import type { ActionFunctionArgs, LoaderFunctionArgs } from "react-router";
import {
  createBand,
  getBandById,
  getBandLinks,
  getBandMembers,
  getIpAddress,
  listBands,
  toSlug,
  updateBand,
  type MemberInput,
} from "~/lib/db.server";

export function loader({ request }: LoaderFunctionArgs) {
  const url = new URL(request.url);
  const id = url.searchParams.get("id");
  if (id) {
    const band = getBandById(id);
    if (!band) return Response.json({ error: "Not found" }, { status: 404 });
    const links = getBandLinks(band.id);
    const members = getBandMembers(band.id);
    return Response.json({ ...band, links, members });
  }
  return Response.json(listBands());
}

export async function action({ request }: ActionFunctionArgs) {
  let body: Record<string, unknown>;
  try {
    body = await request.json();
  } catch {
    return Response.json({ error: "Invalid JSON body" }, { status: 400 });
  }

  if (request.method === "PATCH") {
    const id = body.id as string | undefined;
    if (!id) return Response.json({ error: "id is required" }, { status: 400 });
    const band = getBandById(id);
    if (!band) return Response.json({ error: "Not found" }, { status: 404 });

    const currentLinks = getBandLinks(band.id);
    const currentMembers = getBandMembers(band.id);

    const patchLinks = (body.links as { label: string; url: string }[] | undefined) ?? [];
    const patchMembers = (body.members as MemberInput[] | undefined) ?? [];
    const appendLinks = body.append_links !== false;
    const appendMembers = body.append_members !== false;

    const existingUrls = new Set(currentLinks.map((l) => l.url));
    const newLinks = appendLinks
      ? [...currentLinks.map((l) => ({ label: l.label, url: l.url })), ...patchLinks.filter((l) => !existingUrls.has(l.url))]
      : patchLinks;

    const existingArtistIds = new Set(currentMembers.map((m) => m.artist_id));
    const newMembers: MemberInput[] = appendMembers
      ? [
          ...currentMembers.map((m) => ({ artist_id: m.artist_id, role: m.role, since: m.since ?? "", until: m.until ?? "", note: m.note ?? "" })),
          ...patchMembers.filter((m) => !existingArtistIds.has(m.artist_id)),
        ]
      : patchMembers;

    updateBand(band.id, {
      slug: (body.slug as string | undefined) ?? band.slug,
      name: (body.name as string | undefined) ?? band.name,
      area: (body.area as string | undefined) ?? band.area,
      description: "description" in body ? (body.description as string | null) : band.description,
      status: (body.status as string | undefined) ?? band.status,
      links: newLinks,
      members: newMembers,
      message: (body.message as string | undefined) || "API update",
      ip_address: getIpAddress(request),
    });

    return Response.json(getBandById(band.id));
  }

  if (request.method !== "POST") {
    return Response.json({ error: "Method not allowed" }, { status: 405 });
  }

  const name = (body.name as string | undefined)?.trim();
  if (!name) return Response.json({ error: "name is required" }, { status: 400 });

  const slug = (body.slug as string | undefined)?.trim() || toSlug(name);
  if (!slug) return Response.json({ error: "could not derive slug from name" }, { status: 400 });

  const id = crypto.randomUUID();
  try {
    const band = createBand({
      id,
      slug,
      name,
      area: (body.area as string) || null,
      description: (body.description as string) || null,
      status: (body.status as string) || "active",
      links: (body.links as { label: string; url: string }[]) || [],
      members: (body.members as MemberInput[]) || [],
      message: (body.message as string) || "API import",
      ip_address: getIpAddress(request),
    });
    return Response.json(band, { status: 201 });
  } catch (e) {
    if (e instanceof Error && e.message.includes("UNIQUE constraint failed: bands.slug")) {
      return Response.json({ error: "slug already in use" }, { status: 409 });
    }
    throw e;
  }
}