/** Astra educational example. Bound to a Google Spreadsheet. */
const REQUESTS = 'Requests';
const SUMMARY = 'Summary';
const HEADERS = ['Request ID','Timestamp','Name','Type','Description','Status','Updated At'];
const STATUSES = ['New','In Progress','Done'];
function setup() {
  const book = SpreadsheetApp.getActiveSpreadsheet();
  let sheet = book.getSheetByName(REQUESTS) || book.insertSheet(REQUESTS);
  if (sheet.getLastRow() === 0) sheet.appendRow(HEADERS);
  const actual = sheet.getRange(1,1,1,HEADERS.length).getValues()[0];
  if (JSON.stringify(actual) !== JSON.stringify(HEADERS)) throw Error('Unexpected Requests headers');
  if (!book.getSheetByName(SUMMARY)) book.insertSheet(SUMMARY);
  return sheet;
}
function addRequest(name,type,description) {
  for (const [key,val] of Object.entries({name,type,description})) {
    if (typeof val !== 'string' || !val.trim() || val.length > 500) throw Error('Invalid '+key);
  }
  const lock = LockService.getDocumentLock();
  if (!lock) throw Error('Run as a spreadsheet-bound script');
  lock.waitLock(15000);
  try {
    const sheet = setup(), id = Utilities.getUuid(), now = new Date();
    sheet.appendRow([id,now,name.trim(),type.trim(),description.trim(),'New',now]);
    return id;
  } finally {lock.releaseLock();}
}
function updateStatus(id,status) {
  if (typeof id !== 'string' || !id.trim() || !STATUSES.includes(status)) throw Error('Invalid ID/status');
  const lock = LockService.getDocumentLock();
  lock.waitLock(15000);
  try {
    const sheet = setup();
    const count = sheet.getLastRow()-1;
    if (count < 1) throw Error('No requests');
    const ids = sheet.getRange(2,1,count,1).getValues();
    const pos = ids.findIndex(row => row[0] === id);
    if (pos < 0) throw Error('Request not found');
    sheet.getRange(pos+2,6,1,2).setValues([[status,new Date()]]);
  } finally {lock.releaseLock();}
}
function updateSummary() {
  const sheet = setup(), summary = SpreadsheetApp.getActiveSpreadsheet().getSheetByName(SUMMARY);
  const count = Math.max(0,sheet.getLastRow()-1);
  const statuses = count ? sheet.getRange(2,6,count,1).getValues().flat() : [];
  const data = [['Metric','Count'],['Total',count],...STATUSES.map(s => [s,statuses.filter(x=>x===s).length])];
  summary.clearContents();
  summary.getRange(1,1,data.length,2).setValues(data);
}
function demoAddRequest() {
  const id = addRequest('Demo Student','IT Support','Fictional laptop setup request');
  PropertiesService.getDocumentProperties().setProperty('DEMO_REQUEST_ID',id);
  updateSummary();
  Logger.log('Created demo request: '+id);
}
function demoUpdateRequest() {
  const id = PropertiesService.getDocumentProperties().getProperty('DEMO_REQUEST_ID');
  if (!id) throw Error('Run demoAddRequest first');
  updateStatus(id,'In Progress'); updateSummary();
}
function runSelfTests() {
  if (STATUSES.length !== 3 || HEADERS.length !== 7) throw Error('Schema mismatch');
  if (!STATUSES.includes('Done') || STATUSES.includes('Deleted')) throw Error('Status list mismatch');
  Logger.log('Schema and allowed-status checks passed (no rows modified)');
}