module Depend
  (dependSingle,  dependSingle',
   dependGallery, dependGallery',
   thumbFile, pageFile, bigFile)
where

import BuilderQQ hiding (CanBuild (..))
import Info hiding (Text)

import Data.Maybe (fromMaybe, mapMaybe)
import Data.Text.Lazy (Text)
import Data.Foldable
import System.FilePath


dependSingle :: FilePath -- ^ yaml file name (relative to data dir!)
             -> FilePath -- ^ index file name
             -> Info
             -> FilePath -- ^ output prefix
             -> FilePath -- ^ build dir
             -> Bool     -- ^ include nsfw?
             -> Text
dependSingle yamlDir indexFile info prefix build nsfw =
  toLazyText $ dependSingle' yamlDir indexFile info prefix build nsfw

dependSingle' :: FilePath -> FilePath -> Info -> FilePath -> FilePath -> Bool
              -> Builder
dependSingle' yamlDir indexFile info prefix build nsfw =
  [b|$page: $deps $indexFile $$(MAKEPAGES)|]
 where
  images =
    maybe [] (toList . allImages) $
    if nsfw then Just $ info.images else sfwImages info

  dls    = mapMaybe (.download) images
  extras = info.extras

  dir  = build </> prefix </> yamlDir
  page = dir </> "index.html"
  deps = unwords $ map (dir </>) $
    thumbFile (thumbnail info) :
    map pageFile images ++
    map bigFile  images ++
    dls ++ extras

dependGallery :: GalleryInfo
              -> FilePath -- ^ index file
              -> [(FilePath, Info)] -- ^ relative to data dir
              -> FilePath -- ^ build dir
              -> FilePath -- ^ data dir
              -> FilePath -- ^ tmp dir
              -> Text
dependGallery ginfo index infos build data_ tmp =
  toLazyText $ dependGallery' ginfo index infos build data_ tmp

dependGallery' :: GalleryInfo -> FilePath -> [(FilePath, Info)]
               -> FilePath -> FilePath -> FilePath -> Builder
dependGallery' (GalleryInfo {prefix, filters})
               indexFile infos' build data_ tmp = [b|@0
    $index: $gallery

    $gallery: $pages' $files' $rss $indexFile $$(MAKEPAGES)
    	$$(call gallery,$indexFile,$prefix)

    $rss: $files' $indexFile $$(MAKEPAGES)
    	$$(call rss,$indexFile,$prefix,$data_)

    $rules

    $incs
  |]
 where
  infos = filter (matchFilters filters . snd) infos'

  files  = map fst infos
  files' = unwords $ map (data_ </>) files

  page d = build </> prefix </> takeDirectory d </> "index.html"
  pages  = map page files
  pages' = unwords pages

  index   = build </> "index.html"
  gallery = build </> prefix </> "index.html"
  rss     = build </> prefix </> "rss.xml"

  rules = makeRules prefix indexFile filters build data_ tmp

  inc d    = tmp </> prefix </> takeDirectory d <.> "mk"
  incFiles = unwords $ map inc files
  incs     = if null infos then "" else [b|include $incFiles|]

makeRules :: FilePath -- ^ prefix
          -> FilePath -- ^ index file
          -> GalleryFilters
          -> FilePath -- ^ build dir
          -> FilePath -- ^ data dir
          -> FilePath -- ^ tmp dir
          -> Builder
makeRules prefix indexFile filters build data_ tmp = [b|@0
    $buildPrefix/%/index.html: $data_/%/info.yaml $$(MAKEPAGES)
    	$$(call single,$data_,$prefix,$indexFile,$flags)

    $tmpPrefix/%.mk: $data_/%/info.yaml $$(MAKEPAGES)
    	$$(call depend-single,$prefix,$indexFile,$build,$data_,$flags)

    $buildPrefix/%: $tmp/%
    	$$(call copy,-l)

    $buildPrefix/%: $data_/%
    	$$(call copy)
  |]
 where
  buildPrefix = build </> prefix
  tmpPrefix   = tmp </> prefix
  flags       = filtersToFlags filters

filtersToFlags :: GalleryFilters -> Builder
filtersToFlags (GalleryFilters {nsfw}) =
  case nsfw of NoNsfw -> ""; _ -> "-n"

thumbnail :: Info -> FilePath
thumbnail = fromMaybe (error "no thumbnail or sfw images") . thumb