<?php

/**
 * elFinder - file manager for web.
 * Session Wrapper Class.
 *
 * @package elfinder
 * @author Naoki Sawada
 **/

class elFinderSession implements elFinderSessionInterface
{
	protected $started = false;
	
	protected $keys = array();
	
	protected $prevVal = null;
	
	protected $base64encode = false;
	
	protected $opts = array(
		'base64encode' => false,
		'keys' => array(
			'default'   => 'elFinderCaches',
			'netvolume' => 'elFinderNetVolumes'
		)
	);
	
	public function __construct($opts)
	{
		$this->opts = array_merge($this->opts, $opts);
		$this->base64encode = !empty($this->opts['base64encode']);
		$this->keys = $this->opts['keys'];
		
		return $this;
	}
	
    /**
     * {@inheritdoc}
     */
	public function start()
	{
		if (version_compare(PHP_VERSION, '5.4.0', '>=')) {
			if (session_status() !== PHP_SESSION_ACTIVE) {
				session_start();
			}
		} else {
			set_error_handler(array($this, 'session_start_error'),  E_NOTICE);
			session_start();
			restore_error_handler();
		}
		$this->started = session_id()? true : false;
		
		if ($this->started && is_null($this->prevVal)) {
			$this->prevVal = $_SESSION;
		}
		
		return $this;
	}
	
    /**
     * {@inheritdoc}
     */
	public function close()
	{
		if ($this->started && $this->prevVal !== $_SESSION) {
			session_write_close();
			$this->prevVal = $_SESSION;
		}
		$this->started = false;
		
		return $this;
	}
	
    /**
     * {@inheritdoc}
     */
	public function get($key, $empty = null)
	{
		$closed = false;
		if (! $this->started) {
			$closed = true;
			$this->start();
		}
		
		$data = null;
		
		if ($this->started) {
			$session =& $this->getSessionRef($key);
			$data = $session;
			if ($data && $this->base64encode) {
				$data = $this->decodeData($data);
			}
		}
		
		$checkFn = null;
		if (! is_null($empty)) {
			if (is_string($empty)) {
				$checkFn = 'is_string';
			} elseif (is_array($empty)) {
				$checkFn = 'is_array';
			} elseif (is_object($empty)) {
				$checkFn = 'is_object';
			} elseif (is_float($empty)) {
				$checkFn = 'is_float';
			} elseif (is_int($empty)) {
				$checkFn = 'is_int';
			}
		}
		
		if (is_null($data) || ($checkFn && ! $checkFn($data))) {
			$session = $data = $empty;
		}
		
		if ($closed) {
			$this->close();
		}

		return $data;
	}
	
    /**
     * {@inheritdoc}
     */
	public function set($key, $data)
	{
		$closed = false;
		if (! $this->started) {
			$closed = true;
			$this->start();
		}
		$session =& $this->getSessionRef($key);
		if ($this->base64encode) {
			$data = $this->encodeData($data);
		}
		$session = $data;
		
		if ($closed) {
			$this->close();
		}
		
		return $this;
	}
	
    /**
     * {@inheritdoc}
     */
	public function remove($key)
	{
		$closed = false;
		if (! $this->started) {
			$closed = true;
			$this->start();
		}

		list($cat, $name) = array_pad(explode('.', $key, 2), 2, null);
		if (is_null($name)) {
			if (! isset($this->keys[$cat])) {
				$name = $cat;
				$cat = 'default';
			}
		}
		if (isset($this->keys[$cat])) {
			$cat = $this->keys[$cat];
		} else {
			$name = $cat . '.' . $name;
			$cat = $this->keys['default'];
		}
		if (is_null($name)) {
			unset($_SESSION[$cat]);
		} else {
			if (isset($_SESSION[$cat]) && is_array($_SESSION[$cat])) {
				unset($_SESSION[$cat][$name]);
			}
		}

		if ($closed) {
			$this->close();
		}
		
		return $this;
	}
	
	protected function & getSessionRef($key)
	{
		$session = null;
		if ($this->started) {
			list($cat, $name) = array_pad(explode('.', $key, 2), 2, null);
			if (is_null($name)) {
				if (! isset($this->keys[$cat])) {
					$name = $cat;
					$cat = 'default';
				}
			}
			if (isset($this->keys[$cat])) {
				$cat = $this->keys[$cat];
			} else {
				$name = $cat . '.' . $name;
				$cat = $this->keys['default'];
			}
			if (is_null($name)) {
				if (! isset($_SESSION[$cat])) {
					$_SESSION[$cat] = null;
				}
				$session =& $_SESSION[$cat];
			} else {
				if (! isset($_SESSION[$cat]) || ! is_array($_SESSION[$cat])) {
					$_SESSION[$cat] = array();
				}
				if (! isset($_SESSION[$cat][$name])) {
					$_SESSION[$cat][$name] = null;
				}
				$session =& $_SESSION[$cat][$name];
			}
		}
		return $session;
	}
	
	protected function encodeData($data)
	{
		if ($this->base64encode) {
			$data = base64_encode(serialize($data));
		}
		return $data;
	}
	
	protected function decodeData($data)
	{
		if ($this->base64encode) {
			if (is_string($data)) {
				if (($data = base64_decode($data)) !== false) {
					$data = unserialize($data);
				} else {
					$data = null;
				}
			} else {
				$data = null;
			}
		}
		return $data;
	}

	protected function session_start_error($errno , $errstr) {}
}
