<?php
/**
 * Crutch Cache
 * Class for saving data to a text file.
 *
 * @date		01/06/2010
 * @author		Ladislav Vondracek, http://www.twitter.com/Lawondyss
 * @copyright	2010 Ladislav Vondracek
 * @license		http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0
 */

class CrutchCache
{
	/**
	 * Filepath to file with data
	 *
	 * @var string filepath
	 */
	private $storage;

	/**
	 * Array of loaded data
	 *
	 * @var array loaded variables
	 */
	private $variables;

	/**
	 * File pointer opened storage file
	 *
	 * @var resource file stream
	 */
	private $fp;

	/**
	 * Constructor
	 *
	 * @param string $file File name for storage data
	 * @param string $dir Dir with file
	 */
	public function  __construct($file, $dir='temp/')
	{
		// added slash at the endof the directory name
		if(substr($dir, -1) != '/')
		{
			$dir .= '/';
		}

		// create a non-existing directory and settings permissions
		if(!is_dir($dir))
		{
			mkdir($dir, 0700, TRUE);
		}

		// filepath
		$this->storage = $dir.$file.'.cc';

		// loaded data if the file exists
		if(is_file($this->storage))
		{
			// serialized string
			$serialized = file_get_contents($this->storage);

			// unserialized
			$this->variables = unserialize($serialized);

			if(!is_array($this->variables))
			{
				$this->error('Cache "'.$file.'" is probably already open somewhere before.', E_USER_ERROR, debug_backtrace());
			}
		}
		// file does not exist
		else
		{
			// empty array
			$this->variables = array();
		}

		// create/overwrite the file for write
		$this->fp = fopen($this->storage, 'w');
	}


	/**
	 * Destructor
	 */
	public function  __destruct()
	{
		if($this->fp)
		{
			// serialized data
			$serialized = serialize($this->variables);

			// write to the file
			fwrite($this->fp, $serialized);

			// close the file
			fclose($this->fp);
		}
	}


	/**
	 * Magical method to retrieve the stored variable
	 *
	 * @param string $name Variable name
	 * @return mixed Variable value
	 */
	public function __get($name)
	{
		// only if variable exists
		if(array_key_exists($name, $this->variables))
		{
			return $this->variables[$name];
		}
		else
		{
			$this->error('Variable "'.$name.'" was not created.', E_USER_ERROR, debug_backtrace());
		}
	}


	/**
	 * Sets the variable to store
	 *
	 * @param string $name Variable name
	 * @param mixed $value Variable value
	 */
	public function __set($name, $value)
	{
		$this->variables[$name] = $value;
	}


	/**
	 * Deletes one or all values
	 *
	 * @param string $name Variable name
	 * @internal if $name is NULL, delete all
	 * @return bool Deleted
	 */
	public function delete($name=NULL)
	{
		if(is_null($name))
		{
			$this->variables = array();

			return TRUE;
		}
		elseif(array_key_exists($name, $this->variables))
		{
			unset($this->variables[$name]);

			return TRUE;
		}
		else
		{
			return FALSE;
		}
	}


	/**
	 * Returns all variables
	 *
	 * @return array All variables
	 */
	public function all()
	{
		return $this->variables;
	}


	private function error($message, $type, $backtrace)
	{
		$backtrace = array_shift($backtrace);
		$head = basename($backtrace['file']).'['.$backtrace['line'].']: ';
		trigger_error($head.$message, $type);
	}
}