<?php
/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

namespace Doctrine\ORM\Query;

/**
 * Description of Expression
 *
 * @author robo
 */
class Expr
{
    /* type => method */
    private static $_methodMap = array(
        'and' => '_andExpr',
        'or' => '_orExpr',
        'in' => '_inExpr',
        'eq' => '_equalExpr',
        'trim' => '_trimExpr',
        'literal' => '_literalExpr',
        'lt' => '_ltExpr',
        'prod' => '_prodExpr',
        'sum' => '_sumExpr',
        'trim' => '_trimExpr'
    );

    private $_type;
    private $_parts;

    protected function __construct($type, array $parts)
    {
        $this->_type = $type;
        $this->_parts = $parts;
    }

    public function getDql()
    {
        return $this->{self::$_methodMap[$this->_type]}();
    }

    private function _inExpr()
    {

    }

    private function _equalExpr()
    {
        return (is_string($this->_parts[0]) ? $this->_parts[0] : $this->_parts[0]->getDql())
                . ' = ' .
                (is_string($this->_parts[1]) ? $this->_parts[1] : $this->_parts[1]->getDql());
    }

    private function _andExpr()
    {
        return '(' . $this->_parts[0]->getDql() . ' and ' . $this->_parts[1]->getDql() . ')';
    }

    private function _orExpr()
    {
        return '(' . $this->_parts[0]->getDql() . ' or ' . $this->_parts[1]->getDql() . ')';
    }

    private function _literalExpr()
    {
        if (is_numeric($this->_parts[0])) {
            return $this->_parts[0];
        } else {
            return "'" . $this->_parts[0] . "'";
        }
    }

    private function _ltExpr()
    {
        return '(' .
                (is_string($this->_parts[0]) ? $this->_parts[0] : $this->_parts[0]->getDql())
                . ' < ' .
                (is_string($this->_parts[1]) ? $this->_parts[1] : $this->_parts[1]->getDql())
                . ')';
    }

    private function _prodExpr()
    {
        return '(' .
                (is_string($this->_parts[0]) ? $this->_parts[0] : $this->_parts[0]->getDql())
                . ' * ' .
                (is_string($this->_parts[1]) ? $this->_parts[1] : $this->_parts[1]->getDql())
                . ')';
    }

    private function _sumExpr()
    {
        return '(' .
                (is_string($this->_parts[0]) ? $this->_parts[0] : $this->_parts[0]->getDql())
                . ' + ' .
                (is_string($this->_parts[1]) ? $this->_parts[1] : $this->_parts[1]->getDql())
                . ')';
    }

    private function _trimExpr()
    {
        return 'trim(' . (is_string($this->_parts[0]) ? $this->_parts[0] : $this->_parts[0]->getDql()) . ')';
    }

    //---

    public static function avg($x)
    {
        return new self('avg', array($x));
    }

    public static function max($x)
    {
        return new self('max', array($x));
    }

    public static function min($x)
    {
        return new self('min', array($x));
    }

    public static function count($x)
    {
        return new self('count', array($x));
    }

    public static function countDistinct($x)
    {
        return new self('countDistinct', array($x));
    }

    public static function exists($subquery)
    {

    }

    public static function all($subquery)
    {

    }

    public static function some($subquery)
    {

    }

    public static function any($subquery)
    {

    }

    public static function not($restriction)
    {

    }

    public static function andx($x, $y)
    {

    }

    public static function orx($x, $y)
    {
        return new self('or', array($x, $y));
    }

    public static function abs($x)
    {
        return new self('abs', array($x));
    }

    public static function prod($x, $y)
    {
        return new self('prod', array($x, $y));
    }

    public static function diff($x, $y)
    {

    }

    public static function sum($x, $y)
    {
        return new self('sum', array($x, $y));
    }

    public static function quot($x, $y)
    {

    }

    public static function sqrt($x)
    {

    }

    public static function eq($x, $y)
    {
        return new self('eq', array($x, $y));
    }

    public static function notEqual($x, $y)
    {

    }

    public static function like($x, $pattern, $escapeChar = null)
    {

    }

    public static function concat($x, $y)
    {

    }

    public static function substr($x, $from = null, $len = null)
    {

    }

    public static function lower($x)
    {

    }

    public static function upper($x)
    {

    }

    public static function lengt($x)
    {

    }

    public static function greaterThan($x, $y)
    {

    }

    public static function lessThan($x, $y)
    {

    }

    public static function lt($x, $y)
    {
        return new self('lt', array($x, $y));
    }

    public static function path($path)
    {
        return new self('path', array($path));
    }

    public static function literal($literal)
    {
        return new self('literal', array($literal));
    }

    public static function greaterThanOrEqualTo($x, $y)
    {

    }

    public static function lessThanOrEqualTo($x, $y)
    {

    }

    public static function between($val, $x, $y)
    {

    }

    public static function trim($val, $spec = null, $char = null)
    {
        return new self('trim', array($val, $spec, $char));
    }
}