module Main exposing (Flags, Model, Msg, Object3d, main)

import Angle
import Array
import Browser
import Browser.Events as Events
import Browser.Navigation as Nav
import Camera3d
import Clipboard exposing (copyToClipboard)
import Color
import Dict exposing (Dict)
import Direction3d
import Element exposing (..)
import Element.Background as Background
import Element.Border as Border
import Element.Font as Font
import Element.Input exposing (button)
import Html exposing (Html)
import Html.Attributes
import Http
import Json.Decode as Decode
import Length
import List exposing (length)
import List.Extra exposing (getAt)
import Obj.Decode
import Pixels
import Point3d exposing (Point3d)
import Scene3d exposing (Entity)
import Scene3d.Material as Material
import Scene3d.Mesh as Mesh
import Scroll exposing (scrollTo)
import Simple.Animation as Animation exposing (Animation)
import Simple.Animation.Animated as Animated
import Simple.Animation.Property as P
import Task
import Time
import TriangularMesh exposing (TriangularMesh)
import Url
import Viewpoint3d
import WebGL.Texture


getMesh : Cmd Msg
getMesh =
    Http.get
        { url = "../assets/3d/macg/macgregor.obj.txt"
        , expect = Obj.Decode.expectObj GotMesh Length.meters Obj.Decode.texturedTriangles
        }


getTexture : Cmd Msg
getTexture =
    Material.loadWith Material.nearestNeighborFiltering "../assets/3d/macg/image0.jpg" |> Task.attempt GotTexture


animatedUi :
    (List (Attribute msg) -> children -> Element msg)
    -> Animation
    -> List (Attribute msg)
    -> children
    -> Element msg
animatedUi =
    Animated.ui
        { behindContent = Element.behindContent
        , htmlAttribute = Element.htmlAttribute
        , html = Element.html
        }


animatedEl : Animation -> List (Element.Attribute msg) -> Element msg -> Element msg
animatedEl =
    animatedUi Element.el


main : Program Flags Model Msg
main =
    Browser.application { init = init, update = update, subscriptions = subscribe, view = view, onUrlRequest = Request, onUrlChange = Load }


type alias Model =
    { w : Int
    , h : Int
    , last : String
    , url : Url.Url
    , path : String
    , key : Nav.Key
    , mesh : Maybe Object3d
    , textures : Maybe (Material.Textured Obj.Decode.ObjCoordinates)
    , angle : Float
    , radius : Float
    , elevation : Float
    , mainColor : Color.Color
    , show : Bool
    , entry : String
    }


type alias Flags =
    ( Int, Int, String )


init : Flags -> Url.Url -> Nav.Key -> ( Model, Cmd Msg )
init flags url key =
    let
        ( width, height, path ) =
            flags
    in
    ( { w = width
      , h = height
      , last = ""
      , url = url
      , path = path
      , key = key
      , mesh = Nothing
      , textures = Nothing
      , angle = 0
      , radius = 7.5
      , elevation = 5
      , mainColor = Color.rgb 173 111 101
      , show = False
      , entry = "zero"
      }
    , Cmd.batch [ getMesh, getTexture ]
    )


type alias Object3d =
    TriangularMesh { position : Point3d Length.Meters Obj.Decode.ObjCoordinates, uv : ( Float, Float ) }


type Msg
    = Resize Int Int
    | Request Browser.UrlRequest
    | Load Url.Url
    | GotMesh (Result Http.Error Object3d)
    | GotTexture (Result WebGL.Texture.Error (Material.Texture Color.Color))
    | Rotate Time.Posix
    | Copy String String
    | Key String
    | Scroll String
    | ScrollToEntry String


modulo : Float -> Float -> Float
modulo a b =
    b - toFloat (floor (b / a)) * a


canonicalize : Float -> Float
canonicalize angle =
    modulo 360 angle


frac : Float -> Float
frac x =
    x - toFloat (floor x)


