/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 * Logic for reading, writing, and subscribing to atoms within the context of
 * a particular React render tree. EVERYTHING IN THIS MODULE SHOULD BE PURE
 * FUNCTIONS BETWEEN IMMUTABLE TreeState VALUES. It is permissible to call
 * `getAtomDef` because atom definitions are constant.
 *
 * @emails oncall+recoil
 * @flow strict-local
 * @format
 */
'use strict';

import type { Loadable } from '../adt/Recoil_Loadable';
import type { DependencyMap } from './Recoil_Graph';
import type { DefaultValue } from './Recoil_Node';
import type { AtomValues, NodeKey, Store, TreeState } from './Recoil_State';

const {
  mapByDeletingFromMap,
  mapBySettingInMap,
  setByAddingToSet
} = require('../util/Recoil_CopyOnWrite');

const {
  getNode,
  getNodeMaybe
} = require('./Recoil_Node'); // flowlint-next-line unclear-type:off


const emptySet: $ReadOnlySet<any> = Object.freeze(new Set());
declare class ReadOnlyRecoilValueError extends Error {} // Get the current value loadable of a node and update the state.
// Update dependencies and subscriptions for selectors.
// Update saved value validation for atoms.

declare function getNodeLoadable<T>(store: Store, state: TreeState, key: NodeKey): [DependencyMap, Loadable<T>]; // Peek at the current value loadable for a node without any evaluation or state change

declare function peekNodeLoadable<T>(store: Store, state: TreeState, key: NodeKey): ?Loadable<T>; // Write value directly to state bypassing the Node interface as the node
// definitions may not have been loaded yet when processing the initial snapshot.

declare function setUnvalidatedAtomValue<T>(state: TreeState, key: NodeKey, newValue: T): TreeState; // Return the discovered dependencies and values to be written by setting
// a node value. (Multiple values may be written due to selectors getting to
// set upstreams; deps may be discovered because of reads in updater functions.)

declare function setNodeValue<T>(store: Store, state: TreeState, key: NodeKey, newValue: T | DefaultValue): [DependencyMap, AtomValues]; // Find all of the recursively dependent nodes

declare function getDownstreamNodes(store: Store, state: TreeState, keys: $ReadOnlySet<NodeKey>): $ReadOnlySet<NodeKey>;
module.exports = {
  getNodeLoadable,
  peekNodeLoadable,
  setNodeValue,
  setUnvalidatedAtomValue,
  getDownstreamNodes
};