const POST_NEW_REVIEW_PATH_PREFIX = '/posts/new?urls='
const MAX_POST_NEW_REVIEW_TARGET_BYTES = 6_144

const textEncoder = new TextEncoder ()


const rawUrlsParam = (search: string): string | null => {
  const query = search.startsWith ('?') ? search.slice (1) : search
  if (query === '')
    return null

  for (const segment of query.split ('&'))
    {
      if (segment === 'urls')
        return ''
      if (segment.startsWith ('urls='))
        return segment.slice ('urls='.length)
    }

  return null
}


export const buildPostNewReviewPath = (urls: string[]): string =>
    `${ POST_NEW_REVIEW_PATH_PREFIX }${ urls.map (url => encodeURIComponent (url)).join ('+') }`


export const postNewReviewPathByteLength = (urls: string[]): number =>
    textEncoder.encode (buildPostNewReviewPath (urls)).byteLength


export const isPostNewReviewPathWithinLimit = (urls: string[]): boolean =>
    postNewReviewPathByteLength (urls) < MAX_POST_NEW_REVIEW_TARGET_BYTES


export const parsePostNewReviewUrls = (search: string): string[] => {
  const raw = rawUrlsParam (search)
  if (raw == null)
    return []

  return raw
      .split ('+')
      .filter (segment => segment !== '')
      .map (segment => {
        try
        {
          return decodeURIComponent (segment)
        }
        catch
        {
          return segment
        }
      })
}


export const hasPostNewReviewState = (search: string): boolean =>
    rawUrlsParam (search) != null