mainColors : List ( Float, Float, Float )
mainColors =
    [ ( 173, 111, 101 ), ( 200, 0, 100 ), ( 100, 0, 200 ), ( 100, 200, 0 ), ( 200, 100, 0 ), ( 173, 111, 101 ) ]


blend : Float -> ( Float, Float, Float ) -> ( Float, Float, Float ) -> Color.Color
blend p ( r1, g1, b1 ) ( r2, g2, b2 ) =
    let
        blendFlux : Float -> Float -> Float -> Int
        blendFlux t a b =
            round (sqrt ((1 - t) * (a ^ 2) + t * (b ^ 2)))
    in
    Color.rgb255 (blendFlux p r1 r2) (blendFlux p g1 g2) (blendFlux p b1 b2)


blender : Float -> Color.Color
blender t =
    let
        n : Int
        n =
            length mainColors

        c1 : Maybe ( Float, Float, Float )
        c1 =
            getAt (floor (t * toFloat n)) mainColors

        c2 : Maybe ( Float, Float, Float )
        c2 =
            getAt (ceiling (t * toFloat n)) mainColors
    in
    case c2 of
        Nothing ->
            case c1 of
                Nothing ->
                    -- no colors to blend
                    Color.rgb255 173 111 101

                Just ( r, g, b ) ->
                    -- missing color to blend
                    Color.rgb255 (round r) (round g) (round b)

        Just color2 ->
            case c1 of
                Nothing ->
                    -- missing main color to blend
                    Color.rgb255 173 111 101

                Just color1 ->
                    let
                        p : Float
                        p =
                            frac (t * toFloat n)
                    in
                    -- blend both colors
                    blend p color1 color2


update : Msg -> Model -> ( Model, Cmd Msg )
update msg model =
    let
        wrap : Model -> ( Model, Cmd Msg )
        wrap data =
            ( data, Cmd.none )

        pass : ( Model, Cmd Msg )
        pass =
            wrap model
    in
    case msg of
        Resize width height ->
            wrap { model | w = width, h = height }

        Request req ->
            case req of
                Browser.Internal url ->
                    ( model, Nav.pushUrl model.key (Url.toString url) )

                Browser.External href ->
                    ( model, Nav.load href )

        Load url ->
            wrap { model | url = url }

        GotMesh response ->
            case response of
                Err _ ->
                    pass

                Ok object ->
                    wrap { model | mesh = Just object }

        GotTexture result ->
            case result of
                Err _ ->
                    pass

                Ok texture ->
                    wrap
                        { model
                            | textures =
                                Just (Material.texturedMatte texture)
                        }

        Rotate time ->
            wrap
                { model
                    | angle = canonicalize (model.angle + 2 * (2 + sin (toFloat (Time.posixToMillis time) / 1000)))
                    , radius = 7.5 + 1 / 8 * model.radius + 5 * 13 / 11 * sin (toFloat (Time.posixToMillis time + 250) / 1000)
                    , elevation = 9 + 1 / 4 * model.elevation + 5 * cos (toFloat (Time.posixToMillis time) / 1000)
                    , mainColor = blender (frac (toFloat (Time.posixToMillis time) / 3500))
                    , show = modBy 4000 (Time.posixToMillis time) > 2000
                }

        Copy label text ->
            ( model, copyToClipboard ( label, text ) )

        Key key ->
            ( { model | last = key }, Cmd.none )

        Scroll loc ->
            ( model, scrollTo loc )

