const initJson = require('init-package-json')
const npa = require('npm-package-arg')

const npm = require('./npm.js')
const usageUtil = require('./utils/usage.js')
const output = require('./utils/output.js')

const usage = usageUtil(
  'init',
  '\nnpm init [--force|-f|--yes|-y|--scope]' +
  '\nnpm init <@scope> (same as `npx <@scope>/create`)' +
  '\nnpm init [<@scope>/]<name> (same as `npx [<@scope>/]create-<name>`)'
)

const cmd = (args, cb) => init(args).then(() => cb()).catch(cb)

const init = async args => {
  // the new npx style way
  if (args.length) {
    const initerName = args[0]
    let packageName = initerName
    if (/^@[^/]+$/.test(initerName))
      packageName = initerName + '/create'
    else {
      const req = npa(initerName)
      if (req.type === 'git' && req.hosted) {
        const { user, project } = req.hosted
        packageName = initerName
          .replace(user + '/' + project, user + '/create-' + project)
      } else if (req.registry) {
        packageName = req.name.replace(/^(@[^/]+\/)?/, '$1create-')
        if (req.rawSpec)
          packageName += '@' + req.rawSpec
      } else {
        throw Object.assign(new Error(
          'Unrecognized initializer: ' + initerName +
          '\nFor more package binary executing power check out `npx`:' +
          '\nhttps://www.npmjs.com/package/npx'
        ), { code: 'EUNSUPPORTED' })
      }
    }
    npm.config.set('package', [])
    const newArgs = [packageName, ...args.slice(1)]
    return new Promise((res, rej) => {
      npm.commands.exec(newArgs, er => er ? rej(er) : res())
    })
  }

  // the old way
  const dir = process.cwd()
  npm.log.pause()
  npm.log.disableProgress()
  const initFile = npm.config.get('init-module')
  if (!npm.flatOptions.yes && !npm.flatOptions.force) {
    output([
      'This utility will walk you through creating a package.json file.',
      'It only covers the most common items, and tries to guess sensible defaults.',
      '',
      'See `npm help init` for definitive documentation on these fields',
      'and exactly what they do.',
      '',
      'Use `npm install <pkg>` afterwards to install a package and',
      'save it as a dependency in the package.json file.',
      '',
      'Press ^C at any time to quit.',
    ].join('\n'))
  }
  // XXX promisify init-package-json
  await new Promise((res, rej) => {
    initJson(dir, initFile, npm.config, (er, data) => {
      npm.log.resume()
      npm.log.enableProgress()
      npm.log.silly('package data', data)
      if (er && er.message === 'canceled') {
        npm.log.warn('init', 'canceled')
        return res()
      }
      if (er)
        rej(er)
      else {
        npm.log.info('init', 'written successfully')
        res(data)
      }
    })
  })
}

module.exports = Object.assign(cmd, { usage })