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

import BuilderQQ
import Info hiding (Text)

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


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

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

  paths  = map #path images
  dls    = mapMaybe #download images
  extras = #extras info

  dir  = build </> prefix </> yamlDir
  page = dir </> "index.html"
  deps = unwords $ map (dir </>) $
    thumbFile (thumbnail info) : map pageFile paths ++ paths ++ 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 . #second) infos'

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

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