// Convert standalone display math $$...$$ to inline \(...\) (with \frac -> \dfrac)
// so in-sentence fractions render inline, not as oversized display blocks.
$conv = function($t) {
  if ($t === null || $t === '') return $t;
  if (strpos($t, '$$') === false) return $t;
  return preg_replace_callback('/\$\$(.*?)\$\$/s', function($m) {
    $inner = trim($m[1]);
    $inner = str_replace('\\frac', '\\dfrac', $inner);
    return '\\(' . $inner . '\\)';
  }, $t);
};

$qChanged=[]; $qn=0;
DB::table('questions')->where('qa_status','ai_generated')->orderBy('id')
  ->chunkById(1000, function($rows) use (&$qChanged,&$qn,$conv){
    foreach ($rows as $r) {
      $upd=[];
      foreach (['question','explanation','answer0','answer1','answer2','answer3'] as $c) {
        $new=$conv((string)$r->$c);
        if ($new !== (string)$r->$c) $upd[$c]=$new;
      }
      if ($upd) { $qChanged[]=['id'=>$r->id]+(array)$r; $upd['updated_at']=now(); DB::table('questions')->where('id',$r->id)->update($upd); $qn++; }
    }
  });
file_put_contents(storage_path('app/fracinline_q_backup_'.date('Ymd_His').'.json'), json_encode($qChanged, JSON_UNESCAPED_UNICODE));

$sChanged=[]; $sn=0;
DB::table('solutions')->where('source','ai')->orderBy('id')
  ->chunkById(1000, function($rows) use (&$sChanged,&$sn,$conv){
    foreach ($rows as $r) {
      $new=$conv((string)$r->solution);
      if ($new !== (string)$r->solution) { $sChanged[]=['id'=>$r->id,'solution'=>$r->solution]; DB::table('solutions')->where('id',$r->id)->update(['solution'=>$new,'updated_at'=>now()]); $sn++; }
    }
  });
file_put_contents(storage_path('app/fracinline_s_backup_'.date('Ymd_His').'.json'), json_encode($sChanged, JSON_UNESCAPED_UNICODE));

echo "questions_updated=$qn solutions_updated=$sn\n";
$resQ=0;
DB::table('questions')->where('qa_status','ai_generated')->orderBy('id')->chunkById(2000,function($rows)use(&$resQ){ foreach($rows as $r){ if(strpos((string)$r->question,'$$')!==false) $resQ++; } });
echo "questions still containing \$\$ : $resQ\n";