<?php
/**
 * @package   admintools
 * @copyright Copyright (c)2010-2025 Nicholas K. Dionysopoulos / Akeeba Ltd
 * @license   GNU General Public License version 3, or later
 */

namespace Akeeba\Component\AdminTools\Administrator\Scanner;

/**
 * =====================================================================================================================
 * Software copyright notice
 *
 * This software has been modified by Akeeba Ltd to make it compatible with newer versions of PHP, address minor issues,
 * implement namespaces and other minor modifications of a similar nature. The following copyright notice accompanies
 * the original software; we are required to copy it verbatim in our modified copy. Please do keep in mind that this is
 * NOT the original software. It's a modified copy. Thank you.
 * =====================================================================================================================
 *
 * Diff
 *
 * A comprehensive library for generating differences between two strings
 * in multiple formats (unified, side by side HTML etc)
 *
 * PHP version 5
 *
 * Copyright (c) 2009 Chris Boulton <[email protected]>
 *
 * 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 Chris Boulton 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 OWNER OR 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.
 *
 * @package       Diff
 * @author        Chris Boulton <[email protected]>
 * @copyright (c) 2009 Chris Boulton
 * @license       New BSD License http://www.opensource.org/licenses/bsd-license.php
 * @version       1.1
 * @link          http://github.com/chrisboulton/php-diff
 */

defined('_JEXEC') || die();

use Akeeba\Component\AdminTools\Administrator\Scanner\Diff\RendererAbstract;
use Akeeba\Component\AdminTools\Administrator\Scanner\Diff\SequenceMatcher;

class Diff
{
	/**
	 * @var array The "old" sequence to use as the basis for the comparison.
	 */
	private $a = null;

	/**
	 * @var array The "new" sequence to generate the changes for.
	 */
	private $b = null;

	/**
	 * @var array Array containing the generated opcodes for the differences between the two items.
	 */
	private $groupedCodes = null;

	/**
	 * @var array Associative array of the default options available for the diff class and their default value.
	 */
	private $defaultOptions = [
		'context'          => 3,
		'ignoreNewLines'   => false,
		'ignoreWhitespace' => false,
		'ignoreCase'       => false,
	];

	/**
	 * @var array Array of the options that have been applied for generating the diff.
	 */
	private $options = [];

	/**
	 * The constructor.
	 *
	 * @param   array  $a  Array containing the lines of the first string to compare.
	 * @param   array  $b  Array containing the lines for the second string to compare.
	 */
	public function __construct($a, $b, $options = [])
	{
		$this->a = $a;
		$this->b = $b;

		if (is_array($options))
		{
			$this->options = array_merge($this->defaultOptions, $options);
		}
		else
		{
			$this->options = $this->defaultOptions;
		}
	}

	/**
	 * Render a diff using the supplied rendering class and return it.
	 *
	 * @param   object  $renderer  An instance of the rendering object to use for generating the diff.
	 *
	 * @return mixed The generated diff. Exact return value depends on the rendered.
	 */
	public function render(RendererAbstract $renderer)
	{
		$renderer->diff = $this;

		return $renderer->render();
	}

	/**
	 * Get a range of lines from $start to $end from the first comparison string
	 * and return them as an array. If no values are supplied, the entire string
	 * is returned. It's also possible to specify just one line to return only
	 * that line.
	 *
	 * @param   int  $start  The starting number.
	 * @param   int  $end    The ending number. If not supplied, only the item in $start will be returned.
	 *
	 * @return array Array of all of the lines between the specified range.
	 */
	public function getA($start = 0, $end = null)
	{
		if ($start == 0 && $end === null)
		{
			return $this->a;
		}

		if ($end === null)
		{
			$length = 1;
		}
		else
		{
			$length = $end - $start;
		}

		return array_slice($this->a, $start, $length);

	}

	/**
	 * Get a range of lines from $start to $end from the second comparison string
	 * and return them as an array. If no values are supplied, the entire string
	 * is returned. It's also possible to specify just one line to return only
	 * that line.
	 *
	 * @param   int  $start  The starting number.
	 * @param   int  $end    The ending number. If not supplied, only the item in $start will be returned.
	 *
	 * @return array Array of all of the lines between the specified range.
	 */
	public function getB($start = 0, $end = null)
	{
		if ($start == 0 && $end === null)
		{
			return $this->b;
		}

		if ($end === null)
		{
			$length = 1;
		}
		else
		{
			$length = $end - $start;
		}

		return array_slice($this->b, $start, $length);
	}

	/**
	 * Generate a list of the compiled and grouped opcodes for the differences between the
	 * two strings. Generally called by the renderer, this class instantiates the sequence
	 * matcher and performs the actual diff generation and return an array of the opcodes
	 * for it. Once generated, the results are cached in the diff class instance.
	 *
	 * @return array Array of the grouped opcodes for the generated diff.
	 */
	public function getGroupedOpcodes()
	{
		if (!is_null($this->groupedCodes))
		{
			return $this->groupedCodes;
		}

		$sequenceMatcher    = new SequenceMatcher($this->a, $this->b, null, $this->options);
		$this->groupedCodes = $sequenceMatcher->getGroupedOpcodes($this->options['context']);

		return $this->groupedCodes;
	}
}