#!/usr/bin/env node

let { nanoid, customAlphabet } = require('..')

function print(msg) {
  process.stdout.write(msg + '\n')
}

function error(msg) {
  process.stderr.write(msg + '\n')
  process.exit(1)
}

if (process.argv.includes('--help') || process.argv.includes('-h')) {
  print(`
  Usage
    $ nanoid [options]

  Options
    -s, --size       Generated ID size
    -a, --alphabet   Alphabet to use
    -h, --help       Show this help

  Examples
    $ nano --s 15
    S9sBF77U6sDB8Yg

    $ nano --size 10 --alphabet abc
    bcabababca`)
  process.exit()
}

let alphabet, size
for (let i = 2; i < process.argv.length; i++) {
  let arg = process.argv[i]
  if (arg === '--size' || arg === '-s') {
    size = Number(process.argv[i + 1])
    i += 1
    if (Number.isNaN(size) || size <= 0) {
      error('Size must be positive integer')
    }
  } else if (arg === '--alphabet' || arg === '-a') {
    alphabet = process.argv[i + 1]
    i += 1
  } else {
    error('Unknown argument ' + arg)
  }
}

if (alphabet) {
  if (typeof size === 'undefined') {
    error('You must also specify size option, when using custom alphabet')
  }
  let customNanoid = customAlphabet(alphabet, size)
  print(customNanoid())
} else {
  print(nanoid(size))
}