function doPost(e) {
  var sheet = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
  var data = JSON.parse(e.postData.contents);
  
  // Add header row if empty
  if (sheet.getLastRow() === 0) {
    sheet.appendRow(['#','Student Name','Father Name',
      'DOB','Class','Sibling','School Name',
      'School Class','Mobile','WhatsApp',
      'Category','Date','Time']);
  }
  
  var row = sheet.getLastRow();
  sheet.appendRow([
    row, data.studentName, data.fatherName,
    data.dob, data.className, data.sibling,
    data.schoolName, data.schoolClass,
    data.mobile, data.whatsapp,
    data.category,
    new Date().toLocaleDateString('en-IN'),
    new Date().toLocaleTimeString('en-IN')
  ]);
  
  return ContentService
    .createTextOutput(JSON.stringify({status:'success',row:row}))
    .setMimeType(ContentService.MimeType.JSON);
}