<?php

/*
* Fork this project on GitHub!
* https://github.com/Philipp15b/php-i18n
*
* License: MIT
*/

class i18n {

	/**
	* Language file path
	*
	* This is the path for the language files.
	* You must use the '{LANGUAGE}' placeholder for the language or
	* the script wont find any language files.
	*
	* @var string
	*/
	protected $filePath = './lang/lang_{LANGUAGE}.ini';

	/**
	* Cache file path
	*
	* This is the path for all the cache files.
	* Best is an empty directory with no other files in it.
	*
	* @var string
	*/
	protected $cachePath = './cache/lang/';

	/**
	* Fallback language
	*
	* This is the language which is used when there is no language file for
	* all other user languages.
	* It has the lowest priority.
	* Remember to create a language file for the fallback!!
	*
	* @var string
	*/
	protected $fallbackLang = 'en';

	/**
	* Merge in fallback language
	*
	* Whether to merge current language's strings with the strings of
	* the fallback language ($fallbackLang).
	*
	* @var bool
	*/
	protected $mergeFallback = true;

	/**
	* The class name of the compiled class that contains the translated texts.
	* @var string
	*/
	protected $prefix = 'L';

	/**
	* Forced language
	*
	* If you want to force a specific language define it here.
	*
	* @var string
	*/
	protected $forcedLang = NULL;

	/**
	* This is the separator used if you use sections in your ini-file
	*
	* For example, if you have a string 'greeting' in a section 'welcomepage'
	* you will can access it via 'L::welcomepage_greeting'.
	* If you changed it to 'ABC' you could access your string
	* via 'L::welcomepageABCgreeting'
	*
	* @var string
	*/
	protected $sectionSeparator = '_';


	/*
	* The following properties are only available after calling init().
	*/

	/**
	* User languages
	*
	* These are the languages the user uses.
	* Normally, if you use the getUserLangs-method this array will be
	* filled in like this:
	* 1. Forced language
	* 2. Language in $_GET['lang']
	* 3. Language in $_SESSION['lang']
	* 4. Fallback language
	*
	* @var array
	*/
	protected $userLangs = array();

	protected $appliedLang = NULL;
	protected $langFilePath = NULL;
	protected $cacheFilePath = NULL;
	protected $isInitialized = false;


	/**
	* Constructor
	*
	* The constructor sets all important settings.
	* All params are optional, you can set the options via extra functions too.
	*
	* @param string [$filePath] This is the path for the language files.
	* You must use the '{LANGUAGE}' placeholder for the language.
	* @param string [$cachePath] This is the path for all the cache files.
	* Best is an empty directory with no other files in it. No placeholders.
	* @param string [$fallbackLang] This is the language which is used
	* when there is no language file for all other user languages.
	* It has the lowest priority.
	* @param string [$prefix] The class name of the compiled class
	* that contains the translated texts. Defaults to 'L'.
	*/
	public function __construct(
		$filePath = NULL,
		$cachePath = NULL,
		$fallbackLang = NULL,
		$prefix = NULL)
	{
		// Apply settings
		if ($filePath != NULL) {
			$this->filePath = $filePath;
		}

		if ($cachePath != NULL) {
			$this->cachePath = $cachePath;
		}

		if ($fallbackLang != NULL) {
			$this->fallbackLang = $fallbackLang;
		}

		if ($prefix != NULL) {
			$this->prefix = $prefix;
		}
	}

	public function init() {
		if ($this->isInitialized()) {
			throw new BadMethodCallException(
				'This object from class ' . __CLASS__ .
				' is already initialized. ' .
				'It is not possible to init one object twice!');
		}

		$this->isInitialized = true;

		$this->userLangs = $this->getUserLangs();

		// search for language file
		$this->appliedLang = NULL;
		foreach ($this->userLangs as $priority => $langcode) {
			$this->langFilePath = $this->getConfigFilename($langcode);
			if (file_exists($this->langFilePath)) {
				$this->appliedLang = $langcode;
				break;
			}
		}
		if ($this->appliedLang == NULL) {
			throw new RuntimeException('No language file was found.');
		}

		// search for cache file
		$this->cacheFilePath =
			$this->cachePath . '/php_i18n_' . md5_file(__FILE__) . '_' .
			$this->prefix . '_' . $this->appliedLang . '.cache.php';

		// whether we need to create a new cache file
		$outdated = !file_exists($this->cacheFilePath) ||
		filemtime($this->cacheFilePath) < filemtime($this->langFilePath) || // the language config was updated
		($this->mergeFallback && filemtime($this->cacheFilePath) < filemtime($this->getConfigFilename($this->fallbackLang))); // the fallback language config was updated

		if ($outdated || true) {
			$config = $this->load($this->langFilePath);
			if ($this->mergeFallback)
			$config = array_replace_recursive($this->load($this->getConfigFilename($this->fallbackLang)), $config);

