<?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-search-ultimate
* @version 2.3.2
* @copyright Copyright (C) 2024 Mirasvit (https://mirasvit.com/)
*/



declare(strict_types=1);

namespace Mirasvit\Misspell\Adapter\Mysql;

use Mirasvit\Misspell\Api\Data\SuggestInterface;
use Magento\Framework\App\ResourceConnection;
use Mirasvit\Misspell\Service\TextService;
use Mirasvit\Misspell\Service\DamerauService;

class Suggester implements SuggestInterface
{
private $diffs;

private $keys;

private $resource;

private $connection;

private $damerauService;

private $textService;

public function __construct(
ResourceConnection $resource,
TextService $textService,
DamerauService $damerauService
) {
$this->resource = $resource;
$this->textService = $textService;
$this->damerauService = $damerauService;
$this->connection = $resource->getConnection();
}

public function suggest(string $baseQuery): string
{
$this->diffs = [];
$this->keys = [];
$final = [];

$baseQuery = $this->textService->cleanString($baseQuery);
$queries = $this->textService->splitWords($baseQuery);

foreach ($queries as $query) {
$len = $this->textService->strlen($query);

if ($len < $this->textService->getGram() || is_numeric($query)) {
$final[] = $query;
continue;
}

$result = $this->getBestMatch($query);
$keyword = $result['keyword'];

$this->split($query, '', $query);
$splitKeyword = '';

if (count($this->diffs)) {
arsort($this->diffs);
$keys = array_keys($this->diffs);
$key = $keys[0];
$splitKeyword = $this->keys[$key];
}

$basePer = $this->damerauService->similarity($query, $keyword);
$splitPer = $this->damerauService->similarity($query, $splitKeyword);

if ($basePer > $splitPer) {
$final[] = $keyword;
} else {
$final[] = $splitKeyword;
}
}

$result = implode(' ', $final);

if ($this->damerauService->similarity($result, $baseQuery) < 50) {
$result = '';
}

return $result;
}

protected function split(string $query, string $prefix = '', string $base = ''): bool
{
$keyword = $query;
$len = $this->textService->strlen($query);

if ($len > 20) {
return false;
}

for ($i = $this->textService->getGram(); $i <= $len - $this->textService->getGram() + 1; $i++) {
$a = $this->textService->substr($query, 0, $i);
$b = $this->textService->substr($query, $i);

$aa = $this->getBestMatch($a);
$bb = $this->getBestMatch($b);

$key = $a . '|' . $b;

if ($prefix) {
$key = $prefix . '|' . $key;
}

$this->keys[$key] = '';
if ($prefix) {
$this->keys[$key] = $prefix . ' ';
}
$this->keys[$key] .= $aa['keyword'] . ' ' . $bb['keyword'];

$this->diffs[$key] = ($this->damerauService->similarity($base, $this->keys[$key]) + $aa['diff'] + $bb['diff']) / 3;

if ($prefix) {
$kwd = $prefix . '|' . $aa['keyword'];
} else {
$kwd = $aa['keyword'];
}

if ($aa['diff'] > 50) {
$this->split($b, $kwd, $query);
}
}

return true;
}

public function getBestMatch(string $query): array
{
$query = trim($query);

if (!$query) {
return ['keyword' => $query, 'diff' => 100];
}

$len = (int)$this->textService->strlen($query);
$trigram = $this->textService->getTrigram($this->textService->strtolower($query));

$tableName = $this->resource->getTableName('mst_misspell_index');

$select = $this->connection->select();
$relevance = '(-ABS(LENGTH(keyword) - ' . $len . ') + MATCH (trigram) AGAINST("' . $trigram . '"))';
$relevancy = new \Zend_Db_Expr('AVG(' . $relevance . ' + frequency) AS relevancy');
$select->from($tableName, ['keyword', $relevancy, 'AVG(frequency) as frequency'])
->where('MATCH (trigram) AGAINST("' . $trigram . '")')
->group('keyword')
->order('relevancy desc')
->limit(10);

try {
$keywords = $this->connection->fetchAll($select);
} catch (\Exception $e) {
return ['keyword' => $query, 'diff' => 100];
}

$maxFreq = 0.0001;
foreach ($keywords as $keyword) {
$maxFreq = max($keyword['frequency'], $maxFreq);
}

$preResults = [];
foreach ($keywords as $keyword) {
$preResults[$keyword['keyword']] = $this->damerauService->similarity($query, $keyword['keyword'])
+ $keyword['frequency'] * (10 / $maxFreq);
}
arsort($preResults);

$keys = array_keys($preResults);

if (count($keys) > 0) {
$keyword = $keys[0];
$keyword = $this->toSameRegister($keyword, $query);
$diff = $preResults[$keys[0]];
$result = ['keyword' => $keyword, 'diff' => $diff];
} else {
$result = ['keyword' => $query, 'diff' => 100];
}

return $result;
}

protected function toSameRegister(string $str, string $base): string
{
$minLen = min($this->textService->strlen($base), $this->textService->strlen($str));

for ($i = 0; $i < $minLen; $i++) {
$chr = $this->textService->substr($base, $i, 1);

if ($chr != $this->textService->strtolower($chr)) {
$chrN = $this->textService->substr($str, $i, 1);
$chrN = strtoupper($chrN);
$str = substr_replace($str, $chrN, $i, 1);
}
}

return $str;
}
}