module Core exposing (Model, Msg(..), Page(..), init, subscriptions, update)

import Browser
import Browser.Events as Events
import Browser.Navigation as Nav
import Dict exposing (Dict)
import Element
import Hover exposing (Hover)
import Http
import Ports
import Task
import Time
import TimeZone
import Twitch
import Url
import Video
import Video.Events


type alias Model =
    { playlists : List Twitch.Playlist
    , zone : Time.Zone
    , page : Page
    , key : Nav.Key
    , device : Element.Device
    , time : Time.Posix
    , currentDate : Time.Posix
    , url : Url.Url
    , darkMode : Bool
    , darkSetting : Maybe Bool
    }


type Page
    = Home (Maybe (Hover Twitch.Playlist))
    | Playlist Twitch.Playlist (Maybe (Hover Twitch.Video))
    | Video Twitch.Playlist Twitch.Video Video.Video (Maybe (Hover Twitch.Video))


type Msg
    = Noop
    | PlaylistsReceived (List Twitch.Playlist)
    | HomeClicked
    | PlaylistClicked Twitch.Playlist
    | VideoClicked Twitch.Playlist Twitch.Video
    | UrlReceived Url.Url
    | UrlRequested Browser.UrlRequest
    | SizeReceived Int Int
    | TimeZoneReceivedResult (Result TimeZone.Error ( String, Time.Zone ))
    | TimeZoneReceived Time.Zone
    | HoverPlaylist Twitch.Playlist
    | HoverVideo Twitch.Video
    | Unhover
    | TimeReceived Time.Posix
    | CurrentDateReceived Time.Posix
    | DarkMode Bool
    | DarkModeClicked
    | VideoMsg Video.Msg


init : { width : Int, height : Int, darkMode : Bool, darkSetting : Maybe Bool } -> Url.Url -> Nav.Key -> ( Model, Cmd Msg )
init { width, height, darkMode, darkSetting } url key =
    ( Model
        []
        Time.utc
        (Home Nothing)
        key
        (Element.classifyDevice { width = width, height = height })
        (Time.millisToPosix 0)
        (Time.millisToPosix 0)
        url
        darkMode
        darkSetting
    , Cmd.batch
        [ Task.attempt TimeZoneReceivedResult TimeZone.getZone
        , Task.perform CurrentDateReceived Time.now
        , Twitch.fetchPlaylists resultToMsg
        ]
    )


resultToMsg : Result Http.Error (List Twitch.Playlist) -> Msg
resultToMsg result =
    case result of
        Ok o ->
            PlaylistsReceived o

        Err _ ->
            Noop


subscriptions : Model -> Sub Msg
subscriptions model =
    Sub.batch
        [ Events.onResize (\w h -> SizeReceived w h)
        , Time.every 200 TimeReceived
        , Ports.darkMode DarkMode
        , Sub.map VideoMsg
            (case model.page of
                Video _ _ v _ ->
                    Video.Events.subs v

                _ ->
                    Sub.none
            )
        ]


update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
    case msg of
        Noop ->
            ( model, Cmd.none )

        TimeZoneReceived z ->
            ( { model | zone = z }, Cmd.none )

        TimeZoneReceivedResult (Ok ( _, zone )) ->
            ( { model | zone = zone }, Cmd.none )

        TimeZoneReceivedResult (Err _) ->
            ( model, Task.perform TimeZoneReceived Time.here )

        TimeReceived p ->
            ( { model | time = p }, Cmd.none )

        CurrentDateReceived d ->
            ( { model | currentDate = d }, Cmd.none )

        HoverPlaylist hover ->
            case model.page of
                Home Nothing ->
                    ( { model | page = Home (Just (Hover.hover hover model.time)) }, Cmd.none )

                _ ->
                    ( model, Cmd.none )

        HoverVideo hover ->
            case model.page of
                Playlist p Nothing ->
                    ( { model | page = Playlist p (Just (Hover.hover hover model.time)) }, Cmd.none )

                Video p v x Nothing ->
                    ( { model | page = Video p v x (Just (Hover.hover hover model.time)) }, Cmd.none )

                _ ->
                    ( model, Cmd.none )

        Unhover ->
            case model.page of
                Home _ ->
                    ( { model | page = Home Nothing }, Cmd.none )

