const path = require('path')
const gulp = require('gulp')
const clean = require('gulp-clean')
const connect = require('gulp-connect')
const eslint = require('gulp-eslint')
const os = require('os')
const open = require('gulp-open')
const pug = require('gulp-pug')
const less = require('gulp-less')
const LessAutoPrefix = require('less-plugin-autoprefix')
const autoprefixer = new LessAutoPrefix({ browsers: ['last 2 versions'] })
const cssmin = require('gulp-cssmin')
const rename = require('gulp-rename')
const sourcemaps = require('gulp-sourcemaps')
const run = require('gulp-run')
const watch = require('gulp-watch')

const SOURCE_PATH = ['./*.js']

/* ==================== 清理相关 gulp 任务 ==================== */
const cleanHtml = () => {
    return gulp
        .src('./docs/**/*.html', {
            allowEmpty: true
        })
        .pipe(clean())
}

const cleanStyle = () => {
    return gulp
        .src('./docs/css/*.css', {
            allowEmpty: true
        })
        .pipe(clean())
}

const cleanScript = () => {
    return gulp
        .src('./docs/js/docs.*.js', {
            allowEmpty: true
        })
        .pipe(clean())
}

const cleanDocs = gulp.parallel(cleanHtml, cleanStyle, cleanScript)

/* ==================== 代码规范校验相关的 gulp 任务 ==================== */
const lint = () => {
    return gulp
        .src(SOURCE_PATH)
        .pipe(eslint())
        .pipe(eslint.format())
        .pipe(eslint.failOnError())
}

const check = () => {
    return run('npm run prettier:write').exec()
}

const test = gulp.series(lint, check)

/* ==================== 编译代码的 gulp 任务 ==================== */
const buildSourceScript = () => {
    return run('npm run build:lib').exec()
}

const buildSourceStyles = () => {
  return gulp
    .src([
      './src/theme/anchors.less',
      './src/theme/chapters.less',
      './src/theme/drawer.less',
      './src/theme/toolbar.less',
      './src/theme/outline.less'
    ], {
      allowEmpty: true
    })
    .pipe(sourcemaps.init())
    .pipe(
      less({
        paths: [path.join(__dirname, 'less', 'includes')],
        plugins: [autoprefixer]
      })
    )
    .pipe(sourcemaps.write())
    .pipe(gulp.dest('./'))
}

const minifySourcesStyle = () => {
  return gulp
    .src([
      './anchors.css',
      './chapters.css',
      './drawer.css',
      './toolbar.css',
      './outline.css'
    ], {
      allowEmpty: true
    })
    .pipe(sourcemaps.init())
    .pipe(cssmin())
    .pipe(rename({ suffix: '.min' }))
    .pipe(sourcemaps.write())
    .pipe(gulp.dest('./'))
}

const buildAllSourceStyles = gulp.series(buildSourceStyles, minifySourcesStyle)

const buildScript = () => {
    return run('npm run build:api').exec()
}

const buildApi = () => {
    return gulp
        .src('api/pug/index.pug')
        .pipe(
            pug({
                verbose: true
            })
        )
        .pipe(gulp.dest('docs'))
}

const buildExample = () => {
    return gulp.src('api/pug/example.pug')
        .pipe(
            pug({
                verbose: true
            })
        )
        .pipe(gulp.dest('docs'))
}

const buildStyle = () => {
    return gulp
        .src([
          './api/less/docs.less',
          './api/less/example.less'
        ])
        .pipe(sourcemaps.init())
        .pipe(
            less({
                paths: [path.join(__dirname, 'less', 'includes')],
                plugins: [autoprefixer]
            })
        )
        .pipe(sourcemaps.write())
        .pipe(gulp.dest('./docs/css'))
}

const minifyStyle = () => {
    return gulp
        .src('./docs/**/*.css')
        .pipe(sourcemaps.init())
        .pipe(cssmin())
        .pipe(rename({ suffix: '.min' }))
        .pipe(sourcemaps.write())
        .pipe(gulp.dest('./docs'))
}

const buildDocs = gulp.series(
    cleanDocs,
    buildApi,
    buildExample,
    buildStyle,
    minifyStyle,
    buildScript
)

const build = gulp.series(test, cleanDocs, buildDocs)

/* ==================== 文档查看相关的 gulp 任务 ==================== */
const openDocs = () => {
    let browser
    if (os.platform() === 'darwin') {
        browser = os.platform() === 'linux' ? 'google-chrome' : 'google chrome'
    } else {
        if (os.platform() === 'win32') {
            browser = os.platform() === 'linux' ? 'google-chrome' : 'chrome'
        } else {
            browser = os.platform() === 'linux' ? 'google-chrome' : 'firefox'
        }
    }
    return gulp.src('docs/index.html').pipe(
        open({
            app: browser,
            uri: 'http://localhost:8260'
        })
    )
}

const connectDocs = () => {
    return connect.server({
        root: 'docs',
        port: 8260,
        livereload: true
    })
}

const reload = () => {
    return connect.reload()
}

const start = gulp.series(build, connectDocs, openDocs)

/* ==================== 检测源代码变更相关的 gulp 任务 ==================== */
const watchSource = () => {
    return watch(['src/**/*.(js|less)'], gulp.series(lint, buildSourceScript, buildAllSourceStyles))
}

const watchApi = () => {
    return watch(['api/**/*.*'], gulp.series(buildDocs))
}

const watchDocs = () => {
    return watch('docs/**/*.*', {
        ignoreInitial: false
    }).pipe(reload())
}

const watchAll = gulp.parallel(watchSource, watchApi, watchDocs)

// 导出公共方法
module.exports.start = start
module.exports.clean = cleanDocs
module.exports.build = build
module.exports.buildAllStyles = buildAllSourceStyles
module.exports.lint = lint
module.exports.check = check
module.exports.test = test
module.exports.watch = watchAll