import type { MetadataRoute } from 'next'
import { SITE_URL } from '@/app/metadata'
import { getAllCategories } from '@/lib/categories'
import { getAllPostsMeta } from '@/lib/posts'
import { getAllTags } from '@/lib/tags'
import { slugify } from '@/utils/slug'

export default function sitemap(): MetadataRoute.Sitemap {
  const posts = getAllPostsMeta()
  const lastPostUpdate = posts
    .map((post) => post.updated ?? post.date)
    .toSorted()
    .at(-1)

  return [
    { url: SITE_URL, lastModified: lastPostUpdate, changeFrequency: 'weekly', priority: 1 },
    ...['about', 'projects', 'setup'].map((page) => ({
      url: `${SITE_URL}/${page}`,
      changeFrequency: 'monthly' as const,
      priority: 0.8,
    })),
    ...posts.map((post) => ({
      url: `${SITE_URL}/posts/${post.slug}`,
      lastModified: post.updated ?? post.date,
      changeFrequency: 'monthly' as const,
      priority: 0.9,
    })),
    { url: `${SITE_URL}/categories`, changeFrequency: 'weekly', priority: 0.4 },
    ...Object.keys(getAllCategories()).map((category) => ({
      url: `${SITE_URL}/categories/${slugify(category)}`,
      changeFrequency: 'weekly' as const,
      priority: 0.3,
    })),
    { url: `${SITE_URL}/tags`, changeFrequency: 'weekly', priority: 0.4 },
    ...Object.keys(getAllTags()).map((tag) => ({
      url: `${SITE_URL}/tags/${slugify(tag)}`,
      changeFrequency: 'weekly' as const,
      priority: 0.3,
    })),
  ]
}