                Playlist p _ ->
                    ( { model | page = Playlist p Nothing }, Cmd.none )

                Video p v x _ ->
                    ( { model | page = Video p v x Nothing }, Cmd.none )

        SizeReceived w h ->
            ( { model | device = Element.classifyDevice { width = w, height = h } }
            , Cmd.none
            )

        PlaylistsReceived playlists ->
            update
                (UrlReceived model.url)
                { model | playlists = playlists, page = Home Nothing }

        HomeClicked ->
            ( model
            , Nav.pushUrl model.key "#"
            )

        DarkModeClicked ->
            let
                next =
                    nextDarkSetting model.darkSetting
            in
            ( { model | darkSetting = next }, Ports.setDarkMode next )

        PlaylistClicked playlist ->
            ( model
            , Nav.pushUrl model.key ("#" ++ playlist.url)
            )

        VideoClicked playlist video ->
            ( model
            , Nav.pushUrl model.key ("#" ++ playlist.url ++ video.url)
            )

        UrlReceived url ->
            if List.isEmpty model.playlists then
                ( { model | url = url }, Cmd.none )

            else
                let
                    splits =
                        String.split "?" (Maybe.withDefault "" url.fragment)

                    ( split, args ) =
                        case splits of
                            h1 :: h2 :: _ ->
                                ( String.split "/" h1, parseQueryString h2 )

                            h1 :: _ ->
                                ( String.split "/" h1, Dict.empty )

                            _ ->
                                ( [], Dict.empty )

                    time =
                        case Dict.get "t" args of
                            Just "0" ->
                                Nothing

                            Just t ->
                                Just t

                            _ ->
                                Nothing

                    ( playlistName, videoName ) =
                        case split of
                            p :: v :: _ ->
                                ( Just (p ++ "/"), Just (v ++ "/") )

                            p :: _ ->
                                ( Just (p ++ "/"), Nothing )

                            _ ->
                                ( Nothing, Nothing )

                    playlist =
                        List.head (List.filter (\x -> Just x.url == playlistName) model.playlists)

                    video =
                        case playlist of
                            Just p ->
                                List.head (List.filter (\x -> Just x.url == videoName) p.videos)

                            _ ->
                                Nothing

                    ( page, cmd ) =
                        case ( playlist, video ) of
                            ( Just p, Just v ) ->
                                let
                                    ( el, videoCommand ) =
                                        Video.fromConfig
                                            { url = "/videos/" ++ p.url ++ v.url ++ "/manifest.m3u8"
                                            , id = "video"
                                            , autoplay = True
                                            , enableMiniatures = True
                                            , startTime = Nothing
                                            }
                                in
                                ( Video p v el Nothing, Cmd.map VideoMsg videoCommand )

                            ( Just p, Nothing ) ->
                                ( Playlist p Nothing, Cmd.none )

                            _ ->
                                ( Home Nothing, Cmd.none )
                in
                ( { model | page = page }, cmd )

        UrlRequested u ->
            case u of
                Browser.Internal url ->
                    ( model, Nav.pushUrl model.key (Url.toString url) )

                Browser.External s ->
                    ( model, Nav.load s )

        DarkMode dark ->
            ( { model | darkMode = dark }, Cmd.none )

        VideoMsg vMsg ->
            let
                ( newPage, newCommand ) =
                    case model.page of
                        Video a b v c ->
                            let
                                ( newVideo, cmd ) =
                                    Video.update vMsg v
                            in
                            ( Video a b newVideo c, cmd )

                        _ ->
                            ( model.page, Cmd.none )
            in
            ( { model | page = newPage }, Cmd.map VideoMsg newCommand )


splitter : String -> Maybe ( String, String )
splitter input =
    case String.split "=" input of
        h :: t ->
            Just ( h, String.join "=" t )

        _ ->
            Nothing


parseQueryString : String -> Dict String String
parseQueryString input =
    Dict.fromList (List.filterMap splitter (String.split "&" input))


nextDarkSetting : Maybe Bool -> Maybe Bool
nextDarkSetting current =
    case current of
        Nothing ->
            Just True

        Just True ->
            Just False

        Just False ->
            Nothing