metamask-extension/ui/app/ducks/gas/gas.duck.js

import { cloneDeep } from 'lodash'
import BigNumber from 'bignumber.js'
import { getStorageItem, setStorageItem } from '../../../lib/storage-helpers'
import { decGWEIToHexWEI } from '../../helpers/utils/conversions.util'
import getFetchWithTimeout from '../../../../shared/modules/fetch-with-timeout'

const fetchWithTimeout = getFetchWithTimeout(30000)

// Actions
const BASIC_GAS_ESTIMATE_LOADING_FINISHED =
  'metamask/gas/BASIC_GAS_ESTIMATE_LOADING_FINISHED'
const BASIC_GAS_ESTIMATE_LOADING_STARTED =
  'metamask/gas/BASIC_GAS_ESTIMATE_LOADING_STARTED'
const RESET_CUSTOM_GAS_STATE = 'metamask/gas/RESET_CUSTOM_GAS_STATE'
const RESET_CUSTOM_DATA = 'metamask/gas/RESET_CUSTOM_DATA'
const SET_BASIC_GAS_ESTIMATE_DATA = 'metamask/gas/SET_BASIC_GAS_ESTIMATE_DATA'
const SET_CUSTOM_GAS_LIMIT = 'metamask/gas/SET_CUSTOM_GAS_LIMIT'
const SET_CUSTOM_GAS_PRICE = 'metamask/gas/SET_CUSTOM_GAS_PRICE'
const SET_BASIC_PRICE_ESTIMATES_LAST_RETRIEVED =
  'metamask/gas/SET_BASIC_PRICE_ESTIMATES_LAST_RETRIEVED'

const initState = {
  customData: {
    price: null,
    limit: null,
  },
  basicEstimates: {
    safeLow: null,
    average: null,
    fast: null,
  },
  basicEstimateIsLoading: true,
  basicPriceEstimatesLastRetrieved: 0,
}

// Reducer
export default function reducer(state = initState, action) {
  switch (action.type) {
    case BASIC_GAS_ESTIMATE_LOADING_STARTED:
      return {
        ...state,
        basicEstimateIsLoading: true,
      }
    case BASIC_GAS_ESTIMATE_LOADING_FINISHED:
      return {
        ...state,
        basicEstimateIsLoading: false,
      }
    case SET_BASIC_GAS_ESTIMATE_DATA:
      return {
        ...state,
        basicEstimates: action.value,
      }
    case SET_CUSTOM_GAS_PRICE:
      return {
        ...state,
        customData: {
          ...state.customData,
          price: action.value,
        },
      }
    case SET_CUSTOM_GAS_LIMIT:
      return {
        ...state,
        customData: {
          ...state.customData,
          limit: action.value,
        },
      }
    case SET_BASIC_PRICE_ESTIMATES_LAST_RETRIEVED:
      return {
        ...state,
        basicPriceEstimatesLastRetrieved: action.value,
      }
    case RESET_CUSTOM_DATA:
      return {
        ...state,
        customData: cloneDeep(initState.customData),
      }
    case RESET_CUSTOM_GAS_STATE:
      return cloneDeep(initState)
    default:
      return state
  }
}

// Action Creators
export function basicGasEstimatesLoadingStarted() {
  return {
    type: BASIC_GAS_ESTIMATE_LOADING_STARTED,
  }
}

export function basicGasEstimatesLoadingFinished() {
  return {
    type: BASIC_GAS_ESTIMATE_LOADING_FINISHED,
  }
}

async function basicGasPriceQuery() {
  const url = `https://api.metaswap.codefi.network/gasPrices`
  return await fetchWithTimeout(url, {
    headers: {},
    referrer: 'https://api.metaswap.codefi.network/gasPrices',
    referrerPolicy: 'no-referrer-when-downgrade',
    body: null,
    method: 'GET',
    mode: 'cors',
  })
}

export function fetchBasicGasEstimates() {
  return async (dispatch, getState) => {
    const { basicPriceEstimatesLastRetrieved } = getState().gas
    const timeLastRetrieved =
      basicPriceEstimatesLastRetrieved ||
      (await getStorageItem('BASIC_PRICE_ESTIMATES_LAST_RETRIEVED')) ||
      0

    dispatch(basicGasEstimatesLoadingStarted())

    let basicEstimates
    if (Date.now() - timeLastRetrieved > 75000) {
      basicEstimates = await fetchExternalBasicGasEstimates(dispatch)
    } else {
      const cachedBasicEstimates = await getStorageItem('BASIC_PRICE_ESTIMATES')
      basicEstimates =
        cachedBasicEstimates || (await fetchExternalBasicGasEstimates(dispatch))
    }

    dispatch(setBasicGasEstimateData(basicEstimates))
    dispatch(basicGasEstimatesLoadingFinished())

    return basicEstimates
  }
}

async function fetchExternalBasicGasEstimates(dispatch) {
  const response = await basicGasPriceQuery()

  const { SafeGasPrice, ProposeGasPrice, FastGasPrice } = await response.json()

  const [safeLow, average, fast] = [
    SafeGasPrice,
    ProposeGasPrice,
    FastGasPrice,
  ].map((price) => new BigNumber(price, 10).toNumber())

  const basicEstimates = {
    safeLow,
    average,
    fast,
  }

  const timeRetrieved = Date.now()
  await Promise.all([
    setStorageItem('BASIC_PRICE_ESTIMATES', basicEstimates),
    setStorageItem('BASIC_PRICE_ESTIMATES_LAST_RETRIEVED', timeRetrieved),
  ])
  dispatch(setBasicPriceEstimatesLastRetrieved(timeRetrieved))

  return basicEstimates
}

export function setCustomGasPriceForRetry(newPrice) {
  return async (dispatch) => {
    if (newPrice === '0x0') {
      const { fast } = await getStorageItem('BASIC_PRICE_ESTIMATES')
      dispatch(setCustomGasPrice(decGWEIToHexWEI(fast)))
    } else {
      dispatch(setCustomGasPrice(newPrice))
    }
  }
}

export function setBasicGasEstimateData(basicGasEstimateData) {
  return {
    type: SET_BASIC_GAS_ESTIMATE_DATA,
    value: basicGasEstimateData,
  }
}

export function setCustomGasPrice(newPrice) {
  return {
    type: SET_CUSTOM_GAS_PRICE,
    value: newPrice,
  }
}

export function setCustomGasLimit(newLimit) {
  return {
    type: SET_CUSTOM_GAS_LIMIT,
    value: newLimit,
  }
}

export function setBasicPriceEstimatesLastRetrieved(retrievalTime) {
  return {
    type: SET_BASIC_PRICE_ESTIMATES_LAST_RETRIEVED,
    value: retrievalTime,
  }
}

export function resetCustomGasState() {
  return { type: RESET_CUSTOM_GAS_STATE }
}

export function resetCustomData() {
  return { type: RESET_CUSTOM_DATA }
}