<?php
/**
 * Piwik - Open source web analytics
 * 
 * @link http://piwik.org
 * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
 * @version $Id$
 * 
 * @category Piwik
 * @package Piwik
 */

/**
 * Piwik_Option provides a very simple mechanism to save/retrieve key-values pair
 * from the database (persistent key-value datastore).
 * 
 * This is useful to save Piwik-wide preferences, configuration values.
 * 
 * @package Piwik
 */
class Piwik_Option
{
	/**
	 * @var array
	 */
	private $all = array();

	/**
	 * @var bool
	 */
	private $loaded = false;

	/**
	 * Singleton instance
	 * @var self
	 */
	static private $instance = null;

	/**
	 * Returns Singleton instance
	 *
	 * @return Piwik_Option
	 */
	static public function getInstance()
	{
		if (self::$instance == null)
		{
			self::$instance = new self;
		}
		return self::$instance;
	}

	/**
	 * Private Constructor
	 */
	private function __construct() {}

	/**
	 * Returns the option value for the requested option $name, fetching from database, if not in cache.
	 *
	 * @param string  $name  Key
 	 * @return string|false  Value or false, if not found
	 */
	public function get($name)
	{
		$this->autoload();
		if(isset($this->all[$name]))
		{
			return $this->all[$name];
		}
		$value = Piwik_FetchOne( 'SELECT option_value '. 
							'FROM `' . Piwik_Common::prefixTable('option') . '`'.
							'WHERE option_name = ?', $name);
		if($value === false)
		{
			return false;
		}
		$this->all[$name] = $value;
		return $value;
	}
	
	/**
	 * Sets the option value in the database and cache
	 *
	 * @param string  $name
	 * @param string  $value
	 * @param int     $autoload  if set to 1, this option value will be automatically loaded; should be set to 1 for options that will always be used in the Piwik request.
	 */
	public function set($name, $value, $autoload = 0)
	{
		$autoload = (int)$autoload;
		Piwik_Query('INSERT INTO `'. Piwik_Common::prefixTable('option') . '` (option_name, option_value, autoload) '.
					' VALUES (?, ?, ?) '.
					' ON DUPLICATE KEY UPDATE option_value = ?', 
					array($name, $value, $autoload, $value));
		$this->all[$name] = $value;
	}

	/**
	 * Delete key-value pair from database and reload cache.
	 *
	 * @param string  $name   Key to match exactly
	 * @param string  $value  Optional value
	 */
	public function delete($name, $value = null)
	{
		$sql = 'DELETE FROM `'. Piwik_Common::prefixTable('option') . '` WHERE option_name = ?';
		$bind[] = $name;

		if(isset($value))
		{
			$sql .= ' AND option_value = ?';
			$bind[] = $value;
		}

		Piwik_Query($sql, $bind);

		$this->clearCache();
	}

	/**
	 * Delete key-value pair(s) from database and reload cache.
	 * The supplied pattern should use '%' as wildcards, and literal '_' should be escaped.
	 *
	 * @param string  $name   Pattern of key to match.
	 * @param string  $value  Optional value
	 */
	public function deleteLike($name, $value = null)
	{
		$sql = 'DELETE FROM `'. Piwik_Common::prefixTable('option') . '` WHERE option_name LIKE ?';
		$bind[] = $name;

		if(isset($value))
		{
			$sql .= ' AND option_value = ?';
			$bind[] = $value;
		}

		Piwik_Query($sql, $bind);

		$this->clearCache();
	}

	/**
	 * Initialize cache with autoload settings.
	 *
	 * @return void
	 */
	private function autoload()
	{
		if($this->loaded)
		{
			return;
		}

		$all = Piwik_FetchAll('SELECT option_value, option_name
								FROM `'. Piwik_Common::prefixTable('option') . '` 
								WHERE autoload = 1');
		foreach($all as $option)
		{
			$this->all[$option['option_name']] = $option['option_value'];
		}

		$this->loaded = true;
	}
	
	/**
	 * Clears the cache 
	 * Used in unit tests to reset the state of the object between tests
	 * 
	 * @return void
	 */
	public function clearCache()
	{
		$this->loaded = false;
		$this->all = array();
	}
}

/**
 * Returns the option value for the requested option $name
 *
 * @param string  $name  Key
 * @return string|false  Value or false, if not found
 */
function Piwik_GetOption($name)
{
	return Piwik_Option::getInstance()->get($name);
}

/**
 * Sets the option value in the database
 *
 * @param string  $name
 * @param string  $value
 * @param int     $autoload  if set to 1, this option value will be automatically loaded; should be set to 1 for options that will always be used in the Piwik request.
 */
function Piwik_SetOption($name, $value, $autoload = 0)
{
	Piwik_Option::getInstance()->set($name, $value, $autoload);
}