<?php
/* $Id$ */
namespace Mammut\DB\Sql\Expression;

(defined('MAMMUT') && (basename(__FILE__) != basename($_SERVER['PHP_SELF']))) or die('ACCESS DENIED');

use Mammut\DB\Sql\Dialect\iDialect;

/**
 * Calculate operator
 *
 * @author Stefan Daurer <s.daurer@q-spot.org>
 * @package Mammut\DB\Sql
 */
class Calc extends \Mammut\StrictObject implements iExprCalc, iExprValue {

	protected $elements = array();
	protected $unnest = null;
	
	public function __construct($basecontent, $type = self::TYPE_IDENTIFIER) {
		if($basecontent instanceof Parameter)
			$contenttype = self::TYPE_PARAMETER;

		$e = new \stdClass();
		$e->value = $basecontent;
		$e->valuetype = $type;
		
		$this->elements[] = $e;
	}
	
	/**
	 * 
	 * @param mixed $a
	 * @param mixed $b
	 * @return \Mammut\DB\Sql\Expression\Calc
	 */
	public static function newC($a, $typeA = self::TYPE_IDENTIFIER) {
		$obj = new self($a, $typeA);
		return $obj;
	}

	/**
	 * Begin nesting calc
	 *
	 * @return Calc
	 */
	public function nest($operation, $basecontent, $type = self::TYPE_IDENTIFIER) {
		$calc = new self($basecontent, $type);
		$calc->setUnnest($this);
		$this->addOperation($operation, $calc, self::TYPE_EXPRESSION);
		return $calc;
	}
	
	/**
	 * Indicate end of nested calc
	 *
	 * @return Calc
	 * @throws \RuntimeException
	 */
	public function unnest() {
		if($this->unnest == null) 
			throw new \RuntimeException('Not nested');
		$unnset = $this->unnest;
		$this->unnest = null;
		return $unnset;
	}
	
	/**
	 * Indicate what predicate will be unnested
	 *
	 * @param Calc $calc
	 * @return void
	 */
	public function setUnnest(Calc $calc) {
		$this->unnest = $calc;
	}
	
	public function addOperation($operator, $content, $type = self::TYPE_VALUE) {
		$allowed = [self::OP_ADD,self::OP_SUB,self::OP_MULT,self::OP_DIV,self::OP_MOD];
		if (!in_array($operator, $allowed))
			throw new \InvalidArgumentException('invalid operator');
		
		$o = new \stdClass();
		$o->operator = $operator;
		$o->value = $content;
		$o->valuetype = $type;
		$this->elements[] = $o;
		return $this;
	}

	/**
	 *
	 * @param mixed $content        	
	 * @param string $type        	
	 * @return Calc
	 */
	public function add($content, $type = self::TYPE_VALUE) {
		return $this->addOperation(self::OP_ADD, $content, $type);
	}

	/**
	 *
	 * @param mixed $content        	
	 * @param string $type        	
	 * @return Calc
	 */
	public function sub($content, $type = self::TYPE_VALUE) {
		return $this->addOperation(self::OP_SUB, $content, $type);
	}

	/**
	 *
	 * @param mixed $content        	
	 * @param string $type        	
	 * @return Calc
	 */
	public function mult($content, $type = self::TYPE_VALUE) {
		return $this->addOperation(self::OP_MULT, $content, $type);
	}

	/**
	 *
	 * @param mixed $content        	
	 * @param string $type        	
	 * @return Calc
	 */
	public function div($content, $type = self::TYPE_VALUE) {
		return $this->addOperation(self::OP_DIV, $content, $type);
	}

	public function getElements() {
		return $this->elements;
	}
}