<?php
namespace Modules\AI\Services;
use Modules\AI\Models\AIKnowledgeSource;
final class KnowledgeIndexer
{
    public function index(AIKnowledgeSource $source,int $chunkSize=1800): AIKnowledgeSource
    {
        $content=trim((string)$source->content); $source->chunks()->delete();
        $chunks=$content===''?[]:$this->split($content,max(500,$chunkSize));
        foreach($chunks as $position=>$chunk) $source->chunks()->create(['position'=>$position+1,'content'=>$chunk]);
        $source->update(['checksum'=>hash('sha256',$content),'status'=>'indexed','chunk_count'=>count($chunks),'indexed_at'=>now()]);
        return $source->refresh();
    }
    private function split(string $content,int $size): array
    {
        $paragraphs=preg_split('/\R{2,}/',$content) ?: [$content]; $chunks=[]; $buffer='';
        foreach($paragraphs as $paragraph){ if(strlen($buffer)+strlen($paragraph)+2>$size && $buffer!==''){ $chunks[]=trim($buffer); $buffer=''; } $buffer.=$paragraph."\n\n"; }
        if(trim($buffer)!=='') $chunks[]=trim($buffer); return $chunks;
    }
}