{-# LANGUAGE OverloadedStrings #-}
module Main where

import           Control.Monad (when)
import           Control.Monad.IO.Class (liftIO)
import           Data.Foldable (for_)
import           Data.Function (on)
import           Data.List (groupBy,sortOn)
import           Data.Monoid ((<>))
import qualified Data.Text as T
import qualified Data.Text.IO as T
import           Data.Time.Calendar (Day, fromGregorian, toGregorian)
import           Data.Time.Calendar.WeekDate (toWeekDate, fromWeekDate)
import           Data.Time.Clock (UTCTime(..), getCurrentTime, addUTCTime)
import           Data.Time.Format (formatTime, defaultTimeLocale, parseTimeM)
import           GHC.IO.Handle.FD (stderr)
import           Network.HTTP.Client (newManager)
import           Network.HTTP.Client.TLS (tlsManagerSettings)
import           Options.Applicative
import           Servant.Client
import           System.Exit (exitFailure, exitFailure)
import           System.IO (hPutStrLn)

import           Network.Hoggl
import           Network.Hoggl.Types
import           Network.Hoggl.Pretty

main :: IO ()
main = execParser opts >>= run
  where opts = info (helper <*> hoggleArgsParser)
                    (fullDesc
                  <> progDesc "Haskell client for Toggl."
                  <> header "hoggl - the Haskell Toggl client.")

run :: HoggleArgs -> IO ()
run (HoggleArgs auth _ _ TimeToday) = do
  manager <- newManager tlsManagerSettings
  let clientEnv = ClientEnv manager togglBaseUrl
  e <- runClientM (timeEntriesToday auth) clientEnv
  case e of
    Left _ -> die "There was an error."
    Right ts -> do
      ds <- traverse calcDuration ts
      T.putStrLn (pretty (sum ds))

run (HoggleArgs auth _ _ TimeWeek) = do
  day <- utctDay <$> getCurrentTime
  let (year,weekNr,dow) = toWeekDate day
  doReport auth (fromWeekDate year weekNr 1) (fromWeekDate year weekNr dow)

run (HoggleArgs auth _ _ TimeMonth) = do
  day <- utctDay <$> getCurrentTime
  let (year,month,dom) = toGregorian day
  doReport auth (fromGregorian year month 1) (fromGregorian year month dom)

run (HoggleArgs auth _ _ StartTimer) = do
  e <- tryStartDefault auth
  case e of
    Left _ -> die "Failed to start timer."
    Right _ -> return ()

run (HoggleArgs auth _ _ StopTimer) = do
  e <- tryStopRunning auth
  case e of
    Left _ -> die "Failed to stop timer."
    Right _ -> return ()

run (HoggleArgs auth _ _ Info) = do
  manager <- newManager tlsManagerSettings
  let clientEnv = ClientEnv manager togglBaseUrl
  e <- runClientM (listWorkspaces auth) clientEnv
  case e of
    Left _ -> die "Failed to get workspaces."
    Right ws -> do
      putStrLn "Workspaces:"
      for_ ws (putStrLn . ("- " <>) . workspacePretty)

run (HoggleArgs auth lastDow workHours HowLong) = do
  manager <- newManager tlsManagerSettings
  let clientEnv = ClientEnv manager togglBaseUrl
  start <- startOfCurrentWeek
  eCurLogged <- runClientM (timeEntriesFromTillNow auth start) clientEnv
  case eCurLogged of
    Left _ -> die "Failed to get time entries."
    Right ts -> do
      worked <- sum <$> traverse calcDuration ts
      req <- requiredTime lastDow workHours
      let diff = fromIntegral req - worked
      endTime <- addUTCTime diff <$> getCurrentTime
      let fendTime = formatTime defaultTimeLocale "%R" endTime
      T.putStrLn $ pretty diff <> T.pack (", average reached at " <> fendTime)

run (HoggleArgs auth _ _ (Report rSince rUntil)) = do
  tSince <- parseTimeM True defaultTimeLocale dateFormat rSince
  tUntil <- case rUntil of
    Just rUntil' -> parseTimeM True defaultTimeLocale dateFormat rUntil'
    Nothing -> utctDay <$> getCurrentTime
  doReport auth tSince tUntil

