// GET  /api/selections        -> { picks: { [groupId]: string | string[] } }
// POST /api/selections { groupId, value } -> merges value into stored picks, returns updated state.
//
// Single shared document in KV under key "picks" — no auth, no per-user accounts.
// Good enough for a private link shared between two people; anyone with the URL can edit.

const KEY = "picks";

export async function onRequestGet({ env }) {
  const raw = await env.PICKS.get(KEY);
  const picks = raw ? JSON.parse(raw) : {};
  return Response.json({ picks });
}

export async function onRequestPost({ request, env }) {
  let body;
  try {
    body = await request.json();
  } catch {
    return new Response("Invalid JSON body", { status: 400 });
  }

  const { groupId, value } = body;
  if (!groupId || typeof groupId !== "string") {
    return new Response("groupId is required", { status: 400 });
  }

  const raw = await env.PICKS.get(KEY);
  const picks = raw ? JSON.parse(raw) : {};

  if (value === "" || value == null) {
    delete picks[groupId];
  } else {
    picks[groupId] = value; // string for day radio picks, string[] for collection checkboxes
  }

  await env.PICKS.put(KEY, JSON.stringify(picks));
  return Response.json({ picks });
}