module Main exposing (init, main)

import Accessibility.Styled as Html exposing (Html, img, text)
import AtomicDesignType exposing (AtomicDesignType)
import Browser exposing (Document, UrlRequest(..))
import Browser.Dom
import Browser.Navigation exposing (Key)
import Category
import Css exposing (..)
import Dict exposing (Dict)
import Example exposing (Example)
import Examples
import Html as RootHtml
import Html.Attributes
import Html.Styled.Attributes as Attributes exposing (..)
import Html.Styled.Events as Events
import Nri.Ui.Colors.V1 as Colors
import Nri.Ui.Css.VendorPrefixed as VendorPrefixed
import Nri.Ui.Fonts.V1 as Fonts
import Nri.Ui.Heading.V2 as Heading
import Routes as Routes exposing (Route(..))
import Sort.Set as Set exposing (Set)
import Task
import Url exposing (Url)


main : Program () Model Msg
main =
    Browser.application
        { init = init
        , update = update
        , subscriptions = subscriptions
        , view = view
        , onUrlRequest = OnUrlRequest
        , onUrlChange = OnUrlChange
        }


type alias Model =
    { -- Global UI
      route : Route
    , moduleStates : Dict String (Example Examples.State Examples.Msg)
    , atomicDesignTypes : Set AtomicDesignType
    , navigationKey : Key
    }


init : () -> Url -> Key -> ( Model, Cmd Msg )
init () url key =
    ( { route = Routes.fromLocation url
      , moduleStates =
            Dict.fromList
                (List.map (\example -> ( example.name, example )) Examples.all)
      , atomicDesignTypes = Set.fromList AtomicDesignType.sorter AtomicDesignType.all
      , navigationKey = key
      }
    , Cmd.none
    )


type Msg
    = UpdateModuleStates String Examples.Msg
    | OnUrlRequest Browser.UrlRequest
    | OnUrlChange Url
    | ToggleAtomicDesignType AtomicDesignType Bool
    | SkipToMainContent
    | NoOp


update : Msg -> Model -> ( Model, Cmd Msg )
update action model =
    case action of
        UpdateModuleStates key exampleMsg ->
            case Dict.get key model.moduleStates of
                Just example ->
                    example.update exampleMsg example.state
                        |> Tuple.mapFirst
                            (\newState ->
                                { model
                                    | moduleStates =
                                        Dict.insert key
                                            { example | state = newState }
                                            model.moduleStates
                                }
                            )
                        |> Tuple.mapSecond (Cmd.map (UpdateModuleStates key))

                Nothing ->
                    ( model, Cmd.none )

        OnUrlRequest request ->
            case request of
                Internal loc ->
                    ( model, Browser.Navigation.pushUrl model.navigationKey (Url.toString loc) )

                External loc ->
                    ( model, Browser.Navigation.load loc )

        OnUrlChange route ->
            ( { model | route = Routes.fromLocation route }, Cmd.none )

        ToggleAtomicDesignType atomicDesignType isOpen ->
            ( { model
                | atomicDesignTypes =
                    (if isOpen then
                        Set.insert

                     else
                        Set.remove
                    )
                        atomicDesignType
                        model.atomicDesignTypes
              }
            , Cmd.none
            )

        SkipToMainContent ->
            ( model
            , Task.attempt (\_ -> NoOp) (Browser.Dom.focus "maincontent")
            )

        NoOp ->
            ( model, Cmd.none )


subscriptions : Model -> Sub Msg
subscriptions model =
    Dict.values model.moduleStates
        |> List.map (\example -> Sub.map (UpdateModuleStates example.name) (example.subscriptions example.state))
        |> Sub.batch


view : Model -> Document Msg
view model =
    { title = "Style Guide"
    , body = [ view_ model |> Html.toUnstyled ]
    }


view_ : Model -> Html Msg
view_ model =
    let
        examples filterBy =
            List.filter
                (\m ->
                    filterBy m
                        && Set.memberOf model.atomicDesignTypes m.atomicDesignType
                )
                (Dict.values model.moduleStates)

        mainContentHeader heading =
            Heading.h1
                [ Heading.customAttr (id "maincontent")
                , Heading.customAttr (tabindex -1)
                , Heading.css [ marginBottom (px 30) ]
                ]
                [ Html.text heading ]
    in
    Html.div
        [ css
            [ displayFlex
            , alignItems flexStart
            , minHeight (vh 100)
            ]
        ]
        [ navigation model.route model.atomicDesignTypes
        , Html.main_ [ css [ flexGrow (int 1), sectionStyles ] ]
            (case model.route of
                Routes.Doodad doodad ->
                    case List.head (examples (\m -> m.name == doodad)) of
                        Just example ->
                            [ mainContentHeader ("Viewing " ++ doodad ++ " doodad only")
                            , Html.div [ id (String.replace "." "-" example.name) ]
                                [ Example.view example
                                    |> Html.map (UpdateModuleStates example.name)
                                ]
                            ]

