Step 1: Open a new Google Sheet.
Step 2: Click Extensions → Apps Script.
Step 3: Delete any existing code and paste the Apps Script code shown below.
Step 4: Click Deploy → New deployment → Web app. Set "Who has access" to Anyone. Click Deploy and copy the URL.
Step 5: Paste the URL into the box above and click "Push Now".
⚠️ Existing users: If you already have an Apps Script deployed, replace the code with the version below and Deploy → Manage deployments → update to latest version. This unlocks multi-user live sync.

Apps Script code to paste:

function doPost(e) {
  try {
    var ss = SpreadsheetApp.getActiveSpreadsheet();
    var body = JSON.parse(e.postData.contents);

    // ── PULL REQUEST: return all jobs stored in _Sync sheet ──
    if (body && body.action === 'get') {
      var syncSheet = ss.getSheetByName('_Sync');
      if (!syncSheet) return ContentService.createTextOutput('[]').setMimeType(ContentService.MimeType.TEXT);
      var val = syncSheet.getRange('A1').getValue();
      return ContentService.createTextOutput(val || '[]').setMimeType(ContentService.MimeType.TEXT);
    }

    // ── PUSH REQUEST: body is the full jobs array ──
    var data = Array.isArray(body) ? body : null;
    if (!data) return ContentService.createTextOutput('ERROR: expected array').setMimeType(ContentService.MimeType.TEXT);

    // Write human-readable Jobs sheet (visible in Google Sheets)
    var sheet = ss.getSheetByName('Jobs') || ss.insertSheet('Jobs');
    sheet.clearContents();
    var headers = ['ID','Job Ref','Customer','Address','Postcode','Install Date',
                   'Job Price','Labour','Materials','Profit/Unit','Total Profit',
                   'Units','Type','Saved At','Invoiced At','Engineer','Email','Phone'];
    sheet.appendRow(headers);
    data.forEach(function(j) {
      sheet.appendRow([
        j.id, j.jobRef||'', j.custName||'', j.custAddr||'', j.custPostcode||'',
        j.instDate||'', j.jobPrice||0, j.labour||0, j.totalMaterials||0,
        j.perUnit||0, (j.perUnit||0)*(j.numUnits||1),
        j.numUnits||1, j.jobType||'quote', j.savedAt||'', j.invoicedAt||'',
        j.engineer||'', j.custEmail||'', j.custPhone||''
      ]);
    });

    // Store full JSON in _Sync sheet (read by all users on load / every 30s)
    var syncSheet = ss.getSheetByName('_Sync') || ss.insertSheet('_Sync');
    syncSheet.getRange('A1').setValue(JSON.stringify(data));
    syncSheet.getRange('B1').setValue(new Date().toISOString());
    syncSheet.getRange('C1').setValue(data.length + ' jobs');

    return ContentService.createTextOutput('OK').setMimeType(ContentService.MimeType.TEXT);
  } catch(err) {
    return ContentService.createTextOutput('ERROR: ' + err.toString()).setMimeType(ContentService.MimeType.TEXT);
  }
}

function doGet(e) {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var sync = ss.getSheetByName('_Sync');
  var ts  = sync ? sync.getRange('B1').getValue() : 'never';
  var cnt = sync ? sync.getRange('C1').getValue() : '0 jobs';
  return ContentService.createTextOutput('Prestige Air sync OK — ' + cnt + ' — last push: ' + ts).setMimeType(ContentService.MimeType.TEXT);
}