{-# LANGUAGE DeriveGeneric #-}

module F2Md.Config (getUserdata, FeedUserdata(..)) where

import F2Md.Utils
import Data.Maybe
import Data.Text (Text)
import Data.Time
import GHC.Generics
import qualified Data.HashMap.Strict as HM
import Data.Aeson
import qualified Data.ByteString.Lazy as BSL

data Config = Config
  { dbPath :: String
  , maildir :: String
  , feeds :: [Text]
  } deriving (Generic, Show)

instance FromJSON Config

data FeedUserdata = FeedUserdata
  { url :: Text
  , lastUpdated :: Maybe ZonedTime } deriving (Generic, Show)

getUserdata :: FilePath -> IO ([FeedUserdata], Maybe FilePath)
getUserdata file = do
  config <- decode <$> BSL.readFile file
  case config of
    Nothing -> return ([], Nothing)
    Just config' -> do
      feedData <- getUserdata' config'
      maildir' <- expandPath $ maildir config'
      return (feedData, Just maildir')

getUserdata' :: Config -> IO [FeedUserdata]
getUserdata' (Config dbPath _ feeds) = do
  decoded <- decode <$> (BSL.readFile =<< expandPath dbPath)
  let decoded' = fromMaybe (HM.fromList []) decoded
  return $
    map (\url -> FeedUserdata url $ HM.lookup url decoded') feeds