import { HttpError } from "@/lib/errors";
import { readJson, route } from "@/lib/http";
import { deleteImageDir, renameImageDir } from "@/lib/images";
import { findPost, mutatePosts, readPosts } from "@/lib/store";
import { validatePost } from "@/lib/validate";

export const dynamic = "force-dynamic";

type Ctx = { params: Promise<{ slug: string }> };

export const GET = route<Ctx>(async (_req, { params }) => {
  const { slug } = await params;
  const { posts, revision } = await readPosts();
  return Response.json({ post: findPost(posts, slug), revision });
});

/** Body: { post: PostInput, revision? }. A changed slug also moves the
 *  post's image folder and rewrites references to it. */
export const PUT = route<Ctx>(async (req, { params }) => {
  const { slug } = await params;
  const body = await readJson<{ post?: unknown; revision?: string }>(req);
  const { post: input, errors } = validatePost(body.post);
  if (!input) throw new HttpError(400, "invalid post", errors);

  const { result, revision } = await mutatePosts(body.revision, async (posts) => {
    const existing = findPost(posts, slug);
    const updated = { ...input, id: existing.id };
    if (input.slug !== slug) {
      if (posts.some((p) => p.slug === input.slug)) {
        throw new HttpError(409, `a post with slug "${input.slug}" already exists`);
      }
      await renameImageDir(updated, slug, input.slug);
    }
    // images is optional: an editor that cleared the gallery drops the key.
    if (!input.images) delete (updated as { images?: unknown }).images;
    posts[posts.indexOf(existing)] = updated;
    return updated;
  });
  return Response.json({ post: result, revision });
});

/** Query: ?revision=…&images=1 (also delete the post's image folder). */
export const DELETE = route<Ctx>(async (req, { params }) => {
  const { slug } = await params;
  const url = new URL(req.url);
  const { revision } = await mutatePosts(url.searchParams.get("revision") ?? undefined, (posts) => {
    posts.splice(posts.indexOf(findPost(posts, slug)), 1);
  });
  if (url.searchParams.get("images") === "1") await deleteImageDir(slug);
  return Response.json({ deleted: slug, revision });
});