Removes all kind of Arabic diacritical signs and markers and replaces them with their plain letter form. For the use of SearchWP Wordpress plugin.

searchwp_removearabic.php

/*
Plugin Name: SearchWP Remove Arabic Diacritics
Description: Removes all kind of إعراب-signs as well as تشكيل-signs for the use of SearchWP Wordpress plugin.
Author: Gerald Drissner
Note: This is a fork and extension of https://gist.github.com/BrElio/bd84d8035278adf834b29ec5e1187567 and Relevannsi's code snippet regarding foreign languages.
Version: 1.0.0
Last update: 2022-10-20
*/

add_filter( 'searchwp\tokens\string', 'swp_arabic_remap', 9);
		   
function swp_arabic_remap( $a ) {
    $remap = array(
        'إ' => 'ا',
        'آ' => 'ا',
        'أ' => 'ا',
        'ئ' => 'ى',
        'ة' => 'ه',
        'ؤ' => 'و',
        'ـ' => '',
        'آ' => 'ا',
    );

    $diacritics = array(
        '~[\x{0600}-\x{061F}]~u',   
        '~[\x{063B}-\x{063F}]~u',   
        '~[\x{064B}-\x{065E}]~u',   
        '~[\x{066A}-\x{06FF}]~u',   
    );

    $a = preg_replace( $diacritics, '', $a );
    $a = str_replace( array_keys( $remap ), array_values( $remap ), $a );

    return $a;
}