<?php

/**
* Hoa
*
*
* @license
*
* New BSD License
*
* Copyright © 2007-2017, Hoa community. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the Hoa nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

namespace Hoa\Console\Chrome;

use Hoa\Console;

/**
* Class \Hoa\Console\Chrome\Pager.
*
* Use a pager for the output buffer. Example:
*
* ob_start('Hoa\Console\Chrome\Pager::less');
* echo file_get_contents(__FILE__);
*
* @copyright Copyright © 2007-2017 Hoa community
* @license New BSD License
*/
class Pager
{
/**
* Represent LESS(1).
*
* @const string
*/
const LESS = 'less';

/**
* Represent MORE(1).
*
* @const string
*/
const MORE = 'more';



/**
* Use less.
*
* @param string $output Output (from the output buffer).
* @param int $mode Mode (from the output buffer).
* @return string
*/
public static function less($output, $mode)
{
return self::pager($output, $mode, self::LESS);
}

/**
* Use more.
*
* @param string $output Output (from the output buffer).
* @param int $mode Mode (from the output buffer).
* @return string
*/
public static function more($output, $mode)
{
return self::pager($output, $mode, self::MORE);
}

/**
* Use pager set in the environment (i.e. $_ENV['PAGER']).
*
* @param string $output Output (from the output buffer).
* @param int $mode Mode (from the output buffer).
* @param string $type Type. Please, see self::LESS or self::MORE.
* @return string
*/
public static function pager($output, $mode, $type = null)
{
static $process = null;

if ($mode & PHP_OUTPUT_HANDLER_START) {
$pager
= null !== $type
? Console\Processus::locate($type)
: (isset($_ENV['PAGER']) ? $_ENV['PAGER'] : null);

if (null === $pager) {
return $output;
}

$process = new Console\Processus(
$pager,
null,
[['pipe', 'r']]
);
$process->open();
}

$process->writeAll($output);

if ($mode & PHP_OUTPUT_HANDLER_FINAL) {
$process->close();
}

return null;
}
}