<?php
  
  /*
   * This file is part of the Symfony package.
   *
   * (c) Fabien Potencier <fabien@symfony.com>
   *
   * For the full copyright and license information, please view the LICENSE
   * file that was distributed with this source code.
   */
  
  namespace Symfony\Component\Translation\Loader;
  
  /**
   * @copyright Copyright (c) 2010, Union of RAD https://github.com/UnionOfRAD/lithium
   * @copyright Copyright (c) 2012, Clemens Tolboom
   */
  class PoFileLoader extends FileLoader
  {
      /**
       * Parses portable object (PO) format.
       *
       * From https://www.gnu.org/software/gettext/manual/gettext.html#PO-Files
       * we should be able to parse files having:
       *
       * white-space
       * #  translator-comments
       * #. extracted-comments
       * #: reference...
       * #, flag...
       * #| msgid previous-untranslated-string
       * msgid untranslated-string
       * msgstr translated-string
       *
       * extra or different lines are:
       *
       * #| msgctxt previous-context
       * #| msgid previous-untranslated-string
       * msgctxt context
       *
       * #| msgid previous-untranslated-string-singular
       * #| msgid_plural previous-untranslated-string-plural
       * msgid untranslated-string-singular
       * msgid_plural untranslated-string-plural
       * msgstr[0] translated-string-case-0
       * ...
       * msgstr[N] translated-string-case-n
       *
       * The definition states:
       * - white-space and comments are optional.
       * - msgid "" that an empty singleline defines a header.
       *
       * This parser sacrifices some features of the reference implementation the
       * differences to that implementation are as follows.
       * - No support for comments spanning multiple lines.
       * - Translator and extracted comments are treated as being the same type.
       * - Message IDs are allowed to have other encodings as just US-ASCII.
       *
       * Items with an empty id are ignored.
       *
       * {@inheritdoc}
       */
      protected function loadResource(string $resource)
      {
          $stream = fopen($resource, 'r');
  
          $defaults = [
              'ids' => [],
              'translated' => null,
          ];
  
          $messages = [];
          $item = $defaults;
          $flags = [];
  
          while ($line = fgets($stream)) {
              $line = trim($line);
  
              if ('' === $line) {
                  // Whitespace indicated current item is done
                  if (!\in_array('fuzzy', $flags)) {
                      $this->addMessage($messages, $item);
                  }
                  $item = $defaults;
                  $flags = [];
              } elseif ('#,' === substr($line, 0, 2)) {
                  $flags = array_map('trim', explode(',', substr($line, 2)));
              } elseif ('msgid "' === substr($line, 0, 7)) {
                  // We start a new msg so save previous
                  // TODO: this fails when comments or contexts are added
                  $this->addMessage($messages, $item);
                  $item = $defaults;
                  $item['ids']['singular'] = substr($line, 7, -1);
              } elseif ('msgstr "' === substr($line, 0, 8)) {
                  $item['translated'] = substr($line, 8, -1);
              } elseif ('"' === $line[0]) {
                  $continues = isset($item['translated']) ? 'translated' : 'ids';
  
                  if (\is_array($item[$continues])) {
                      end($item[$continues]);
                      $item[$continues][key($item[$continues])] .= substr($line, 1, -1);
                  } else {
                      $item[$continues] .= substr($line, 1, -1);
                  }
              } elseif ('msgid_plural "' === substr($line, 0, 14)) {
                  $item['ids']['plural'] = substr($line, 14, -1);
              } elseif ('msgstr[' === substr($line, 0, 7)) {
                  $size = strpos($line, ']');
                  $item['translated'][(int) substr($line, 7, 1)] = substr($line, $size + 3, -1);
              }
          }
          // save last item
          if (!\in_array('fuzzy', $flags)) {
              $this->addMessage($messages, $item);
          }
          fclose($stream);
  
          return $messages;
      }
  
      /**
       * Save a translation item to the messages.
       *
       * A .po file could contain by error missing plural indexes. We need to
       * fix these before saving them.
       */
      private function addMessage(array &$messages, array $item)
      {
          if (!empty($item['ids']['singular'])) {
              $id = stripcslashes($item['ids']['singular']);
              if (isset($item['ids']['plural'])) {
                  $id .= '|'.stripcslashes($item['ids']['plural']);
              }
  
              $translated = (array) $item['translated'];
              // PO are by definition indexed so sort by index.
              ksort($translated);
              // Make sure every index is filled.
              end($translated);
              $count = key($translated);
              // Fill missing spots with '-'.
              $empties = array_fill(0, $count + 1, '-');
              $translated += $empties;
              ksort($translated);
  
              $messages[$id] = stripcslashes(implode('|', $translated));
          }
      }
  }