/*
 * © 2021 Thoughtworks, Inc.
 */

import fetch from 'node-fetch'
import {
  getElectricityMapsData,
  getEmissionsFactors,
  zoneIntensityFactors,
} from '../EmissionsFactors'
import { Logger } from '../index'

jest.mock('node-fetch', () => jest.fn())
const { Response } = jest.requireActual('node-fetch')
jest.mock('../index', () => ({
  ...(jest.requireActual('../index') as Record<string, unknown>),
  configLoader: jest.fn().mockImplementation(() => {
    return {
      ELECTRICITY_MAPS_TOKEN: 'testToken',
    }
  }),
}))

describe('getEmissionsFactors', () => {
  const emissionsFactors = { default: 0.5 }
  const mappedRegionsToElectricityMapZones = { 'region-1': 'zone-1' }

  const logger = { warn: jest.fn() } as unknown as Logger

  beforeEach(() => {
    jest.clearAllMocks()
    // Clear the cache before each test
    Object.keys(zoneIntensityFactors).forEach(
      (key) => delete zoneIntensityFactors[key],
    )
  })

  it('returns default emissions factors if there is no zone for the region', async () => {
    const result = await getEmissionsFactors(
      'region-2',
      '2022-01-01T00:00:00.000Z',
      emissionsFactors,
      mappedRegionsToElectricityMapZones,
      logger,
    )
    expect(result).toEqual(emissionsFactors)
  })

  it('returns cached emissions factors if they exist', async () => {
    zoneIntensityFactors['2022-01-01T00:00:00.000Z'] = { 'zone-1': 0.1 }
    const result = await getEmissionsFactors(
      'region-1',
      '2022-01-01T00:00:00.000Z',
      emissionsFactors,
      mappedRegionsToElectricityMapZones,
      logger,
    )
    expect(result).toEqual({ 'region-1': 0.1 })
  })

  it('returns carbon intensity values from Electricity Maps (gCO2eq/kWh) in t/kWh if there is no cached value for the zone', async () => {
    const response = {
      carbonIntensity: 300, // gCO2eq/kWh
    }
    ;(fetch as jest.MockedFunction<typeof fetch>).mockResolvedValue(
      new Response(JSON.stringify(response), {
        url: 'url',
        status: 200,
        statusText: 'OK',
      }),
    )

    const result = await getEmissionsFactors(
      'region-1',
      '2022-01-01T00:00:00.000Z',
      emissionsFactors,
      mappedRegionsToElectricityMapZones,
      logger,
    )

    expect(result).toEqual({ 'region-1': 0.0003 })
    expect(zoneIntensityFactors['2022-01-01T00:00:00.000Z']['zone-1']).toEqual(
      0.0003,
    )
  })
})

describe('getElectricityMapsData', () => {
  const electricityMapsZone = 'testZone'
  const dateTime = '2022-01-01T00:00:00.000Z'
  const response = {
    carbonIntensity: 300,
  }

  beforeEach(() => {
    jest.clearAllMocks()
  })

  it('should make a request to electricity maps and return the response', async () => {
    ;(fetch as jest.MockedFunction<typeof fetch>).mockResolvedValue(
      new Response(JSON.stringify(response), {
        url: 'url',
        status: 200,
        statusText: 'OK',
      }),
    )

    const result = await getElectricityMapsData(electricityMapsZone, dateTime)

    expect(result).toEqual(response)
    expect(fetch).toHaveBeenCalledWith(
      `https://api.electricitymap.org/v3/carbon-intensity/past?zone=${electricityMapsZone}&datetime=${dateTime}`,
      {
        headers: {
          'auth-token': 'testToken',
        },
      },
    )
  })

  it('should throw an error if the request to electricity maps fails', async () => {
    const errorMessage = 'testError'
    ;(fetch as jest.MockedFunction<typeof fetch>).mockRejectedValue(
      new Error(errorMessage),
    )

    await expect(
      getElectricityMapsData(electricityMapsZone, dateTime),
    ).rejects.toThrow(
      `Electricity Maps request failed. Reason: ${errorMessage}.`,
    )
  })
})