import { makeDataProvider, defaultAppend } from './generic-data-provider';
import type {
  Query,
  UpdateCallback,
  Update,
  PageInfo,
} from './generic-data-provider';
import type {
  ApolloClient,
  FetchResult,
  SubscriptionOptions,
  OperationVariables,
  ApolloQueryResult,
  QueryOptions,
} from '@apollo/client';
import type { Subscription, Observable } from 'zen-observable-ts';

type Item = {
  cursor: string;
  node: {
    id: string;
  };
};
type Data = Item[];
type QueryData = {
  data: Data;
  pageInfo?: PageInfo;
  totalCount?: number;
};

type SubscriptionData = QueryData;
type Delta = Data;

describe('data provider', () => {
  const update = jest.fn<
    ReturnType<Update<Data, Delta>>,
    Parameters<Update<Data, Delta>>
  >();

  const callback = jest.fn<
    ReturnType<UpdateCallback<Data, Delta>>,
    Parameters<UpdateCallback<Data, Delta>>
  >();

  const query: Query<QueryData> = {
    kind: 'Document',
    definitions: [],
  };
  const subscriptionQuery: Query<SubscriptionData> = query;

  const subscribe = makeDataProvider<QueryData, Data, SubscriptionData, Delta>(
    query,
    subscriptionQuery,
    update,
    (r) => r.data,
    (r) => r.data
  );

  const first = 100;
  const paginatedSubscribe = makeDataProvider<
    QueryData,
    Data,
    SubscriptionData,
    Delta
  >(
    query,
    subscriptionQuery,
    update,
    (r) => r.data,
    (r) => r.data,
    {
      first,
      append: defaultAppend,
      getPageInfo: (r) => r?.pageInfo ?? null,
      getTotalCount: (r) => r?.totalCount,
    }
  );

  const generateData = (start = 0, size = first) => {
    return new Array(size).fill(null).map((v, i) => ({
      cursor: (i + start + 1).toString(),
      node: {
        id: (i + start + 1).toString(),
      },
    }));
  };

  const clientSubscribeUnsubscribe = jest.fn();
  const clientSubscribeSubscribe = jest.fn<
    Subscription,
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    [(value: FetchResult<SubscriptionData>) => void, (error: any) => void]
  >(() => ({
    unsubscribe: clientSubscribeUnsubscribe,
    closed: false,
  }));

  const clientSubscribe = jest.fn<
    Observable<FetchResult<SubscriptionData>>,
    [SubscriptionOptions<OperationVariables, SubscriptionData>]
  >(
    () =>
      ({
        subscribe: clientSubscribeSubscribe,
      } as unknown as Observable<FetchResult<SubscriptionData>>)
  );

  const clientQueryPromise: {
    resolve?: (
      value:
        | ApolloQueryResult<QueryData>
        | PromiseLike<ApolloQueryResult<QueryData>>
    ) => void;
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    reject?: (reason?: any) => void;
  } = {};

  const clientQuery = jest.fn<
    Promise<ApolloQueryResult<QueryData>>,
    [QueryOptions<OperationVariables, QueryData>]
  >(() => {
    return new Promise((resolve, reject) => {
      clientQueryPromise.resolve = resolve;
      clientQueryPromise.reject = reject;
    });
  });

  const client = {
    query: clientQuery,
    subscribe: clientSubscribe,
  } as unknown as ApolloClient<object>;

  const resolveQuery = async (data: QueryData) => {
    if (clientQueryPromise.resolve) {
      await clientQueryPromise.resolve({
        data,
        loading: false,
        networkStatus: 8,
      });
    }
  };

  it('memoize instance and unsubscribe if no subscribers', () => {
    const subscription1 = subscribe(jest.fn(), client);
    const subscription2 = subscribe(jest.fn(), client);
    expect(clientSubscribeSubscribe.mock.calls.length).toEqual(1);
    subscription1.unsubscribe();
    expect(clientSubscribeUnsubscribe.mock.calls.length).toEqual(0);
    subscription2.unsubscribe();
    expect(clientSubscribeUnsubscribe.mock.calls.length).toEqual(1);
  });

  it('calls callback before and after initial fetch', async () => {
    callback.mockClear();
    const data: Item[] = [];
    const subscription = subscribe(callback, client);
    expect(callback.mock.calls.length).toBe(1);
    expect(callback.mock.calls[0][0].data).toBe(null);
    expect(callback.mock.calls[0][0].loading).toBe(true);
    await resolveQuery({ data });
    expect(callback.mock.calls.length).toBe(2);
    expect(callback.mock.calls[1][0].data).toBe(data);
    expect(callback.mock.calls[1][0].loading).toBe(false);
    subscription.unsubscribe();
  });

