require('isomorphic-fetch')
const warning = require('warning')
const gunzip = require('gunzip-maybe')
const ndjson = require('ndjson')

const CloudflareAPIURL = 'https://api.cloudflare.com'
const CloudflareEmail = process.env.CLOUDFLARE_EMAIL
const CloudflareKey = process.env.CLOUDFLARE_KEY

warning(
  CloudflareEmail,
  'Missing the $CLOUDFLARE_EMAIL environment variable'
)

warning(
  CloudflareKey,
  'Missing the $CLOUDFLARE_KEY environment variable'
)

function get(path, headers) {
  return fetch(`${CloudflareAPIURL}/client/v4${path}`, {
    headers: Object.assign({}, headers, {
      'X-Auth-Email': CloudflareEmail,
      'X-Auth-Key': CloudflareKey
    })
  })
}

function getJSON(path, headers) {
  return get(path, headers).then(function (res) {
    return res.json()
  }).then(function (data) {
    if (!data.success) {
      console.error(`CloudflareAPI.getJSON failed at ${path}`)
      console.error(data)
      throw new Error('Failed to getJSON from Cloudflare')
    }

    return data.result
  })
}

function getZones(domains) {
  return Promise.all(
    (Array.isArray(domains) ? domains : [ domains ]).map(function (domain) {
      return getJSON(`/zones?name=${domain}`)
    })
  ).then(function (results) {
    return results.reduce(function (memo, zones) {
      return memo.concat(zones)
    })
  })
}

function reduceResults(target, values) {
  Object.keys(values).forEach(key => {
    const value = values[key]

    if (typeof value === 'object' && value) {
      target[key] = reduceResults(target[key] || {}, value)
    } else if (typeof value === 'number') {
      target[key] = (target[key] || 0) + values[key]
    }
  })

  return target
}

function getZoneAnalyticsDashboard(zones, since, until) {
  return Promise.all(
    (Array.isArray(zones) ? zones : [ zones ]).map(function (zone) {
      return getJSON(`/zones/${zone.id}/analytics/dashboard?since=${since.toISOString()}&until=${until.toISOString()}`)
    })
  ).then(function (results) {
    return results.reduce(reduceResults)
  })
}

function getJSONStream(path, headers) {
  const acceptGzipHeaders = Object.assign({}, headers, { 'Accept-Encoding': 'gzip' })

  return get(path, acceptGzipHeaders).then(function (res) {
    return res.body.pipe(gunzip())
  }).then(function (stream) {
    return stream.pipe(ndjson.parse())
  })
}

function getLogs(zoneId, startTime, endTime) {
  return getJSONStream(`/zones/${zoneId}/logs/requests?start=${startTime}&end=${endTime}`)
}

module.exports = {
  get,
  getJSON,
  getZones,
  getZoneAnalyticsDashboard,
  getJSONStream,
  getLogs
}