<?php

namespace Picea\ControlStructure;

abstract class AbstractLoop implements ControlStructure {

    protected function openLoop(\Picea\Compiler\Context &$context, ?string $arguments, string $token,) : string
    {
        $name = "$".uniqid("{$token}_");

        $stack = array_filter($context->iterationStack ?? [], function($item) {
            return ! $item['or'];
        });

        $count = count($stack);

        if ( $count > 0 ) {
            $name .= "[" . end($stack)['uid'] . "]";
        }

        $context->iterationStack[] = [
            'or' => false,
            'uid' => $name,
            'token' => "end{$token}",
        ];

        return "<?php $token ($arguments): \$__loop_index = $name = ( $name ?? 0 ) + 1; ?>";
    }

    protected function closeLoop(\Picea\Compiler\Context &$context, ?string $arguments, string $token,) : string
    {
        $last = end($context->iterationStack);

        if ( $last['or'] === false ) {
            $output = "<?php $token; ?>";
        }
        else {
            $output = "<?php endif; if ( isset({$last['uid']}) ) unset({$last['uid']}); ?>";
        }

        array_pop($context->iterationStack);

        return $output;
    }
}