<?php
// namespace administrator\components\com_jmap\libraries\framework;
/**
 *
 * @package JMAP::administrator::components::com_jmap
 * @subpackage framework
 * @author Joomla! Extensions Store
 * @copyright (C) 2015 - Joomla! Extensions Store
 * @license GNU/GPLv2 http://www.gnu.org/licenses/gpl-2.0.html
 */
defined ( '_JEXEC' ) or die ( 'Restricted access' );

/**
 * Framework autoloader based on camel case and prefix namespacing
 *
 * @package JMAP::administrator::components::com_jmap
 * @subpackage framework
 * @since 2.0
 */
abstract class JMapLoader {
	/**
	 * Container for already imported library paths.
	 *
	 * @var array
	 */
	protected static $classes = array ();
	
	/**
	 * Container for already imported library paths.
	 *
	 * @var array
	 */
	protected static $imported = array ();
	
	/**
	 * Container for registered library class prefixes and path lookups.
	 *
	 * @var array
	 */
	protected static $prefixes = array ();
	
	/**
	 * Method to discover classes of a given type in a given path.
	 *
	 * @param string $classPrefix
	 *        	The class name prefix to use for discovery.
	 * @param string $parentPath
	 *        	Full path to the parent folder for the classes to discover.
	 * @param boolean $force
	 *        	True to overwrite the autoload path value for the class if it already exists.
	 * @param boolean $recurse
	 *        	Recurse through all child directories as well as the parent path.
	 *        	
	 * @return void
	 */
	public static function discover($classPrefix, $parentPath, $force = true, $recurse = false) {
		try {
			if ($recurse) {
				$iterator = new RecursiveIteratorIterator ( new RecursiveDirectoryIterator ( $parentPath ), RecursiveIteratorIterator::SELF_FIRST );
			} else {
				$iterator = new DirectoryIterator ( $parentPath );
			}
			
			foreach ( $iterator as $file ) {
				$fileName = $file->getFilename ();
				
				// Only load for php files.
				// Note: DirectoryIterator::getExtension only available PHP >= 5.3.6
				if ($file->isFile () && substr ( $fileName, strrpos ( $fileName, '.' ) + 1 ) == 'php') {
					// Get the class name and full path for each file.
					$class = strtolower ( $classPrefix . preg_replace ( '#\.php$#', '', $fileName ) );
					
					// Register the class with the autoloader if not already registered or the force flag is set.
					if (empty ( self::$classes [$class] ) || $force) {
						self::register ( $class, $file->getPath () . '/' . $fileName );
					}
				}
			}
		} catch ( UnexpectedValueException $e ) {
			// Exception will be thrown if the path is not a directory. Ignore it.
		}
	}
	
	/**
	 * Method to get the list of registered classes and their respective file paths for the autoloader.
	 *
	 * @return array The array of class => path values for the autoloader.
	 */
	public static function getClassList() {
		return self::$classes;
	}
	
	/**
	 * Loads a class from specified directories.
	 *
	 * @param string $key
	 *        	The class name to look for (dot notation).
	 * @param string $base
	 *        	Search this directory for the class.
	 *        	
	 * @return boolean True on success.
	 */
	public static function import($key, $base = null) {
		// Only import the library if not already attempted.
		if (! isset ( self::$imported [$key] )) {
			// Setup some variables.
			$success = false;
			$parts = explode ( '.', $key );
			$class = array_pop ( $parts );
			$base = (! empty ( $base )) ? $base : dirname ( __FILE__ );
			$path = str_replace ( '.', DIRECTORY_SEPARATOR, $key );
			
			// Handle special case for helper classes.
			if ($class == 'helper') {
				$class = ucfirst ( array_pop ( $parts ) ) . ucfirst ( $class );
			} 			// Standard class.
			else {
				$class = ucfirst ( $class );
			}
			
			// If we are importing a library from the Joomla namespace set the class to autoload.
			if (strpos ( $path, 'joomla' ) === 0) {
				// Since we are in the Joomla namespace prepend the classname with J.
				$class = 'J' . $class;
				
				// Only register the class for autoloading if the file exists.
				if (is_file ( $base . '/' . $path . '.php' )) {
					self::$classes [strtolower ( $class )] = $base . '/' . $path . '.php';
					$success = true;
				}
			} 			/*
			 * If we are not importing a library from the Joomla namespace directly include the file since we cannot assert the file/folder naming conventions.
			 */
			else {
				// If the file exists attempt to include it.
				if (is_file ( $base . '/' . $path . '.php' )) {
					$success = ( bool ) include_once $base . '/' . $path . '.php';
				}
			}
			
