backend-php/controllers/DocumentDownloadController.php

<?php

namespace Controllers;

use Libs\ResponseLib;
use Models\DocumentModel;
use Psr\Http\Message\ServerRequestInterface;
use React\Http\Message\Response;
use Respect\Validation\Exceptions\ValidationException;
use Respect\Validation\Validator as val;

class DocumentDownloadController
{
    private DocumentModel $documentModel;

    public function __construct()
    {
        $this->documentModel = new DocumentModel();
    }

    public function __invoke(ServerRequestInterface $request)
    {
        $userId = (int)($request->getAttribute('api_user_id') ?? 0);
        $companyId = (int)($request->getAttribute('api_company_id') ?? 0);

        if ($userId <= 0 || $companyId <= 0) {
            return ResponseLib::sendFail('Unauthorized', [], 'E_VALIDATE')->withStatus(401);
        }

        $body = json_decode((string)$request->getBody(), true) ?? [];

        try {
            val::key('document_type', val::stringType()->notEmpty()->length(1, 255))
                ->assert($body);
        } catch (ValidationException $e) {
            return ResponseLib::sendFail('Validation failed: ' . $e->getFullMessage(), [], 'E_VALIDATE')->withStatus(400);
        }

        $documentType = (string)$body['document_type'];

        try {
            $doc = $this->documentModel->findLatestByUserIdAndType($userId, $documentType);
        } catch (\Throwable $e) {
            return ResponseLib::sendFail('Database error: ' . $e->getMessage(), [], 'E_DATABASE')->withStatus(500);
        }

        if (!$doc) {
            return ResponseLib::sendFail('Document not found', [], 'E_NOT_FOUND')->withStatus(404);
        }

        $path = (string)($doc['document_path'] ?? '');
        if ($path === '' || !is_file($path)) {
            return ResponseLib::sendFail('Document file not found', [], 'E_NOT_FOUND')->withStatus(404);
        }

        $filename = basename($path);
        $content = @file_get_contents($path);
        if ($content === false) {
            return ResponseLib::sendFail('Failed to read document file', [], 'E_INTERNAL')->withStatus(500);
        }

        $contentType = 'application/octet-stream';
        $ext = strtolower((string)pathinfo($filename, PATHINFO_EXTENSION));
        if ($ext === 'pdf') {
            $contentType = 'application/pdf';
        }

        return new Response(
            200,
            [
                'Content-Type' => $contentType,
                'Content-Disposition' => 'attachment; filename="' . $filename . '"',
            ],
            $content
        );
    }
}