<?php

namespace EesyPHP;

use EesyPHP\Log;

use Locale;
use add_js_file;

class I18n {
  // Gettext text domain
  public const TEXT_DOMAIN = 'DEFAULT';

  /**
   * The root directory path of translation files
   * @var string
   */
  protected static string $root_path = 'locales';

  /**
   * The default locale
   * @var string
   */
  protected static string $default_locale = 'en_US.UTF8';

  /**
   * Initialize translation system
   *
   * Detect best translation language and configure the translation
   * system.
   *
   * @param string|null $root_path The root directory path of translation files
   *                               (optional, default: ./locales)
   * @param string|null $default_locale The default locale
   *                                    (optional, default: en_US.UTF8)
   * @return void
   */
  public static function init($root_path=null, $default_locale=null) {
    global $root_dir_path;
    if (!is_null($root_path))
      self :: $root_path = $root_path;
    if (!is_null($default_locale))
      self :: $default_locale = $default_locale;

    if (!class_exists('Locale')) {
      Log :: error('Locale PHP class does not exist. May be php-intl is not installed?');
      return;
    }

    $available_langs = self :: get_available_langs();
    if (php_sapi_name() != "cli") {
      if (isset($_REQUEST['lang']) && in_array($_REQUEST['lang'], $available_langs)) {
        $lang = $_REQUEST['lang'];
        Log :: trace("Select lang from request parameter: '$lang'");
      }
      elseif (isset($_SESSION['lang']) && in_array($_SESSION['lang'], $available_langs) && !isset($_REQUEST['reset_lang'])) {
        $lang = $_SESSION['lang'];
        Log :: trace("Restore lang from session: '$lang'");
      }
      else {
        $lang = Locale::lookup(
          self :: get_available_langs(),
          Locale::acceptFromHttp($_SERVER['HTTP_ACCEPT_LANGUAGE']),
          true,
          Locale::getPrimaryLanguage(self :: $default_locale)
        );
        Log :: trace("Best lang found is '$lang'");
      }
    }
    else {
      $lang = null;
      $sys_current = getenv('LC_ALL');
      if (!$sys_current)
        $sys_current = getenv('LANG');
      if ($sys_current)
        $lang = Locale::getPrimaryLanguage($sys_current);
      if (is_null($lang)) {
        Log :: trace('No configured lang detected from CLI env, use default.');
        $lang = Locale::getPrimaryLanguage(self :: $default_locale);
      }
      else
        Log :: trace("Lang detected from CLI env : '$lang'");
    }

    // Keep selected lang in session
    $_SESSION['lang'] = $lang;

    $locale = self :: lang2locale($lang);
    Log :: trace("Matching locale found with language '$lang' is '$locale'");

    // Gettext firstly look the LANGUAGE env variable, so set it
    if (!putenv("LANGUAGE=$locale"))
      Log :: error("Fail to set LANGUAGE variable in environnement to '$locale'");

    // Set the locale
    if (setlocale(LC_ALL, $locale) === false)
      Log :: error("An error occured setting locale to '$locale'");

    // Configure and set the text domain
    $fullpath = bindtextdomain(self :: TEXT_DOMAIN, self :: $root_path);
    Log :: trace("Text domain fullpath is '$fullpath'.");
    Log :: trace("Text domain is '".textdomain(self :: TEXT_DOMAIN)."'.");
    Log :: trace("Test: "._('Hello world !'));

    // JS translation file
    $js_translation_file = "translations/$lang.js";
    if (
      php_sapi_name() != "cli"
      && isset($root_dir_path) && $root_dir_path
      && is_file("$root_dir_path/public_html/$js_translation_file")
      && function_exists('add_js_file')
    ) {
      add_js_file(array("lib/babel.js", "js/translation.js", $js_translation_file));
    }

    if (php_sapi_name() == 'cli') {
      add_cli_command(
        'extract_messages',
        array('\\EesyPHP\\I18n', 'cli_extract_messages'),
        self :: ___("Extract messages that need to be translated"),
        null,
        self :: ___("This command could be used to generate/update lang/messages.pot file.")
      );

      add_cli_command(
        'update_messages',
        array('\\EesyPHP\\I18n', 'cli_update_messages'),
        self :: ___("Update messages in translation PO lang files"),
        null,
        self :: ___("This command could be used to init/update PO files in lang/*/LC_MESSAGES directories.")
      );

      add_cli_command(
        'compile_messages',
        array('\\EesyPHP\\I18n', 'cli_compile_messages'),
        self :: ___(
          "Compile messages from existing translation PO lang files to ".
          "corresponding MO files and JSON catalogs"
        ),
        null,
        self :: ___(
          "This command could be used to compile PO files in lang/*/LC_MESSAGES ".
          "directories to MO files and as JSON catalogs in public_html/translations."
        )
      );
    }
  }

