<?php
/**
 * @private
 */
class Less_Visitor_joinSelector extends Less_Visitor {

	public $contexts = [ [] ];

	/**
	 * @param Less_Tree_Ruleset $root
	 */
	public function run( $root ) {
		return $this->visitObj( $root );
	}

	public function visitRule( $ruleNode, &$visitDeeper ) {
		$visitDeeper = false;
	}

	public function visitMixinDefinition( $mixinDefinitionNode, &$visitDeeper ) {
		$visitDeeper = false;
	}

	public function visitRuleset( $rulesetNode ) {
		$context = end( $this->contexts );
		$paths = [];

		if ( !$rulesetNode->root ) {
			$selectors = $rulesetNode->selectors;
			if ( $selectors !== null ) {
				$filtered = [];
				foreach ( $selectors as $selector ) {
					if ( $selector->getIsOutput() ) {
						$filtered[] = $selector;
					}
				}
				$selectors = $rulesetNode->selectors = $filtered ?: null;
				if ( $selectors ) {
					$paths = $rulesetNode->joinSelectors( $context, $selectors );
				}
			}

			if ( $selectors === null ) {
				$rulesetNode->rules = null;
			}

			$rulesetNode->paths = $paths;
		}

		// NOTE: Assigned here instead of at the start like less.js,
		// because PHP arrays aren't by-ref
		$this->contexts[] = $paths;
	}

	public function visitRulesetOut() {
		array_pop( $this->contexts );
	}

	public function visitMedia( $mediaNode ) {
		$context = end( $this->contexts );

		if ( count( $context ) === 0 || ( is_object( $context[0] ) && $context[0]->multiMedia ) ) {
			$mediaNode->rules[0]->root = true;
		}
	}

	public function visitDirective( $directiveNode ) {
		$context = end( $this->contexts );

		if ( $directiveNode->rules && count( $directiveNode->rules ) > 0 ) {
			$directiveNode->rules[0]->root = $directiveNode->isRooted || count( $context ) === 0;
		}
	}

}
