<?php

/**
 * Condition
 *
 * @package Less
 * @subpackage tree
 */
class Less_Tree_Condition extends Less_Tree {

	public $op;
	public $lvalue;
	public $rvalue;
	public $index;
	public $negate;
	public $type = 'Condition';

	public function __construct( $op, $l, $r, $i = 0, $negate = false ) {
		$this->op = trim( $op );
		$this->lvalue = $l;
		$this->rvalue = $r;
		$this->index = $i;
		$this->negate = $negate;
	}

	public function accept( $visitor ) {
		$this->lvalue = $visitor->visitObj( $this->lvalue );
		$this->rvalue = $visitor->visitObj( $this->rvalue );
	}

	public function compile( $env ) {
		$a = $this->lvalue->compile( $env );
		$b = $this->rvalue->compile( $env );

		switch ( $this->op ) {
			case 'and':
				$result = $a && $b;
			break;

			case 'or':
				$result = $a || $b;
			break;

			default:
				if ( Less_Parser::is_method( $a, 'compare' ) ) {
					$result = $a->compare( $b );
				} elseif ( Less_Parser::is_method( $b, 'compare' ) ) {
					$result = $b->compare( $a );
				} else {
					throw new Less_Exception_Compiler( 'Unable to perform comparison', null, $this->index );
				}

				switch ( $result ) {
					case -1:
					$result = $this->op === '<' || $this->op === '=<' || $this->op === '<=';
					break;

					case  0:
					$result = $this->op === '=' || $this->op === '>=' || $this->op === '=<' || $this->op === '<=';
					break;

					case  1:
					$result = $this->op === '>' || $this->op === '>=';
					break;
				}
			break;
		}

		return $this->negate ? !$result : $result;
	}

}