        ScrollToEntry entry ->
            ( { model | entry = entry }, scrollTo entry )


keyDecoder : Decode.Decoder String
keyDecoder =
    Decode.field "key" Decode.string


subscribe : Model -> Sub Msg
subscribe _ =
    Sub.batch
        [ Events.onResize Resize
        , Events.onKeyPress (Decode.map Key keyDecoder)
        , Time.every (1000 / 30) Rotate
        ]


vw : Model -> Float -> Float
vw model percent =
    Basics.toFloat model.w * percent / 100


vh : Model -> Float -> Float
vh model percent =
    Basics.toFloat model.h * percent / 100


white : Color
white =
    rgb 255 255 255


black : Color
black =
    rgb 0 0 0


btnStyle : List (Attribute msg)
btnStyle =
    [ padding 10
    , Font.color white
    , Font.family [ Font.typeface "Rubik" ]
    , Font.semiBold
    , Font.size 20
    , Border.width 2
    , Border.color white
    , mouseOver [ Background.color white, Font.color black ]
    ]


linkBtn : String -> String -> Element msg
linkBtn disp addr =
    newTabLink btnStyle { url = addr, label = text (String.toUpper disp) }


linkBtnInt : String -> String -> Element msg
linkBtnInt disp addr =
    link btnStyle { url = addr, label = text (String.toUpper disp) }


entryLink : String -> String -> Element Msg
entryLink disp addr =
    button
        [ Font.underline
        , Font.bold
        ]
        { onPress = Just (ScrollToEntry addr)
        , label = text disp
        }


btn : String -> Msg -> Element Msg
btn disp act =
    button btnStyle { onPress = Just act, label = text (String.toUpper disp) }


vw2pt : Model -> Float -> Int
vw2pt model ratio =
    (round << vw model) ratio


vw2px : Model -> Float -> Length
vw2px model ratio =
    px (vw2pt model ratio)


vh2pt : Model -> Float -> Int
vh2pt model ratio =
    (round << vh model) ratio


vh2px : Model -> Float -> Length
vh2px model ratio =
    px (vh2pt model ratio)


heading : List (Attr () msg)
heading =
    [ Font.color white
    , Font.family [ Font.typeface "Imbue" ]
    , Font.size 96
    ]


subheading : List (Attr () msg)
subheading =
    [ Font.color white
    , Font.family [ Font.typeface "Imbue" ]
    , Font.size 72
    , width (px 600)
    ]


bodyText : List (Attr () msg)
bodyText =
    [ Font.color white
    , Font.family [ Font.typeface "Inter" ]
    , Font.size 20
    , width (px 500)
    ]


page : Model -> List (Attr () msg)
page model =
    [ width fill
    , height (vh2px model 100)
    , spacing (vh2pt model -100)
    , Background.color black
    ]


fullImage : Model -> List (Attr () msg)
fullImage model =
    [ width fill
    , height (vh2px model 100)
    , alpha 0.5
    ]


pageText : Model -> List (Attr () msg)
pageText model =
    [ spacing 30
    , alignLeft
    , alignTop
    , width (vw2px model 50)
    , height (vh2px model 100)
    , paddingEach
        { top = vh2pt model 50 - 96 * 2
        , bottom = 0
        , left = vw2pt model 10
        , right = 0
        }
    ]


inlineLink : String -> String -> Element msg
inlineLink disp addr =
    newTabLink
        [ Font.underline
        , Font.bold
        ]
        { url = addr
        , label = text disp
        }


inlineLinkInt : String -> String -> Element msg
inlineLinkInt disp addr =
    link
        [ Font.underline
        , Font.bold
        ]
        { url = addr
        , label = text disp
        }


id : String -> Element.Attribute msg
id =
    Html.Attributes.id >> Element.htmlAttribute


getPaths : String -> String -> List String
getPaths path base =
    let
        root : String
        root =
            path ++ base
    in
    List.map ((++) root) [ "", "/", "/index.html" ]


itemize : List String -> a -> List ( String, a )
itemize multikeys entry =
    let
        key : Maybe String
        key =
            List.head multikeys
    in
    case key of
        Just k ->
            ( k, entry ) :: itemize (List.drop 1 multikeys) entry

