// gulpfile.js
const { series, parallel, src, dest } = require('gulp');
const uglify = require('gulp-uglify');
const htmlmini = require('gulp-htmlmin');
const useref = require('gulp-useref');
const csso = require('gulp-csso');
const filter = require('gulp-filter');
const babel = require('gulp-babel');
const RevAll = require('gulp-rev-all');
const base64 = require('gulp-base64');
const autoprefixer = require('gulp-autoprefixer');
const del = require('del');

// 压缩html配置
const options = {
    removeComments: true,
    collapseWhitespace: true,
    collapseBooleanAttributes: true,
    removeEmptyAttributes: true,
    removeScriptTypeAttributes: true,
    removeStyleLinkTypeAttributes: true,
    minifyJS: true,
    minifyCSS: true
};

const defaultTask = cb => {
    const jsFilter = filter('**/*.js', { restore: true });
    const cssFilter = filter('**/*.css', { restore: true });
    const htmlFilter = filter(['**/*.html'], { restore: true });
    src('*.html')
        .pipe(useref())                     // 解析html中的构建块
        .pipe(jsFilter)                     // 过滤所有js
        .pipe(babel({
            presets: ['@babel/env'],
            sourceType: 'script'
        }))
        .pipe(uglify())                     // 压缩js
        .pipe(jsFilter.restore)
        .pipe(cssFilter)                    // 过滤所有css
        .pipe(autoprefixer())               // 添加css前缀
        .pipe(base64())
        .pipe(csso())                       // 压缩优化css
        .pipe(cssFilter.restore)
        .pipe(RevAll.revision({             // 生成版本号
            dontRenameFile: ['.html'],      // 不给 html 文件添加版本号
            dontUpdateReference: ['.html']  // 不给文件里链接的html加版本号
        }))
        .pipe(htmlFilter)                   // 过滤所有html
        .pipe(htmlmini(options))            // 压缩html
        .pipe(htmlFilter.restore)
        .pipe(dest('./dist'))
        .on('error', function (err) {
            throw new Error(err.toString())
        })
    cb();
}

const delDist = cb => {
    del.sync(['./dist']);
    cb();
}

const copyAssets = cb => {
    src('static/img/**').pipe(dest('./dist/static/img/'));
    cb();
}

exports.default = series(delDist, parallel(defaultTask, copyAssets));