packages { pf: "../src/main.roc" }

imports [pf.Stdin, pf.Stdout, pf.Task.{ Task }]

provides [main] to pf

main : Task {} []

main =

_ <- Task.await (Stdout.line "🗣 Shout into this cave and hear the echo! 👂👂👂")

Task.loop {} \_ -> Task.map tick Step

tick : Task.Task {} []

tick =

shout <- Task.await Stdin.line

Stdout.line (echo shout)

echo : Str -> Str

echo = \shout ->

silence = \length ->

spaceInUtf8 = 32

List.repeat spaceInUtf8 length

shout

|> Str.toUtf8

|> List.mapWithIndex

(\_, i ->

length = (List.len (Str.toUtf8 shout) - i)

phrase = (List.split (Str.toUtf8 shout) length).before

List.concat (silence (if i == 0 then 2 * length else length)) phrase)

|> List.join

|> Str.fromUtf8

|> Result.withDefault ""