  /**
   * List available translation languages
   *
   * @param $as_locales boolean  If true, locale names will be return instead
   *                             of primary languages (optional, default: false)
   *
   * @return array Array of available translation languages (or locales)
   */
  public static function get_available_langs($as_locales=false) {
    if (!is_dir(self :: $root_path))
      Log :: fatal("Root land directory not found (%s)", self :: $root_path);
    $langs = array(($as_locales?'en_US.UTF8':'en'));
    if ($dh = opendir(self :: $root_path)) {
      while (($file = readdir($dh)) !== false) {
        if (!is_dir(self :: $root_path . '/' . $file) || in_array($file, array('.', '..')))
          continue;
        if ($as_locales) {
          $langs[] = $file;
          continue;
        }
        $lang = Locale::getPrimaryLanguage($file);
        if (!in_array($lang, $langs))
          $langs[] = $lang;
      }
      closedir($dh);
    }
    $langs = array_unique($langs);
    Log :: trace('Available '.($as_locales?'locales':'languages').': '.implode(', ', $langs));
    return $langs;
  }

  /**
   * Get locale name corresponding to specified translation language
   *
   * @param  $lang string The translation language
   * @param  $default string|null Default locale name to return if any available translation
   *                              locales matched with the specified language
   *                              (optional, default: self :: $default_locale)
   * @return string Corresponding locale
   */
  public static function lang2locale($lang, $default=null) {
    if (is_null($default))
      $default = self :: $default_locale;
    foreach (self :: get_available_langs(true) as $locale) {
      if (strpos($locale, $lang) === false)
        continue;
      return $locale;
    }
    return $default;
  }

  /**
   * Helper function: just mark message for translation
   *
   * @param  string $msg  The message to translate
   *
   * @return string The message without transformation
   */
  public static function ___($msg) {
    return $msg;
  }

  /*
   ********************************************************************
   *                   Translations CLI commands                      *
   ********************************************************************
   */


  /**
   * Convert PO file to JSON file
   *
   * @param  string $locale  The locale of the input PO file
   * @param  string $path    The path of the input PO file
   *
   * @return string JSON encoded file content
   */
  public static function po2json($locale, $path) {
    $fileHandler = new \Sepia\PoParser\SourceHandler\FileSystem($path);
    $poparser = new \Sepia\PoParser\Parser($fileHandler);
    $catalog = $poparser->parse();
    $headers = $catalog->getHeader();

    $messages = array();
    foreach ($catalog->getEntries() as $entry) {
      // msg id json format
      $msg = $entry->getMsgStr();
      if ($entry->isPlural())
        $msg = array($msg, $entry->getMsgIdPlural());
      $messages[$entry->getMsgId()] = $msg;
    }
    return json_encode(array(
      'messages' => $messages,
      'locale' => $locale,
      'domain' => self :: TEXT_DOMAIN,
      'plural_expr' => '(n > 1)',
    ));
  }

  /**
   * Command to extract messages from PHP/JS & template files and
   * generate the lang/messages.pot file.
   *
   * @param  array $command_args  The command arguments
   * @return void
   */
  public static function cli_extract_messages($command_args) {
    global $root_dir_path, $smarty_templates_dir;

    // List PHP files to parse
    $php_files = run_external_command(
      array('find', escapeshellarg($root_dir_path), '-name', "'*.php'"),
      null,   // no STDIN data
      false   // do not escape command args (already done)
    );
    if (!is_array($php_files) || $php_files[0] != 0) {
      Log :: fatal(_("Fail to list PHP files."));
    }

    // Extract messages from PHP files using xgettext
    $result = run_external_command(
      array(
        "xgettext",
        "--from-code utf-8",
        "--language=PHP",
        "-o", self :: $root_path."/php-messages.pot",  // Output
        "--omit-header",                               // No POT header
        "--keyword=___",                               // Handle custom ___() translation function
        "--files=-"                                    // Read files to parse from STDIN
      ),
      $php_files[1]                                    // Pass PHP files list via STDIN
    );
    if (!is_array($result) || $result[0] != 0)
      Log :: fatal(_("Fail to extract messages from PHP files using xgettext."));


    // List JS files to parse
    $js_files = run_external_command(
      array('find', escapeshellarg("$root_dir_path/public_html/js"), '-name', "'*.js'"),
      null,   // no STDIN data
      false   // do not escape command args (already done)
    );
    if (!is_array($js_files) || $js_files[0] != 0) {
      Log :: fatal(_("Fail to list JS files."));
    }

