import AsyncStorage from '@react-native-async-storage/async-storage';

import type { Beneficiary } from '../../../types/app';
import type { CbsBeneficiary } from '../../../types/cbs';

const FAVORITES_KEY = 'bankcbs.beneficiaryFavorites';

/**
 * The API has no favourite flag — starring a payee is a local preference. Kept
 * as a set of beneficiary ids in AsyncStorage: losing it costs the customer a
 * tap, so it does not warrant the Keystore.
 */
export const favoriteStore = {
  async read(): Promise<string[]> {
    try {
      const raw = await AsyncStorage.getItem(FAVORITES_KEY);
      const parsed = raw ? JSON.parse(raw) : [];

      return Array.isArray(parsed) ? parsed.filter((id): id is string => typeof id === 'string') : [];
    } catch {
      return [];
    }
  },

  async write(ids: string[]) {
    try {
      await AsyncStorage.setItem(FAVORITES_KEY, JSON.stringify(ids));
    } catch {
      // A failed preference write is not worth surfacing to the customer.
    }
  },
};

/**
 * Maps a payee as the bank returned it onto the shape the payments screens
 * already read. `validate` leaves `beneficiaryId` null because nothing has been
 * saved yet, so an unsaved payee gets a stable synthetic key from its routing
 * details rather than a fresh one on every keystroke.
 */
export const toBeneficiary = (
  source: CbsBeneficiary,
  favorites: ReadonlySet<string> = new Set(),
): Beneficiary => {
  const id =
    source.beneficiaryId ??
    `draft:${source.mode}:${source.accountNumberMasked}:${source.mmid ?? source.ifsc ?? ''}`;

  return {
    id,
    name: source.name,
    bankName: source.bankName,
    accountMasked: source.accountNumberMasked,
    nickname: source.nickname ?? undefined,
    favorite: favorites.has(id),
    mode: source.mode,
    ifsc: source.ifsc,
    mobileNumber: source.mobileNumber,
    mmid: source.mmid,
    status: source.status,
  };
};