function doGet(e) {
  const ss = SpreadsheetApp.getActiveSpreadsheet();
  if (e.parameter && e.parameter.payload) {
    try {
      const data = JSON.parse(Utilities.newBlob(
        Utilities.base64Decode(e.parameter.payload, Utilities.Charset.UTF_8)
      ).getDataAsString());
      const sheet = ss.getSheetByName(data.sheet || 'clientes');
      if (data.action === 'salvar') { sheet.appendRow(data.row); }
      if (data.action === 'editar') {
        const rows = sheet.getDataRange().getValues();
        for (let i = 1; i < rows.length; i++) {
          if (String(rows[i][0]) === String(data.id)) {
            sheet.getRange(i+1,1,1,data.row.length).setValues([data.row]); break;
          }
        }
      }
      if (data.action === 'deletar') {
        const rows = sheet.getDataRange().getValues();
        for (let i = 1; i < rows.length; i++) {
          if (String(rows[i][0]) === String(data.id)) { sheet.deleteRow(i+1); break; }
        }
      }
      return ContentService.createTextOutput(JSON.stringify({ok:true})).setMimeType(ContentService.MimeType.JSON);
    } catch(err) {
      return ContentService.createTextOutput(JSON.stringify({ok:false,error:err.message})).setMimeType(ContentService.MimeType.JSON);
    }
  }
  const which = (e.parameter && e.parameter.sheet) || 'clientes';
  const sheet = ss.getSheetByName(which);
  if (!sheet) return ContentService.createTextOutput('[]').setMimeType(ContentService.MimeType.JSON);
  const rows = sheet.getDataRange().getValues();
  if (rows.length < 2) return ContentService.createTextOutput('[]').setMimeType(ContentService.MimeType.JSON);
  const headers = rows[0];
  const data = rows.slice(1).map(r => { const o={}; headers.forEach((h,i)=>o[h]=r[i]); return o; });
  return ContentService.createTextOutput(JSON.stringify(data)).setMimeType(ContentService.MimeType.JSON);
}