const SECRET_TOKEN   = 'THAY_DOI_TOKEN_NAY';
const SPREADSHEET_ID = '1Gh8fwrRfxtYCsaFcF_pexf9q3z-Wzn2g1CKpT-OsNSM';
const FORM_ID        = '1hUYeeIK7vSDOjthLEwyEOc9puE8T2Th3a1tbfYASyEU';

function doGet(e) {
  try {
    var p = e.parameter;
    if (p.token !== SECRET_TOKEN) return out({ ok: false, error: 'Unauthorized' });
    var action = p.action || 'read';
    var sheet = SpreadsheetApp.openById(SPREADSHEET_ID).getSheets()[0];
    var form  = FormApp.openById(FORM_ID);

    if (action === 'read') {
      var raw  = sheet.getDataRange().getValues();
      var data = raw.map(function(row) {
        return row.map(function(cell) {
          if (cell instanceof Date)
            return Utilities.formatDate(cell, 'Asia/Ho_Chi_Minh', 'dd/MM/yyyy HH:mm:ss');
          return cell;
        });
      });
      return out({ ok: true, data: data });
    }

    if (action === 'clear') {
      var last = sheet.getLastRow();
      if (last > 1) sheet.deleteRows(2, last - 1);
      return out({ ok: true });
    }

    if (action === 'delete_row') {
      var r = parseInt(p.row);
      if (r >= 2) sheet.deleteRow(r);
      return out({ ok: true });
    }

    if (action === 'update_cell') {
      var r = parseInt(p.row), c = parseInt(p.col), v = p.value;
      sheet.getRange(r, c).setValue(v !== '' && !isNaN(+v) ? +v : v);
      return out({ ok: true });
    }

    if (action === 'add_row') {
      var vals = JSON.parse(p.values);
      vals.unshift(new Date());
      sheet.appendRow(vals);
      return out({ ok: true });
    }

    if (action === 'get_form') {
      var items = form.getItems();
      var result = [];
      for (var i = 0; i < items.length; i++) {
        result.push({ index: i, id: items[i].getId(), title: items[i].getTitle() });
      }
      return out({ ok: true, items: result });
    }

    if (action === 'update_question') {
      var items = form.getItems();
      var idx = parseInt(p.index);
      if (idx >= 0 && idx < items.length) items[idx].setTitle(p.title);
      return out({ ok: true });
    }

    if (action === 'ping') {
      return out({ ok: true, version: 'v3' });
    }

    if (action === 'add_question') {
      var newItem = form.addScaleItem();
      newItem.setTitle(p.title);
      newItem.setBounds(1, 10);
      return out({ ok: true });
    }

    if (action === 'delete_questions') {
      var indices = JSON.parse(p.indices).sort(function(a, b) { return b - a; });
      for (var i = 0; i < indices.length; i++) {
        var items = form.getItems();
        var idx = indices[i];
        if (idx >= 1 && idx < items.length) form.deleteItem(items[idx]);
      }
      return out({ ok: true });
    }

    return out({ ok: false, error: 'Unknown action: ' + action });
  } catch(err) {
    return out({ ok: false, error: err.toString() });
  }
}

function out(obj) {
  return ContentService
    .createTextOutput(JSON.stringify(obj))
    .setMimeType(ContentService.MimeType.JSON);
}