doReport :: Token -> Day -> Day -> IO ()
doReport auth tSince tUntil = do
  manager <- newManager tlsManagerSettings
  let clientEnv = ClientEnv manager togglBaseUrl
  eResult <- runClientM (do
    ws <- listWorkspaces auth
    when (length ws /= 1) (liftIO $ die "Ambiguous workspace")
    detailedReport auth
                   (wsId (head ws))
                   (ISO6801Date tSince)
                   (ISO6801Date tUntil)
                   "hoggl") clientEnv
  case eResult of
    Left e -> do
      print e
      die "Failed to get report."
    Right report -> do
      for_ (groupBy ((==) `on` (utctDay . unpack . teStart)) . sortOn teStart . drData $ report) $ \tesPerDay -> do
        durations <- traverse calcDuration tesPerDay
        T.putStrLn (T.pack (formatTime defaultTimeLocale dateFormat (unpack (teStart (head tesPerDay))))
                 <> ": "
                 <> pretty (sum durations))
      T.putStrLn ("Total: " <> pretty (fromIntegral (drTotalGrand report)))
  where unpack (ISO6801 x) = x

data HoggleArgs = HoggleArgs Token Integer Integer HoggleCmd
data HoggleCmd = TimeToday
               | TimeWeek
               | TimeMonth
               | StartTimer
               | StopTimer
               | HowLong
               | Info
               | Report {reportSince :: String
                        ,reportUntil :: Maybe String
                        }

token :: Parser Token
token = Api <$> strOption (long "token" <> help "API Token")

lastDowOpt :: Parser Integer
lastDowOpt = option auto (long "last-dow"
                       <> short 'l'
                       <> value 5
                       <> showDefault
                       <> help "Last work day of week (1 = Monday)")

workHoursOpt :: Parser Integer
workHoursOpt = option auto (long "work-yours"
                         <> short 'h'
                         <> value 8
                         <> showDefault
                         <> help "Number of hours to work per day in avg.")

todayCmd :: Mod CommandFields HoggleCmd
todayCmd = command "today" (info (pure TimeToday) (progDesc "List today's time."))

weekCmd :: Mod CommandFields HoggleCmd
weekCmd = command "week" (info (pure TimeWeek) (progDesc "List this week's time."))

monthCmd :: Mod CommandFields HoggleCmd
monthCmd = command "month" (info (pure TimeMonth) (progDesc "List this month's time."))

startTimerCmd :: Mod CommandFields HoggleCmd
startTimerCmd = command "start" (info (pure StartTimer) (progDesc "Start a timer."))

stopTimerCmd :: Mod CommandFields HoggleCmd
stopTimerCmd = command "stop" (info (pure StopTimer) (progDesc "Stop the current timer."))

howLongCmd :: Mod CommandFields HoggleCmd
howLongCmd = command "howlong" (info (pure HowLong) (progDesc "How long until 8h per day reached."))

reportCmd :: Mod CommandFields HoggleCmd
reportCmd = command "report" (info (Report <$> strArgument (metavar "SINCE")
                                           <*> optional (strArgument (metavar "UNTIL")))
                                   (progDesc "Request a report for the specified time range."))

infoCmd :: Mod CommandFields HoggleCmd
infoCmd = command "info" (info (pure Info) (progDesc "Display workspaces, clients and projects"))

hoggleArgsParser :: Parser HoggleArgs
hoggleArgsParser = HoggleArgs
               <$> token
               <*> lastDowOpt
               <*> workHoursOpt
               <*> subparser (todayCmd
                           <> weekCmd
                           <> monthCmd
                           <> startTimerCmd
                           <> stopTimerCmd
                           <> howLongCmd
                           <> reportCmd
                           <> infoCmd)

startOfCurrentWeek :: IO Day
startOfCurrentWeek = do
  today <- utctDay <$> getCurrentTime
  let (year,weekNr,_) = toWeekDate today
      monday = fromWeekDate year weekNr 1
  return monday

die :: String -> IO ()
die msg = hPutStrLn stderr msg >> exitFailure

requiredTime :: Integer -> Integer -> IO Integer
requiredTime lastDow hoursPerDay = dowToSecondsNeeded
                                 . min lastDow
                                 . fromIntegral
                                 . thrd
                                 . toWeekDate
                                 . utctDay
                               <$> getCurrentTime
  where thrd (_,_,x) = x
        dowToSecondsNeeded dow = dow * hoursPerDay * 60 * 60

dateFormat :: String
dateFormat = "%Y-%m-%d"