/*
    Copyright 2014 Google LLC

    Use of this source code is governed by the MIT License, available in this package's LICENSE file
    or at http://opensource.org/licenses/MIT.
 */
const path = require('path');

function resolvePaths({ filepath }, paths) {
  if (!paths) {
    return [];
  }

  return paths.slice(0).map((p) => path.resolve(filepath, p));
}

function requirePaths(parentModule, opts) {
  const result = {
    before: [],
    after: [],
  };

  if (!parentModule) {
    return result;
  }

  if (Array.isArray(opts)) {
    result.before = resolvePaths(parentModule, opts);
  } else {
    result.before = resolvePaths(parentModule, opts.before);
    result.after = resolvePaths(parentModule, opts.after);
  }

  return result;
}

exports.before = function before(targetPath, parentModule, opts) {
  const resolvedPaths = requirePaths(parentModule, opts);

  return (
    `module.paths = ${JSON.stringify(resolvedPaths.before)}.concat(module.paths)` +
    `.concat(${JSON.stringify(resolvedPaths.after)}); `
  );
};

exports.after = function after() {
  return '';
};