import { formatLanguages, verifySubjects } from './utils'

export const parameterDescriptions = {
  includeLanguages: 'Languages to include',
  excludeLanguages: 'Languages to exclude',
  withoutLanguageVariants: 'Exclude languages with Country variant. For example `en_CA` will not be present in zim with this argument.',
  mulOnly: 'Skip ZIM files for individual languages',
  createMul: 'Create a ZIM file with all languages',
  subjects: `List of subjects to download. Use csv format (e.g 'math,physics')`,
  output: 'Filesystem folder where ZIM file(s) will be written',
}

export const applyParameterConstraints = (argv): boolean => {
  const languageRegex = /^[A-Za-z]{2}(?:_[A-Za-z]{2})?$/ // checks string to only allow this format : en or en_CA
  if (argv.includeLanguages) {
    if (!formatLanguages(argv.includeLanguages).every((lang: string) => languageRegex.test(lang))) throw new Error(`--includeLanguages must follow this format 'en, pt_BR, ar'`)
  }
  if (argv.excludeLanguages) {
    if (!formatLanguages(argv.excludeLanguages).every((lang: string) => languageRegex.test(lang))) throw new Error(`--excludeLanguages must follow this format 'en, pt_BR, ar'`)
  }
  if (argv.subjects && !verifySubjects(argv.subjects)) throw new Error(`--subjects must include valid subjects formated in csv`)
  if (argv.output && Array.isArray(argv.output)) {
    throw new Error(`Error: duplicate --output option isn't allowed.`)
  }
  return true
}