'use strict'

function getGasPrice () {
  const url = 'https://ethgasstation.info/json/ethgasAPI.json'
  // return new pending promise
  return new Promise((resolve, reject) => {
    // select http or https module, depending on reqested url
    const lib = url.startsWith('https') ? require('https') : require('http')
    const request = lib.get(url, (response) => {
      // handle http errors
      if (response.statusCode < 200 || response.statusCode > 299) {
        reject(new Error(`Failed to load page, status code: ${response.statusCode}`))
      }
      // temporary data holder
      const body = []
      // on every content chunk, push it to the data array
      response.on('data', (chunk) => body.push(chunk))
      // we are done, resolve promise with those joined chunks
      response.on('end', () => {
        // safeLowWait returns GWei (10^10 Wei).
        const jsonBody = JSON.parse(body.join(''))
        const gasPriceWei = parseInt(jsonBody['safeLowWait']) * Math.pow(10, 10)
        resolve(gasPriceWei)
      })
    })
    // handle connection errors of the request
    request.on('error', (err) => reject(err))
  })
}

function getTokenPrice (token) {
  const currency = 'USD'
  const url = `https://min-api.cryptocompare.com/data/price?fsym=${token}&tsyms=${currency}`
  // return new pending promise
  return new Promise((resolve, reject) => {
    // select http or https module, depending on reqested url
    const lib = url.startsWith('https') ? require('https') : require('http')
    const request = lib.get(url, (response) => {
      // handle http errors
      if (response.statusCode < 200 || response.statusCode > 299) {
        reject(new Error(`Failed to load page, status code: ${response.statusCode}`))
      }
      // temporary data holder
      const body = []
      // on every content chunk, push it to the data array
      response.on('data', (chunk) => body.push(chunk))
      // we are done, resolve promise with those joined chunks
      response.on('end', () => {
        const jsonBody = JSON.parse(body.join(''))
        const tokenPrice = parseFloat(jsonBody[currency])
        resolve(tokenPrice)
      })
    })
    // handle connection errors of the request
    request.on('error', (err) => reject(err))
  })
}

module.exports = {
  getGasPrice: getGasPrice,
  getTokenPrice: getTokenPrice
}