
        AddLog('ERRO: ' + E.Message);
        ShowMessage('Erro durante o download: ' + E.Message);
      end;
    end;
  finally
    FileStream.Free;
  end;
end;

procedure TForm1.IdHTTP1Work(Sender: TObject; AWorkMode: TWorkMode;
  const AWorkCount: Integer);
begin
    // Exemplo de uso
end;

end.