documentation/lib/commands

/* @flow */
'use strict';

var fs = require('fs');
var remark = require('remark');
var path = require('path');
var documentation = require('../../');
var inject = require('mdast-util-inject');
var chalk = require('chalk');
var disparity = require('disparity');

module.exports.command = 'readme [input..]';
module.exports.description = 'inject documentation into your README.md';
/**
 * Add yargs parsing for the readme command
 * @param {Object} yargs module instance
 * @returns {Object} yargs with options
 * @private
 */
module.exports.builder = {
  usage: 'Usage: documentation readme [--readme-file=README.md] --section "API"' +
    ' [--compare-only] [other documentationjs options]',
  example: 'documentation readme index.js -s "API Docs" --github',
  'readme-file': {
    describe: 'The markdown file into which to inject documentation',
    default: 'README.md'
  },
  section: {
    alias: 's',
    describe: 'The section heading after which to inject generated documentation',
    required: true
  },
  'diff-only': {
    alias: 'd',
    describe: 'Instead of updating the given README with the generated documentation,' +
      ' just check if its contents match, exiting nonzero if not.',
    default: false
  },
  quiet: {
    alias: 'q',
    describe: 'Quiet mode: do not print messages or README diff to stdout.',
    default: false
  }
};

function noop() {}

/**
 * Insert API documentation into a Markdown readme
 * @private
 * @param {Object} argv args from the CLI option parser
 * @return {undefined} has the side-effect of writing a file or printing to stdout
 */
module.exports.handler = function readme(argv /*: Object*/) {
  argv._handled = true;

  if (!argv.input.length) {
    try {
      argv.input = [
        JSON.parse(
          fs.readFileSync(path.resolve('package.json'), 'utf8')
        ).main || 'index.js'
      ];
    } catch (e) {
      throw new Error(
        'documentation was given no files and was not run in a module directory'
      );
    }
  }

  argv.format = 'remark';
  /* eslint no-console: 0 */
  var log = argv.q
    ? noop
    : console.log.bind(console, '[documentation-readme] ');

  var readmeContent = fs.readFileSync(argv.readmeFile, 'utf8');

  documentation
    .build(argv.input, argv)
    .then(comments => documentation.formats.remark(comments, argv))
    .then(docsAst =>
      remark()
        .use(plugin, {
          section: argv.section,
          toInject: JSON.parse(docsAst)
        })
        .process(readmeContent))
    .then(file => {
      var diffOutput = disparity.unified(readmeContent, file.contents, {
        paths: [argv.readmeFile, argv.readmeFile]
      });
      if (!diffOutput.length) {
        log(`${argv.readmeFile} is up to date.`);
        process.exit(0);
      }

      if (argv.d) {
        log(
          chalk.bold(`${argv.readmeFile} needs the following updates:`),
          `\n${diffOutput}`
        );
        process.exit(1);
      } else {
        log(chalk.bold(`Updating ${argv.readmeFile}`), `\n${diffOutput}`);
      }

      fs.writeFileSync(argv.readmeFile, file.contents);
    })
    .catch(err => {
      console.error(err);
      process.exit(1);
    });
};

// wrap the inject utility as an remark plugin
function plugin(options) {
  return function transform(targetAst, file, next) {
    if (!inject(options.section, targetAst, options.toInject)) {
      return next(new Error(`Heading ${options.section} not found.`));
    }
    next();
  };
}