#!/usr/bin/env node
/**
 * Assembles build/app and build/service from the sources in this repository.
 *
 * There is no bundler and there are no runtime dependencies: the frontend talks
 * to the Luna bus through PalmServiceBridge and the service uses the
 * webos-service module provided by the TV itself. The only thing this script
 * does is copy files and substitute the __APP_ID__ / __SERVICE_ID__ /
 * __VERSION__ / __TITLE__ placeholders, so that the application id lives in
 * exactly one place (the "name" field of package.json).
 */
'use strict';

const fs = require('fs');
const path = require('path');

const root = path.resolve(__dirname, '..');
const pkg = JSON.parse(fs.readFileSync(path.join(root, 'package.json'), 'utf8'));

const vars = {
  __APP_ID__: pkg.name,
  __SERVICE_ID__: `${pkg.name}.service`,
  __VERSION__: pkg.version,
  __TITLE__: pkg.title,
};

const TEXT_EXTENSIONS = ['.js', '.json', '.html', '.css', '.txt', '.sh'];

function substitute(contents) {
  return Object.keys(vars).reduce(
    (acc, key) => acc.split(key).join(vars[key]),
    contents,
  );
}

function copy(src, dst) {
  fs.mkdirSync(path.dirname(dst), { recursive: true });
  if (TEXT_EXTENSIONS.includes(path.extname(src))) {
    fs.writeFileSync(dst, substitute(fs.readFileSync(src, 'utf8')));
  } else {
    fs.copyFileSync(src, dst);
  }
}

function copyTree(src, dst) {
  for (const entry of fs.readdirSync(src, { withFileTypes: true })) {
    const from = path.join(src, entry.name);
    const to = path.join(dst, entry.name);
    if (entry.isDirectory()) {
      copyTree(from, to);
    } else {
      copy(from, to);
    }
  }
}

const build = path.join(root, 'build');
fs.rmSync(build, { recursive: true, force: true });

// Application (frontend)
const appDir = path.join(build, 'app');
copyTree(path.join(root, 'app'), appDir);
copy(path.join(root, 'appinfo.json'), path.join(appDir, 'appinfo.json'));
copy(path.join(root, 'assets', 'icon.png'), path.join(appDir, 'icon.png'));
copy(path.join(root, 'assets', 'largeIcon.png'), path.join(appDir, 'largeIcon.png'));

// JS service
const serviceDir = path.join(build, 'service');
copyTree(path.join(root, 'service'), serviceDir);
fs.writeFileSync(
  path.join(serviceDir, 'services.json'),
  `${JSON.stringify(
    {
      id: vars.__SERVICE_ID__,
      description: `${pkg.title} service`,
      services: [{ name: vars.__SERVICE_ID__ }],
    },
    null,
    2,
  )}\n`,
);

console.log(`Built ${vars.__APP_ID__} ${vars.__VERSION__} into ${build}`);