{-# LANGUAGE NamedFieldPuns #-}
module Main where

import CLI (Invocation(..), Mode(..), invoked)
import CSV (Row, parse)
import Data.Time (Day, UTCTime(..), getCurrentTime)
import Medicine (Pharmacy, pharmacy)
import System.Exit (exitFailure)
import Schedule (schedule)
import Timeline (State(..), stateAt)
import YAML (encode)

readCSV :: Row a => FilePath -> IO [a]
readCSV filePath = do
  parsed <- parse filePath '\t' <$> readFile filePath
  case parsed of
    Left e -> (putStrLn $ show e) >> exitFailure
    Right rows -> return rows

getState :: Pharmacy -> Maybe Day -> IO State
getState aPharmacy atDate =
    stateAt
  <$> maybe (utctDay <$> getCurrentTime) return atDate
  <*> return aPharmacy
  <*> readCSV "timeline.csv"

main :: IO ()
main = do
  invocation <- invoked
  thePharmacy <- pharmacy <$> readCSV "medicine.csv"
  theState <- getState thePharmacy $ date invocation
  let display = case mode invocation of
                  Inventory -> encode
                  Schedule -> encode . schedule thePharmacy
  putStrLn $ display theState