module Main exposing (..)

import Html exposing (Html, Attribute, div, input, text, li, ul, a, h4, label, i, span, hr, small, p)
import Html.Attributes exposing (class, classList, id, type_, for, style)
import Html.Events exposing (onClick)
import WebSocket exposing (listen)
import Json.Decode exposing (int, string, float, list, bool, Decoder)
import Json.Encode
import Json.Decode.Pipeline exposing (decode, required, optional, hardcoded)
import Markdown


main : Program Flags Model Msg
main =
    Html.programWithFlags
        { init = init
        , view = view
        , update = update
        , subscriptions = subscriptions
        }


scheduleServer : String
scheduleServer =
    "ws://localhost:8000/schedule/"



-- MODEL


type alias Model =
    { days : List Day
    , eventInstances : List EventInstance
    , eventLocations : List EventLocation
    , eventTypes : List EventType
    , flags : Flags
    , activeDay : Day
    , filter : Filter
    , activeEventInstance : Maybe EventInstance
    }


type alias Filter =
    { eventTypes : List EventType
    , eventLocations : List EventLocation
    }


type alias Day =
    { day_name : String
    , iso : String
    , repr : String
    }


type alias Speaker =
    { name : String
    , url : String
    }


type alias EventInstance =
    { title : String
    , id : Int
    , url : String
    , abstract : String
    , eventSlug : String
    , eventType : String
    , backgroundColor : String
    , forgroundColor : String
    , from : String
    , to : String
    , timeslots : Float
    , location : String
    , locationIcon : String
    , speakers : List Speaker
    , videoRecording : Bool
    , videoUrl : String
    }


type alias EventLocation =
    { name : String
    , slug : String
    , icon : String
    }


type alias EventType =
    { name : String
    , slug : String
    , color : String
    , lightText : Bool
    }


type alias Flags =
    { schedule_timeslot_length_minutes : Int
    , schedule_midnight_offset_hours : Int
    , ics_button_href : String
    , camp_slug : String
    }


allDaysDay : Day
allDaysDay =
    Day "All Days" "" ""


init : Flags -> ( Model, Cmd Msg )
init flags =
    ( Model [] [] [] [] flags allDaysDay (Filter [] []) Nothing, sendInitMessage flags.camp_slug )


sendInitMessage : String -> Cmd Msg
sendInitMessage camp_slug =
    WebSocket.send scheduleServer
        (Json.Encode.encode 0
            (Json.Encode.object
                [ ( "action", Json.Encode.string "init" )
                , ( "camp_slug", Json.Encode.string camp_slug )
                ]
            )
        )



-- UPDATE


type Msg
    = NoOp
    | WebSocketPayload String
    | MakeActiveday Day
    | ToggleEventTypeFilter EventType
    | ToggleEventLocationFilter EventLocation
    | OpenEventInstanceDetail EventInstance
    | CloseEventInstanceDetail


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

        WebSocketPayload str ->
            let
                newModel =
                    case Json.Decode.decodeString initDataDecoder str of
                        Ok m ->
                            m model.flags allDaysDay (Filter [] []) Nothing

                        Err error ->
                            model
            in
                newModel ! []

        MakeActiveday day ->
            { model | activeDay = day } ! []

        ToggleEventTypeFilter eventType ->
            let
                eventTypesFilter =
                    if List.member eventType model.filter.eventTypes then
                        List.filter (\x -> x /= eventType) model.filter.eventTypes
                    else
                        eventType :: model.filter.eventTypes

                currentFilter =
                    model.filter

                newFilter =
                    { currentFilter | eventTypes = eventTypesFilter }
            in
                { model | filter = newFilter } ! []

        ToggleEventLocationFilter eventLocation ->
            let
                eventLocationsFilter =
                    if List.member eventLocation model.filter.eventLocations then
                        List.filter (\x -> x /= eventLocation) model.filter.eventLocations
                    else
                        eventLocation :: model.filter.eventLocations

                currentFilter =
                    model.filter

                newFilter =
                    { currentFilter | eventLocations = eventLocationsFilter }
            in
                { model | filter = newFilter } ! []

        OpenEventInstanceDetail eventInstance ->
            { model | activeEventInstance = Just eventInstance } ! []

        CloseEventInstanceDetail ->
            { model | activeEventInstance = Nothing } ! []



-- SUBSCRIPTIONS


subscriptions : Model -> Sub Msg
subscriptions model =
    WebSocket.listen scheduleServer WebSocketPayload



-- DECODERS


dayDecoder : Decoder Day
dayDecoder =
    decode Day
        |> required "day_name" string
        |> required "iso" string
        |> required "repr" string


speakerDecoder : Decoder Speaker
speakerDecoder =
    decode Speaker
        |> required "name" string
        |> required "url" string


eventInstanceDecoder : Decoder EventInstance
eventInstanceDecoder =
    decode EventInstance
        |> required "title" string
        |> required "id" int
        |> required "url" string
        |> required "abstract" string
        |> required "event_slug" string
        |> required "event_type" string
        |> required "bg-color" string
        |> required "fg-color" string
        |> required "from" string
        |> required "to" string
        |> required "timeslots" float
        |> required "location" string
        |> required "location_icon" string
        |> required "speakers" (list speakerDecoder)
        |> required "video_recording" bool
        |> optional "video_url" string ""


eventLocationDecoder : Decoder EventLocation
eventLocationDecoder =
    decode EventLocation
        |> required "name" string
        |> required "slug" string
        |> required "icon" string


eventTypeDecoder : Decoder EventType
eventTypeDecoder =
    decode EventType
        |> required "name" string
        |> required "slug" string
        |> required "color" string
        |> required "light_text" bool


initDataDecoder : Decoder (Flags -> Day -> Filter -> Maybe EventInstance -> Model)
initDataDecoder =
    decode Model
        |> required "days" (list dayDecoder)
        |> required "event_instances" (list eventInstanceDecoder)
        |> required "event_locations" (list eventLocationDecoder)
        |> required "event_types" (list eventTypeDecoder)



