<?php

namespace App\Element\UseCases\GetElementPdf;

use App\Exceptions\NotFoundException;
use App\Shared\Files\StoredFileReader;

class GetElementPdf
{
    private const PDF_FOLDERS = ['short', 'long'];

    private const PDF_MIME_TYPE = 'application/pdf';

    public function __construct(private StoredFileReader $storedFileReader)
    {
    }

    /**
     * @throws NotFoundException
     */
    public function execute(GetElementPdfRequest $request): GetElementPdfResult
    {
        if (!$this->isAllowedPdfFolder($request->folder)) {
            throw new NotFoundException('PDF not found');
        }

        if (!$this->isValidPdfFileName($request->fileName)) {
            throw new NotFoundException('PDF not found');
        }

        $path = "element-pdfs/$request->folder/$request->fileName";
        $contents = $this->storedFileReader->read($path);
        if ($contents === null) {
            throw new NotFoundException('PDF not found');
        }

        return new GetElementPdfResult(
            contents: $contents,
            fileName: $request->fileName,
            mimeType: self::PDF_MIME_TYPE,
        );
    }

    private function isAllowedPdfFolder(string $folder): bool
    {
        return in_array($folder, self::PDF_FOLDERS, true);
    }

    private function isValidPdfFileName(string $fileName): bool
    {
        return preg_match('/^[A-Za-z0-9._-]+\.pdf$/', $fileName) === 1;
    }
}