<?php
// class/chatpdf_helper.php

class ChatPDFHelper
{
    private $apiKey = 'sec_Wyk8yl97UBzDW85zVWsuk4YFpSPGlr2Q';
    private $apiBase = 'https://api.chatpdf.com/v1';

    // Carica un PDF e restituisce l'ID del file
    public function uploadPdf($pdfPath)
    {
        $ch = curl_init("{$this->apiBase}/sources/add-file");
        $cfile = new CURLFile($pdfPath, 'application/pdf', basename($pdfPath));

        curl_setopt_array($ch, [
            CURLOPT_POST => true,
            CURLOPT_POSTFIELDS => ['file' => $cfile],
            CURLOPT_HTTPHEADER => [
                "x-api-key: {$this->apiKey}"
            ],
            CURLOPT_RETURNTRANSFER => true,
        ]);

        $response = curl_exec($ch);
        curl_close($ch);

        $result = json_decode($response, true);
        return $result['sourceId'] ?? null;
    }

    // Esegue una domanda al PDF caricato
    public function askPdf($sourceId, $question)
    {
        $apiKey = $_ENV['CHATPDF_API_KEY'] ?? null;
        if (!$apiKey) {
            throw new Exception("ChatPDF API key not found in .env");
        }

        $url = "https://api.chatpdf.com/v1/chats/message";

        $payload = json_encode([
            "sourceId" => $sourceId,
            "messages" => [
                [
                    "role" => "user",
                    "content" => $question
                ]
            ]
        ]);

        $ch = curl_init($url);
        curl_setopt_array($ch, [
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_POST => true,
            CURLOPT_HTTPHEADER => [
                "x-api-key: $apiKey",
                "Content-Type: application/json"
            ],
            CURLOPT_POSTFIELDS => $payload,
        ]);

        $response = curl_exec($ch);
        if (curl_errno($ch)) {
            throw new Exception('cURL error: ' . curl_error($ch));
        }
        curl_close($ch);

        $data = json_decode($response, true);

        // Debug temporaneo
        file_put_contents(
            __DIR__ . '/../debug_chatpdf.log',
            "Question: {$question}\nResponse: {$response}\n\n",
            FILE_APPEND
        );

        if (isset($data['content'])) {
            return trim($data['content']);
        }

        // ChatPDF a volte restituisce una lista di risposte
        if (isset($data[0]['content'])) {
            return trim($data[0]['content']);
        }

        return null;
    }
}