<?php
/**
 * YiiBase class file.
 *
 * @link http://www.yiiframework.com/
 * @copyright Copyright &copy; 2008-2012 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

/**
 * Gets the application start timestamp.
 */
defined('YII_BEGIN_TIME') or define('YII_BEGIN_TIME', microtime(true));
/**
 * This constant defines whether the application should be in debug mode or not. Defaults to false.
 */
defined('YII_DEBUG') or define('YII_DEBUG', false);
/**
 * This constant defines how much call stack information (file name and line number) should be logged by Yii::trace().
 * Defaults to 0, meaning no backtrace information. If it is greater than 0,
 * at most that number of call stacks will be logged. Note, only user application call stacks are considered.
 */
defined('YII_TRACE_LEVEL') or define('YII_TRACE_LEVEL', 0);
/**
 * This constant defines whether exception handling should be enabled. Defaults to true.
 */
defined('YII_ENABLE_EXCEPTION_HANDLER') or define('YII_ENABLE_EXCEPTION_HANDLER', true);
/**
 * This constant defines whether error handling should be enabled. Defaults to true.
 */
defined('YII_ENABLE_ERROR_HANDLER') or define('YII_ENABLE_ERROR_HANDLER', true);
/**
 * This constant defines the framework installation directory.
 */
defined('YII_PATH') or define('YII_PATH', __DIR__);

/**
 * YiiBase is the core helper class for the Yii framework.
 *
 * Do not use YiiBase directly. Instead, use its child class [[Yii]] where
 * you can customize methods of YiiBase.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class YiiBase
{
	/**
	 * @var array class map used by the Yii autoloading mechanism.
	 * The array keys are the class names, and the array values are the corresponding class file paths.
	 * This property mainly affects how [[autoload]] works.
	 */
	public static $classMap = array();
	/**
	 * @var array list of directories where Yii will search for new classes to be included.
	 * The first directory in the array will be searched first, and so on.
	 * This property mainly affects how [[autoload]] works.
	 */
	public static $classPath = array();
	/**
	 * @var yii\base\Application the application instance
	 */
	public static $app;
	/**
	 * @var array registered path aliases
	 */
	public static $aliases = array(
		'@yii' => __DIR__,
	);

	private static $_imported = array();	// alias => class name or directory
	private static $_logger;

	/**
	 * @return string the version of Yii framework
	 */
	public static function getVersion()
	{
		return '2.0-dev';
	}

	/**
	 * Imports a class or a directory.
	 *
	 * Importing a class is like including the corresponding class file.
	 * The main difference is that importing a class is much lighter because it only
	 * includes the class file when the class is referenced in the code the first time.
	 *
	 * Importing a directory will add the directory to the front of the [[classPath]] array.
	 * When [[autoload]] is loading an unknown class, it will search in the directories
	 * specified in [[classPath]] to find the corresponding class file to include.
	 * For this reason, if multiple directories are imported, the directories imported later
	 * will take precedence in class file searching.
	 *
	 * The same class or directory can be imported multiple times. Only the first importing
	 * will count. Importing a directory does not import any of its subdirectories.
	 *
	 * To import a class or a directory, one can use either path alias or class name (can be namespaced):
	 *
	 *  - `@app/components/GoogleMap`: importing the `GoogleMap` class with a path alias;
	 *  - `GoogleMap`: importing the `GoogleMap` class with a class name;
	 *  - `@app/components/*`: importing the whole `components` directory with a path alias.
	 *
	 * @param string $alias path alias or a simple class name to be imported
	 * @param boolean $forceInclude whether to include the class file immediately. If false, the class file
	 * will be included only when the class is being used. This parameter is used only when
	 * the path alias refers to a class.
	 * @return string the class name or the directory that this alias refers to
	 * @throws \yii\base\Exception if the path alias is invalid
	 */
	public static function import($alias, $forceInclude = false)
	{
		if (isset(self::$_imported[$alias])) {
			return self::$_imported[$alias];
		}

		if (class_exists($alias, false) || interface_exists($alias, false)) {
			return self::$_imported[$alias] = $alias;
		}

		if ($alias[0] !== '@') { // a simple class name
			if ($forceInclude && static::autoload($alias)) {
				self::$_imported[$alias] = $alias;
			}
			return $alias;
		}

