const gulp = require('gulp');
const minifyHtml = require('gulp-minify-html');
const cleanCSS = require('gulp-clean-css');
const usemin = require('gulp-usemin');
const uglify = require('gulp-uglify');
const rev = require('gulp-rev');

gulp.task('copy', () =>
  gulp.src(['src/favicon.png'])
    .pipe(gulp.dest('dist/')));

gulp.task('sw', () =>
  gulp.src(['src/service-worker.js'])
    .pipe(uglify())
    .pipe(gulp.dest('dist/')));

gulp.task('build', ['copy', 'sw'], function () {
  return gulp.src('src/index.html')
    .pipe(usemin({
      css: [ rev() ],
      js: [ uglify(), rev() ],
      html: [ minifyHtml({ empty: true }) ],
      inlinecss: [ cleanCSS, 'concat' ]
    }))
    .pipe(gulp.dest('dist/'));
});