{-
Copyright (C) 2022 Yuchen Pei.

This file is part of f2md.

f2md is free software: you can redistribute it and/or modify it under
the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

f2md is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General
Public License for more details.

You should have received a copy of the GNU Affero General Public
License along with f2md.  If not, see <https://www.gnu.org/licenses/>.

-}

{-# LANGUAGE OverloadedStrings #-}

import qualified Data.Text as T
import Options.Applicative
import Control.Monad.IO.Class
import Control.Monad.Logger
import System.Directory
import Control.Monad.Extra
import F2Md.Types
import F2Md.Import
import F2Md.Export
import F2Md.Config
import System.FilePath

main :: IO ()
main = do
  options <- execParser $ opts
  (feeds, maildir, dbPath) <- getUserdata $ configPath options
  whenJust maildir $ \root -> do
    mapM_ (createDirectoryIfMissing True)
      [root </> "new", root </> "cur", root </> "tmp"]
    mapM_ (runStdoutLoggingT . processFeed root dbPath) feeds
  where opts = info (progParser <**> helper)
               (fullDesc <> progDesc "f2md feeds to maildir"
                 <> header "f2md - a utility to pull new items \
                           \from feeds and write them to maildir")

-- TODO: update db on interruption with the latest date
processFeed :: FilePath -> Maybe FilePath -> FeedUserdata -> LoggingT IO ()
processFeed root dbPath feed = do
  logInfoN $ "Fetching " <> (fuUrl feed) <> "..."
  msgs <- liftIO $ toMessagesFromUrl (fuUrl feed) (fuLastUpdated feed)
  logInfoN $ "Writing " <> (T.pack $ show $ length msgs) <> " messages..."
  liftIO $ mapM_ (writeMessage root) msgs
  whenJust dbPath $ \dbPath' -> liftIO $ updateLastUpdated' dbPath' feed msgs

data Options = Options
  { configPath :: FilePath }

progParser :: Parser Options
progParser =
  Options <$> strOption (long "config" <> short 'c' <> metavar "CONFIG"
                           <> value "~/.f2md.json" <> showDefault
                           <> help "Config file storing feeds, maildir \
                                   \location and timestamp file location.")