export type Options = {
  major: boolean,
  minor: boolean,
  seventh: boolean,
  minorSeventh: boolean,
  majorSeventh: boolean,
}

export function generate(o: Options): [string, string] {
  let base = all[Math.floor(Math.random() * all.length)]
  let alterations: string[] = []

  if (o.major) alterations = alterations.concat('')
  if (o.minor) alterations = alterations.concat('-')
  if (o.seventh) alterations = alterations.concat('7')
  if (o.minorSeventh) alterations = alterations.concat('-7')
  if (o.majorSeventh) alterations = alterations.concat('7')

  return [base, alterations[Math.floor(Math.random() * alterations.length)]]
}

const all: string[] = [ 'C', 'D♭', 'D', 'E♭', 'E', 'F', 'G♭', 'G', 'A♭', 'A', 'B♭', 'B' ]