/**

 * Copyright (c) Meta Platforms, Inc. and affiliates.

 *

 * This source code is licensed under the MIT license found in the

 * LICENSE file in the root directory of this source tree.

 *

 * @emails react-core

 * @jest-environment node

 */

'use strict';

let React;

let ReactNoop;

let act;

describe('ReactIncrementalUpdatesMinimalism', () => {

  beforeEach(() => {

    jest.resetModules();

    React = require('react');

    ReactNoop = require('react-noop-renderer');

    act = require('internal-test-utils').act;

  });

  it('should render a simple component', async () => {

    function Child() {

      return <div>Hello World</div>;

    }

    function Parent() {

      return <Child />;

    }

    ReactNoop.startTrackingHostCounters();

    await act(() => ReactNoop.render(<Parent />));

    expect(ReactNoop.stopTrackingHostCounters()).toEqual({

      hostUpdateCounter: 0,

    });

    ReactNoop.startTrackingHostCounters();

    await act(() => ReactNoop.render(<Parent />));

    expect(ReactNoop.stopTrackingHostCounters()).toEqual({

      hostUpdateCounter: 1,

    });

  });

  it('should not diff referentially equal host elements', async () => {

    function Leaf(props) {

      return (

        <span>

          hello

          <b />

          {props.name}

        </span>

      );

    }

    const constEl = (

      <div>

        <Leaf name="world" />

      </div>

    );

    function Child() {

      return constEl;

    }

    function Parent() {

      return <Child />;

    }

    ReactNoop.startTrackingHostCounters();

    await act(() => ReactNoop.render(<Parent />));

    expect(ReactNoop.stopTrackingHostCounters()).toEqual({

      hostUpdateCounter: 0,

    });

    ReactNoop.startTrackingHostCounters();

    await act(() => ReactNoop.render(<Parent />));

    expect(ReactNoop.stopTrackingHostCounters()).toEqual({

      hostUpdateCounter: 0,

    });

  });

  it('should not diff parents of setState targets', async () => {

    let childInst;

    function Leaf(props) {

      return (

        <span>

          hello

          <b />

          {props.name}

        </span>

      );

    }

    class Child extends React.Component {

      state = {name: 'Batman'};

      render() {

        childInst = this;

        return (

          <div>

            <Leaf name={this.state.name} />

          </div>

        );

      }

    }

    function Parent() {

      return (

        <section>

          <div>

            <Leaf name="world" />

            <Child />

            <hr />

            <Leaf name="world" />

          </div>

        </section>

      );

    }

    ReactNoop.startTrackingHostCounters();

    await act(() => ReactNoop.render(<Parent />));

    expect(ReactNoop.stopTrackingHostCounters()).toEqual({

      hostUpdateCounter: 0,

    });

    ReactNoop.startTrackingHostCounters();

    await act(() => childInst.setState({name: 'Robin'}));

    expect(ReactNoop.stopTrackingHostCounters()).toEqual({

      // Child > div

      // Child > Leaf > span

      // Child > Leaf > span > b

      // Child > Leaf > span > #text

      hostUpdateCounter: 4,

    });

    ReactNoop.startTrackingHostCounters();

    await act(() => ReactNoop.render(<Parent />));

    expect(ReactNoop.stopTrackingHostCounters()).toEqual({

      // Parent > section

      // Parent > section > div

      // Parent > section > div > Leaf > span

      // Parent > section > div > Leaf > span > b

      // Parent > section > div > Child > div

      // Parent > section > div > Child > div > Leaf > span

      // Parent > section > div > Child > div > Leaf > span > b

      // Parent > section > div > hr

      // Parent > section > div > Leaf > span

      // Parent > section > div > Leaf > span > b

      hostUpdateCounter: 10,

    });

  });

});