Detect active links

import Save

-- | Generate the Pandoc MetaValue for a navbar from a list of NavItem from a Nebelhorn config.

generateNavbarMeta :: [NavItem] -> MetaValue

generateNavbarMeta navItems = MetaList $ map f navItems where

generateNavbarMeta :: [NavItem] -> Maybe MetaValue -> MetaValue

generateNavbarMeta navItems (Just (MetaString link)) = MetaList $ map f navItems where

    f NavItem{..} = MetaMap $ Map.fromList

        [("name", MetaString $ unpack navItemName), ("link", MetaString $ unpack navItemLink)]

        [ ("name", MetaString $ unpack navItemName)

        , ("link", MetaString $ unpack navItemLink)

        , ("active", if unpack navItemLink == ("/" <> link) then MetaBool True else MetaBool False)

        ]

generateNavbarMeta navItems _ = MetaList $ map f navItems where

    f NavItem{..} = MetaMap $ Map.fromList

        [ ("name", MetaString $ unpack navItemName)

        , ("link", MetaString $ unpack navItemLink)

        , ("active", MetaBool False)

        ]

putNavbarPage :: [NavItem] -> Pandoc -> Pandoc

putNavbarPage navItems pandoc@(Pandoc meta _)

    = addMeta "navbar" (generateNavbarMeta navItems $ lookupMeta "link" meta) pandoc

-- Puts the navbar into all documents of a Nebelhorn.

putNavbar :: Nebelhorn -> Nebelhorn

putNavbar nebelhorn@Nebelhorn{..}

    = nebelhorn{nebelhornArticles = addMeta "navbar" navbar <$> nebelhornArticles,

    nebelhornPages = addMeta "navbar" navbar <$> nebelhornPages,

    nebelhornIndex = addMeta "navbar" navbar nebelhornIndex} where

        navbar = generateNavbarMeta nebelhornNavItems

    = nebelhorn{nebelhornArticles = putNavbarPage nebelhornNavItems <$> nebelhornArticles,

    nebelhornPages = putNavbarPage nebelhornNavItems <$> nebelhornPages,

    nebelhornIndex = putNavbarPage nebelhornNavItems nebelhornIndex}

-- | Gets the previous and next neigbors for each article in the list.

-- This only works if every pandocument has the link meta value set.