// Shared messaging helpers used by both the Messages page and the floating chat dock.
import { useSyncExternalStore } from "react";
import { useQuery } from "@tanstack/react-query";
import { api } from "./api";
import { isUnlocked, subscribeUnlock } from "./e2ee";

export const SYSTEM_ID = 0; // synthetic "Siftlode" system conversation partner id

// Set-once cache of partner public keys (the server is the directory; keys never change).
const pubCache = new Map<number, string>();
export async function partnerPub(partnerId: number): Promise<string> {
  const cached = pubCache.get(partnerId);
  if (cached) return cached;
  const r = await api.messagePublicKey(partnerId);
  pubCache.set(partnerId, r.public_key);
  return r.public_key;
}

// Live "is secure messaging unlocked on this device" — shared so the page and the dock agree.
export function useUnlocked(): boolean {
  return useSyncExternalStore(subscribeUnlock, isUnlocked, isUnlocked);
}

// The SERVER is the source of truth for whether messaging is set up. Combining it with the
// local unlock state gives the real gate: "setup" if the server has no key (even if a stale
// private key lingers in this browser — setup overwrites it), "unlock" if the server has a key
// but this device hasn't unlocked it, else "ready".
export type KeyState = "loading" | "setup" | "unlock" | "ready";
export function useKeyState(): KeyState {
  const unlocked = useUnlocked();
  const q = useQuery({ queryKey: ["message-key"], queryFn: api.messageMyKey, staleTime: 60_000 });
  if (q.isLoading && !q.data) return "loading";
  if (!(q.data?.configured ?? false)) return "setup";
  if (!unlocked) return "unlock";
  return "ready";
}