thorio/KGrabber

/* eslint-env node */
const gulp = require("gulp"),
    concat = require("gulp-concat"),
    header = require("gulp-header"),
    browserify = require("browserify"),
    strictify = require("strictify"),
    less = require("gulp-less"),
    source = require("vinyl-source-stream"),
    strip = require("gulp-strip-comments"),
    del = require("del"),
    shared = require("./shared");

const src_dir = "./src",
    build_dir = "./build",
    file_name = "bundle.user.js",
    header_path = `${src_dir}/header.txt`,
    version_number = require("../package.json").version; // get version from package.json

let watching = false;

/**
 * Suppresses errors and keeps the watcher from crashing
 * @param {Error} error
 */
function swallowIfWatching(error) {
    if (!watching) {
        throw error.toString();
    }
    console.error(error);
}

/**
 * Copy to build directory, strip comments, add filepath headers
 */
function js() {
    return gulp.src(`${src_dir}/js/**/!(package.json)`) // select all files in src/js/, except package.json
        .pipe(strip()) // strip comments
        .pipe(header("// src\\js\\${file.relative}\n")) // add info
        .pipe(gulp.dest(`${build_dir}/js`));
}

/**
 * Compile less, add filepath headers, concatenate to single file, wrap in js
 */
function css() {
    return gulp.src(`${src_dir}/css/*.less`)
        .pipe(header("/* src\\css\\${file.relative} */\n\n")) // add info
        .pipe(less()) // compile less
        .pipe(concat("css.js")) // combine into one file
        .pipe(shared.transform((_, contents) => `// generated file, provides contents of src\\css\nmodule.exports = \`\n${contents}\`;`))
        .pipe(gulp.dest(`${build_dir}/js`));
}

/**
 * Strip comments, add filepath headers, wrap in js
 */
async function html() {
    return gulp.src(`${src_dir}/html/*.html`)
        .pipe(strip()) // strip comments
        .pipe(shared.transform((file, contents) => `// src\\html\\${file.relative}\nexports[\`${file.stem}\`] = \`${contents}\`;`))
        .pipe(concat("html.js")) // combine into one file
        .pipe(header("// generated file, provides contents of src\\html\n")) // add info
        .pipe(gulp.dest(`${build_dir}/js`));
}

/**
 * Generate plugin version file
 */
async function pluginVersion() {
    await shared.genversion(`${src_dir}/js/node_modules/kgrabber-plugin`, `${build_dir}/js/pluginVersion.js`);
}

/**
 * Bundle with browserify, add userscript header
 */
async function bundle() {
    return browserify({
            entries: [`${build_dir}/js/main.js`], // specify entry point
            transform: [strictify], // add the strictify plugin to apply strict mode
        }, {
            prelude: await shared.getPrelude(), // apply the non-minified prelude
        })
        .bundle() // run browserify
        .on("error", swallowIfWatching) // suppress errors if using the watcher
        .pipe(source(file_name))
        .pipe(header(await shared.readFile(header_path), { version: version_number })) // add the userscript header
        .pipe(gulp.dest(build_dir));
}

/**
 * Clear build directory
 */
function clean() {
    return del(`${build_dir}/**/*`);
}

/**
 * Auto-build on file change
 */
async function watch() {
    watching = true;
    gulp.watch(src_dir, build);
}

const build = gulp.series(js, css, html, bundle, pluginVersion);

module.exports = { build, watch, clean };