		$className = basename($alias);
		$isClass = $className !== '*';

		if ($isClass && (class_exists($className, false) || interface_exists($className, false))) {
			return self::$_imported[$alias] = $className;
		}

		if (($path = static::getAlias(dirname($alias))) === false) {
			throw new \yii\base\Exception('Invalid path alias: ' . $alias);
		}

		if ($isClass) {
			if ($forceInclude) {
				require($path . "/$className.php");
				self::$_imported[$alias] = $className;
			}
			else {
				self::$classMap[$className] = $path . "/$className.php";
			}
			return $className;
		}
		else { // a directory
			array_unshift(self::$classPath, $path);
			return self::$_imported[$alias] = $path;
		}
	}

	/**
	 * Translates a path alias into an actual path.
	 *
	 * The path alias can be either a root alias registered via [[setAlias]] or an
	 * alias starting with a root alias (e.g. `@yii/base/Component.php`).
	 * In the latter case, the root alias will be replaced by the corresponding registered path
	 * and the remaining part will be appended to it.
	 *
	 * In case the given parameter is not an alias (i.e., not starting with '@'),
	 * it will be returned back without change.
	 *
	 * Note, this method does not ensure the existence of the resulting path.
	 * @param string $alias alias
	 * @return mixed path corresponding to the alias, false if the root alias is not previously registered.
	 * @see setAlias
	 */
	public static function getAlias($alias)
	{
		if (isset(self::$aliases[$alias])) {
			return self::$aliases[$alias];
		}
		elseif ($alias[0] !== '@') { // not an alias
			return $alias;
		}
		elseif (($pos = strpos($alias, '/')) !== false) {
			$rootAlias = substr($alias, 0, $pos);
			if (isset(self::$aliases[$rootAlias])) {
				return self::$aliases[$alias] = self::$aliases[$rootAlias] . substr($alias, $pos);
			}
		}
		return false;
	}

	/**
	 * Registers a path alias.
	 *
	 * A path alias is a short name representing a path (a file path, a URL, etc.)
	 * A path alias must start with '@' (e.g. '@yii').
	 *
	 * Note that this method neither checks the existence of the path nor normalizes the path.
	 * Any trailing '/' and '\' characters in the path will be trimmed.
	 *
	 * @param string $alias alias to the path. The alias must start with '@'.
	 * @param string $path the path corresponding to the alias. This can be
	 *
	 * - a directory or a file path (e.g. `/tmp`, `/tmp/main.txt`)
	 * - a URL (e.g. `http://www.yiiframework.com`)
	 * - a path alias (e.g. `@yii/base`). In this case, the path alias will be converted into the
	 *   actual path first by calling [[getAlias]].
	 * @see getAlias
	 */
	public static function setAlias($alias, $path)
	{
		if ($path === null) {
			unset(self::$aliases[$alias]);
		}
		elseif ($path[0] !== '@') {
			self::$aliases[$alias] = rtrim($path, '\\/');
		}
		elseif (($p = static::getAlias($path)) !== false) {
			self::$aliases[$alias] = $p;
		}
		else {
			throw new \yii\base\Exception('Invalid path: ' . $path);
		}
	}

	/**
	 * Class autoload loader.
	 * This method is invoked automatically when the execution encounters an unknown class.
	 * The method will attempt to include the class file as follows:
	 *
	 * 1. Search in [[classMap]];
	 * 2. If the class is namespaced (e.g. `yii\base\Component`), it will attempt
	 *    to include the file associated with the corresponding path alias
	 *    (e.g. `@yii/base/Component.php`);
	 * 3. If the class is named in PEAR style (e.g. `PHPUnit_Framework_TestCase`),
	 *    it will attempt to include the file associated with the corresponding path alias
	 *    (e.g. `@PHPUnit/Framework/TestCase.php`);
	 * 4. Search in [[classPath]];
	 * 5. Return false so that other autoloaders have chance to include the class file.
	 *
	 * @param string $className class name
	 * @return boolean whether the class has been loaded successfully
	 */
	public static function autoload($className)
	{
		if (isset(self::$classMap[$className])) {
			include(self::$classMap[$className]);
			return true;
		}

		// namespaced class, e.g. yii\base\Component
		if (strpos($className, '\\') !== false) {
			// convert namespace to path alias, e.g. yii\base\Component to @yii/base/Component
			$alias = '@' . str_replace('\\', '/', ltrim($className, '\\'));
			if (($path = static::getAlias($alias)) !== false) {
				include($path . '.php');
				return true;
			}
			return false;
		}

