<?php
/**
* Mirasvit
*
* This source file is subject to the Mirasvit Software License, which is available at https://mirasvit.com/license/.
* Do not edit or add to this file if you wish to upgrade the to newer versions in the future.
* If you wish to customize this module for your needs.
* Please refer to http://www.magentocommerce.com for more information.
*
* @category Mirasvit
* @package mirasvit/module-misspell
* @version 1.0.38
* @copyright Copyright (C) 2020 Mirasvit (https://mirasvit.com/)
*/


namespace Mirasvit\Misspell\Helper;

/**
* Implementation of Damerau-Levenshtein distance algorithm
* @SuppressWarnings(PHPMD.CyclomaticComplexity)
* @SuppressWarnings(PHPMD.NPathComplexity)
*/
class Damerau
{
/**
* @var Text
*/
private $text;

/**
* Constructor
*
* @param Text $textHelper
*/
public function __construct(
Text $textHelper
) {
$this->text = $textHelper;
}

/**
* Measures the Damerau-Levenshtein distance of two words
*
* @param string $strA
* @param string $strB
* @return int distance
*/
protected function _distance($strA, $strB)
{
$d = [];

$lenA = $this->text->strlen($strA);
$lenB = $this->text->strlen($strB);

if ($lenA == 0) {
return $lenB;
}

if ($lenB == 0) {
return $lenA;
}

for ($i = 0; $i <= $lenA; $i++) {
$d[$i] = [];
$d[$i][0] = $i;
}

for ($j = 0; $j <= $lenB; $j++) {
$d[0][$j] = $j;
}

for ($i = 1; $i <= $lenA; $i++) {
for ($j = 1; $j <= $lenB; $j++) {
$cost = substr($strA, $i - 1, 1) == substr($strB, $j - 1, 1) ? 0 : 1;

$d[$i][$j] = min(
$d[$i - 1][$j] + 1, // deletion
$d[$i][$j - 1] + 1, // insertion
$d[$i - 1][$j - 1] + $cost // substitution
);

if ($i > 1 &&
$j > 1 &&
substr($strA, $i - 1, 1) == substr($strB, $j - 2, 1) &&
substr($strA, $i - 2, 1) == substr($strB, $j - 1, 1)
) {
$d[$i][$j] = min(
$d[$i][$j],
$d[$i - 2][$j - 2] + $cost // transposition
);
}
}
}

return $d[$lenA][$lenB];
}

/**
* Case insensitive version of distance()
*
* @param string $strA
* @param string $strB
* @return int distance
*/
public function distance($strA, $strB)
{
return $this->_distance($this->text->strtolower($strA), $this->text->strtolower($strB));
}

/**
* An attempt to measure word similarity in percent
*
* @param string $strA
* @param string $strB
*
* @return int distance from 0 to 100
*/
protected function _similarity($strA, $strB)
{
$lenA = $this->text->strlen($strA);
$lenB = $this->text->strlen($strB);

if ($lenA == 0 && $lenB == 0) {
return 100;
}

$distance = $this->_distance($strA, $strB);
$similarity = 100 - (int)round(200 * $distance / ($lenA + $lenB));

return $similarity >= 100 ? 100 : $similarity;
}

/**
* Case insensitive version of similarity()
*
* @param string $strA
* @param string $strB
*
* @return int distance from 0 to 100
*/
public function similarity($strA, $strB)
{
return $this->_similarity($this->text->strtolower($strA), $this->text->strtolower($strB));
}
}