elm-twitch/src/Twitch.elm

module Twitch exposing
    ( Playlist
    , Video
    , decodePlaylists
    , fetchPlaylists
    , playlistMiniatureUrl
    , videoId
    , videoMiniatureUrl
    , videoName
    )

import Http
import Iso8601
import Json.Decode as Decode
import Time


type alias Video =
    { name : String
    , url : String
    , duration : Int
    , date : Maybe Time.Posix
    }


type alias Playlist =
    { url : String
    , name : String
    , videos : List Video
    }


decodeVideo : Decode.Decoder Video
decodeVideo =
    Decode.map4 Video
        (Decode.field "title" Decode.string)
        (Decode.field "url" Decode.string)
        (Decode.map Basics.round (Decode.field "duration" Decode.float))
        (Decode.maybe (Decode.field "date" Iso8601.decoder))


decodePlaylist : Decode.Decoder Playlist
decodePlaylist =
    Decode.map3 Playlist
        (Decode.field "url" Decode.string)
        (Decode.field "title" Decode.string)
        (Decode.field "videos" (Decode.map (List.sortBy .url >> List.reverse) (Decode.list decodeVideo)))


decodePlaylists : Decode.Decoder (List Playlist)
decodePlaylists =
    Decode.map (List.sortBy .url >> List.reverse) (Decode.list decodePlaylist)


fetchPlaylists : (Result Http.Error (List Playlist) -> msg) -> Cmd msg
fetchPlaylists resultToMsg =
    Http.get
        { url = "/index.json"
        , expect = Http.expectJson resultToMsg decodePlaylists
        }


videoName : Video -> String
videoName video =
    video.url


videoId : Video -> String
videoId video =
    String.dropLeft 1 video.url |> String.replace "/" "-"


playlistMiniatureUrl : Playlist -> String
playlistMiniatureUrl playlist =
    case List.head (List.reverse playlist.videos) of
        Just v ->
            "videos/" ++ playlist.url ++ v.url ++ "miniature-050.png"

        _ ->
            ""


videoMiniatureUrl : Playlist -> Video -> String
videoMiniatureUrl playlist video =
    "videos/" ++ playlist.url ++ video.url ++ "miniature-050.png"