const API_URL = process.env.NEXT_PUBLIC_API_URL;
const MAIN_DOMAIN = 'https://nobat724.com';
const PER_SITEMAP = 1000;

function toSafeDate(value) {
    if (!value) return new Date();
    const d = new Date(value);
    return isNaN(d.getTime()) ? new Date() : d;
}

export async function generateSitemaps() {
    if (!API_URL) return [{ id: 0 }];

    try {
        const res = await fetch(`${API_URL}/api/v1/blogs?page=1&limit=1`, {
            next: { revalidate: 86400 },
        });
        if (!res.ok) return [{ id: 0 }];
        const json = await res.json();
        const total = json?.meta?.totalRecords || 0;
        const pageCount = Math.max(1, Math.ceil(total / PER_SITEMAP));
        return Array.from({ length: pageCount }, (_, id) => ({ id }));
    } catch {
        return [{ id: 0 }];
    }
}

export default async function sitemap({ id }) {
    if (!API_URL) return [];

    try {
        const res = await fetch(`${API_URL}/api/v1/blogs?page=${id + 1}&limit=${PER_SITEMAP}`, {
            next: { revalidate: 3600 },
        });
        if (!res.ok) return [];
        const json = await res.json();
        const blogs = json?.data || [];
        return blogs
            .filter((b) => b?.slug || b?.uuid)
            .map((b) => ({
                url: `${MAIN_DOMAIN}/blog/${b.slug || b.uuid}`,
                lastModified: toSafeDate(b.created),
                changeFrequency: 'monthly',
                priority: 0.6,
            }));
    } catch {
        return [];
    }
}