  it('calls update and callback on each update', async () => {
    const data: Item[] = [];
    const subscription = subscribe(callback, client);
    await resolveQuery({ data });
    const delta: Item[] = [];
    update.mockImplementationOnce((data, delta) => [...data, ...delta]);
    // calling onNext from client.subscribe({ query }).subscribe(onNext)
    await clientSubscribeSubscribe.mock.calls[
      clientSubscribeSubscribe.mock.calls.length - 1
    ][0]({ data: { data: delta } });
    expect(update.mock.calls[update.mock.calls.length - 1][0]).toBe(data);
    expect(update.mock.calls[update.mock.calls.length - 1][1]).toBe(delta);
    expect(callback.mock.calls[callback.mock.calls.length - 1][0].delta).toBe(
      delta
    );
    subscription.unsubscribe();
  });

  it("don't calls callback on update if data doesn't", async () => {
    callback.mockClear();
    const data: Item[] = [];
    const subscription = subscribe(callback, client);
    await resolveQuery({ data });
    const delta: Item[] = [];
    update.mockImplementationOnce((data, delta) => data);
    const callbackCallsLength = callback.mock.calls.length;
    // calling onNext from client.subscribe({ query }).subscribe(onNext)
    await clientSubscribeSubscribe.mock.calls[
      clientSubscribeSubscribe.mock.calls.length - 1
    ][0]({ data: { data: delta } });
    expect(update.mock.calls[update.mock.calls.length - 1][0]).toBe(data);
    expect(update.mock.calls[update.mock.calls.length - 1][1]).toBe(delta);
    expect(callback.mock.calls.length).toBe(callbackCallsLength);
    subscription.unsubscribe();
  });

  it('refetch data on reload', async () => {
    clientQuery.mockClear();
    clientSubscribeUnsubscribe.mockClear();
    clientSubscribeSubscribe.mockClear();
    const data: Item[] = [];
    const subscription = subscribe(callback, client);
    await resolveQuery({ data });
    subscription.reload();
    await resolveQuery({ data });
    expect(clientQuery.mock.calls.length).toBe(2);
    expect(clientSubscribeSubscribe.mock.calls.length).toBe(1);
    expect(clientSubscribeUnsubscribe.mock.calls.length).toBe(0);
    subscription.unsubscribe();
  });

  it('refetch data and restart subscription on reload with force', async () => {
    clientQuery.mockClear();
    clientSubscribeUnsubscribe.mockClear();
    clientSubscribeSubscribe.mockClear();
    const data: Item[] = [];
    const subscription = subscribe(callback, client);
    await resolveQuery({ data });
    subscription.reload(true);
    await resolveQuery({ data });
    expect(clientQuery.mock.calls.length).toBe(2);
    expect(clientSubscribeSubscribe.mock.calls.length).toBe(2);
    expect(clientSubscribeUnsubscribe.mock.calls.length).toBe(1);
    subscription.unsubscribe();
  });

  it('calls callback on flush', async () => {
    callback.mockClear();
    const data: Item[] = [];
    const subscription = subscribe(callback, client);
    await resolveQuery({ data });
    const callbackCallsLength = callback.mock.calls.length;
    subscription.flush();
    expect(callback.mock.calls.length).toBe(callbackCallsLength + 1);
    subscription.unsubscribe();
  });

  it('fills data with nulls if paginaton is enabled', async () => {
    callback.mockClear();
    const totalCount = 1000;
    const data: Item[] = new Array(first).fill(null).map((v, i) => ({
      cursor: i.toString(),
      node: {
        id: i.toString(),
      },
    }));
    const subscription = paginatedSubscribe(callback, client);
    await resolveQuery({
      data,
      totalCount,
      pageInfo: {
        hasNextPage: true,
      },
    });
    expect(callback.mock.calls[1][0].data?.length).toBe(totalCount);
    subscription.unsubscribe();
  });

  it('loads requested data blocks and inserts data with total count', async () => {
    callback.mockClear();
    const totalCount = 1000;
    const subscription = paginatedSubscribe(callback, client);
    await resolveQuery({
      data: generateData(),
      totalCount,
      pageInfo: {
        hasNextPage: true,
        endCursor: '100',
      },
    });

    // load next page
    subscription.load();
    let lastQueryArgs =
      clientQuery.mock.calls[clientQuery.mock.calls.length - 1][0];
    expect(lastQueryArgs?.variables?.pagination).toEqual({
      after: '100',
      first,
    });
    await resolveQuery({
      data: generateData(100),
      pageInfo: {
        hasNextPage: true,
        endCursor: '200',
      },
    });

