// Do this as the first thing so that any code reading it knows the right env.
process.env.BABEL_ENV = 'development'
process.env.NODE_ENV = 'development'

// Makes the script crash on unhandled rejections instead of silently
// ignoring them. In the future, promise rejections that are not handled will
// terminate the Node.js process with a non-zero exit code.
process.on('unhandledRejection', (err) => {
  throw err
})

// Ensure environment variables are read.
require('../config/env')

const fs = require('fs')
const chalk = require('react-dev-utils/chalk')
const webpack = require('webpack')
const WebpackDevServer = require('webpack-dev-server')
const clearConsole = require('react-dev-utils/clearConsole')
const checkRequiredFiles = require('react-dev-utils/checkRequiredFiles')
const { choosePort, createCompiler, prepareProxy, prepareUrls } = require('react-dev-utils/WebpackDevServerUtils')
const openBrowser = require('react-dev-utils/openBrowser')
const semver = require('semver')
const paths = require('../config/paths')
const configFactory = require('../config/webpack.config')
const createDevServerConfig = require('../config/webpackDevServer.config')
const getClientEnvironment = require('../config/env')
const react = require(require.resolve('react', { paths: [paths.appPath] }))

const env = getClientEnvironment(paths.publicUrlOrPath.slice(0, -1))
const useYarn = fs.existsSync(paths.yarnLockFile)
const isInteractive = process.stdout.isTTY

// Warn and crash if required files are missing
if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
  process.exit(1)
}

// Tools like Cloud9 rely on this.
const DEFAULT_PORT = parseInt(process.env.PORT, 10) || 3000
const HOST = process.env.HOST || '0.0.0.0'

if (process.env.HOST) {
  console.log(
    chalk.cyan(`Attempting to bind to HOST environment variable: ${chalk.yellow(chalk.bold(process.env.HOST))}`)
  )
  console.log(`If this was unintentional, check that you haven't mistakenly set it in your shell.`)
  console.log(`Learn more here: ${chalk.yellow('https://cra.link/advanced-config')}`)
  console.log()
}

// We require that you explicitly set browsers and do not fall back to
// browserslist defaults.
const { checkBrowsers } = require('react-dev-utils/browsersHelper')
checkBrowsers(paths.appPath, isInteractive)
  .then(() => {
    // We attempt to use the default port but if it is busy, we offer the user to
    // run on a different port. `choosePort()` Promise resolves to the next free port.
    return choosePort(HOST, DEFAULT_PORT)
  })
  .then((port) => {
    if (port == null) {
      // We have not found a port.
      return
    }

    const config = configFactory('development')
    const protocol = process.env.HTTPS === 'true' ? 'https' : 'http'
    const appName = require(paths.appPackageJson).name

    const useTypeScript = fs.existsSync(paths.appTsConfig)
    const urls = prepareUrls(protocol, HOST, port, paths.publicUrlOrPath.slice(0, -1))
    // Create a webpack compiler that is configured with custom messages.
    const compiler = createCompiler({
      appName,
      config,
      urls,
      useYarn,
      useTypeScript,
      webpack,
    })
    // Load proxy config
    const proxySetting = require(paths.appPackageJson).proxy
    const proxyConfig = prepareProxy(proxySetting, paths.appPublic, paths.publicUrlOrPath)
    // Serve webpack assets generated by the compiler over a web server.
    const serverConfig = {
      ...createDevServerConfig(proxyConfig, urls.lanUrlForConfig),
      host: HOST,
      port,
    }
    const devServer = new WebpackDevServer(serverConfig, compiler)
    // Launch WebpackDevServer.
    devServer.startCallback(() => {
      if (isInteractive) {
        clearConsole()
      }

      if (env.raw.FAST_REFRESH && semver.lt(react.version, '16.10.0')) {
        console.log(chalk.yellow(`Fast Refresh requires React 16.10 or higher. You are using React ${react.version}.`))
      }

      console.log(chalk.cyan('Starting the development server...\n'))
      openBrowser(urls.localUrlForBrowser)
    })
    ;['SIGINT', 'SIGTERM'].forEach(function (sig) {
      process.on(sig, function () {
        devServer.close()
        process.exit()
      })
    })

    if (process.env.CI !== 'true') {
      // Gracefully exit when stdin ends
      process.stdin.on('end', function () {
        devServer.close()
        process.exit()
      })
    }
  })
  .catch((err) => {
    if (err && err.message) {
      console.log(err.message)
    }
    process.exit(1)
  })
