import "server-only"

import { decrypt, encrypt } from "./encryption"

export function calculateRefId(confirmationNumber: string, lastName: string) {
  const encryptedRefId = encrypt(`${confirmationNumber},${lastName}`)

  return encryptedRefId
}

export function parseRefId(refId: string) {
  // RefId is DES-ECB encryption + Base64 encoding. For legacy reasons we have
  // to do some manual handling here to get a proper Base64 string.
  //
  // - Use case: Current web replaced plus sign with hyphens when generating RefIds.
  //   Handling: We replace hyphens with plus signs.
  //
  // - Use case: Incoming links in the wild do not encode the RefId properly.
  //   Handling: We replace spaces with plus signs. Effectively, reversing the
  //   decoding of plus signs into spaces that Next.js does for us for incoming
  //   search params.
  //   Slash and equal sign are not decoded into anything, so no action needed.
  //   We only need to cater for those three (plus, slash, equals) as RefId is
  //   Base64 encoded which only has these three special characters.
  const data = decrypt(refId.replace(/ |-/g, "+"))
  const parts = data.split(",")
  if (parts.length !== 2) {
    throw new Error("Invalid refId format")
  }
  return {
    confirmationNumber: parts[0],
    lastName: parts[1],
  }
}