module TemplateMethod where

import Adapter (Minute (..), WallTime (..), addMinutesToWallTime, marshalMW, unmarshalWM)

addMinutesTemplate :: (Int -> WallTime -> WallTime) -> Int -> Minute -> Minute

addMinutesTemplate f x =

unmarshalWM .

f x .

marshalMW

-- implements linear addition even for values > 1440

linearTimeAdd :: Int -> Minute -> Minute

linearTimeAdd = addMinutesTemplate addMinutesToWallTime

-- implements cyclic addition, respecting a 24 hour (1440 Min) cycle

cyclicTimeAdd :: Int -> Minute -> Minute

cyclicTimeAdd = addMinutesTemplate addMinutesToWallTime'

-- a 24 hour (1440 min) cyclic version of addition: 1400 + 100 = 60

addMinutesToWallTime' :: Int -> WallTime -> WallTime

addMinutesToWallTime' x (WallTime (h, m)) =

let (hAdd, mAdd) = x `quotRem` 60

hNew = h + hAdd

mNew = m + mAdd

in if mNew >= 60

then WallTime ((hNew + 1) `rem` 24, mNew-60)

else WallTime (hNew, mNew)

addWallTimes :: WallTime -> WallTime -> WallTime

addWallTimes a@(WallTime (h,m)) b =

let aMin = h*60 + m

in addMinutesToWallTime aMin b

instance Semigroup WallTime where

(<>) = addWallTimes

instance Monoid WallTime where

mempty = WallTime (0,0)

templateMethodDemo = do

putStrLn "TemplateMethod -> higher order function -> typeclass default implementations"

putStrLn $ "linear time: " ++ (show $ linearTimeAdd 100 (Minute 1400))

putStrLn $ "cyclic time: " ++ (show $ cyclicTimeAdd 100 (Minute 1400))

putStrLn ""

let a = WallTime (3,20)

print $ mappend a a

print $ mconcat [a,a,a,a,a,a,a,a,a]

putStrLn ""