/** Payroll Enterprise Lao — Google Sheets Sync API
 * ວິທີໃຊ້: ວາງໂຄດນີ້ໃນ Extensions → Apps Script ຂອງ Google Sheet
 * Deploy → New deployment → Web app → Execute as: Me → Who has access: Anyone
 */
function doGet(e){
  return json_({status:'ok',message:'Payroll Sync API is running',time:new Date()});
}
function doPost(e){
  try{
    var data = JSON.parse((e && e.postData && e.postData.contents) || '{}');
    var action = data.action || 'save';
    if(action === 'load') return json_({status:'ok',state:loadState_(),time:new Date()});
    if(action === 'clear') { clearAll_(); return json_({status:'ok',message:'cleared',time:new Date()}); }
    saveState_(data.state || {});
    writeReportSheets_(data.sheets || {});
    return json_({status:'ok',message:'saved',time:new Date()});
  }catch(err){
    return json_({status:'error',message:String(err),time:new Date()});
  }
}
function json_(obj){
  return ContentService.createTextOutput(JSON.stringify(obj)).setMimeType(ContentService.MimeType.JSON);
}
function ss_(){ return SpreadsheetApp.getActiveSpreadsheet(); }
function sheet_(name){
  var sh = ss_().getSheetByName(name);
  if(!sh) sh = ss_().insertSheet(name);
  return sh;
}
function writeReportSheets_(sheets){
  Object.keys(sheets).forEach(function(name){
    var sh = sheet_(name);
    sh.clear();
    var rows = sheets[name] || [];
    if(rows.length){
      sh.getRange(1,1,rows.length,rows[0].length).setValues(rows);
      sh.getRange(1,1,1,rows[0].length).setBackground('#155c2f').setFontColor('#ffffff').setFontWeight('bold');
      sh.setFrozenRows(1);
      sh.autoResizeColumns(1, rows[0].length);
    }
  });
}
function saveState_(state){
  var sh = sheet_('_SYSTEM_STATE');
  sh.clear();
  var json = JSON.stringify(state);
  var chunks = [];
  for(var i=0;i<json.length;i+=45000){ chunks.push([Math.floor(i/45000)+1, json.substring(i,i+45000)]); }
  sh.getRange(1,1,1,2).setValues([['chunk','json']]).setBackground('#155c2f').setFontColor('#ffffff').setFontWeight('bold');
  if(chunks.length) sh.getRange(2,1,chunks.length,2).setValues(chunks);
  sh.hideSheet();
}
function loadState_(){
  var sh = ss_().getSheetByName('_SYSTEM_STATE');
  if(!sh) return null;
  var last = sh.getLastRow();
  if(last < 2) return null;
  var vals = sh.getRange(2,2,last-1,1).getValues().map(function(r){return r[0];}).join('');
  return vals ? JSON.parse(vals) : null;
}
function clearAll_(){
  ss_().getSheets().forEach(function(sh){ sh.clear(); });
}