Delphi Mail OAuth2

uses
  IdSMTP, sgcAuth_Mail_OAuth2;

// Mail is a form field: Mail: TsgcMailOAuth2;
procedure TForm1.FormCreate(Sender: TObject);
begin
  Mail := TsgcMailOAuth2.Create(Self);
  Mail.Provider := mopMicrosoft365;
  Mail.Protocols := [mpSMTP];
  Mail.TenantId := 'contoso.onmicrosoft.com';
  Mail.ClientId := 'your-application-id';
  Mail.OnTokensChanged := OnMailTokensChanged;

  // reuse the stored refresh token, sign in only when it no longer works
  Mail.RefreshToken := LoadRefreshToken;
  if (Mail.RefreshToken = '') or not Mail.Refresh then
    Mail.Start; // opens the browser, PKCE and a loopback redirect
end;

procedure TForm1.OnMailTokensChanged(Sender: TObject; const AccessToken,
  RefreshToken: String; const ExpiresAt: TDateTime);
begin
  SaveRefreshToken(RefreshToken); // encrypt it in your store
end;

// TIdSMTP with UseTLS = utUseExplicitTLS and AuthType = satNone
procedure TForm1.Authenticate(aSMTP: TIdSMTP);
begin
  aSMTP.Connect; // EHLO and STARTTLS
  aSMTP.SendCmd('AUTH XOAUTH2 ' + Mail.GetXOAuth2('user@contoso.com'), 235);
end;