    // Extract messages from JS files using xgettext
    $result = run_external_command(
      array(
        "xgettext",
        "--from-code utf-8",
        "--language=JavaScript",
        "-o", self :: $root_path."/js-messages.pot", // Output
        "--omit-header",                             // No POT header
        "--keyword=___",                             // Handle custom ___() translation function
        "--files=-"                                  // Read files to parse from STDIN
      ),
      $js_files[1]                                   // Pass JS files list via STDIN
    );
    if (!is_array($result) || $result[0] != 0)
      Log :: fatal(_("Fail to extract messages from JS files using xgettext."));

    // Extract messages from templates files using tsmarty2c.php
    $result = run_external_command(
      array (
        "$root_dir_path/vendor/bin/tsmarty2c.php",
        "-o", self :: $root_path."/templates-messages.pot",
        $smarty_templates_dir,
      )
    );
    if (!is_array($result) || $result[0] != 0)
      Log :: fatal(
        _("Fail to extract messages from template files using tsmarty2c.php script."));

    $fd = fopen(self :: $root_path."/headers.pot", 'w');
    $headers = array(
      'msgid ""',
      'msgstr ""',
      '"POT-Creation-Date: '.date('Y-m-d H:iO').'\n"',
      '"PO-Revision-Date: '.date('Y-m-d H:iO').'\n"',
      '"MIME-Version: 1.0\n"',
      '"Content-Type: text/plain; charset=utf-8\n"',
      '"Content-Transfer-Encoding: 8bit\n"',
    );
    fwrite($fd, implode("\n", $headers));
    fclose($fd);

    // Merge previous results in messages.pot file using msgcat
    $result = run_external_command(array(
      'msgcat',
      self :: $root_path."/headers.pot",
      self :: $root_path."/php-messages.pot",
      self :: $root_path."/js-messages.pot",
      self :: $root_path."/templates-messages.pot",
      "-t", "utf-8", "--use-first",
      "-o", self :: $root_path."/messages.pot",
    ));
    if (!is_array($result) || $result[0] != 0)
      Log :: fatal(_("Fail to merge messages using msgcat."));
  }

  /**
   * Command to update messages from lang/messages.pot file to
   * all PO file in lang/[lang]/LC_MESSAGES.
   *
   * @param  array $command_args  The command arguments
   * @return bool
   */
  public static function cli_update_messages($command_args) {
    global $root_dir_path, $smarty_templates_dir;

    $compendium_args = array();
    foreach ($command_args as $path) {
      if (!file_exists($path))
        Log :: fatal(_("Compendium file %s not found."), $path);
      $compendium_args[] = '-C';
      $compendium_args[] = $path;
    }

    $pot_file = self :: $root_path."/messages.pot";
    if (!is_file($pot_file))
      Log :: fatal(_("POT file not found (%s). Please run extract_messages first."), $pot_file);

    if ($dh = opendir(self :: $root_path)) {
      $error = False;
      while (($file = readdir($dh)) !== false) {
        if (
          !is_dir(self :: $root_path . '/' . $file) ||
          in_array($file, array('.', '..')) ||
          is_link(self :: $root_path . '/' . $file)
        )
          continue;

        Log :: debug(_("Lang directory '%s' found"), $file);

        // Check LC_MESSAGES directory exists
        $lang = $file;
        $lang_dir = self :: $root_path . '/' . $file . '/LC_MESSAGES' ;
        if (!is_dir($lang_dir)) {
          Log :: debug(_("LC_MESSAGES directory not found in lang '%s' directory, ignore it."),
            $lang);
          continue;
        }

        $po_file = $lang_dir . '/' . self :: TEXT_DOMAIN . '.po';
        $created = false;
        if (!is_file($po_file)) {
          // Init PO file from POT file using msginit
          $result = run_external_command(
            array("msginit", "-i", "$pot_file", "-l", "$lang", "-o", $po_file)
          );
          if (is_array($result) && $result[0] == 0) {
            $created = true;
          } else {
            Log :: error(_("Fail to init messages in %s PO file using msginit (%s)."),
              $lang, $po_file);
            $error = True;
          }
        }

