test of similar_text

test.php

+<?php
+
+$correctTexts = [
+    "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.",
+    "Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.",
+    "Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.",
+    "Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."
+];
+
+$studentsText = "em ipsum dolor sit anet, consectetr adipiscing elit, sed do eiusmod tempor incddunt ut labore et dole magna aliqua. " .
+    "Ut enim ad minim veniam, quis nostrud exercitation ulamco laboris nisi ut aliquip ex ea commodo conseat. " .
+    "Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. " .
+    "proident, unt in culpa qui officia deserunt mollit anim id est laborum. ";
+
+class textComparision
+{
+    static public function findMatchPartOfText($needle, $haystack) : string
+    {
+        // split text to pieces with length of $needle
+        $partLength = strlen($needle);
+
+        $parts = str_split($haystack, $partLength);
+
+        // evaluate each part
+        // $result consists of consistence percentage for each part
+        $results = [];
+
+        foreach ($parts as $part)
+        {
+            similar_text($needle, $part, $percents);
+
+            $results[] = ceil($percents * 100);
+        }
+
+        // get piece number with max percent of consistence
+        $partNumber = array_search(max($results), $results);
+
+        // defining bounds for search
+        // Extend search area from -50% to +50% of length for the part with max consistence
+        $leftBound = $partNumber * $partLength - ceil($partLength / 2);
+
+        $rightBound = $leftBound + $partLength;
+
+        // bounds normalization.
+        // If left or|and right bound is out of the range, then need to be normalized
+        if ($leftBound < 0) {
+            $leftBound = 0;
+        }
+
+        if ($rightBound >= strlen($haystack)) {
+            $rightBound = strlen($haystack) - 1;
+        }
+
+        // searching text in this range with max consistence
+        $results = [];
+        for($i = $leftBound; $i <= $rightBound; $i++)
+        {
+            similar_text(substr($haystack, $i, $partLength), $needle, $percent);
+            $results[$i] = $percent;
+        }
+
+        return substr($haystack, array_search(max($results), $results), $partLength);
+    }
+}
+
+echo "<h2>Students text</h2>" .
+    "<p>{$studentsText}</p>";
+
+foreach ($correctTexts as $key => $correctText)
+{
+    $userText = textComparision::findMatchPartOfText($correctText, $studentsText);
+
+    $color = $correctText === $userText ?
+        "green" :
+        "red";
+
+    echo "<p style='color: blue'>{$correctText}</p>" .
+        "<p style='color: {$color}'>{$userText}</p>";
+}
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