		// PEAR-styled class, e.g. PHPUnit_Framework_TestCase
		if (($pos = strpos($className, '_')) !== false) {
			// convert class name to path alias, e.g. PHPUnit_Framework_TestCase to @PHPUnit/Framework/TestCase
			$alias = '@' . str_replace('_', '/', $className);
			if (($path = static::getAlias($alias)) !== false) {
				include($path . '.php');
				return true;
			}
		}

		// search in include paths
		foreach (self::$classPath as $path) {
			$classFile = $path . DIRECTORY_SEPARATOR . $className . '.php';
			if (is_file($classFile)) {
				include($classFile);
				return true;
			}
		}

		return false;
	}

	/**
	 * Creates a new component instance using the given configuration.
	 *
	 * The specified configuration can be either a string or an array.
	 * If the former, the string is treated as the object type; if the latter,
	 * the array must contain a `class` element specifying the object type, and
	 * the rest of the name-value pairs in the array will be used to initialize
	 * the corresponding object properties.
	 *
	 * The object type can be either a class name or [[getAlias|path alias]] of
	 * the class. For example,
	 *
	 * ~~~
	 * $component = Yii::create('@app/components/GoogleMap');
	 * $component = Yii::create('\application\components\GoogleMap');
	 * $component = Yii::create(array(
	 *     'class' => '@app/components/GoogleMap',
	 *     'apiKey' => 'xyz',
	 * ));
	 * ~~~
	 *
	 * Any additional parameters passed to this method will be
	 * passed to the constructor of the object being created.
	 *
	 * If a component class implements the [[\yii\base\Initable]] interface,
	 * its [[\yii\base\Initable::init|init]] method will be invoked AFTER
	 * the component properties are initialized.
	 *
	 * @param mixed $config the configuration. It can be either a string or an array.
	 * @return mixed the created object
	 * @throws \yii\base\Exception if the configuration is invalid.
	 */
	public static function create($config)
	{
		if (is_string($config)) {
			$class = $config;
			$config = array();
		}
		elseif (isset($config['class'])) {
			$class = $config['class'];
			unset($config['class']);
		}
		else {
			throw new \yii\base\Exception('Object configuration must be an array containing a "class" element.');
		}

		if (!class_exists($class, false)) {
			$class = static::import($class, true);
		}

		if (($n = func_num_args()) > 1) {
			$args = func_get_args();
			if ($n === 2) {
				$object = new $class($args[1]);
			}
			elseif ($n === 3) {
				$object = new $class($args[1], $args[2]);
			}
			elseif ($n === 4) {
				$object = new $class($args[1], $args[2], $args[3]);
			}
			else {
				unset($args[0]);
				$r = new ReflectionClass($class);
				$object = $r->newInstanceArgs($args);
			}
		}
		else {
			$object = new $class;
		}

		foreach ($config as $name => $value) {
			$object->$name = $value;
		}

		if ($object instanceof \yii\base\Initable) {
			$object->init();
		}

		return $object;
	}

	/**
	 * Logs a trace message.
	 * Trace messages are logged mainly for development purpose to see
	 * the execution work flow of some code.
	 * @param string $message the message to be logged.
	 * @param string $category the category of the message.
	 */
	public static function trace($message, $category = 'application')
	{
		if (YII_DEBUG) {
			self::getLogger()->trace($message, $category);
		}
	}

	/**
	 * Logs an error message.
	 * An error message is typically logged when an unrecoverable error occurs
	 * during the execution of an application.
	 * @param string $message the message to be logged.
	 * @param string $category the category of the message.
	 */
	public static function error($message, $category = 'application')
	{
		self::getLogger()->error($message, $category);
	}

	/**
	 * Logs a warning message.
	 * A warning message is typically logged when an error occurs while the execution
	 * can still continue.
	 * @param string $message the message to be logged.
	 * @param string $category the category of the message.
	 */
	public static function warning($message, $category = 'application')
	{
		self::getLogger()->warning($message, $category);
	}

	/**
	 * Logs an informative message.
	 * An informative message is typically logged by an application to keep record of
	 * something important (e.g. an administrator logs in).
	 * @param string $message the message to be logged.
	 * @param string $category the category of the message.
	 */
	public static function info($message, $category = 'application')
	{
		self::getLogger()->info($message, $category);
	}

