Add QuadrigaCX exchange and ticker (#176)

* Add QuadrigaCX exchange and ticker

* Clean up code from QuadrigaCX

lib/plugins/common/quadrigacx.js

@@ -0,0 +1,91 @@
+const axios = require('axios')
+const crypto = require('crypto')
+const _ = require('lodash/fp')
+
+const API_ENDPOINT = 'https://api.quadrigacx.com/v2'
+
+let counter = -1
+let lastTimestamp = Date.now()
+
+function pad (num) {
+  const asString = num.toString(10)
+  if (num < 10) return '00' + asString
+  if (num < 100) return '0' + asString
+  return asString
+}
+
+function generateNonce () {
+  const timestamp = Date.now()
+  if (timestamp !== lastTimestamp) counter = -1
+  lastTimestamp = timestamp
+  counter = (counter + 1) % 1000
+  return timestamp.toString(10) + pad(counter)
+}
+
+function authRequest (config, path, data) {
+  if (!config.key || !config.secret || !config.clientId) {
+    const err = new Error('Must provide key, secret and client ID')
+    return Promise.reject(err)
+  }
+
+  data = data || {}
+
+  const nonce = generateNonce()
+  const msg = [nonce, config.clientId, config.key].join('')
+
+  const signature = crypto
+    .createHmac('sha256', Buffer.from(config.secret))
+    .update(msg)
+    .digest('hex')
+    .toLowerCase()
+
+  const signedData = _.merge(data, {
+    key: config.key,
+    signature,
+    nonce
+  })
+
+  return request(path, 'POST', signedData)
+}
+
+function buildMarket (fiatCode, cryptoCode) {
+  if (!_.includes(cryptoCode, ['BTC', 'ETH', 'LTC', 'BCH'])) {
+    throw new Error(`Unsupported crypto: ${cryptoCode}`)
+  }
+
+  if (!_.includes(fiatCode, ['USD', 'CAD'])) {
+    throw new Error(`Unsupported fiat: ${fiatCode}`)
+  }
+
+  let market = `${cryptoCode.toLowerCase()}_${fiatCode.toLowerCase()}`
+
+  if (fiatCode === 'USD' && cryptoCode !== 'BTC') {
+    throw new Error(`Unsupported market: ${market}`)
+  }
+
+  return market
+}
+
+function request (path, method, data) {
+  const options = {
+    method,
+    data,
+    url: API_ENDPOINT + path,
+    headers: {
+      'User-Agent': 'Mozilla/4.0 (compatible; Lamassu client)',
+      'Content-Type': 'application/json; charset=utf-8'
+    }
+  }
+
+  return axios(options)
+    .then(r => {
+      if (r.data.error) throw new Error(r.data.error.message)
+      return r.data
+    })
+}
+
+module.exports = {
+  buildMarket,
+  authRequest,
+  request
+}