-- VIEW


dayButton : Day -> Day -> Html Msg
dayButton day activeDay =
    a
        [ classList
            [ ( "btn", True )
            , ( "btn-default", day /= activeDay )
            , ( "btn-primary", day == activeDay )
            ]
        , onClick (MakeActiveday day)
        ]
        [ text day.day_name
        ]


view : Model -> Html Msg
view model =
    div []
        [ div [ class "row" ]
            [ div [ id "schedule-days", class "btn-group" ]
                (List.map (\day -> dayButton day model.activeDay) (allDaysDay :: model.days))
            ]
        , hr [] []
        , case model.activeEventInstance of
            Just eventInstance ->
                eventInstanceDetailView eventInstance

            Nothing ->
                scheduleOverviewView model
        ]


eventInstanceDetailView : EventInstance -> Html Msg
eventInstanceDetailView eventInstance =
    div [ class "row" ]
        [ div [ class "col-sm-9" ]
            [ div [ onClick CloseEventInstanceDetail ]
                [ text "Back"
                ]
            , h4 [] [ text eventInstance.title ]
            , p [] [ Markdown.toHtml [] eventInstance.abstract ]
            ]
        , div
            [ classList
                [ ( "col-sm-3", True )
                , ( "schedule-sidebar", True )
                ]
            ]
            [ h4 [] [ text "Speakers" ]
            ]
        ]


scheduleOverviewView : Model -> Html Msg
scheduleOverviewView model =
    div [ class "row" ]
        [ div
            [ classList
                [ ( "col-sm-3", True )
                , ( "col-sm-push-9", True )
                , ( "schedule-sidebar", True )
                , ( "schedule-filter", True )
                ]
            ]
            [ h4 [] [ text "Filter" ]
            , div [ class "form-group" ]
                [ filterView "Type" model.eventTypes model.filter.eventTypes ToggleEventTypeFilter
                , filterView "Location" model.eventLocations model.filter.eventLocations ToggleEventLocationFilter
                ]
            ]
        , div
            [ classList
                [ ( "col-sm-9", True )
                , ( "col-sm-pull-3", True )
                ]
            ]
            (List.map (\day -> dayRowView day model) model.days)
        ]


dayRowView : Day -> Model -> Html Msg
dayRowView day model =
    let
        types =
            List.map (\eventType -> eventType.slug)
                (if List.isEmpty model.filter.eventTypes then
                    model.eventTypes
                 else
                    model.filter.eventTypes
                )

        locations =
            List.map (\eventLocation -> eventLocation.slug)
                (if List.isEmpty model.filter.eventLocations then
                    model.eventLocations
                 else
                    model.filter.eventLocations
                )

        filteredEventInstances =
            List.filter
                (\eventInstance ->
                    ((String.slice 0 10 eventInstance.from) == day.iso)
                        && List.member eventInstance.location locations
                        && List.member eventInstance.eventType types
                )
                model.eventInstances
    in
        div []
            [ h4 []
                [ text day.repr ]
            , div [ class "schedule-day-row" ]
                (List.map dayEventInstanceView filteredEventInstances)
            ]


dayEventInstanceView : EventInstance -> Html Msg
dayEventInstanceView eventInstance =
    a
        [ class "event"
        , onClick (OpenEventInstanceDetail eventInstance)
        , style
            [ ( "background-color", eventInstance.backgroundColor )
            , ( "color", eventInstance.forgroundColor )
            ]
        ]
        [ small []
            [ text ((String.slice 11 16 eventInstance.from) ++ " - " ++ (String.slice 11 16 eventInstance.to)) ]
        , i [ classList [ ( "fa", True ), ( "fa-" ++ eventInstance.locationIcon, True ), ( "pull-right", True ) ] ] []
        , p
            []
            [ text eventInstance.title ]
        ]


filterView :
    String
    -> List { a | name : String }
    -> List { a | name : String }
    -> ({ a | name : String } -> Msg)
    -> Html Msg
filterView name possibleFilters currentFilters action =
    div []
        [ text (name ++ ":")
        , ul [] (List.map (\filter -> filterChoiceView filter currentFilters action) possibleFilters)
        ]


filterChoiceView :
    { a | name : String }
    -> List { a | name : String }
    -> ({ a | name : String } -> Msg)
    -> Html Msg
filterChoiceView filter currentFilters action =
    let
        active =
            List.member filter currentFilters

        notActive =
            not active
    in
        li []
            [ div
                [ classList
                    [ ( "btn", True )
                    , ( "btn-default", True )
                    , ( "filter-choice-active", active )
                    ]
                , onClick (action filter)
                ]
                [ span []
                    [ i [ classList [ ( "fa", True ), ( "fa-minus", active ), ( "fa-plus", notActive ) ] ] []
                    , text (" " ++ filter.name)
                    ]
                ]
            ]