Laravel artisan command for syncing all translation files for given languages.

LocalizationSync.php

<?php

namespace App\Console\Commands;

use Illuminate\Console\Command;

class LocalizationSync extends Command
{
    /**
     * The name and signature of the console command.
     *
     * @var string
     */
    protected $signature = 'localization:sync {base : Base language} {target : Target language}';

    /**
     * The console command description.
     *
     * @var string
     */
    protected $description = 'Synchronize all lang files in target language with base language';

    /**
     * Create a new command instance.
     *
     * @return void
     */
    public function __construct()
    {
        parent::__construct();
    }

    /**
     * Execute the console command.
     *
     * @return mixed
     */
    public function handle()
    {
        $base_lang = $this->argument('base');
        $target_lang = $this->argument('target');

        $lang_dir = base_path() . DIRECTORY_SEPARATOR . 'resources' . DIRECTORY_SEPARATOR . 'lang';
        $base_dir = $lang_dir . DIRECTORY_SEPARATOR . $base_lang;
        $target_dir = $lang_dir . DIRECTORY_SEPARATOR . $target_lang;

        foreach (scandir($base_dir) as $name) {
            if ($name == '.' || $name == '..' || preg_match('#\.[0-9]{8}_[0-9]{6}\.php$#', $name)) {
                continue;
            }

            $base_path = $base_dir . DIRECTORY_SEPARATOR . $name;
            $target_path = $target_dir . DIRECTORY_SEPARATOR . $name;

            if (file_exists($target_path)) {
                $target = file_get_contents($target_path);
                $lemmas = $this->parse($target);

                if ($lemmas === false) {
                    $this->error("Parsing failed while reading '$target_lang/$name'");
                    continue;
                }
            }
            else {
                $target = false;
                $lemmas = [];
            }

            $base = file_get_contents($base_path);
            $result = $this->parse($base, $lemmas);

            if ($result === false) {
                $this->error("Parsing failed while syncing '$base_lang/$name'");
                continue;
            }

            if ($target === false || $target != $result) {
                file_put_contents($target_path, $result);

                $this->info("File '$target_lang/$name' synchronized");
            }
            else {
                $this->line("File '$target_lang/$name' already in sync");
            }
        }

        return 0;
    }

    /**
     * If lemmas are given substitute them in the content
     * Otherwise extract lemmas from content
     *
     * @param  string       $content
     * @param  false|array  $lemmas
     * @return string
     */
    public function parse($content, $lemmas = false)
    {
        $result = $lemmas === false ? [] : '';
        $tree = [null];
        $expects_key = false;

        while (strlen($content) > 0) {
            // whitespace, multiline comment, single line comment, initial return statement, final semicolon, array pair separator, array item separator, php opening tag, php closing tag
            if (preg_match('#^\s+#', $content, $match) 
                || preg_match('#^/\*.*?\*/#s', $content, $match)
                || preg_match('#^//.*?(?:\r\n?|\n)#', $content, $match)
                || preg_match('#^return#', $content, $match)
                || preg_match('#^;#', $content, $match)
                || preg_match('#^=>#', $content, $match)
                || preg_match('#^,#', $content, $match)
                || preg_match('#^<\?php#', $content, $match)
                || preg_match('#^\?>#', $content, $match)
            ) {
                $segment = $match[0];
            }
            // array opening
            else if (preg_match('#^\[#', $content, $match)) {
                if ($expects_key) {
                    return false;
                }

                $segment = $match[0];

                $expects_key = true;
            }
            // array closing
            else if (preg_match('#^\]#', $content, $match)) {
                // there are no more open array, including top level
                if (count($tree) < 1) {
                    return false;
                }

                $segment = $match[0];

                array_pop($tree);
            }
            // single or double quoted string
            else if (preg_match('#^(")((?:[^"\\\\]|\\\\.)*)"#', $content, $match)
                || preg_match("#^(')((?:[^'\\\\]|\\\\.)*)'#", $content, $match)
            ) {
                if ($expects_key) {
                    $segment = $match[0];

                    // add key to tree structure
                    $tree[] = $match[2];
                    $expects_key = false;
                }
                else {
                    // there is no key to assign the value to
                    if (count($tree) < 2) {
                        return false;
                    }

                    $key = implode('.', $tree);

                    // add value to results array
                    if ($lemmas === false) {
                        $result[$key] = $match[2];
                    }
                    // replace value with matching, non-empty lemma
                    else if (array_key_exists($key, $lemmas) && strlen($lemmas[$key]) > 0) {
                        $segment = $match[1] . $lemmas[$key] . $match[1];
                    }
                    // mark value as not specified
                    else {
                        $segment = $match[1] . '@todo: ' . $key . $match[1];
                    }

                    array_pop($tree);
                    $expects_key = true;
                }
            }
            // non recognized - something gone wrong
            else {
                return false;
            }

            $content = substr($content, strlen($match[0]));

            if ($lemmas !== false) {
                $result .= $segment;
            }
        }

        return $result;
    }
}