	/**
	 * Marks the beginning of a code block for profiling.
	 * This has to be matched with a call to [[endProfile]] with the same category name.
	 * The begin- and end- calls must also be properly nested. For example,
	 *
	 * ~~~
	 * \Yii::beginProfile('block1');
	 * // some code to be profiled
	 *     \Yii::beginProfile('block2');
	 *     // some other code to be profiled
	 *     \Yii::endProfile('block2');
	 * \Yii::endProfile('block1');
	 * ~~~
	 * @param string $token token for the code block
	 * @param string $category the category of this log message
	 * @see endProfile
	 */
	public static function beginProfile($token, $category)
	{
		self::getLogger()->beginProfile($token, $category);
	}

	/**
	 * Marks the end of a code block for profiling.
	 * This has to be matched with a previous call to [[beginProfile]] with the same category name.
	 * @param string $token token for the code block
	 * @param string $category the category of this log message
	 * @see beginProfile
	 */
	public static function endProfile($token, $category)
	{
		self::getLogger()->endProfile($token, $category);
	}

	/**
	 * Returns the message logger object.
	 * @return \yii\logging\Logger message logger
	 */
	public static function getLogger()
	{
		if (self::$_logger !== null) {
			return self::$_logger;
		}
		else {
			return self::$_logger = new \yii\logging\Logger;
		}
	}

	/**
	 * Sets the logger object.
	 * @param \yii\logging\Logger $logger the logger object.
	 */
	public static function setLogger($logger)
	{
		self::$_logger = $logger;
	}

	/**
	 * Returns an HTML hyperlink that can be displayed on your Web page showing Powered by Yii" information.
	 * @return string an HTML hyperlink that can be displayed on your Web page showing Powered by Yii" information
	 */
	public static function powered()
	{
		return 'Powered by <a href="http://www.yiiframework.com/" rel="external">Yii Framework</a>.';
	}

	/**
	 * Translates a message to the specified language.
	 * Starting from version 1.0.2, this method supports choice format (see {@link CChoiceFormat}),
	 * i.e., the message returned will be chosen from a few candidates according to the given
	 * number value. This feature is mainly used to solve plural format issue in case
	 * a message has different plural forms in some languages.
	 * @param string $category message category. Please use only word letters. Note, category 'yii' is
	 * reserved for Yii framework core code use. See {@link CPhpMessageSource} for
	 * more interpretation about message category.
	 * @param string $message the original message
	 * @param array $params parameters to be applied to the message using <code>strtr</code>.
	 * Starting from version 1.0.2, the first parameter can be a number without key.
	 * And in this case, the method will call {@link CChoiceFormat::format} to choose
	 * an appropriate message translation.
	 * Starting from version 1.1.6 you can pass parameter for {@link CChoiceFormat::format}
	 * or plural forms format without wrapping it with array.
	 * @param string $source which message source application component to use.
	 * Defaults to null, meaning using 'coreMessages' for messages belonging to
	 * the 'yii' category and using 'messages' for the rest messages.
	 * @param string $language the target language. If null (default), the {@link CApplication::getLanguage application language} will be used.
	 * This parameter has been available since version 1.0.3.
	 * @return string the translated message
	 * @see CMessageSource
	 */
	public static function t($category, $message, $params = array(), $source = null, $language = null)
	{
		if (self::$app !== null)
		{
			if ($source === null)
				$source = $category === 'yii' ? 'coreMessages' : 'messages';
			if (($source = self::$app->getComponent($source)) !== null)
				$message = $source->translate($category, $message, $language);
		}
		if ($params === array())
			return $message;
		if (!is_array($params))
			$params = array($params);
		if (isset($params[0])) // number choice
		{
			if (strpos($message, '|') !== false)
			{
				if (strpos($message, '#') === false)
				{
					$chunks = explode('|', $message);
					$expressions = self::$app->getLocale($language)->getPluralRules();
					if ($n = min(count($chunks), count($expressions)))
					{
						for ($i = 0;$i < $n;$i++)
							$chunks[$i] = $expressions[$i] . '#' . $chunks[$i];

						$message = implode('|', $chunks);
					}
				}
				$message = CChoiceFormat::format($message, $params[0]);
			}
			if (!isset($params['{n}']))
				$params['{n}'] = $params[0];
			unset($params[0]);
		}
		return $params !== array() ? strtr($message, $params) : $message;
	}
}