module Main exposing (main)

import Browser
import Browser.Navigation as Nav
import Html exposing (..)
import Html.Attributes exposing (..)
import Model exposing (Model)
import Navigation
import Url
import Url.Parser


main =
    Browser.application
        { init = init
        , onUrlChange = UrlChanged
        , onUrlRequest = LinkClicked
        , subscriptions = subscriptions
        , update = update
        , view = view
        }


{-| currently no flags are needed
that's the reason for the generic type and \_ as param name
-}
init : () -> Url.Url -> Nav.Key -> ( Model, Cmd Msg )
init _ url key =
    let
        route : Navigation.Route
        route =
            Url.Parser.parse Navigation.routeParser url
                |> Maybe.withDefault Navigation.Home

        model : Model
        model =
            Model.initialModel key route url
    in
    routeChanged route model


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


type Msg
    = UrlChanged Url.Url
    | LinkClicked Browser.UrlRequest


update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
    case msg of
        -- Navigation based messages
        LinkClicked urlRequest ->
            Navigation.linkClicked urlRequest model.key model

        UrlChanged url ->
            case Url.Parser.parse Navigation.routeParser url of
                Just route ->
                    routeChanged route model

                Nothing ->
                    -- TODO error reporting
                    ( { model | route = Navigation.Home }, Cmd.none )


routeChanged : Navigation.Route -> Model -> ( Model, Cmd Msg )
routeChanged route model =
    case route of
        Navigation.Home ->
            ( { model | route = route }
            , Cmd.none
            )


view : Model -> Browser.Document Msg
view model =
    { title = "OpenAgile"
    , body =
        [ h1 [] [ text "OpenAgile" ]
        , div [ class "content" ]
            [ nav [] [ Navigation.navTree ]
            , main_ [] (appContent model)
            ]
        , node "link" [ rel "stylesheet", href "/assets/style.css" ] []
        ]
    }


appContent : Model -> List (Html Msg)
appContent model =
    case model.route of
        Navigation.Home ->
            homePage model


homePage : Model -> List (Html Msg)
homePage model =
    [ h2 [] [ text "Home" ]
    ]