<?php

declare(strict_types=1);

namespace App\Command;

use App\Repository\DocumentRepository;
use Doctrine\ORM\EntityManagerInterface;
use Symfony\Component\Console\Attribute\AsCommand;
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\Style\SymfonyStyle;

#[AsCommand(
    name: 'app:compress-pdf',
    description: 'Compress all PDF documents stored in database without quality loss',
)]
class CompressPdfCommand extends Command
{
    public function __construct(
        private readonly DocumentRepository $documentRepository,
        private readonly EntityManagerInterface $em,
    ) {
        parent::__construct();
    }

    protected function configure(): void
    {
        $this
            ->addOption('dry-run', null, InputOption::VALUE_NONE, 'Show what would be compressed without actually doing it')
        ;
    }

    protected function execute(InputInterface $input, OutputInterface $output): int
    {
        $io     = new SymfonyStyle($input, $output);
        $dryRun = $input->getOption('dry-run');

        // Check if qpdf is installed
        exec('which qpdf', $qpdfPath, $returnCode);
        if (0 !== $returnCode) {
            $io->error('qpdf is not installed. Run: sudo apt install qpdf');

            return Command::FAILURE;
        }

        $documents = $this->documentRepository->findBy(['mimeType' => 'application/pdf']);

        if (empty($documents)) {
            $io->info('No PDF documents found.');

            return Command::SUCCESS;
        }

        $io->title('PDF Compression');
        $io->text(sprintf('Found %d PDF documents', count($documents)));

        $totalSaved = 0;
        $compressed = 0;

        foreach ($documents as $document) {
            $base64Data = $document->getPath();

            // Remove data URI prefix if present
            if (str_contains($base64Data, ',')) {
                $base64Data = explode(',', $base64Data, 2)[1];
            }

            $pdfContent = base64_decode($base64Data, true);
            if (false === $pdfContent) {
                $io->warning(sprintf('Failed to decode document: %s', $document->getName()));

                continue;
            }

            $originalSize = strlen($pdfContent);

            if ($dryRun) {
                $io->text(sprintf(
                    '  [DRY-RUN] Would compress: %s (%s)',
                    $document->getName(),
                    $this->formatBytes($originalSize)
                ));

                continue;
            }

            // Create temp files
            $tempInput  = tempnam(sys_get_temp_dir(), 'pdf_in_');
            $tempOutput = tempnam(sys_get_temp_dir(), 'pdf_out_');

            file_put_contents($tempInput, $pdfContent);

            // Compress with qpdf (lossless)
            $command = sprintf(
                'qpdf --linearize --object-streams=generate %s %s 2>&1',
                escapeshellarg($tempInput),
                escapeshellarg($tempOutput)
            );

            exec($command, $cmdOutput, $returnCode);

            if (0 !== $returnCode || !file_exists($tempOutput)) {
                $io->warning(sprintf('Failed to compress: %s', $document->getName()));
                @unlink($tempInput);
                @unlink($tempOutput);

                continue;
            }

            $compressedContent = file_get_contents($tempOutput);
            $compressedSize    = strlen($compressedContent);

            // Only update if we actually saved space
            if ($compressedSize < $originalSize) {
                $saved = $originalSize - $compressedSize;
                $totalSaved += $saved;
                ++$compressed;

                // Rebuild base64 with data URI prefix
                $newBase64 = 'data:application/pdf;base64,'.base64_encode($compressedContent);
                $document->setPath($newBase64);
                $document->setSize($compressedSize);

                $io->text(sprintf(
                    '  ✓ %s: %s → %s (-%s, -%.1f%%)',
                    $document->getName(),
                    $this->formatBytes($originalSize),
                    $this->formatBytes($compressedSize),
                    $this->formatBytes($saved),
                    ($saved / $originalSize) * 100
                ));
            } else {
                $io->text(sprintf(
                    '  - %s: Already optimal (%s)',
                    $document->getName(),
                    $this->formatBytes($originalSize)
                ));
            }

            @unlink($tempInput);
            @unlink($tempOutput);
        }

        if (!$dryRun && $compressed > 0) {
            $this->em->flush();
            $io->success(sprintf(
                'Compressed %d/%d PDFs. Total space saved: %s',
                $compressed,
                count($documents),
                $this->formatBytes($totalSaved)
            ));
        } elseif ($dryRun) {
            $io->info('Dry run completed. No changes made.');
        } else {
            $io->info('No PDFs needed compression.');
        }

        return Command::SUCCESS;
    }

    private function formatBytes(int $bytes): string
    {
        $units = ['B', 'KB', 'MB', 'GB'];
        $i     = 0;
        while ($bytes >= 1024 && $i < count($units) - 1) {
            $bytes /= 1024;
            ++$i;
        }

        return round($bytes, 2).' '.$units[$i];
    }
}