'use strict'
exports.start = startMetrics
exports.stop = stopMetrics
exports.save = saveMetrics
exports.send = sendMetrics

const fs = require('fs')
const path = require('path')
const npm = require('../npm.js')
const regFetch = require('libnpm/fetch')
const uuid = require('uuid')
const cacheFile = require('./cache-file.js')

let inMetrics = false

function startMetrics () {
  if (inMetrics) return
  // loaded on demand to avoid any recursive deps when `./metrics-launch` requires us.
  var metricsLaunch = require('./metrics-launch.js')
  npm.metricsProcess = metricsLaunch()
}

function stopMetrics () {
  if (inMetrics) return
  if (npm.metricsProcess) npm.metricsProcess.kill('SIGKILL')
}

function saveMetrics (itWorked) {
  if (inMetrics) return
  // If the metrics reporter hasn't managed to PUT yet then kill it so that it doesn't
  // step on our updating the anonymous-cli-metrics json
  stopMetrics()
  var metricsFile = path.join(npm.config.get('cache'), 'anonymous-cli-metrics.json')
  var metrics
  try {
    metrics = JSON.parse(fs.readFileSync(metricsFile))
    metrics.metrics.to = new Date().toISOString()
    if (itWorked) {
      ++metrics.metrics.successfulInstalls
    } else {
      ++metrics.metrics.failedInstalls
    }
  } catch (ex) {
    metrics = {
      metricId: uuid.v4(),
      metrics: {
        from: new Date().toISOString(),
        to: new Date().toISOString(),
        successfulInstalls: itWorked ? 1 : 0,
        failedInstalls: itWorked ? 0 : 1
      }
    }
  }
  try {
    cacheFile.write(metricsFile, JSON.stringify(metrics))
  } catch (ex) {
    // we couldn't write and/or chown the error metrics file, oh well.
  }
}

function sendMetrics (metricsFile, metricsRegistry) {
  inMetrics = true
  var cliMetrics = JSON.parse(fs.readFileSync(metricsFile))
  regFetch(
    `/-/npm/anon-metrics/v1/${encodeURIComponent(cliMetrics.metricId)}`,
    // NOTE: skip npmConfig() to prevent auth
    {
      registry: metricsRegistry,
      method: 'PUT',
      body: cliMetrics.metrics,
      retry: false
    }
  ).then(() => {
    fs.unlinkSync(metricsFile)
  }, err => {
    cacheFile.write(path.join(path.dirname(metricsFile), 'last-send-metrics-error.txt'), err.stack)
  })
}