class LineCountingVisitor

final class LineCountingVisitor extends NodeVisitorAbstract {
    
    /**
     * @psalm-var non-negative-int
     */
    private readonly int $linesOfCode;
    
    /**
     * @var Comment[]
     */
    private array $comments = [];
    
    /**
     * @var int[]
     */
    private array $linesWithStatements = [];
    
    /**
     * @psalm-param non-negative-int $linesOfCode
     */
    public function __construct(int $linesOfCode) {
        $this->linesOfCode = $linesOfCode;
    }
    public function enterNode(Node $node) : void {
        $this->comments = array_merge($this->comments, $node->getComments());
        if (!$node instanceof Expr) {
            return;
        }
        $this->linesWithStatements[] = $node->getStartLine();
    }
    public function result() : LinesOfCode {
        $commentLinesOfCode = 0;
        foreach ($this->comments() as $comment) {
            $commentLinesOfCode += $comment->getEndLine() - $comment->getStartLine() + 1;
        }
        $nonCommentLinesOfCode = $this->linesOfCode - $commentLinesOfCode;
        $logicalLinesOfCode = count(array_unique($this->linesWithStatements));
        assert($commentLinesOfCode >= 0);
        assert($nonCommentLinesOfCode >= 0);
        assert($logicalLinesOfCode >= 0);
        return new LinesOfCode($this->linesOfCode, $commentLinesOfCode, $nonCommentLinesOfCode, $logicalLinesOfCode);
    }
    
    /**
     * @return Comment[]
     */
    private function comments() : array {
        $comments = [];
        foreach ($this->comments as $comment) {
            $comments[$comment->getStartLine() . '_' . $comment->getStartTokenPos() . '_' . $comment->getEndLine() . '_' . $comment->getEndTokenPos()] = $comment;
        }
        return $comments;
    }

}