The function relativedate() take date as argument in ISO 8601 format and returns an array with Arabic text that has the relative time since the time of the input and the other value in the array tells if the post is new or not, it is considered as new if the input is less than 4 hours old

arabic_post_date.php

<?php
/*  
  Copyright 2020 KAMEL LABIAD

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated 
documentation files (the "Software"), to deal in the Software without restriction, including without limitation 
the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and 
to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions 
of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED 
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THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF 
CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 
DEALINGS IN THE SOFTWARE.

The function relativedate() take date as argument in ISO 8601 format and returns an array with Arabic text 
that has the relative time since the time of the input and the other value in the array tells if the post 
is new or not, it is considered as new if the input is less than 4 hours old
*/  



function relativedate($postDate){
    
    $today  = date("Y-m-d H:i:s");  

    $timedif = strtotime($today)-strtotime($postDate);

          $oneminute = 60;    // 1 minute
         $towminutes = 120;   // 2 minutes
       $threeminutes = 180;   // 3 minutes
      $elevenminutes = 660;   // 11 minutes
            $onehour = 3600;  // 1 hour 
           $towhours = 7200;  // 2 hours
         $threehours = 10800; // 3 hours
          $fourhours = 14400; // 4 hours
        $elevenhours = 39600; // 11 hours
    $Twentyfourhours = 86400; // 24 hours

    $timeStamp['new'] = false;

    // one minute
    if ($timedif < $towminutes) {
        
        $timeStamp['time'] = ' قبل دقيقة واحدة';
        $timeStamp['new'] = true;
    }

    // tow minutes
    if ($timedif >= $towminutes && $timedif < $threeminutes) { 
        
        $timeStamp['time'] = ' قبل دقيقتين';
        $timeStamp['new'] = true;
    }

    // three minutes or more
    if ($timedif >= $threeminutes && $timedif < $elevenminutes) { 
        
        $timeStamp['time'] = ' قبل '. floor($timedif/60) . ' دقائق ';
        $timeStamp['new'] = true;
    }

    // eleven minutes and more
    if ($timedif >= $elevenminutes && $timedif < $onehour) { 
        
        $timeStamp['time'] = ' قبل '. floor($timedif/60) . ' دقيقة ';
        $timeStamp['new'] = true;
    }

    // one hour
    if ($timedif >= $onehour && $timedif < $towhours) { 
        
        $timeStamp['time'] = ' قبل ساعة ';
        $timeStamp['new'] = true;
    }

    // tow hours
    if ($timedif >= $towhours && $timedif < $threehours) { 
        
        $timeStamp['time'] = ' قبل ساعتين ';
        $timeStamp['new'] = true;
    }

    // three hours or more
    if ($timedif >= $threehours && $timedif < $elevenhours) { 
        
        $timeStamp['time'] = ' قبل '. floor($timedif/3600) . ' ساعات ';
        if ($timedif < $fourhours)
        { 
            $timeStamp['new'] = true;  
        }  
    }

    // eleven hours or more
    if ($timedif >= $elevenhours && $timedif < $Twentyfourhours) { 
        
        $timeStamp['time'] = ' قبل '. floor($timedif/3600) . ' ساعة ';
    }

    // more than 24 hours start showing the post date in arabic
    if ($timedif >= $Twentyfourhours ) { 
        
        $timeStamp['time'] = arabicDate($postDate);
    }


    return $timeStamp;

}


function arabicDate($rawDate){
    // construct arabic dates with arabic months

    $month = intval(date("m",strtotime($rawDate)));        
        $day = intval(date("d",strtotime($rawDate)));
    $year = date("Y",strtotime($rawDate));
        
    $monthsArabic = array( 
        1=>'يناير', 
        2=>'فبراير',
        3=>'مارس',  
        4=>'أبريل', 
        5=>'مايو', 
        6=>'يونيو', 
        7=>'يوليو', 
        8=>'أغسطس', 
        9=>'سبتمبر', 
        10=>'أكتوبر', 
        11=>'نوفمبر', 
        12=>'ديسمبر' 
    );
    
    $newDateMark ='  '.$day.' '.$monthsArabic[$month].' '.$year;
    
   return $newDateMark;
}