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const ObservableStore = require('obs-store')
const { warn } = require('loglevel')
const contracts = require('eth-contract-metadata')
const {
ROPSTEN,
RINKEBY,
KOVAN,
MAINNET,
OCALHOST,
} = require('./network/enums')
// By default, poll every 3 minutes
const DEFAULT_INTERVAL = 15 * 1000
/**
* A controller that polls for token exchange
* rates based on a user's current token list
*/
class DetectTokensController {
/**
* Creates a DetectTokensController
*
* @param {Object} [config] - Options to configure controller
*/
constructor ({ interval = DEFAULT_INTERVAL, preferences, network } = {}) {
this.preferences = preferences
this.interval = interval
this.network = network
this.contracts = contracts
}
/**
* For each token in eth-contract-metada, find check selectedAddress balance.
*
*/
async exploreNewTokens () {
if (!this.isActive) { return }
if (this._network.getState().provider.type !== MAINNET) { return }
let detectedTokenAddress, token
for (const address in this.contracts) {
const contract = this.contracts[address]
if (contract.erc20 && !(address in this.tokens)) {
detectedTokenAddress = await this.fetchContractAccountBalance(address)
if (detectedTokenAddress) {
token = this.contracts[detectedTokenAddress]
this._preferences.addToken(detectedTokenAddress, token['symbol'], token['decimals'])
}
}
// etherscan restriction, 5 request/second, lazy scan
setTimeout(() => {}, 200)
}
}
/**
* Find if selectedAddress has tokens with contract in contractAddress.
*
* @param {string} contractAddress Hex address of the token contract to explore.
* @returns {string} Contract address to be added to tokens.
*
*/
async fetchContractAccountBalance (contractAddress) {
const address = this._preferences.store.getState().selectedAddress
const response = await fetch(`https://api.etherscan.io/api?module=account&action=tokenbalance&contractaddress=${contractAddress}&address=${address}&tag=latest&apikey=NCKS6GTY41KPHWRJB62ES1MDNRBIT174PV`)
const parsedResponse = await response.json()
if (parsedResponse.result !== '0') {
return contractAddress
}
return null
}
/**
* @type {Number}
*/
set interval (interval) {
this._handle && clearInterval(this._handle)
if (!interval) { return }
this._handle = setInterval(() => { this.exploreNewTokens() }, interval)
}
/**
* @type {Object}
*/
set preferences (preferences) {
if (!preferences) { return }
this._preferences = preferences
this.tokens = preferences.store.getState().tokens
}
/**
* @type {Object}
*/
set network (network) {
if (!network) { return }
this._network = network
}
}
module.exports = DetectTokensController
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