<?php

declare(strict_types=1);

namespace LogseqGem;

use League\CommonMark\Node\Inline\Text;
use League\CommonMark\Extension\CommonMark\Node\Inline\Link;
use League\CommonMark\Extension\CommonMark\Node\Block\ListBlock;

class ArticleParser extends Parser {
    private ?array $properties;

    public function convert(): string {
        $gemtext = [];
        $this->properties = [];

        $in_frontmatter = true;

        $walker = $this->document->walker();
        while ($event = $walker->next()) {
            $entering = $event->isEntering();
            $node = $event->getNode();

            if ($entering && $node instanceof ListBlock) {
                $in_frontmatter = false;
                continue;
            }

            if ($entering && $node instanceof Text) {
                $text = $node->getLiteral();

                if ($in_frontmatter) {
                    if (preg_match('/^([A-Za-z-]+):: (.*)/', $text, $matches)) {
                        $this->properties[$matches[1]] = $matches[2];
                        continue;
                    } else {
                        $in_frontmatter = false;
                    }
                }

                $gemtext[] = $text;

                continue;
            }

            if ($entering && $node instanceof Link) {
                $label = $walker->next()->getNode();
                if (!$label instanceof Text) {
                    throw new \Exception('Expected next node in Link to be Text, got ' . get_class($label));
                }

                $gemtext[] = sprintf('=> %s %s', $node->getUrl(), $label->getLiteral());

                continue;
            }
        }

        return implode("\n\n", $gemtext);
    }

    public function getProperties(): array {
        if (is_null($this->properties)) {
            throw new \Exception("Cannot get properties before converting a document");
        }
        return $this->properties;
    }

    public function isPublished(): bool {
        return (($this->getProperties()['status'] ?? '') === 'published');
    }
}