                        Nothing ->
                            [ Html.text <| "Oops! We couldn't find " ++ doodad ]

                Routes.Category category ->
                    [ mainContentHeader (Category.forDisplay category)
                    , examples
                        (\doodad ->
                            Set.memberOf
                                (Set.fromList Category.sorter doodad.categories)
                                category
                        )
                        |> List.map
                            (\example ->
                                Example.view example
                                    |> Html.map (UpdateModuleStates example.name)
                            )
                        |> Html.div [ id (Category.forId category) ]
                    ]

                Routes.All ->
                    [ mainContentHeader "All"
                    , examples (\_ -> True)
                        |> List.map
                            (\example ->
                                Example.view example
                                    |> Html.map (UpdateModuleStates example.name)
                            )
                        |> Html.div []
                    ]
            )
        ]


navigation : Route -> Set AtomicDesignType -> Html Msg
navigation route openAtomicDesignTypes =
    let
        isActive category =
            case route of
                Routes.Category routeCategory ->
                    category == routeCategory

                _ ->
                    False

        link active hash displayName =
            Html.a
                [ css
                    [ backgroundColor transparent
                    , borderStyle none
                    , textDecoration none
                    , if active then
                        color Colors.navy

                      else
                        color Colors.azure
                    , Fonts.baseFont
                    ]
                , Attributes.href hash
                ]
                [ Html.text displayName ]

        navLink category =
            link (isActive category)
                ("#/category/" ++ Debug.toString category)
                (Category.forDisplay category)

        toNavLi element =
            Html.li
                [ css
                    [ margin2 (px 10) zero
                    , listStyle none
                    , textDecoration none
                    ]
                ]
                [ element ]
    in
    Html.nav
        [ css
            [ flexBasis (px 200)
            , backgroundColor Colors.gray96
            , marginRight (px 40)
            , padding (px 20)
            , VendorPrefixed.value "position" "sticky"
            , top (px 55)
            , flexShrink zero
            , borderRadius (px 8)
            ]
        , attribute "aria-label" "Main Navigation"
        ]
        [ Html.button
            [ css
                [ backgroundColor transparent
                , borderStyle none
                , textDecoration none
                , color Colors.azure
                , Fonts.baseFont
                , Css.marginBottom (px 20)
                , Css.pseudoClass "not(:focus)"
                    [ Css.property "clip" "rect(1px, 1px, 1px, 1px)"
                    , Css.position Css.absolute
                    , Css.height (Css.px 1)
                    , Css.width (Css.px 1)
                    , Css.overflow Css.hidden
                    , Css.margin (Css.px -1)
                    , Css.padding Css.zero
                    , Css.border Css.zero
                    ]
                ]
            , Events.onClick SkipToMainContent
            , id "skip"
            ]
            [ Html.text "Skip to main content" ]
        , Heading.h4 [] [ Html.text "Categories" ]
        , (link (route == Routes.All) "#/" "All"
            :: List.map navLink Category.all
          )
            |> List.map toNavLi
            |> Html.ul
                [ css [ margin4 zero zero (px 40) zero, padding zero ]
                , id "categories"
                ]
        , Html.fieldset []
            (Html.legend [] [ text "Atomic Design type" ]
                :: List.map (checkAtomicDesignType openAtomicDesignTypes) AtomicDesignType.all
            )
        ]


checkAtomicDesignType : Set AtomicDesignType -> AtomicDesignType -> Html Msg
checkAtomicDesignType openAtomicDesignTypes atomicDesignType =
    let
        isChecked =
            Set.memberOf openAtomicDesignTypes atomicDesignType

        name =
            AtomicDesignType.toString atomicDesignType
    in
    Html.labelAfter [ css [ display block ] ] (text name) <|
        Html.checkbox name
            (Just isChecked)
            [ Events.onCheck (ToggleAtomicDesignType atomicDesignType) ]


sectionStyles : Css.Style
sectionStyles =
    Css.batch [ margin2 (px 40) zero ]