/**
 * Copyright (c) 2017-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @flow strict-local
 * @format
 */

import {Cache} from '../cache';

describe('Cache', () => {
  const key1 = 'key1';
  const key2 = 'key2';
  const value = 'value';

  it('creates values on demand', () => {
    let callCount = 0;
    const factory = jest.fn().mockImplementation(key => {
      callCount += 1;
      expect(key).toEqual(key1);
      return value;
    });
    const cache: Cache<string, string> = new Cache(factory);

    expect(factory).not.toHaveBeenCalled();
    expect(cache.has(key1)).toEqual(false);
    expect(cache.get(key1)).toEqual(value);
    expect(callCount).toEqual(1);
    expect(cache.has(key1)).toEqual(true);
    expect(factory).toHaveBeenCalledWith(key1);
    expect(Array.from(cache.values())).toEqual([value]);

    expect(cache.get(key1)).toEqual(value);
    expect(callCount).toEqual(1);
  });

  it('delete', () => {
    const factory = jest.fn().mockReturnValue(value);
    const cache: Cache<string, string> = new Cache(factory);

    expect(cache.delete(key1)).toEqual(false);
    cache.get(key1);
    expect(cache.has(key1)).toEqual(true);
    expect(cache.delete(key1)).toEqual(true);
    expect(cache.has(key1)).toEqual(false);
  });

  it('delete disposes values', () => {
    const factory = jest.fn().mockReturnValue(value);
    const dispose = jest.fn();
    const cache: Cache<string, string> = new Cache(factory, dispose);

    cache.get(key1);
    cache.delete(key1);
    expect(dispose).toHaveBeenCalledWith(value);
  });

  it('clear disposes values', () => {
    const factory = jest.fn().mockReturnValue(value);
    const dispose = jest.fn();
    const cache: Cache<string, string> = new Cache(factory, dispose);

    cache.get(key1);
    cache.clear();
    expect(dispose).toHaveBeenCalledWith(value);
  });

  it('dispose disposes values', () => {
    const factory = jest.fn().mockReturnValue(value);
    const dispose = jest.fn();
    const cache: Cache<string, string> = new Cache(factory, dispose);

    cache.get(key1);
    cache.dispose();
    expect(dispose).toHaveBeenCalledWith(value);
  });

  it('observeValues sees existing and new values', async () => {
    const factory = jest.fn().mockImplementation(key => key);
    const cache: Cache<string, string> = new Cache(factory);

    cache.get(key1);
    const values = cache
      .observeValues()
      .toArray()
      .toPromise();
    cache.get(key2);
    cache.dispose();
    expect(await values).toEqual([key1, key2]);
  });

  it('observeKeys sees existing and new keys', async () => {
    const factory = jest.fn().mockImplementation(key => value);
    const cache: Cache<string, string> = new Cache(factory);

    cache.get(key1);
    const values = cache
      .observeKeys()
      .toArray()
      .toPromise();
    cache.get(key2);
    cache.dispose();
    expect(await values).toEqual([key1, key2]);
  });
});