module Page.Greet exposing (Data, Model, Msg, page)

import DataSource exposing (DataSource)
import Dict exposing (Dict)
import Head
import Head.Seo as Seo
import Html exposing (Html)
import Html.Attributes as Attr
import MySession
import Page exposing (Page, PageWithState, StaticPayload)
import Pages.PageUrl exposing (PageUrl)
import Pages.Url
import Server.Request as Request exposing (Request)
import Server.Response exposing (Response)
import Server.Session as Session
import Shared
import Time
import View exposing (View)


type alias Model =
    {}


type alias Msg =
    ()


type alias RouteParams =
    {}


page : Page RouteParams Data
page =
    Page.serverRender
        { head = head
        , data = data
        }
        |> Page.buildNoState { view = view }


data : RouteParams -> Request.Request (DataSource (Server.Response.Response Data))
data routeParams =
    Request.oneOf
        [ Request.map2 (\a b -> Data a b Nothing)
            (Request.expectQueryParam "name")
            Request.requestTime
            |> Request.map
                (\requestData ->
                    requestData
                        |> Server.Response.render
                        |> Server.Response.withHeader
                            "x-greeting"
                            ("hello there " ++ requestData.username ++ "!")
                        |> DataSource.succeed
                )
        , MySession.expectSessionOrRedirect
            Request.requestTime
            (\requestTime session ->
                let
                    username : String
                    username =
                        session
                            |> Session.get "name"
                            |> Maybe.withDefault "NONAME"

                    flashMessage : Maybe String
                    flashMessage =
                        session
                            |> Session.get "message"
                in
                ( session
                , { username = username
                  , requestTime = requestTime
                  , flashMessage = flashMessage
                  }
                    |> Server.Response.render
                    |> Server.Response.withHeader
                        "x-greeting"
                        ("hello " ++ username ++ "!")
                )
                    |> DataSource.succeed
            )
        ]


head :
    StaticPayload Data RouteParams
    -> List Head.Tag
head static =
    Seo.summary
        { canonicalUrlOverride = Nothing
        , siteName = "elm-pages"
        , image =
            { url = Pages.Url.external "TODO"
            , alt = "elm-pages logo"
            , dimensions = Nothing
            , mimeType = Nothing
            }
        , description = "TODO"
        , locale = Nothing
        , title = "TODO title" -- metadata.title -- TODO
        }
        |> Seo.website


type alias Data =
    { username : String
    , requestTime : Time.Posix
    , flashMessage : Maybe String
    }


view :
    Maybe PageUrl
    -> Shared.Model
    -> StaticPayload Data RouteParams
    -> View Msg
view maybeUrl sharedModel static =
    { title = "Hello!"
    , body =
        [ static.data.flashMessage
            |> Maybe.map (\message -> flashView (Ok message))
            |> Maybe.withDefault (Html.p [] [ Html.text "No flash" ])
        , Html.text <| "Hello " ++ static.data.username ++ "!"
        , Html.text <| "Requested page at " ++ String.fromInt (Time.posixToMillis static.data.requestTime)
        , Html.div []
            [ Html.form
                [ Attr.method "post"
                , Attr.action "/api/logout"
                ]
                [ Html.button
                    [ Attr.type_ "submit"
                    ]
                    [ Html.text "Logout" ]
                ]
            ]
        ]
    }


flashView : Result String String -> Html msg
flashView message =
    Html.p
        [ Attr.style "background-color" "rgb(163 251 163)"
        ]
        [ Html.text <|
            case message of
                Ok okMessage ->
                    okMessage

                Err error ->
                    "Something went wrong: " ++ error
        ]