const { src, dest, series, parallel, watch } = require("gulp");

const path = require("path");
const del = require("del");
const babel = require("gulp-babel");
const terser = require("gulp-terser");
const sass = require("gulp-sass");
const postcss = require("gulp-postcss");
const postcssPresetEnv = require("postcss-preset-env");
const cssnano = require("cssnano");
const browserSync = require("browser-sync");

sass.compiler = require("node-sass");

const server = browserSync.create();

const babelConfig = require("./babel.config.js");
const postcssPlugins = [postcssPresetEnv(), cssnano()];

const srcDir = "./src/";
const buildDir = "./build/";
const jsSrc = path.join(srcDir, "js/**/*.js");
const jsDest = path.join(buildDir, "js/");
const scssSrc = path.join(srcDir, "scss/**/*.scss");
const cssDest = path.join(buildDir, "css/");
const htmlSrc = path.join(srcDir, "html/**/*.html");
const htmlDest = buildDir;
const assetSrc = path.join(srcDir, "assets/**/*");
const assetDest = path.join(buildDir, "assets/");

function jsClean() {
  return del(jsDest, { force: true });
}

function cssClean() {
  return del(cssDest, { force: true });
}

function htmlClean() {
  return del(htmlDest, { force: true });
}

function assetClean() {
  return del(assetDest, { force: true });
}

function jsTranspile() {
  return src(jsSrc, { sourcemaps: true })
    .pipe(babel(babelConfig))
    .pipe(terser())
    .pipe(dest(jsDest, { sourcemaps: true }));
}

function scssCompile() {
  return src(scssSrc, { sourcemaps: true })
    .pipe(sass().on("error", sass.logError))
    .pipe(postcss(postcssPlugins))
    .pipe(dest(cssDest, { sourcemaps: true }))
    .pipe(server.stream());
}

function htmlCompile() {
  return src(htmlSrc).pipe(dest(htmlDest));
}

function assetCompile() {
  return src(assetSrc).pipe(dest(assetDest));
}

function serve(done) {
  server.init({
    open: false,
    server: {
      baseDir: buildDir
    }
    // or instead of server
    // proxy: "example.home"
  });
  done();
}

function reload(done) {
  server.reload();
  done();
}

const jsWatch = () =>
  watch(jsSrc, { ignoreInitial: false }, series(jsClean, jsTranspile, reload));
const cssWatch = () =>
  watch(scssSrc, { ignoreInitial: false }, series(cssClean, scssCompile));
const htmlWatch = () =>
  watch(
    htmlSrc,
    { ignoreInitial: false },
    series(htmlClean, htmlCompile, reload)
  );
const assetWatch = () =>
  watch(
    assetSrc,
    { ignoreInitial: false },
    series(assetClean, assetCompile, reload)
  );

exports.default = parallel(jsWatch, cssWatch, htmlWatch, assetWatch, serve);