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    <h3>Editing: SelfUpdate.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

/*
 * This file is part of Psy Shell.
 *
 * (c) 2012-2023 Justin Hileman
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace Psy\VersionUpdater;

use Psy\Exception\ErrorException;
use Psy\Shell;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;

/**
 * Self update command.
 *
 * If a new version is available, this command will download it and replace the currently installed version
 */
class SelfUpdate
{
    const URL_PREFIX = 'https://github.com/bobthecow/psysh/releases/download';
    const SUCCESS = 0;
    const FAILURE = 1;

    /** @var Checker */
    private $checker;

    /** @var Installer */
    private $installer;

    /** @var Downloader */
    private $downloader;

    public function __construct(Checker $checker, Installer $installer)
    {
        $this-&gt;checker = $checker;
        $this-&gt;installer = $installer;
    }

    /**
     * Allow the downloader to be injected for testing.
     *
     * @param Downloader $downloader
     *
     * @return void
     */
    public function setDownloader(Downloader $downloader)
    {
        $this-&gt;downloader = $downloader;
    }

    /**
     * Get the currently set Downloader or create one based on the capabilities of the php environment.
     *
     * @throws ErrorException if a downloader cannot be created for the php environment
     */
    private function getDownloader(): Downloader
    {
        if (!isset($this-&gt;downloader)) {
            return Downloader\Factory::getDownloader();
        }

        return $this-&gt;downloader;
    }

    /**
     * Build the download URL for the latest release.
     *
     * The file name used in the URL will include the flavour postfix extracted from the current version
     * if it's present
     *
     * @param string $latestVersion
     */
    private function getAssetUrl(string $latestVersion): string
    {
        $versionPostfix = '';
        if (\strpos(Shell::VERSION, '+')) {
            $versionPostfix = '-'.\substr(Shell::VERSION, \strpos(Shell::VERSION, '+') + 1);
        }
        $downloadFilename = \sprintf('psysh-%s%s.tar.gz', $latestVersion, $versionPostfix);

        // check if latest release data contains an asset matching the filename?

        return \sprintf('%s/%s/%s', self::URL_PREFIX, $latestVersion, $downloadFilename);
    }

    /**
     * Execute the self-update process.
     *
     * @param InputInterface  $input
     * @param OutputInterface $output
     *
     * @throws ErrorException if the current version is not restored when installation fails
     */
    public function run(InputInterface $input, OutputInterface $output): int
    {
        $currentVersion = Shell::VERSION;

        // already have the latest version?
        if ($this-&gt;checker-&gt;isLatest()) {
            // current version is latest version...
            $output-&gt;writeln('&lt;info&gt;Current version is up-to-date.&lt;/info&gt;');

            return self::SUCCESS;
        }

        // can overwrite current version?
        if (!$this-&gt;installer-&gt;isInstallLocationWritable()) {
            $output-&gt;writeln('&lt;error&gt;Installed version is not writable.&lt;/error&gt;');

            return self::FAILURE;
        }
        // can download to, and create a backup in the temp directory?
        if (!$this-&gt;installer-&gt;isTempDirectoryWritable()) {
            $output-&gt;writeln('&lt;error&gt;Temporary directory is not writable.&lt;/error&gt;');

            return self::FAILURE;
        }

        $latestVersion = $this-&gt;checker-&gt;getLatest();
        $downloadUrl = $this-&gt;getAssetUrl($latestVersion);

        $output-&gt;write(&quot;Downloading PsySH $latestVersion ...&quot;);

        try {
            $downloader = $this-&gt;getDownloader();
            $downloader-&gt;setTempDir($this-&gt;installer-&gt;getTempDirectory());
            $downloaded = $downloader-&gt;download($downloadUrl);
        } catch (ErrorException $e) {
            $output-&gt;write(' &lt;error&gt;Failed.&lt;/error&gt;');
            $output-&gt;writeln(\sprintf('&lt;error&gt;%s&lt;/error&gt;', $e-&gt;getMessage()));

            return self::FAILURE;
        }

        if (!$downloaded) {
            $output-&gt;writeln('&lt;error&gt;Download failed.&lt;/error&gt;');
            $downloader-&gt;cleanup();

            return self::FAILURE;
        } else {
            $output-&gt;write(' &lt;info&gt;OK&lt;/info&gt;'.\PHP_EOL);
        }

        $downloadedFile = $downloader-&gt;getFilename();

        if (!$this-&gt;installer-&gt;isValidSource($downloadedFile)) {
            $downloader-&gt;cleanup();
            $output-&gt;writeln('&lt;error&gt;Downloaded file is not a valid archive.&lt;/error&gt;');

            return self::FAILURE;
        }

        // create backup as bin.old-version in the temporary directory
        $backupCreated = $this-&gt;installer-&gt;createBackup($currentVersion);
        if (!$backupCreated) {
            $downloader-&gt;cleanup();
            $output-&gt;writeln('&lt;error&gt;Failed to create a backup of the current version.&lt;/error&gt;');

            return self::FAILURE;
        } elseif ($input-&gt;getOption('verbose')) {
            $backupFilename = $this-&gt;installer-&gt;getBackupFilename($currentVersion);
            $output-&gt;writeln('Created backup of current version: '.$backupFilename);
        }

        if (!$this-&gt;installer-&gt;install($downloadedFile)) {
            $this-&gt;installer-&gt;restoreFromBackup($currentVersion);
            $downloader-&gt;cleanup();
            $output-&gt;writeln(&quot;&lt;error&gt;Failed to install new PsySH version $latestVersion.&lt;/error&gt;&quot;);

            return self::FAILURE;
        }

        // Remove the downloaded archive file from the temporary directory
        $downloader-&gt;cleanup();

        $output-&gt;writeln(&quot;Updated PsySH from $currentVersion to &lt;info&gt;$latestVersion&lt;/info&gt;&quot;);

        return self::SUCCESS;
    }
}
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