tutor/www/src/Route.elm

module Route exposing (Route(..), fromUrl, toUrl)

import Url exposing (Url)
import Url.Builder
import Url.Parser exposing ((</>), Parser, int, map, oneOf, parse, s, top)


type Route
    = Collection
    | DeckList
    | Deck Int


parser : Parser (Route -> a) a
parser =
    oneOf
        [ map Collection top
        , map Collection (s "collection")
        , map DeckList (s "decks")
        , map Deck (s "decks" </> int)
        ]


toUrl : Route -> String
toUrl route =
    case route of
        Collection ->
            Url.Builder.absolute [ "collection" ] []

        DeckList ->
            Url.Builder.absolute [ "decks" ] []

        Deck deckId ->
            Url.Builder.absolute [ "decks", String.fromInt deckId ] []


fromUrl : Url.Url -> Maybe Route
fromUrl url =
    parse parser url