{-# 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


getLinkAndText xpathCondition = proc doc -> do
  xpathTrees <- getXPathTrees xpathCondition -< doc
  name <- getElemName -< xpathTrees
  txt <- (listA (deep isText >>> getText)  >>> arr (intercalate " ")) -< xpathTrees
  href <- (getXPathTrees "//a" >>> getAttrValue "href") -< xpathTrees
  returnA -< href, txt


extractNestedLinksWithText xpathCondition = proc url -> do
  doc <- downloadDocument -< url
  (link, text) <- getLinkAndText xpathCondition -< doc
  uriFixed <- expandURIFixed -< (link, url)
  returnA -< (uriFixed, text)


extractRecords = proc startUrl -> do 
                 (catUrl, catText) <- extractLinksWithText "//aside[@class='widget widget_maxmegamenu']//a[@class='mega-menu-link']" -< startUrl  -- pary adres-tytuł podstrony
                 (collUrl, collText) <- (extractLinksWithText "//aside[@class='widget widget_maxmegamenu']//a[@class='mega-menu-link']") -< catUrl -- pobieramy podstronę kategorii i kolejne podstrony z menu
                 (relUrl, relText) <- (extractNestedLinksWithText "//big[a[contains(@href,'.pdf')][img]]") -< collUrl -- pobieramy stronę z wydaniami z danej kolekcji i linki do PDFów
                 returnA -< (((relUrl, relText), collText), catText) -- ostatecznie wyjdą krotki (((adres URL PDFa wydania, tytuł wydania), tytuł zbioru), tytuł kategorii)

-- ... a tutaj te krotki przerabiamy do docelowej struktury ShadowItem
toShadowItem :: (((String, String), String), String) -> ShadowItem
toShadowItem (((url, releaseTitle), collectionTitle), categoryTitle) =
  (defaultShadowItem url title) {
    originalDate = Just date,
    itype = "periodical",
    format = Just "pdf",
    finalUrl = url
    }
  where title = categoryTitle ++ (" " ++ collectionTitle)
        date = getDate $ releaseTitle


getDate yearlyTitle =
  case yearlyTitle =~~ "/(19[0-9][0-9]|20[0-9][0-9])/" :: Maybe [[String]] of
    Just [[_, year]] -> year
    -- otherwise -> error $ "unexpected yearlyTitle: " ++ yearlyTitle
    otherwise -> yearlyTitle


main = do
    let start = "http://zborbielawa.pl/archiwum/"
    let shadowLibrary = ShadowLibrary {logoUrl=Nothing,
                                       lname="Zbór Bielawa",
                                       abbrev="ZboBiel",
                                       lLevel=0,
                                       webpage=start}
    extractItemsStartingFromUrl shadowLibrary start (extractRecords >>> arr toShadowItem)