import {NextResponse} from "next/server";

interface SitemapRoute {
    url: string;
    lastModified: string;
    changeFrequency?:
        | "always"
        | "hourly"
        | "daily"
        | "weekly"
        | "monthly"
        | "yearly"
        | "never";
    priority?: number;
}

const baseUrl = "https://dki.one";

export async function GET() {
    console.log("Generating sitemap...");

    const staticRoutes: SitemapRoute[] = [
        {url: `${baseUrl}/`, lastModified: new Date().toISOString(), changeFrequency: "weekly", priority: 1.0},
        {
            url: `${baseUrl}/privacy-policy`,
            lastModified: new Date().toISOString(),
            changeFrequency: "yearly",
            priority: 0.3
        },
        {
            url: `${baseUrl}/legal-notice`,
            lastModified: new Date().toISOString(),
            changeFrequency: "yearly",
            priority: 0.3
        },
    ];

    try {
        const response = await fetch(`${baseUrl}/api/sitemap`);
        if (!response.ok) {
            console.error(`Failed to fetch dynamic routes: ${response.statusText}`);
        }

        const dynamicRoutes = (await response.json()) as SitemapRoute[];
        const sitemap = [...staticRoutes, ...dynamicRoutes];

        return new NextResponse(generateXml(sitemap), {
            headers: {"Content-Type": "application/xml"},
        });
    } catch (error) {
        console.error("Error fetching dynamic routes, using fallback:", error);
        return new NextResponse(generateXml(staticRoutes), {
            headers: {"Content-Type": "application/xml"},
        });
    }
}

function generateXml(routes: SitemapRoute[]): string {
    const xmlHeader = '<?xml version="1.0" encoding="UTF-8"?>';
    const urlsetOpen = '<urlset xmlns="https://www.sitemaps.org/schemas/sitemap/0.9">';
    const urlsetClose = '</urlset>';

    const urlEntries = routes
        .map(
            (route) => `
    <url>
      <loc>${route.url}</loc>
      <lastmod>${route.lastModified}</lastmod>
      ${route.changeFrequency ? `<changefreq>${route.changeFrequency}</changefreq>` : ""}
      ${route.priority ? `<priority>${route.priority}</priority>` : ""}
    </url>`
        )
        .join("");

    return `${xmlHeader}${urlsetOpen}${urlEntries}${urlsetClose}`;
}