{-# LANGUAGE OverloadedStrings #-}
module Main where
  
import TableParser
import Requester
import Config
import Data.Time.Calendar
import Data.Time.Clock
import qualified Data.List as L
import System.IO
import qualified Data.Text as T
import qualified Data.Text.IO as T
import qualified Data.Text.Lazy as LT
import Data.Maybe
import System.Environment
import System.Exit
import Data.Time.Format.ISO8601
import Sender

isChoirThisWeek :: Day -> Day -> Bool
isChoirThisWeek today day = today <= day && diffDays day today <= 6
  
getToday :: IO Day
getToday = utctDay <$> getCurrentTime

reportError :: String -> IO ()
reportError err = hPutStr stderr err

main :: IO ()
main = do
  args <- getArgs
  if length args /= 1
  then
    die "We need exactly one argument"
  else do
    configE <- parseFile (head args)
    case configE of
      Left text -> reportError text
      Right config -> do
        bs <- request
        let eitherTable = parseBString bs
        case eitherTable of
          Left x -> reportError x
          Right table -> do
            today <- getToday
            maybe 
              (T.putStr "Keine Probe :(")
              (\record -> send (mailDomain config) (mailUsername config) (mailPassword config) (mailTo config) (mailFrom config) (mailSubject record) (mailText record))
              (L.find ((isChoirThisWeek today) . date) table)

mailText :: MailRecord -> LT.Text
mailText record = LT.fromStrict $T.concat ["Guten Morgen,\n\n"
                           , announcement record
                           ,"\n\ndiesen Donnerstag\n\nDurchsingen: "
                           ,song1 record
                           ,", "
                           ,song2 record
                           ,"\nStimmproben: "
                           ,voice1 record
                           ,", "
                           ,voice2 record
                           ,"\n\nLG\nMalte\n" ]

mailSubject :: MailRecord -> T.Text
mailSubject record = T.concat ["Donnerstag ", T.pack $ iso8601Show $ date record]