add navigation module

app/EpubParser.hs

@@ -25,8 +25,9 @@ import Data.Maybe (fromMaybe)
 import qualified Data.Text as T
 import qualified Data.Text.Encoding as TE
 import System.FilePath (normalise, takeDirectory, (</>))
-import Text.HTML.Scalpel (Scraper, ScraperT, anySelector, attr, chroot, chroots, html, innerHTML, scrapeStringLike, text, (@:), (@=))
+import Text.HTML.Scalpel (Scraper, ScraperT, anySelector, attr, chroot, chroots, html, innerHTML, scrapeStringLike, text)
 import Types (Chapter (..), EpubAction, EpubEnv (..))
+import Navigation (navFinder)
 
 openEpub :: FilePath -> IO (Either String EpubEnv)
 openEpub path = do
@@ -155,7 +156,3 @@ chapterScraper = do
   title <- chTitleScraper <|> pure "Untitled Chapter"
   content <- chroot "body" (innerHTML anySelector) <|> innerHTML anySelector
   pure (title, content)
-
--- needed for epub3 support, find the nav file
-navFinder :: Scraper String FilePath
-navFinder = attr "href" ("item" @: ["properties" @= "nav"])

app/Navigation.hs

@@ -0,0 +1,41 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module Navigation
+  ( navFinder,
+    lndmkScraper
+  )
+where
+
+import Text.HTML.Scalpel (Scraper, attr, (@:), (@=), chroot, chroots, text, match)
+import Types (NavItem(..))
+import Data.Maybe (fromMaybe)
+import Control.Applicative (optional)
+import Control.Monad (guard)
+import qualified Data.Text as T
+
+-- ------------------------------------------------------------
+-- EPub 3 navigation
+-- ------------------------------------------------------------
+-- The epub-metadata library is good for epub 2.x. As there could be a seperate nav.xhtml file in the epub 3.x spec, we need these functions to support it.
+
+navFinder :: Scraper String FilePath
+navFinder = attr "href" ("item" @: ["properties" @= "nav"])
+
+itemScraper :: [T.Text] -> Scraper T.Text NavItem
+itemScraper allowedTypes = do
+  label <- text "a"
+  path  <- attr "href" "a"
+  rawTypes <- fromMaybe "" <$> optional (attr "epub:type" "a")
+
+  let foundTypes = T.words rawTypes
+  guard $ any (`elem` allowedTypes) foundTypes
+
+  pure $ NavItem label (T.unpack path) foundTypes
+
+lndmkScraper :: [T.Text] -> Scraper T.Text [NavItem]
+lndmkScraper labels =
+  chroot ("nav" @: [match navPredicate]) $ chroots "li" (itemScraper labels)
+
+  where
+    navPredicate "epub:type" xs = T.pack xs `elem` labels
+    navPredicate _ _ = False

app/Types.hs

@@ -4,7 +4,8 @@ module Types
     Chapter(..),
     AppState(..),
     UserAction(..),
-    EpubAction
+    EpubAction,
+    NavItem(..)
   )
 where
 
@@ -55,3 +56,9 @@ data UserAction
   | ZoomIn
   | ZoomOut
   | LoadSpecific Int
+
+data NavItem = NavItem
+  { navLabel :: T.Text,
+    navPath :: FilePath,
+    navTypes :: [T.Text]
+  } deriving (Show)

svitak.cabal

@@ -55,7 +55,8 @@ executable svitak
                       UI,
                       Persistence,
                       State,
-                      Types
+                      Types,
+                      Navigation
 
     build-depends:    base ^>=4.21.0.0,
                       base64-bytestring,