'use strict';

/**
 * Module dependencies
 */

// Node.js core.
const path = require('path');

// Public node modules.
const _ = require('lodash');
const async = require('async');
const fs = require('fs-extra');
const reportback = require('reportback')();

/**
 * Generate a file using the specified string
 */

/* eslint-disable prefer-template */
module.exports = function(options, cb) {
  // Provide default values for switchback.
  cb = reportback.extend(cb, {
    alreadyExists: 'error',
  });

  // Provide defaults and validate required options.
  _.defaults(options, {
    force: false,
  });

  const missingOpts = _.difference(['contents', 'rootPath'], Object.keys(options));

  if (missingOpts.length) {
    return cb.invalid(missingOpts);
  }

  // In case we ended up here with a relative path,
  // resolve it using the process's CWD
  const rootPath = path.resolve(process.cwd(), options.rootPath);

  // Only override an existing file if `options.force` is true.
  fs.exists(rootPath, exists => {
    if (exists && !options.force) {
      return cb.alreadyExists('Something else already exists at `' + rootPath + '`.');
    }

    // Don't actually write the file if this is a dry run.
    if (options.dry) {
      return cb.success();
    }

    async.series(
      [
        function deleteExistingFileIfNecessary(cb) {
          if (!exists) {
            return cb();
          }
          return fs.remove(rootPath, cb);
        },
        function writeToDisk(cb) {
          fs.outputFile(rootPath, options.contents, cb);
        },
      ],
      cb
    );
  });
};