const path = require('path');
const gulp = require('gulp');
const less = require('gulp-less');
const rename = require('gulp-rename');
const postcss = require('gulp-postcss');
const cssnano = require('gulp-cssnano');
const header = require('gulp-header');
const autoprefixer = require('autoprefixer');
const pkg = require('./package.json');
const childProcess = require('child_process');
const replace = require('gulp-replace');

const banner = [
  '/*!',
  ' * WeUI v<%= pkg.version %> (<%= pkg.homepage %>)',
  ' * Copyright <%= new Date().getFullYear() %> Tencent, Inc.',
  ' * Licensed under the <%= pkg.license %> license',
  ' */',
  '',
].join('\n');

let watchTimeout = null;

function exec(cmd) {
  return new Promise((resolve, reject) => {
    const process = childProcess.exec(cmd, (error) => {
      if (error) {
        reject(error);
      } else {
        resolve();
      }
    });
    process.stdout.on('data', (data) => {
      console.log(data);
    });
  });
}

function buildStyle() {
  console.log('buildStyle');
  return gulp
    .src(['src/**/*.less'], { base: 'src' })
    .pipe(less())
    .pipe(postcss([autoprefixer(['iOS >= 8', 'Android >= 4.1'])]))
    .pipe(cssnano({
      discardComments: { removeAll: true },
      reduceIdents: false,
      zindex: false,
      autoprefixer: false,
      svgo: false,
      minifySelectors: false,
    }))
    .pipe(header(banner, { pkg }))
    // px版本
    .pipe(rename((path) => {
      path.extname = '.wxss';
    }))
    .pipe(gulp.dest('dist'))

    // rpx版本
    .pipe(replace(/([\d.]+)px/g, (w, m) => `${2 * m}rpx`))
    .pipe(gulp.dest('dist-rpx-mode'));
}
function buildExample() {
  return gulp
    .src(
      [
        'src/*.!(less)',
        'src/**/*.!(less)',
      ],
      { base: 'src' },
    )
    .pipe(gulp.dest('dist-rpx-mode'))
    .pipe(gulp.dest('dist'));
}
function buildExampleStyle() {
  return gulp
    .src(
      [
        'dist/example/**/*.wxss',
        'dist/app.wxss',
      ],
      { base: 'src' },
    )
    .pipe(replace(/font-size\s*:\s*([\d.]+)px/g, (w, m) =>
    // 小程序采用rem方式从客户端拿的默认字号，客户端默认是17px
      `font-size:${m / 17}rem`))
    .pipe(gulp.dest('dist'));
}

gulp.task('build:style', buildStyle);
gulp.task('build:example', gulp.parallel(buildExample, buildExampleStyle));
gulp.task('build', gulp.series('build:style', 'build:example'));

gulp.task('default', gulp.parallel('build', () => gulp.watch(path.resolve(__dirname, 'src/**/*')).on('change', () => {
  clearTimeout(watchTimeout);

  console.log('wxss change');
  watchTimeout = setTimeout(() => {
    buildStyle().on('end', () => {
      console.log('buildStyle End');
      buildExample().on('end', () => {
        console.log('buildExample End');
      });
      buildExampleStyle().on('end', () => {
        console.log('buildExampleStyle End');
      });
    });
  }, 300);
})));

gulp.task('tag', () => new Promise((resolve) => {
  const tag = `v${pkg.version}`;
  exec(`git tag ${tag}`).then(resolve);
}));