import { useCallback } from 'react';
import { useMatrixClient } from './useMatrixClient';
import { createAccountDataListStore } from './createAccountDataListStore';
import { StatusPreset, upsertPreset } from '../utils/statusPresets';

const STATUS_PRESETS_KEY = 'io.lotus.status_presets';
const MAX_PRESETS = 20;

type StatusPresetsContent = {
  presets: StatusPreset[];
};

// Shared, concurrency-safe store. See createAccountDataListStore for why the
// snapshot + write queue must be module-scoped (writes are serialized to avoid
// lost updates, since setAccountData replaces the whole content with no merge).
const statusPresetsStore = createAccountDataListStore<StatusPreset[], StatusPresetsContent>({
  eventType: STATUS_PRESETS_KEY,
  read: (content) => content?.presets ?? [],
  write: (presets) => ({ presets }),
});

export function useStatusPresets(): {
  presets: StatusPreset[];
  addPreset: (preset: StatusPreset) => Promise<void>;
  removePreset: (id: string) => Promise<void>;
} {
  const mx = useMatrixClient();
  const presets = statusPresetsStore.useValue(mx);

  const addPreset = useCallback(
    (preset: StatusPreset) =>
      statusPresetsStore.enqueueWrite(mx, (current) => upsertPreset(current, preset, MAX_PRESETS)),
    [mx],
  );

  const removePreset = useCallback(
    (id: string) =>
      statusPresetsStore.enqueueWrite(mx, (current) => current.filter((p) => p.id !== id)),
    [mx],
  );

  return { presets, addPreset, removePreset };
}