Plank script in idris

plank.idr

-- Counter app, count up in 30 seconds increments, and
-- then count down the last 10 seconds
module Main
import System

-- given a second, what should we say at that second?
sayWhatAt : Int -> String
sayWhatAt 30 = "30 seconds passed"
sayWhatAt 60 = "1 minute passed"
sayWhatAt seconds =
    case seconds `mod` 60 of
        0  => minutes ++ " minutes passed"
        30 => minutes ++ " 30 passed"
        n  => ""
    where 
        minutes : String
        minutes = show (seconds `div` 60)

-- generate the list that counts up every 30s, then does the final countdown
generateTimings : Int -> List String
generateTimings t = 
    let startCountdown = t - 10 in
    let countUp = map sayWhatAt [1..startCountdown-1]
        countDown = map show [10..1] in
        countUp ++ countDown

-- print every item in the list, sleeping for 1s after printing
-- both usleep and print result in IO
speakTimings : List String -> IO ()
speakTimings [] = putStrLn ""
speakTimings (t::ts) = do
    putStrLn t
    usleep 1000000
    speakTimings ts

main : IO ()
main = do
    putStrLn "Hi everyone, ready? Start planking in 5, 4, 3, 2, 1"
    speakTimings (generateTimings 100)
    putStrLn "Good job everyone! I knew you could do it!"