        Nothing ->
            []


sitemap : Model -> Dict String (Model -> List (Html Msg))
sitemap model =
    let
        getter : String -> List String
        getter =
            getPaths model.path
    in
    Dict.fromList
        (itemize ([ "/", "/index.html", model.path ] ++ getter "src" ++ getter "index" ++ getter "home") pageHome
            ++ itemize (getter "entries") pageEntries
            ++ itemize (getter "about") pageAbout
            ++ itemize (getter "colophon") colophon
        )


loadUrl : Model -> List (Html Msg)
loadUrl model =
    let
        req : Maybe (Model -> List (Html Msg))
        req =
            Dict.get model.url.path (sitemap model)
    in
    case req of
        Just builder ->
            builder model

        Nothing ->
            notFound model


view : Model -> Browser.Document Msg
view model =
    { title = "MacGregor House"
    , body = loadUrl model
    }


menu : Model -> Element Msg
menu model =
    el
        [ alignLeft
        , alignTop
        , width (vw2px model 25)
        , paddingEach
            { top = 0
            , bottom = vh2pt model 22.5
            , left = 0
            , right = 0
            }
        , Font.color white
        , Font.family [ Font.typeface "Inter" ]
        , Font.size 18
        ]
        (row [ spacing 20 ]
            [ inlineLinkInt "Entries" (model.path ++ "entries")
            , inlineLinkInt "Access" (model.path ++ "about")
            , inlineLinkInt "Colophon" (model.path ++ "colophon")
            ]
        )


