import React from 'react'
import { expect } from 'chai'
import { screen, waitForElementToBeRemoved } from '@testing-library/react'
import fetchMock from 'fetch-mock'

import ChatPane from '../../../../../frontend/js/features/chat/components/chat-pane'
import { renderWithChatContext } from '../../../helpers/render-with-context'
import {
  stubChatStore,
  stubMathJax,
  stubUIConfig,
  tearDownChatStore,
  tearDownMathJaxStubs,
  tearDownUIConfigStubs
} from './stubs'

describe('<ChatPane />', function() {
  const currentUser = {
    id: 'fake_user',
    first_name: 'fake_user_first_name',
    email: 'fake@example.com'
  }

  const testMessages = [
    {
      id: 'msg_1',
      content: 'a message',
      user: currentUser,
      timestamp: new Date().getTime()
    },
    {
      id: 'msg_2',
      content: 'another message',
      user: currentUser,
      timestamp: new Date().getTime()
    }
  ]

  beforeEach(function() {
    global.localStorage.clear()
    stubChatStore({ user: currentUser })
    stubUIConfig()
    stubMathJax()
    fetchMock.reset()
  })

  afterEach(function() {
    tearDownChatStore()
    tearDownUIConfigStubs()
    tearDownMathJaxStubs()
    fetchMock.reset()
  })

  it('renders multiple messages', async function() {
    fetchMock.get(/messages/, testMessages)
    // unmounting before `beforeEach` block is executed is required to prevent cleanup errors
    const { unmount } = renderWithChatContext(<ChatPane />)

    await screen.findByText('a message')
    await screen.findByText('another message')
    unmount()
  })

  it('A loading spinner is rendered while the messages are loading, then disappears', async function() {
    fetchMock.get(/messages/, [])
    const { unmount } = renderWithChatContext(<ChatPane />)
    await waitForElementToBeRemoved(() => screen.getByText('Loading…'))
    unmount()
  })

  describe('"send your first message" placeholder', function() {
    it('is rendered when there are no messages ', async function() {
      fetchMock.get(/messages/, [])
      const { unmount } = renderWithChatContext(<ChatPane />)
      await screen.findByText('Send your first message to your collaborators')
      unmount()
    })

    it('is not rendered when messages are displayed', function() {
      fetchMock.get(/messages/, testMessages)
      const { unmount } = renderWithChatContext(<ChatPane />)
      expect(
        screen.queryByText('Send your first message to your collaborators')
      ).to.not.exist
      unmount()
    })
  })
})