			// Add the import key to the memory cache container.
			self::$imported [$key] = $success;
		}
		
		return self::$imported [$key];
	}
	
	/**
	 * Load the file for a class.
	 *
	 * @param string $class
	 *        	The class to be loaded.
	 *        	
	 * @return boolean True on success
	 */
	public static function load($class) {
		// Sanitize class name.
		$class = strtolower ( $class );
		
		// If the class already exists do nothing.
		if (class_exists ( $class )) {
			return true;
		}
		
		// If the class is registered include the file.
		if (isset ( self::$classes [$class] )) {
			include_once self::$classes [$class];
			return true;
		}
		
		return false;
	}
	
	/**
	 * Directly register a class to the autoload list.
	 *
	 * @param string $class
	 *        	The class name to register.
	 * @param string $path
	 *        	Full path to the file that holds the class to register.
	 * @param boolean $force
	 *        	True to overwrite the autoload path value for the class if it already exists.
	 *        	
	 * @return void
	 */
	public static function register($class, $path, $force = true) {
		// Sanitize class name.
		$class = strtolower ( $class );
		
		// Only attempt to register the class if the name and file exist.
		if (! empty ( $class ) && is_file ( $path )) {
			// Register the class with the autoloader if not already registered or the force flag is set.
			if (empty ( self::$classes [$class] ) || $force) {
				self::$classes [$class] = $path;
			}
		}
	}
	
	/**
	 * Register a class prefix with lookup path.
	 * This will allow developers to register library
	 * packages with different class prefixes to the system autoloader. More than one lookup path
	 * may be registered for the same class prefix, but if this method is called with the reset flag
	 * set to true then any registered lookups for the given prefix will be overwritten with the current
	 * lookup path.
	 *
	 * @param string $prefix
	 *        	The class prefix to register.
	 * @param string $path
	 *        	Absolute file path to the library root where classes with the given prefix can be found.
	 * @param boolean $reset
	 *        	True to reset the prefix with only the given lookup path.
	 *        	
	 * @return void
	 */
	public static function registerPrefix($prefix, $path, $reset = false) {
		// Verify the library path exists.
		if (! file_exists ( $path )) {
			throw new RuntimeException ( 'Library path ' . $path . ' cannot be found.', 500 );
		}
		
		// If the prefix is not yet registered or we have an explicit reset flag then set set the path.
		if (! isset ( self::$prefixes [$prefix] ) || $reset) {
			self::$prefixes [$prefix] = array (
					$path 
			);
		} 		// Otherwise we want to simply add the path to the prefix.
		else {
			self::$prefixes [$prefix] [] = $path;
		}
	}
	
	/**
	 * Method to setup the autoloaders for the Joomla Platform.
	 * Since the SPL autoloaders are
	 * called in a queue we will add our explicit, class-registration based loader first, then
	 * fall back on the autoloader based on conventions. This will allow people to register a
	 * class in a specific location and override platform libraries as was previously possible.
	 *
	 * @return void
	 */
	public static function setup() {
		// Register the autoloader functions.
		spl_autoload_register ( array (
				'JMapLoader',
				'load' 
		) );
		spl_autoload_register ( array (
				'JMapLoader',
				'_autoload' 
		) );
	}
	
	/**
	 * Autoload a class based on name.
	 *
	 * @param string $class
	 *        	The class to be loaded.
	 *        	
	 * @return void
	 */
	private static function _autoload($class) {
		foreach ( self::$prefixes as $prefix => $lookup ) {
			if (strpos ( $class, $prefix ) === 0) {
				return self::_load ( substr ( $class, strlen ( $prefix ) ), $lookup );
			}
		}
	}
	
	/**
	 * Load a class based on name and lookup array.
	 *
	 * @param string $class
	 *        	The class to be loaded (wihtout prefix).
	 * @param array $lookup
	 *        	The array of base paths to use for finding the class file.
	 *        	
	 * @return void
	 */
	private static function _load($class, $lookup) {
		// Split the class name into parts separated by camelCase.
		$parts = preg_split ( '/(?<=[a-z0-9])(?=[A-Z])/x', $class );
		
		// If there is only one part we want to duplicate that part for generating the path.
		$parts = (count ( $parts ) === 1) ? array (
				$parts [0],
				$parts [0] 
		) : $parts;
		
		foreach ( $lookup as $base ) {
			// Generate the path based on the class name parts.
			$path = $base . '/' . implode ( '/', array_map ( 'strtolower', $parts ) ) . '.php';
			
			// Load the file if it exists.
			if (file_exists ( $path )) {
				return include $path;
			} else {
				// Try if an exact folder/name match
				// Generate the path based on the class name parts.
				$parts[] = $parts[count($parts) - 1];
				$path = $base . '/' . implode ( '/', array_map ( 'strtolower', $parts ) ) . '.php';
				if (file_exists ( $path )) {
					return include $path;
				}
			}
		}
	}
}