module Main exposing (..)

import Browser
import Browser.Navigation as Nav
import CommonElements exposing (..)
import Element exposing (..)
import NavRow exposing (..)
import PageState exposing (..)
import Session exposing (Session)
import Url
import Viewer exposing (..)


type Model
    = Redirect Session
    | NotFound Session
    | About Session
    | Home Home.Model
    | Account Account.Model
    | Login Login.Model
    | Signup Signup.Model
    | Todo Todo.Model
    | Editor (Maybe UUID) Editor.Model


type Msg
    = UrlChange Url.Url
    | Request Browser.UrlRequest
    | GotHomeMsg Home.Msg
    | GotAccountMsg Account.Msg
    | GotLoginMsg Login.Msg
    | GotSignupMsg Signup.Msg
    | GotEditorMsg Editor.Msg
    | GotTodoMsg Todo.Msg
    | GotSession Session


init : Maybe Viewer -> Url.Url -> Nav.Key -> ( Model, Cmd Msg )
init maybeViewer url key =
    changeRouteTo (Route.fromUrl url)
        (Redirect (Session.fromViewer navKey maybeViewer))


toSession : Model -> Session
toSession page =
    case page of
        Redirect session ->
            session

        NotFound session ->
            session

        About session ->
            session

        Home home ->
            Home.toSession home

        Account settings ->
            Settings.toSession settings

        Login login ->
            Login.toSession login

        Signup signup ->
            Signup.toSession signup

        Todo todo ->
            Todo.toSession todo

        Editor _ editor ->
            Editor.toSession editor


changeRouteTo : Maybe Route -> Model -> ( Model, Cmd Msg )
changeRouteTo maybeRoute model =
    let
        session =
            toSession model
    in
    case maybeRoute of
        Nothing ->
            ( NotFound session, Cmd.none )

        Just Route.Root ->
            ( model, Route.replaceUrl (Session.navKey session) Route.Home )

        Just Route.Logout ->
            ( model, Api.logout )

        Just Route.NewTodo ->
            Editor.initNew session
                |> updateWith (Editor Nothing) GotEditorMsg model

        Just (Route.EditTodo slug) ->
            Editor.initEdit session slug
                |> updateWith (Editor (Just slug)) GotEditorMsg model

        Just Route.Account ->
            Account.init session
                |> updateWith Account GotAccountMsg model

        Just Route.Home ->
            Home.init session
                |> updateWith Home GotHomeMsg model

        Just Route.Login ->
            Login.init session
                |> updateWith Login GotLoginMsg model

        Just Route.Signup ->
            Signup.init session
                |> updateWith Signup GotSignupMsg model

        Just (Route.Profile username) ->
            Profile.init session username
                |> updateWith (Profile username) GotProfileMsg model

        Just (Route.Todo slug) ->
            Todo.init session slug
                |> updateWith Todo GotArticleMsg model


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


updateWith : (subModel -> Model) -> (subMsg -> Msg) -> Model -> ( subModel, Cmd subMsg ) -> ( Model, Cmd Msg )
updateWith toModel toMsg model ( subModel, subCmd ) =
    ( toModel subModel
    , Cmd.map toMsg subCmd
    )



-- view takes current application state and is responsible
-- for rendering the document based on it


view : Model -> Browser.Document Msg
view model =
    { title = "Elm App Test"
    , body =
        [ layout [ height fill ]
            (column [ width fill ]
                [ getNavRow model
                , getMainContent model
                ]
            )
        ]
    }



-- subscriptions takes the current state and
-- maybe returns the subscriptions based on it (?)
-- might be used to subscribe to different events based on
-- the url, etc.


subscriptions : Model -> Sub Msg
subscriptions _ =
    Sub.none


main : Program Value Model Msg
main =
    Api.application Viewer.decoder
        { init = init
        , view = view
        , update = update
        , subscriptions = subscriptions
        , onUrlChange = UrlChange -- these are actual types from Msg
        , onUrlRequest = Request
        }