{-# LANGUAGE Arrows, NoMonomorphismRestriction #-}
import ShadowLibrary.Core

import Text.XML.HXT.Core
import Text.XML.HXT.XPath
import Data.List
import Data.List.Utils (replace)

import Text.Regex.Posix
import Text.Printf


extractRecords = extractLinksWithText "//div[@class='artifact-title']/a"  -- pary adres-tytuł

extractPages = extractLinksWithText "//div[@class='pagination-masked clearfix top']//a[@class='next-page-link']" -- pary adres-tytuł

extractPublicationFiles = extractLinksWithText "//div[@class='file-link']/a" -- pary adres-tytuł

runExtractor url = runX $ (arr (const url) >>> setTraceLevel 1 >>> extractPages)

runDocumentsExtractor url = runX $ (arr (const url) >>> setTraceLevel 1 >>> extractRecords)

runFileExtractor url = runX $ (arr (const url) >>> setTraceLevel 1 >>> extractPublicationFiles)


mapToUrl :: ([Char], [Char]) -> [Char]
mapToUrl (url, title) = url


merge [] ys = ys
merge (x:xs) ys = x:merge ys xs


withEmptyCheck current [] = do 
  publications <- runDocumentsExtractor current
  let publicationUrls = map mapToUrl publications
  publicationFiles <- mapM runFileExtractor publicationUrls
  let publicationFileUrls = map mapToUrl (map head publicationFiles)
  return publicationFileUrls
  
withEmptyCheck current nextUrls = do
  let single = head nextUrls
  publications <- runDocumentsExtractor current
  let publicationUrls = map mapToUrl publications
  publicationFiles <- mapM runFileExtractor publicationUrls
  let publicationFileUrls = map mapToUrl (map head publicationFiles)
  recursive <- getAllPages single
  let results = merge publicationFileUrls recursive
  return results


getAllPages url = do
  items <- runExtractor url
  let urls = map mapToUrl items
  results <- (withEmptyCheck url urls)
  return results


main = do
    let start = "https://pbsociety.org.pl/repository/discover?filtertype=has_content_in_original_bundle&filter_relational_operator=equals&filter=true"
    results <- getAllPages start
    print results