import { test } from 'node:test';
import assert from 'node:assert/strict';
import { createStore } from 'jotai';
import type { ScheduledMessage } from './scheduledMessages';

// scheduledMessagesAtom is backed by jotai's atomWithStorage over
// `createJSONStorage(() => localStorage)`, which dereferences `localStorage`
// (absent in node) lazily on first store access. We install an in-memory mock
// before importing the module so both module init and the storage reads/writes
// resolve against it.
const STORAGE_KEY = 'cinny_scheduled_messages_v1';

const installStorage = (): Map<string, string> => {
  const map = new Map<string, string>();
  (globalThis as { localStorage?: unknown }).localStorage = {
    getItem: (k: string) => (map.has(k) ? map.get(k)! : null),
    setItem: (k: string, v: string) => {
      map.set(k, v);
    },
    removeItem: (k: string) => {
      map.delete(k);
    },
  };
  return map;
};

installStorage();
const { scheduledMessagesAtom } = await import('./scheduledMessages');

// jotai's `atomWithStorage` binds to the `localStorage` captured at module
// evaluation. To exercise hydration from pre-existing storage we install seeded
// storage and then import a *fresh* (cache-busted) copy of the module.
let freshCounter = 0;
const importWithStorage = async (
  seed?: Record<string, ScheduledMessage[]>,
): Promise<typeof import('./scheduledMessages').scheduledMessagesAtom> => {
  const backing = installStorage();
  if (seed) backing.set(STORAGE_KEY, JSON.stringify(seed));
  freshCounter += 1;
  const mod = await import(`./scheduledMessages?fresh=${freshCounter}`);
  return mod.scheduledMessagesAtom;
};

const msg = (delayId: string, roomId: string): ScheduledMessage => ({
  delayId,
  roomId,
  content: { body: delayId, msgtype: 'm.text' },
  sendAt: 1000,
});

test('starts as an empty Map', () => {
  installStorage();
  const store = createStore();
  const map = store.get(scheduledMessagesAtom);
  assert.ok(map instanceof Map);
  assert.equal(map.size, 0);
});

test('setting a Map is readable back as an equivalent Map (round-trip)', () => {
  installStorage();
  const store = createStore();

  const next = new Map<string, ScheduledMessage[]>([['!room:s', [msg('d1', '!room:s')]]]);
  store.set(scheduledMessagesAtom, next);

  const got = store.get(scheduledMessagesAtom);
  assert.ok(got instanceof Map);
  assert.deepEqual(got.get('!room:s'), [msg('d1', '!room:s')]);
});

test('functional-updater form receives the previous Map', () => {
  installStorage();
  const store = createStore();

  store.set(scheduledMessagesAtom, new Map([['!a:s', [msg('d1', '!a:s')]]]));

  let seenPrev: Map<string, ScheduledMessage[]> | undefined;
  store.set(scheduledMessagesAtom, (prev) => {
    seenPrev = prev;
    const copy = new Map(prev);
    copy.set('!b:s', [msg('d2', '!b:s')]);
    return copy;
  });

  assert.ok(seenPrev instanceof Map);
  assert.deepEqual(seenPrev?.get('!a:s'), [msg('d1', '!a:s')]);

  const got = store.get(scheduledMessagesAtom);
  assert.deepEqual([...got.keys()].sort(), ['!a:s', '!b:s']);
});

test('persists to localStorage as a plain Record keyed by roomId', () => {
  const backing = installStorage();
  const store = createStore();

  store.set(
    scheduledMessagesAtom,
    new Map<string, ScheduledMessage[]>([
      ['!a:s', [msg('d1', '!a:s')]],
      ['!b:s', [msg('d2', '!b:s'), msg('d3', '!b:s')]],
    ]),
  );

  const raw = backing.get(STORAGE_KEY);
  assert.ok(raw, 'expected the storage key to be written');
  const parsed = JSON.parse(raw!) as Record<string, ScheduledMessage[]>;
  assert.deepEqual(Object.keys(parsed).sort(), ['!a:s', '!b:s']);
  assert.equal(parsed['!b:s'].length, 2);
  assert.equal(parsed['!a:s'][0].delayId, 'd1');
});

test('hydrates the Map from a previously stored Record once the atom is mounted', async () => {
  const freshAtom = await importWithStorage({ '!room:s': [msg('stored', '!room:s')] });
  const store = createStore();

  // The underlying jotai atomWithStorage is created without `getOnInit`, so a
  // bare `store.get` returns the default ({}); storage is synced on mount. We
  // model the React mount with `store.sub`, which fires the onMount hydration.
  const unsub = store.sub(freshAtom, () => {});
  try {
    assert.deepEqual(store.get(freshAtom).get('!room:s'), [msg('stored', '!room:s')]);
  } finally {
    unsub();
  }
});

test('supports multiple rooms independently', () => {
  installStorage();
  const store = createStore();

  store.set(scheduledMessagesAtom, (prev) => {
    const copy = new Map(prev);
    copy.set('!r1:s', [msg('a', '!r1:s')]);
    return copy;
  });
  store.set(scheduledMessagesAtom, (prev) => {
    const copy = new Map(prev);
    copy.set('!r2:s', [msg('b', '!r2:s')]);
    return copy;
  });

  const map = store.get(scheduledMessagesAtom);
  assert.deepEqual(map.get('!r1:s'), [msg('a', '!r1:s')]);
  assert.deepEqual(map.get('!r2:s'), [msg('b', '!r2:s')]);
});