<?php

declare(strict_types=1);

namespace App\Tools\Phpstan\Rule;

use PhpParser\Node;
use PHPStan\Analyser\Scope;
use PHPStan\Rules\Rule;
use PHPStan\Rules\RuleErrorBuilder;
use PHPStan\ShouldNotHappenException;

/**
 * @implements Rule<Node\Stmt\Foreach_>
 */
class MissingUnsetAfterByRefForeachRule implements Rule
{
    public function getNodeType(): string
    {
        return Node\Stmt\Foreach_::class;
    }

    public function processNode(Node $node, Scope $scope): array
    {
        if (!$node->byRef) {
            return [];
        }

        if (
            !$node->valueVar instanceof Node\Expr\Variable
            || !\is_string($node->valueVar->name)
        ) {
            throw new ShouldNotHappenException();
        }
        $byRefVarName = $node->valueVar->name;

        /** @var \WeakReference<Node>|null $weakNextNode */
        $weakNextNode = $node->getAttribute('weak_next');
        $nextNode = $weakNextNode?->get();
        if ($nextNode instanceof Node\Stmt\Unset_) {
            foreach ($nextNode->vars as $var) {
                if (
                    $var instanceof Node\Expr\Variable
                    && $var->name === $byRefVarName
                ) {
                    return [];
                }
            }
        }

        return [
            RuleErrorBuilder::message(\sprintf('Missing unset($%s) after by ref foreach.', $byRefVarName))
            ->identifier('hc.missingUnsetAfterByRefForeach')
            ->build(),
        ];
    }
}