<?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;
/**
 * 
 * @author Stefan Daurer <s.daurer@q-spot.org>
 * @package Mammut\DB\Sql
 */
class Cases extends \Mammut\StrictObject implements iExpression {

	protected $expression = '';
    protected $matches = array();

    public function __construct($expression){
        if ($expression)
            $this->setExpression($expression);
        if ($parameters)
            $this->setParameters($parameters);
        if ($types)
            $this->setTypes($types);
    }

    public function setExpression($expression)  {
        if (!is_string($expression) || $expression == '')
            throw new \InvalidArgumentException('Supplied expression must be a string.');
        $this->expression = $expression;
        return $this;
    }

    public function getExpression()  {
        return $this->expression;
    }

    /**
     * @return iExpression
     */
    public function setTypes(array $matches) {
        $this->matches = $matches;
        return $this;
    }

    /**
     * @return array
     */
    public function getTypes() {
        return $this->matches;
    }

    /**
     * @return array
     */
    public function getSql(iDialect $dialect) {
        $parameters = (is_scalar($this->parameters)) ? array($this->parameters) : $this->parameters;

        $types = array();
        $parametersCount = count($parameters);

        if ($parametersCount == 0 && strpos($this->expression, self::PLACEHOLDER) !== false) {
            // if there are no parameters, but there is a placeholder
            $parametersCount = substr_count($this->expression, self::PLACEHOLDER);
            $parameters = array_fill(0, $parametersCount, null);
        }

        for ($i = 0; $i < $parametersCount; $i++) {
            $types[$i] = (isset($this->types[$i]) && ($this->types[$i] == self::TYPE_IDENTIFIER || $this->types[$i] == self::TYPE_LITERAL))
                ? $this->types[$i] : self::TYPE_VALUE;
        }

        // assign locally, escaping % signs
        $expression = str_replace('%', '%%', $this->expression);

        if ($parametersCount > 0) {
            $count = 0;
            $expression = str_replace(self::PLACEHOLDER, '%s', $expression, $count);
            if ($count !== $parametersCount) {
                throw new \RuntimeException('The number of replacements in the expression does not match the number of parameters');
            }
        }

        return array(array(
            $expression,
            $parameters,
            $types
        ));
    }
}