<?php
/* $Id$ */
namespace Mammut\DB;

(defined('MAMMUT') && (basename(__FILE__) != basename($_SERVER['PHP_SELF']))) or die('ACCESS DENIED');

use \Mammut\Exception\IllegalStateException;

/**
 * Represents a prepared statement
 * 
 * @author Stefan Daurer <s.daurer@q-spot.org>
 * @package Mammut\DB
 */
class Statement extends Result implements iFetchable {
	
	/**
	 * @var DB
	 */
	protected $db;
	/**
	 * @var mixed
	 */
	protected $query;
	protected $limit;
	protected $skip;
	protected $rownr = 0;
	protected $executed = false;
	protected $affected = -1;
	
	/**
	 * @var Result
	 */
	protected $result = NULL;

	/**
	 * Generic statement emulation class.
	 *
	 * This class emulates the prepared statement behaviour.
	 * 
	 * @param DB $database
	 *        	The database link object
	 * @param string $query
	 *        	SQL query of the statement
	 * @param integer $limit
	 *        	Maximum number of rows returned
	 * @param integer $skip
	 *        	Skipping the first N rows
	 */
	public function __construct(DB $database, $query, $limit = -1, $skip = 0) {
		$this->db = $database;
		$this->query = $query;
		$this->limit = $limit;
		$this->skip = $skip;
	}

	/**
	 * Executes the statement.
	 *
	 * @param array $param
	 *        	The parameter values
	 * @return boolean TRUE if the execute was successfull
	 * @throws IllegalStateException If count($param) doesn't match the number of parameters in the SQL query
	 */
	public function execute(array $param = array()) {
		if(substr_count($this->query, '?') != count($param))
			throw new IllegalStateException('Wrong parameter count, needs to be ' . substr_count($this->query, '?'));
		$parts = explode('?', $this->query);
		$newquery = '';
		foreach($param as $p) {
			$newquery .= current($parts);
			$newquery .= $this->db->escapeValue($p);
			next($parts);
		}
		$newquery .= current($parts);
		
		$this->result = $this->db->query($newquery, $this->limit, $this->skip);
		if(is_bool($this->result))
			$this->affected = $this->db->getAffectedRowCount();
		$this->executed = true;
		
		return true;
	}

	public function getColumns() {
		return $this->result->getColumns();
	}

	public function getColumnInfo($column) {
		return $this->result->getColumnInfo($column);
	}

	public function getColumnCount() {
		if(empty($this->result))
			return -1;
		return $this->result->getColumnCount();
	}

	public function getRowNumber() {
		if(empty($this->result))
			return -1;
		return $this->rownr;
	}

	public function getRowCount() {
		if(empty($this->result))
			return -1;
		if(is_bool($this->result))
			return $this->affected;
		return $this->result->getRowCount();
	}

	public function fetchRow() {
		return $this->result->fetchRow();
	}

	public function fetchArray() {
		return $this->result->fetchArray();
	}

	public function fetchObject($class = false, $param = array()) {
		return $this->result->fetchObject($class, $param);
	}

	/**
	 * Frees all resources.
	 */
	public function free() {
		if(is_object($this->result))
			$this->result->close();
		$this->result = NULL;
		$this->executed = false;
	}

	/**
	 * Closes the statement and frees all resources.
	 * After calling this method, the statement cannot be used again.
	 */
	public function close() {
		$this->free();
	}

	public function __destruct() {
		$this->close();
	}
}