import Api from '~/api';
import UsersCache from '~/lib/utils/users_cache';

describe('UsersCache', () => {
  const dummyUsername = 'win';
  const dummyUser = 'has a farm';

  beforeEach(() => {
    UsersCache.internalStorage = { };
  });

  describe('get', () => {
    it('returns undefined for empty cache', () => {
      expect(UsersCache.internalStorage).toEqual({ });

      const user = UsersCache.get(dummyUsername);

      expect(user).toBe(undefined);
    });

    it('returns undefined for missing user', () => {
      UsersCache.internalStorage['no body'] = 'no data';

      const user = UsersCache.get(dummyUsername);

      expect(user).toBe(undefined);
    });

    it('returns matching user', () => {
      UsersCache.internalStorage[dummyUsername] = dummyUser;

      const user = UsersCache.get(dummyUsername);

      expect(user).toBe(dummyUser);
    });
  });

  describe('hasData', () => {
    it('returns false for empty cache', () => {
      expect(UsersCache.internalStorage).toEqual({ });

      expect(UsersCache.hasData(dummyUsername)).toBe(false);
    });

    it('returns false for missing user', () => {
      UsersCache.internalStorage['no body'] = 'no data';

      expect(UsersCache.hasData(dummyUsername)).toBe(false);
    });

    it('returns true for matching user', () => {
      UsersCache.internalStorage[dummyUsername] = dummyUser;

      expect(UsersCache.hasData(dummyUsername)).toBe(true);
    });
  });

  describe('remove', () => {
    it('does nothing if cache is empty', () => {
      expect(UsersCache.internalStorage).toEqual({ });

      UsersCache.remove(dummyUsername);

      expect(UsersCache.internalStorage).toEqual({ });
    });

    it('does nothing if cache contains no matching data', () => {
      UsersCache.internalStorage['no body'] = 'no data';

      UsersCache.remove(dummyUsername);

      expect(UsersCache.internalStorage['no body']).toBe('no data');
    });

    it('removes matching data', () => {
      UsersCache.internalStorage[dummyUsername] = dummyUser;

      UsersCache.remove(dummyUsername);

      expect(UsersCache.internalStorage).toEqual({ });
    });
  });

  describe('retrieve', () => {
    let apiSpy;

    beforeEach(() => {
      spyOn(Api, 'users').and.callFake((query, options) => apiSpy(query, options));
    });

    it('stores and returns data from API call if cache is empty', (done) => {
      apiSpy = (query, options) => {
        expect(query).toBe('');
        expect(options).toEqual({ username: dummyUsername });
        return Promise.resolve([dummyUser]);
      };

      UsersCache.retrieve(dummyUsername)
      .then((user) => {
        expect(user).toBe(dummyUser);
        expect(UsersCache.internalStorage[dummyUsername]).toBe(dummyUser);
      })
      .then(done)
      .catch(done.fail);
    });

    it('returns undefined if Ajax call fails and cache is empty', (done) => {
      const dummyError = new Error('server exploded');
      apiSpy = (query, options) => {
        expect(query).toBe('');
        expect(options).toEqual({ username: dummyUsername });
        return Promise.reject(dummyError);
      };

      UsersCache.retrieve(dummyUsername)
      .then(user => fail(`Received unexpected user: ${JSON.stringify(user)}`))
      .catch((error) => {
        expect(error).toBe(dummyError);
      })
      .then(done)
      .catch(done.fail);
    });

    it('makes no Ajax call if matching data exists', (done) => {
      UsersCache.internalStorage[dummyUsername] = dummyUser;
      apiSpy = () => fail(new Error('expected no Ajax call!'));

      UsersCache.retrieve(dummyUsername)
      .then((user) => {
        expect(user).toBe(dummyUser);
      })
      .then(done)
      .catch(done.fail);
    });
  });
});