/** Astra Learning Hub - educational Google Sheets approval tracker.
 * Bound to a Google Sheet. Does not send messages or use external APIs.
 * Authorization: only accounts in APPROVERS may approve/reject.
 * IMPORTANT: This is a demonstration, not an enterprise access-control system.
 */
const CFG = Object.freeze({
  REQUESTS: 'Requests', AUDIT: 'Audit',
  APPROVERS: ['approver@example.com'], // REPLACE before use
  REQUEST_HEADERS: ['ID','Created At','Requester','Type','Description','Status','Updated At','Reviewer','Decision Note'],
  AUDIT_HEADERS: ['At','ID','Action','Actor','Note']
});
function onOpen() {
  SpreadsheetApp.getUi().createMenu('Astra Tracker')
    .addItem('1. Initialize sheets','initializeTracker')
    .addItem('2. Add sample request','addSampleRequest')
    .addItem('3. Review selected request','reviewSelectedRequest')
    .addToUi();
}
function initializeTracker() {
  const ss = SpreadsheetApp.getActiveSpreadsheet();
  [[CFG.REQUESTS, CFG.REQUEST_HEADERS],[CFG.AUDIT, CFG.AUDIT_HEADERS]].forEach(([name,headers])=>{
    let sh=ss.getSheetByName(name) || ss.insertSheet(name);
    if (sh.getLastRow()===0) sh.appendRow(headers);
    else {
      const found=sh.getRange(1,1,1,headers.length).getValues()[0];
      if (JSON.stringify(found)!==JSON.stringify(headers)) throw new Error('Unexpected headers in '+name+'; do not overwrite existing data.');
    }
    sh.setFrozenRows(1);
  });
  SpreadsheetApp.getUi().alert('Tracker sheets ready. Set APPROVERS in Code.gs.');
}
function addSampleRequest(){
  const ui=SpreadsheetApp.getUi();
  const who=ui.prompt('Requester name').getResponseText().trim();
  if(!who || who.length>100){ui.alert('Enter a name (1–100 characters).');return;}
  const description=ui.prompt('Request description').getResponseText().trim();
  if(!description || description.length>500){ui.alert('Enter a description (1–500 characters).');return;}
  const id=createRequest_(who,'General',description);
  ui.alert('Created request: '+id);
}
function createRequest_(requester,type,description){
  const lock=LockService.getDocumentLock();
  if(!lock)throw new Error('Open as a spreadsheet-bound script.');
  lock.waitLock(20000);
  try {
    const ss=SpreadsheetApp.getActiveSpreadsheet();
    const sh=ss.getSheetByName(CFG.REQUESTS),audit=ss.getSheetByName(CFG.AUDIT);
    if(!sh || !audit)throw new Error('Run Initialize sheets first.');
    const id='AST-'+Utilities.getUuid().slice(0,8).toUpperCase();
    const now=new Date();
    sh.appendRow([id,now,requester,type,description,'Pending',now,'','']);
    audit.appendRow([now,id,'CREATED',requester,'']);
    return id;
  } finally {lock.releaseLock();}
}
function reviewSelectedRequest(){
  const ui=SpreadsheetApp.getUi(),ss=SpreadsheetApp.getActiveSpreadsheet();
  const sh=ss.getActiveSheet();
  if(sh.getName()!==CFG.REQUESTS || sh.getActiveRange().getRow()<2){ui.alert('Select a request row in Requests sheet.');return;}
  const row=sh.getActiveRange().getRow();
  const actor=Session.getActiveUser().getEmail().toLowerCase();
  if(!actor || !CFG.APPROVERS.map(x=>x.toLowerCase()).includes(actor)){
    ui.alert('Not authorized. Set your verified email in APPROVERS.');return;
  }
  const action=ui.prompt('Decision: APPROVE or REJECT').getResponseText().trim().toUpperCase();
  if(!['APPROVE','REJECT'].includes(action)){ui.alert('Cancelled: enter APPROVE or REJECT.');return;}
  const note=ui.prompt('Decision note').getResponseText().trim();
  if(!note || note.length>500){ui.alert('A decision note (1–500 characters) is required.');return;}
  const lock=LockService.getDocumentLock();lock.waitLock(20000);
  try{
    const id=String(sh.getRange(row,1).getValue());
    const status=String(sh.getRange(row,6).getValue());
    if(!id || status!=='Pending'){ui.alert('Only Pending requests can be reviewed.');return;}
    const now=new Date();
    sh.getRange(row,6,1,4).setValues([[action==='APPROVE'?'Approved':'Rejected',now,actor,note]]);
    ss.getSheetByName(CFG.AUDIT).appendRow([now,id,action,actor,note]);
    ui.alert(id+' '+(action==='APPROVE'?'Approved':'Rejected'));
  }finally{lock.releaseLock();}
}