        // Update messages in PO file from POT file using msgmerge
        // Note: msginit does not accept compendium files, so we also run
        // msgmerge on creation with compendium file(s).
        if (is_file($po_file) && (!$created || $compendium_args)) {
          $result = run_external_command(
            array_merge(
              array("msgmerge", "-q", "-U"),
              $compendium_args,
              array($po_file, $pot_file)
            )
          );
          if (!is_array($result) || $result[0] != 0) {
            Log :: error(_("Fail to update messages in %s PO file using msgmerge (%s)."),
              $lang, $po_file);
            $error = True;
          }
        }
        elseif (!$created) {
          Log :: debug(_("PO file not found in lang '%s' directory, ignore it."), $lang);
        }
      }
      closedir($dh);
      return !$error;
    }

    Log :: fatal(_("Fail to open root lang directory (%s)."), $root_dir_path);
    return false;
  }

  /**
   * Command to compile messages from existing translation PO lang files
   * to corresponding MO files and as JSON catalog (for translation in JS).
   *
   * @param  array $command_args  The command arguments
   * @return bool
   */
  public static function cli_compile_messages($command_args) {
    global $root_dir_path, $smarty_templates_dir;

    if ($dh = opendir(self :: $root_path)) {
      $error = False;
      while (($file = readdir($dh)) !== false) {
        if (
          !is_dir(self :: $root_path . '/' . $file) ||
          in_array($file, array('.', '..'))
        )
          continue;

        if (is_link(self :: $root_path . '/' . $file)) {
          $real_lang_dir = readlink(self :: $root_path . '/' . $file);
          if (dirname($real_lang_dir) != '.' || !is_dir(self :: $root_path . '/' . $real_lang_dir))
            continue;
          $lang = $file;
          Log :: debug(_("Lang alias symlink found: %s -> %s"), $lang, $real_lang_dir);

          // Create JSON catalog symlink (if not exists)
          $js_link = "$root_dir_path/public_html/translations/$lang.js";
          $link_target = "$real_lang_dir.js";
          if (!file_exists($js_link)) {
            if (symlink($link_target, $js_link)) {
              Log :: info(_("JSON catalog symlink for %s -> %s created (%s)"),
                $lang, $real_lang_dir, $js_link);
            }
            else {
              Log :: error(_("Fail to create JSON catalog symlink for %s -> %s (%s)"),
                $lang, $real_lang_dir, $js_link);
              $error = True;
            }
          }
          elseif (readlink($js_link) == $link_target) {
            Log :: debug(_("JSON catalog symlink for %s -> %s already exist (%s)"),
              $lang, $real_lang_dir, $js_link);
          }
          else {
            Log :: warning(
              _("JSON catalog file for %s already exist, but it's not a symlink to %s (%s)"),
              $lang, $real_lang_dir, $js_link
            );
            $error = True;
          }
          continue;
        }

        Log :: debug(_("Lang directory '%s' found"), $file);

        // Check LC_MESSAGES directory exists
        $lang = $file;
        $lang_dir = self :: $root_path . '/' . $file . '/LC_MESSAGES' ;
        if (!is_dir($lang_dir)) {
          Log :: debug(_("LC_MESSAGES directory not found in lang '%s' directory, ignore it."),
            $lang);
          continue;
        }

        // Test .PO file is present
        $po_file = $lang_dir . '/' . self :: TEXT_DOMAIN . '.po';
        if (!is_file($po_file)) {
          Log :: debug(_("PO file not found in lang '%s' directory, ignore it."),
            $lang);
          continue;
        }

        $mo_file = preg_replace('/\.po$/', '.mo', $po_file);

        // Compile messages from PO file to MO file using msgfmt
        $result = run_external_command(
          array("msgfmt", "-o", $mo_file, $po_file)
        );
        if (!is_array($result) || $result[0] != 0) {
          Log :: error(
            _("Fail to compile messages from %s PO file as MO file using msgfmt (%s)."),
            $lang, $po_file
          );
          $error = True;
        }

        // Compile messages from PO file to JSON catalog file
        $json_catalog = self :: po2json($lang, $po_file);
        $js_file = "$root_dir_path/public_html/translations/$lang.js";
        if(!$fd = fopen($js_file, 'w')) {
          Log :: error(_("Fail to open %s JSON catalog file in write mode (%s)."),
            $lang, $js_file);
          $error = True;
        }
        elseif (fwrite($fd, sprintf("translations_data = %s;", $json_catalog)) === false) {
          Log :: error(_("Fail to write %s JSON catalog in file (%s)."),
            $lang, $js_file);
          $error = True;
        }
        else {
          Log :: info(_("%s JSON catalog writed (%s)."), $lang, $js_file);
        }
      }
      closedir($dh);

      return !$error;
    }
    Log :: fatal(_("Fail to open root lang directory (%s)."), $root_dir_path);
    return false;
  }

}

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