'use strict';

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

// 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 path = require('path');
const chalk = require('chalk');
const fs = require('fs-extra');
const webpack = require('webpack');
const bfj = require('bfj');
const configFactory = require('../config/webpack.config');
const paths = require('../config/paths');
const checkRequiredFiles = require('react-dev-utils/checkRequiredFiles');
const formatWebpackMessages = require('react-dev-utils/formatWebpackMessages');
const printHostingInstructions = require('react-dev-utils/printHostingInstructions');
const FileSizeReporter = require('react-dev-utils/FileSizeReporter');
const printBuildError = require('react-dev-utils/printBuildError');

const measureFileSizesBeforeBuild =
 FileSizeReporter.measureFileSizesBeforeBuild;
const printFileSizesAfterBuild = FileSizeReporter.printFileSizesAfterBuild;
const useYarn = fs.existsSync(paths.yarnLockFile);

// These sizes are pretty large. We'll warn for bundles exceeding them.
const WARN_AFTER_BUNDLE_GZIP_SIZE = 512 * 1024;
const WARN_AFTER_CHUNK_GZIP_SIZE = 1024 * 1024;

const isInteractive = process.stdout.isTTY;

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

// Process CLI arguments
const argv = process.argv.slice(2);
const writeStatsJson = argv.indexOf('--stats') !== -1;

// Generate configuration
const config = configFactory('production');

// 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(() => {
 // First, read the current file sizes in build directory.
 // This lets us display how much they changed later.
 return measureFileSizesBeforeBuild(paths.appBuild);
 })
 .then(previousFileSizes => {
 // Remove all content but keep the directory so that
 // if you're in it, you don't end up in Trash
 fs.emptyDirSync(paths.appBuild);
 // Merge with the public folder
 copyPublicFolder();
 // Start the webpack build
 return build(previousFileSizes);
 })
 .then(
 ({ stats, previousFileSizes, warnings }) => {
 if (warnings.length) {
 console.log(chalk.yellow('Compiled with warnings.\n'));
 console.log(warnings.join('\n\n'));
 console.log(
 '\nSearch for the ' +
 chalk.underline(chalk.yellow('keywords')) +
 ' to learn more about each warning.'
 );
 console.log(
 'To ignore, add ' +
 chalk.cyan('// eslint-disable-next-line') +
 ' to the line before.\n'
 );
 } else {
 console.log(chalk.green('Compiled successfully.\n'));
 }

 console.log('File sizes after gzip:\n');
 printFileSizesAfterBuild(
 stats,
 previousFileSizes,
 paths.appBuild,
 WARN_AFTER_BUNDLE_GZIP_SIZE,
 WARN_AFTER_CHUNK_GZIP_SIZE
 );
 console.log();

 const appPackage = require(paths.appPackageJson);
 const publicUrl = paths.publicUrl;
 const publicPath = config.output.publicPath;
 const buildFolder = path.relative(process.cwd(), paths.appBuild);
 printHostingInstructions(
 appPackage,
 publicUrl,
 publicPath,
 buildFolder,
 useYarn
 );
 },
 err => {
 console.log(chalk.red('Failed to compile.\n'));
 printBuildError(err);
 process.exit(1);
 }
 )
 .catch(err => {
 if (err && err.message) {
 console.log(err.message);
 }
 process.exit(1);
 });

// Create the production build and print the deployment instructions.
function build(previousFileSizes) {
 console.log('Creating an optimized production build...');

 let compiler = webpack(config);
 return new Promise((resolve, reject) => {
 compiler.run((err, stats) => {
 let messages;
 if (err) {
 if (!err.message) {
 return reject(err);
 }
 messages = formatWebpackMessages({
 errors: [err.message],
 warnings: [],
 });
 } else {
 messages = formatWebpackMessages(
 stats.toJson({ all: false, warnings: true, errors: true })
 );
 }
 if (messages.errors.length) {
 // Only keep the first error. Others are often indicative
 // of the same problem, but confuse the reader with noise.
 if (messages.errors.length > 1) {
 messages.errors.length = 1;
 }
 return reject(new Error(messages.errors.join('\n\n')));
 }
 if (
 process.env.CI &&
 (typeof process.env.CI !== 'string' ||
 process.env.CI.toLowerCase() !== 'false') &&
 messages.warnings.length
 ) {
 console.log(
 chalk.yellow(
 '\nTreating warnings as errors because process.env.CI = true.\n' +
 'Most CI servers set it automatically.\n'
 )
 );
 return reject(new Error(messages.warnings.join('\n\n')));
 }

 const resolveArgs = {
 stats,
 previousFileSizes,
 warnings: messages.warnings,
 };
 if (writeStatsJson) {
 return bfj
 .write(paths.appBuild + '/bundle-stats.json', stats.toJson())
 .then(() => resolve(resolveArgs))
 .catch(error => reject(new Error(error)));
 }

 return resolve(resolveArgs);
 });
 });
}

function copyPublicFolder() {
 fs.copySync(paths.appPublic, paths.appBuild, {
 dereference: true,
 filter: file => file !== paths.appHtml,
 });
}