<?php
class Database
{
	/* Singleton ***********************************/
	private static $instance;

	public static function init($name, $server, $user, $password)
	{
		self::$instance = new Database($name, $server, $user, $password);
	}

	public static function get()
	{
		if(!self::$instance->is_open()) self::$instance->open();
		return self::$instance;
	}

	/* Instance ***********************************/
	private $name, $server, $user, $password = '';
	private $connection = NULL;

	public function Database($name, $server, $user, $password)
	{
		$this->name = $name;
		$this->server = $server;
		$this->user = $user;
		$this->password = $password;
	}

	public function is_open()
	{
		return ($this->connection != NULL);
	}

	public function open()
	{
		$this->connection = mysql_connect($this->server, $this->user, $this->password) or $this->dump_error('none');
		mysql_select_db($this->name, $this->connection) or die('Database "' . $this->name . '" does not exist! Contact system administrator.');
	}

	public function close()
	{
		if($this->connection != NULL)
		{
			mysql_close($this->connection);
			$this->connection = NULL;
		}
	}

	public function row($query)
	{
		$result = mysql_query($query, $this->connection) or $this->dump_error($query);
		if(mysql_num_rows($result) > 0)
		{
			return mysql_fetch_assoc($result);
		}
		else
		{
			return NULL;
		}
	}

	public function rows($query)
	{
		$result = mysql_query($query, $this->connection) or $this->dump_error($query);
		$rows = array();
		if(mysql_num_rows($result) > 0)
		{
			while($row = mysql_fetch_assoc($result))
			{
				$rows[] = $row;
			}
		}
		return $rows;
	}

	public function execute($query)
	{
		return mysql_query($query, $this->connection) or $this->dump_error($query);
	}

	private function dump_error($query)
	{
		?>

		<div id="error">
			<h3>Database error!</h3>
			<p><strong>Query:</strong> <em><?=$query?></em></p>
			<p><strong>Message:</strong> <em><?=mysql_error()?></em></p>
		</div>

		<?php
	}
}
?>