<?php

  /////////////////////////////////////////////////
 // Avaliable variables after importing this file
/////////////////////////////////////////////////

// The actual language being used
$lang = null;
// Avaliable detected languages
$langs = [];
// Function that gets the strings
$trans = function(){ return 'N/A'; };

/* I use functions to create scopes. Anything below
 * shouldn't be accesible from outside
 */

/* -------------------------------------------------*/

$__langfunc = function() use (&$lang, &$langs, &$trans){


    ///////////////
   /// Get basedir
  ///////////////

  // DOCUMENT_ROOT makes sure we always get the right folder
  $basedir = sprintf('%s/lang', $_SERVER['DOCUMENT_ROOT']);


    ///////////////////////////////////////
   /// Get the languages we have avaliable 
  ///////////////////////////////////////

  // To get the langs we scan the folder with the ini files
  $langs = scandir($basedir);
  // Filter for those that have to letters and end in ".ini"
  $langs = array_filter($langs, fn($x) => preg_match('/.*\.ini/', $x) === 1);
  // And we remove the ".ini" part
  $langs = array_map(fn($x) => substr($x, 0, 2), $langs);


    ////////////////////////////////////
   /// Get the optimal language to use
  ////////////////////////////////////

  /* Try to get the language from browser-sent headers. The
   * format for the header is like this: "en_US,es;q=0.5,ar;q=0.1".
   * q=N represents the weight of preference, no q means q=1.0.
   */
  {
    // Divide language string per language
    $http_langs = explode(',', $_SERVER['HTTP_ACCEPT_LANGUAGE']);

    // Sanitize lang string and cast weight
    $http_langs = array_map(function($x){
      $x = explode(';',$x);
      $x[0] = strtolower(substr($x[0], 0, 2));
      $x[1] = (float)(explode('=',$x[1]??'q=1.0')[1]??1.0);
      return $x;
    }, $http_langs);

    // Sort by weight
    usort($http_langs, function($a, $b){
      if($a[1] === $b[1]) return 0;
      return ($a[1] > $b[1]) ? -1 : 1;
    });


    // Create new neat array like this: ['en', 'es', 'ar']
    $user_langs = [];
    array_walk($http_langs, function($arr) use (&$user_langs){
      if(!in_array($arr[0], $user_langs)) $user_langs[] = $arr[0];
    });

    // Assign the first match
    foreach($user_langs as $ilang){
      if(in_array($ilang, $langs)) {
        $lang = $ilang;
        break;
      }
    }

  }

  // Manully selected lang > HTTP lang > fallback lang
  $lang = ($_GET['lang']??null) ?: $lang ?: 'en';


    ///////////////////////////////////////////////////
   /// Get file and build function to get the strings
  ///////////////////////////////////////////////////

  $text = parse_ini_file("$basedir/$lang.ini", true);
  $trans = function (string $index) use ($text): string{
    return htmlspecialchars($text[$index]??"N/A", ENT_QUOTES);
  };
};

// Burn after reading
$__langfunc();
unset($__langfunc);