			$compiled =
				  "<?php\n"
				. "class " . $this->prefix . " {\n"
				. $this->compile($config)
				. '  public static function __callStatic($string, $args) {' . "\n"
				. '    if (defined("self::" . $string)) {' . "\n"
				. '      return vsprintf(constant("self::" . $string), $args);' . "\n"
				. "    }\n"
				. "  }\n"
				. "  function ".$this->prefix .'($string, $args=NULL) {' . "\n"
				. '    $return = constant("'.$this->prefix.'::".$string);' . "\n"
				. '    return $args ? vsprintf($return,$args) : $return;' . "\n"
				. "  }\n"
				. '}';

			if( ! is_dir($this->cachePath)) {
				mkdir($this->cachePath, 0755, true);
			}
			if (file_put_contents($this->cacheFilePath, $compiled) === FALSE) {
				throw new Exception("Could not write cache file to path '" . $this->cacheFilePath . "'. Is it writable?");
			}
			chmod($this->cacheFilePath, 0755);

		}

		require_once $this->cacheFilePath;
	}

	public function isInitialized() {
		return $this->isInitialized;
	}

	public function getAppliedLang() {
		return $this->appliedLang;
	}

	public function getCachePath() {
		return $this->cachePath;
	}

	public function getFallbackLang() {
		return $this->fallbackLang;
	}

	public function setFilePath($filePath) {
		$this->fail_after_init();
		$this->filePath = $filePath;
	}

	public function setCachePath($cachePath) {
		$this->fail_after_init();
		$this->cachePath = $cachePath;
	}

	public function setFallbackLang($fallbackLang) {
		$this->fail_after_init();
		$this->fallbackLang = $fallbackLang;
	}

	public function setMergeFallback($mergeFallback) {
		$this->fail_after_init();
		$this->mergeFallback = $mergeFallback;
	}

	public function setPrefix($prefix) {
		$this->fail_after_init();
		$this->prefix = $prefix;
	}

	public function setForcedLang($forcedLang) {
		$this->fail_after_init();
		$this->forcedLang = $forcedLang;
	}

	public function setSectionSeparator($sectionSeparator) {
		$this->fail_after_init();
		$this->sectionSeparator = $sectionSeparator;
	}

	/**
	* @deprecated Use setSectionSeparator.
	*/
	public function setSectionSeperator($sectionSeparator) {
		$this->setSectionSeparator($sectionSeparator);
	}

	/**
	* Returns the user languages
	*
	* Normally it returns an array like this:
	* 1. Forced language
	* 2. Language in $_GET['lang']
	* 3. Language in $_SESSION['lang']
	* 4. HTTP_ACCEPT_LANGUAGE
	* 5. Fallback language
	* Note: duplicate values are deleted.
	*
	* @return array with the user languages sorted by priority.
	*/
	public function getUserLangs() {
		$userLangs = array();

		// Highest priority: forced language
		if ($this->forcedLang != NULL) {
			$userLangs[] = $this->forcedLang;
		}

		// 2nd highest priority: GET parameter 'lang'
		if (isset($_GET['lang']) && is_string($_GET['lang'])) {
			$userLangs[] = $_GET['lang'];
		}

		// 3rd highest priority: SESSION parameter 'lang'
		if (isset($_SESSION['lang']) && is_string($_SESSION['lang'])) {
			$userLangs[] = $_SESSION['lang'];
		}

		// 4th highest priority: HTTP_ACCEPT_LANGUAGE
		if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
			foreach (explode(',', $_SERVER['HTTP_ACCEPT_LANGUAGE']) as $part) {
				$userLangs[] = strtolower(substr($part, 0, 2));
			}
		}

		// Lowest priority: fallback
		$userLangs[] = $this->fallbackLang;

		// remove duplicate elements
		$userLangs = array_unique($userLangs);

		// remove illegal userLangs
		$userLangs2 = array();
		foreach ($userLangs as $key => $value) {
			// only allow a-z, A-Z and 0-9 and _ and -
			if (preg_match('/^[a-zA-Z0-9_-]*$/', $value) === 1)
			$userLangs2[$key] = $value;
		}

		return $userLangs2;
	}

	protected function getConfigFilename($langcode) {
		return str_replace('{LANGUAGE}', $langcode, $this->filePath);
	}

	protected function load($filename) {
		$ext = substr(strrchr($filename, '.'), 1);
		switch ($ext) {
			case 'properties':
			case 'ini':
			$config = parse_ini_file($filename, true);
			break;
			case 'yml':
			case 'yaml':
			$config = spyc_load_file($filename);
			break;
			case 'json':
			$config = json_decode(file_get_contents($filename), true);
			break;
			default:
			throw new InvalidArgumentException($ext . " is not a valid extension!");
		}
		return $config;
	}

	/**
	* Recursively compile an associative array to PHP code.
	*/
	protected function compile($config, $prefix = '') {
		$code = '';
		foreach ($config as $key => $value) {
			if (is_array($value)) {
				$code .= $this->compile($value, $prefix . $key . $this->sectionSeparator);
			} else {
				$fullName = $prefix . $key;
				if (!preg_match('/^[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*$/', $fullName)) {
					throw new InvalidArgumentException(__CLASS__ . ": Cannot compile translation key " . $fullName . " because it is not a valid PHP identifier.");
				}
				$code .= '  const ' . $fullName . ' = \'' . str_replace('\'', '\\\'', $value) . "';\n";
			}
		}
		return $code;
	}

	protected function fail_after_init() {
		if ($this->isInitialized()) {
			throw new BadMethodCallException('This ' . __CLASS__ . ' object is already initalized, so you can not change any settings.');
		}
	}
}