    // load page with skip
    subscription.load(500, 600);
    lastQueryArgs =
      clientQuery.mock.calls[clientQuery.mock.calls.length - 1][0];
    expect(lastQueryArgs?.variables?.pagination).toEqual({
      after: '200',
      first,
      skip: 300,
    });
    await resolveQuery({
      data: generateData(500),
      pageInfo: {
        hasNextPage: true,
        endCursor: '600',
      },
    });

    // load in the gap
    subscription.load(400, 500);
    lastQueryArgs =
      clientQuery.mock.calls[clientQuery.mock.calls.length - 1][0];
    expect(lastQueryArgs?.variables?.pagination).toEqual({
      after: '200',
      first,
      skip: 200,
    });
    await resolveQuery({
      data: generateData(400),
      pageInfo: {
        hasNextPage: true,
        endCursor: '500',
      },
    });

    // load page after last block
    subscription.load(700, 800);
    lastQueryArgs =
      clientQuery.mock.calls[clientQuery.mock.calls.length - 1][0];
    expect(lastQueryArgs?.variables?.pagination).toEqual({
      after: '600',
      first,
      skip: 100,
    });
    await resolveQuery({
      data: generateData(700),
      pageInfo: {
        hasNextPage: true,
        endCursor: '800',
      },
    });

    // load last page shorter than expected
    subscription.load(950, 1050);
    lastQueryArgs =
      clientQuery.mock.calls[clientQuery.mock.calls.length - 1][0];
    expect(lastQueryArgs?.variables?.pagination).toEqual({
      after: '800',
      first,
      skip: 150,
    });
    await resolveQuery({
      data: generateData(950, 20),
      pageInfo: {
        hasNextPage: false,
        endCursor: '970',
      },
    });
    let lastCallbackArgs = callback.mock.calls[callback.mock.calls.length - 1];
    expect(lastCallbackArgs[0].totalCount).toBe(970);

    // load next page when pageInfo.hasNextPage === false
    const clientQueryCallsLength = clientQuery.mock.calls.length;
    subscription.load();
    expect(clientQuery.mock.calls.length).toBe(clientQueryCallsLength);

    // load last page longer than expected
    subscription.load(960, 1000);
    lastQueryArgs =
      clientQuery.mock.calls[clientQuery.mock.calls.length - 1][0];
    expect(lastQueryArgs?.variables?.pagination).toEqual({
      after: '960',
      first,
    });
    await resolveQuery({
      data: generateData(960, 40),
      pageInfo: {
        hasNextPage: true,
        endCursor: '1000',
      },
    });
    lastCallbackArgs = callback.mock.calls[callback.mock.calls.length - 1];
    expect(lastCallbackArgs[0].totalCount).toBe(1000);

    subscription.unsubscribe();
  });

  it('loads requested data blocks and inserts data without totalCount', async () => {
    callback.mockClear();
    const totalCount = undefined;
    const subscription = paginatedSubscribe(callback, client);
    await resolveQuery({
      data: generateData(),
      totalCount,
      pageInfo: {
        hasNextPage: true,
        endCursor: '100',
      },
    });
    let lastCallbackArgs = callback.mock.calls[callback.mock.calls.length - 1];
    expect(lastCallbackArgs[0].totalCount).toBe(undefined);

    // load next page
    subscription.load();
    await resolveQuery({
      data: generateData(100),
      pageInfo: {
        hasNextPage: true,
        endCursor: '200',
      },
    });
    lastCallbackArgs = callback.mock.calls[callback.mock.calls.length - 1];
    expect(lastCallbackArgs[0].totalCount).toBe(undefined);

    // load last page
    subscription.load();
    await resolveQuery({
      data: generateData(200, 50),
      pageInfo: {
        hasNextPage: false,
        endCursor: '250',
      },
    });
    lastCallbackArgs = callback.mock.calls[callback.mock.calls.length - 1];
    expect(lastCallbackArgs[0].totalCount).toBe(250);
    subscription.unsubscribe();
  });

  it('sets total count when first page has no next page', async () => {
    const subscription = paginatedSubscribe(callback, client);
    await resolveQuery({
      data: generateData(),
      pageInfo: {
        hasNextPage: false,
        endCursor: '100',
      },
    });
    const lastCallbackArgs =
      callback.mock.calls[callback.mock.calls.length - 1];
    expect(lastCallbackArgs[0].totalCount).toBe(100);
    subscription.unsubscribe();
  });
});