<?php

namespace App\Http\Controllers\Api;

use App\Models\LegalPage;
use App\Support\ApiError;
use Illuminate\Http\Request;
use Illuminate\Routing\Controller as BaseController;
use League\CommonMark\Environment\Environment;
use League\CommonMark\Extension\Autolink\AutolinkExtension;
use League\CommonMark\Extension\CommonMark\CommonMarkCoreExtension;
use League\CommonMark\Extension\Strikethrough\StrikethroughExtension;
use League\CommonMark\Extension\Table\TableExtension;
use League\CommonMark\Extension\TaskList\TaskListExtension;
use League\CommonMark\MarkdownConverter;
use Symfony\Component\HttpFoundation\Response;

class LegalController extends BaseController
{
    protected MarkdownConverter $markdown;

    public function __construct()
    {
        $environment = new Environment([
            'html_input' => 'strip',
            'allow_unsafe_links' => false,
        ]);

        $environment->addExtension(new CommonMarkCoreExtension);
        $environment->addExtension(new TableExtension);
        $environment->addExtension(new AutolinkExtension);
        $environment->addExtension(new StrikethroughExtension);
        $environment->addExtension(new TaskListExtension);

        $this->markdown = new MarkdownConverter($environment);
    }

    public function show(Request $request, string $slug)
    {
        $locale = $request->query('lang', 'de');
        $slugs = $this->resolveSlugs($slug);

        $page = LegalPage::query()
            ->whereIn('slug', $slugs)
            ->where('is_published', true)
            ->orderByDesc('version')
            ->first();
        if (! $page) {
            return ApiError::response(
                'legal_page_not_found',
                'Legal Page Not Found',
                'The requested legal document does not exist.',
                Response::HTTP_NOT_FOUND,
                ['slug' => $slugs[0]]
            );
        }

        $title = $page->title[$locale] ?? $page->title[$page->locale_fallback] ?? $page->title['de'] ?? $page->title['en'] ?? $page->slug;
        $body = $page->body_markdown[$locale] ?? $page->body_markdown[$page->locale_fallback] ?? reset($page->body_markdown) ?? '';

        return response()->json([
            'slug' => $page->slug,
            'version' => (int) $page->version,
            'effective_from' => optional($page->effective_from)->toIso8601String(),
            'locale' => $locale,
            'title' => $title,
            'body_markdown' => (string) $body,
            'body_html' => $this->convertMarkdownToHtml($body),
        ])->header('Cache-Control', 'no-store');
    }

    protected function resolveSlugs(string $slug): array
    {
        $s = strtolower($slug);
        $aliasMap = [
            'imprint' => 'impressum',
            'privacy' => 'datenschutz',
            'terms' => 'agb',
            'withdrawal' => 'widerrufsbelehrung',
            'cancellation' => 'widerrufsbelehrung',
            'cancellation-policy' => 'widerrufsbelehrung',
            'widerruf' => 'widerrufsbelehrung',
        ];

        $canonical = $aliasMap[$s] ?? $s;

        return array_values(array_unique(
            $canonical === 'widerrufsbelehrung'
                ? ['widerrufsbelehrung', 'widerruf']
                : [$canonical]
        ));
    }

    protected function convertMarkdownToHtml(string $markdown): string
    {
        return trim((string) $this->markdown->convert($markdown));
    }
}