import {spawn} from 'node:child_process';

const pools=new Set();let terminating;
const terminate=signal=>{
 if(terminating)return;
 // Every close starts synchronously by killing only its captured child groups;
 // wait for all close events before forwarding the conventional exit status.
 terminating=Promise.allSettled([...pools].map(close=>close())).then(results=>{
  process.exit(results.some(result=>result.status==='rejected')?1:(signal==='SIGTERM'?143:130));
 });
};
const term=()=>terminate('SIGTERM'),interrupt=()=>terminate('SIGINT');
function register(close){
 if(pools.size===0){process.on('SIGTERM',term);process.on('SIGINT',interrupt)}
 pools.add(close);
}
function unregister(close){
 pools.delete(close);
 if(pools.size===0){process.removeListener('SIGTERM',term);process.removeListener('SIGINT',interrupt)}
}

// Fixture children have their own groups so abort/teardown can stop descendants
// without signalling the test runner or another fixture's work.
export function createOwnedRunner(t,env){
 const children=new Map();let closed=false;
 const stop=child=>{
  if(!child.pid)return;
  try{process.kill(-child.pid,'SIGKILL')}catch(e){if(e.code!=='ESRCH')throw e}
 };
 const close=async()=>{
  closed=true;
  for(const child of children.keys())stop(child);
  await Promise.all(children.values());
  unregister(close);
 };
 register(close);
 t.after(close);
 const run=(command,args=[],options={})=>{
  if(closed)throw Error('fixture runner closed');
  const child=spawn(command,args,{env:env(),...options,detached:true,stdio:['ignore','pipe','pipe']});
  let stdout='',stderr='',error;
  child.stdout.setEncoding('utf8');child.stderr.setEncoding('utf8');
  child.stdout.on('data',chunk=>{stdout+=chunk});child.stderr.on('data',chunk=>{stderr+=chunk});
  const abort=()=>stop(child);
  const done=new Promise(resolve=>{
   child.on('error',e=>{error=e});
   child.once('close',(status,signal)=>{
    children.delete(child);t.signal.removeEventListener('abort',abort);
    resolve({status,signal,stdout,stderr,...(error?{error}: {})});
   });
  });
  children.set(child,done);
  t.signal.addEventListener('abort',abort,{once:true});
  if(t.signal.aborted)abort();
  return done;
 };
 return {run,close};
}