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    <h3>Editing: ShellOutput.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\Output;

use Symfony\Component\Console\Formatter\OutputFormatter;
use Symfony\Component\Console\Formatter\OutputFormatterInterface;
use Symfony\Component\Console\Output\ConsoleOutput;

/**
 * A ConsoleOutput subclass specifically for Psy Shell output.
 */
class ShellOutput extends ConsoleOutput
{
    const NUMBER_LINES = 128;

    private $paging = 0;

    /** @var OutputPager */
    private $pager;

    /** @var Theme */
    private $theme;

    /**
     * Construct a ShellOutput instance.
     *
     * @param mixed                         $verbosity (default: self::VERBOSITY_NORMAL)
     * @param bool|null                     $decorated (default: null)
     * @param OutputFormatterInterface|null $formatter (default: null)
     * @param string|OutputPager|null       $pager     (default: null)
     */
    public function __construct($verbosity = self::VERBOSITY_NORMAL, $decorated = null, ?OutputFormatterInterface $formatter = null, $pager = null, $theme = null)
    {
        parent::__construct($verbosity, $decorated, $formatter);

        $this-&gt;theme = $theme ?? new Theme('modern');
        $this-&gt;initFormatters();

        if ($pager === null) {
            $this-&gt;pager = new PassthruPager($this);
        } elseif (\is_string($pager)) {
            $this-&gt;pager = new ProcOutputPager($this, $pager);
        } elseif ($pager instanceof OutputPager) {
            $this-&gt;pager = $pager;
        } else {
            throw new \InvalidArgumentException('Unexpected pager parameter: '.$pager);
        }
    }

    /**
     * Page multiple lines of output.
     *
     * The output pager is started
     *
     * If $messages is callable, it will be called, passing this output instance
     * for rendering. Otherwise, all passed $messages are paged to output.
     *
     * Upon completion, the output pager is flushed.
     *
     * @param string|array|\Closure $messages A string, array of strings or a callback
     * @param int                   $type     (default: 0)
     */
    public function page($messages, int $type = 0)
    {
        if (\is_string($messages)) {
            $messages = (array) $messages;
        }

        if (!\is_array($messages) &amp;&amp; !\is_callable($messages)) {
            throw new \InvalidArgumentException('Paged output requires a string, array or callback');
        }

        $this-&gt;startPaging();

        if (\is_callable($messages)) {
            $messages($this);
        } else {
            $this-&gt;write($messages, true, $type);
        }

        $this-&gt;stopPaging();
    }

    /**
     * Start sending output to the output pager.
     */
    public function startPaging()
    {
        $this-&gt;paging++;
    }

    /**
     * Stop paging output and flush the output pager.
     */
    public function stopPaging()
    {
        $this-&gt;paging--;
        $this-&gt;closePager();
    }

    /**
     * Writes a message to the output.
     *
     * Optionally, pass `$type | self::NUMBER_LINES` as the $type parameter to
     * number the lines of output.
     *
     * @throws \InvalidArgumentException When unknown output type is given
     *
     * @param string|array $messages The message as an array of lines or a single string
     * @param bool         $newline  Whether to add a newline or not
     * @param int          $type     The type of output
     */
    public function write($messages, $newline = false, $type = 0): void
    {
        if ($this-&gt;getVerbosity() === self::VERBOSITY_QUIET) {
            return;
        }

        $messages = (array) $messages;

        if ($type &amp; self::NUMBER_LINES) {
            $pad = \strlen((string) \count($messages));
            $template = $this-&gt;isDecorated() ? &quot;&lt;aside&gt;%{$pad}s&lt;/aside&gt;: %s&quot; : &quot;%{$pad}s: %s&quot;;

            if ($type &amp; self::OUTPUT_RAW) {
                $messages = \array_map([OutputFormatter::class, 'escape'], $messages);
            }

            foreach ($messages as $i =&gt; $line) {
                $messages[$i] = \sprintf($template, $i, $line);
            }

            // clean this up for super.
            $type = $type &amp; ~self::NUMBER_LINES &amp; ~self::OUTPUT_RAW;
        }

        parent::write($messages, $newline, $type);
    }

    /**
     * Writes a message to the output.
     *
     * Handles paged output, or writes directly to the output stream.
     *
     * @param string $message A message to write to the output
     * @param bool   $newline Whether to add a newline or not
     */
    public function doWrite($message, $newline): void
    {
        if ($this-&gt;paging &gt; 0) {
            $this-&gt;pager-&gt;doWrite($message, $newline);
        } else {
            parent::doWrite($message, $newline);
        }
    }

    /**
     * Set the output Theme.
     */
    public function setTheme(Theme $theme)
    {
        $this-&gt;theme = $theme;
        $this-&gt;initFormatters();
    }

    /**
     * Flush and close the output pager.
     */
    private function closePager()
    {
        if ($this-&gt;paging &lt;= 0) {
            $this-&gt;pager-&gt;close();
        }
    }

    /**
     * Initialize output formatter styles.
     */
    private function initFormatters()
    {
        $useGrayFallback = !$this-&gt;grayExists();
        $this-&gt;theme-&gt;applyStyles($this-&gt;getFormatter(), $useGrayFallback);
        $this-&gt;theme-&gt;applyErrorStyles($this-&gt;getErrorOutput()-&gt;getFormatter(), $useGrayFallback);
    }

    /**
     * Checks if the &quot;gray&quot; color exists on the output.
     */
    private function grayExists(): bool
    {
        try {
            $this-&gt;write('&lt;fg=gray&gt;&lt;/&gt;');
        } catch (\InvalidArgumentException $e) {
            return false;
        }

        return true;
    }
}
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