pageHome : Model -> List (Html Msg)
pageHome model =
    [ Element.layout
        [ width fill
        ]
        (column [ width fill ]
            [ column
                [ width fill
                , height fill
                , spacing (vh2pt model -100)
                , id "zero"
                ]
                [ el
                    [ width fill
                    , height (vh2px model 100)
                    , Background.color black
                    ]
                    Element.none
                , animatedEl crossfadeIn
                    [ width fill
                    , height (vh2px model 100)
                    , Background.gradient { angle = 45, steps = [ rgb255 200 0 100, rgb255 100 0 200 ] }
                    ]
                    Element.none
                , animatedEl crossfadeOut
                    [ width fill
                    , height (vh2px model 100)
                    , Background.gradient { angle = 45, steps = [ rgb255 0 100 200, rgb255 0 200 100 ] }
                    ]
                    Element.none
                , el
                    ([ alignLeft
                     , alignTop
                     , width (vw2px model 50)
                     , height (vh2px model 100)
                     , paddingEach
                        { top = vh2pt model 20 - 96
                        , bottom = 0
                        , left = vw2pt model 10
                        , right = 0
                        }
                     ]
                        ++ heading
                    )
                    (column
                        [ spacing 35
                        ]
                        [ menu model
                        , text "MacGregor House"
                        , column [ spacing 15 ]
                            [ row
                                [ spacing 15
                                ]
                                [ linkBtn "See events" "https://calendar.google.com/calendar/embed?src=c_c9fb13003264d5becb74cf9ba42a087d8a4a180d927441994458a07ac146eb88%40group.calendar.google.com&ctz=America%2FNew_York"
                                , linkBtn "Reserve space" "https://forms.gle/KxFAG65TQuPxdYak8"
                                ]
                            , row [ spacing 15 ]
                                [ btn "↓" (Scroll "one")
                                , btn "Copy iCal link" (Copy "iCal link" "https://calendar.google.com/calendar/ical/c_c9fb13003264d5becb74cf9ba42a087d8a4a180d927441994458a07ac146eb88%40group.calendar.google.com/public/basic.ics")
                                ]
                            ]
                        ]
                    )
                , el
                    [ alignRight
                    , alignTop
                    , width (vw2px model 60)
                    , height (vh2px model 100)
                    , paddingEach
                        { top = vh2pt model 25
                        , bottom = vh2pt model 25
                        , left = 0
                        , right = 0
                        }
                    ]
                    (view3D model)
                ]
            , column
                (page model ++ [ id "one" ])
                [ image (fullImage model)
                    { src = "../assets/img/tall.jpg"
                    , description = "the imposing macgregor superstructure stands tall in defiance of strong winds"
                    }
                , column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (Scroll "zero")
                        , btn "↓" (Scroll "two")
                        ]
                    , paragraph
                        subheading
                        [ text "The tallest undergraduate dormitory." ]
                    , paragraph bodyText
                        [ text "Enrico Fermi once said, \"Before I came here I was confused about this subject. Having listened to your lecture, I am still confused, but on a higher level.\" "
                        , inlineLink "Pietro Belluschi" "https://listart.mit.edu/art-artists/macgregor-house-1970"
                        , text " attended that lecture."
                        ]
                    ]
                ]
            , column
                (page model ++ [ id "two" ])
                [ image (fullImage model)
                    { src = "../assets/img/view.jpg"
                    , description = "the macgregor pov just hits different"
                    }
                , column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (Scroll "one")
                        , btn "↓" (Scroll "three")
                        ]
                    , paragraph subheading [ text "Stunning vistas are just the beginning." ]
                    , paragraph bodyText
                        [ text "A view from MacGregor is like looking down on Earth from the stars. MacGregor's prime waterfront real estate offers breathtaking views of the Charles and the Boston skyline beyond."
                        ]
                    ]
                ]
            , column
                (page model ++ [ id "three" ])
                [ image (fullImage model)
                    { src = "../assets/img/free.jpg"
                    , description = "macgregor is often seen as the gateway to new worlds, especially briggs field"
                    }
                , column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (Scroll "two")
                        , btn "↓" (Scroll "four")
                        ]
                    , paragraph subheading [ text "Free as in freedom." ]
                    , paragraph bodyText
                        [ text "This website's source code and infrastructure, the ability to cook, your choice of living community and room assignments—they operate in the public interest of all MacGregorites. You won't get this freedom at many other undergraduate dormitories at MIT."
                        ]
                    ]
                ]
            , column
                (page model ++ [ id "four" ])
                [ image (fullImage model)
                    { src = "../assets/img/location.jpg"
                    , description = "the bright lights of the macgregor high rise shine down upon the glossy snow-covered surface of briggs field"
                    }
                , column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (Scroll "three")
                        , btn "↓" (Scroll "five")
                        ]
                    , paragraph subheading [ text "Nestled between Kendall and Cambridgeport." ]
                    , paragraph bodyText
                        [ text "Between "
                        , inlineLink "the innovative spirit of Kendall" "https://kendallsquare.org/kendalls-history-orientation/"
                        , text " and the industrial crossroads of Cambridgeport, there is a place—on a tiny stretch of street called Amherst Alley—that fills the quiet void with a voracious intellectual appetite and an unparalleled creative vision."
                        ]
                    ]
                ]
            , column
                (page model ++ [ id "five" ])
                [ image (fullImage model)
                    { src = "../assets/img/brick.jpg"
                    , description = "multicolored bricks shine in the limelight of macgregorian festivities"
                    }
                , column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (Scroll "four")
                        , btn "↓" (Scroll "six")
                        ]
                    , paragraph subheading [ text "We like the ", el [ Font.bold, Font.size 96 ] (text "brick"), text "." ]
                    , paragraph bodyText
                        [ text "The bricks are everywhere—by far the most recognizable feature of MacGregor. You'll find them protecting the building's exterior from harsh Bostonian winters, lining its fabled corridors, and in your room, as much an architectural statement as they are a testament to the people of MacGregor."
                        ]
                    ]
                ]
            , column
                (page model ++ [ id "six" ])
                [ image (fullImage model)
                    { src = "../assets/img/belong.jpg"
                    , description = "the cultural murals of macgregor breathe life into its ancient pedestrian thoroughfares"
                    }
                , column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (Scroll "five")
                        , btn "Top" (Scroll "zero")
                        ]
                    , paragraph subheading [ text "You belong here." ]
                    , paragraph bodyText
                        [ text "MacGregor's greatness is the greatness of its people. Living in MacGregor inevitably connects you to its people and its culture—one of the most diverse, unique, and historic of any MIT dorm—spanning nine entries, countless murals and traditions, and a couple hundred current residents."
                        ]
                    ]
                ]
            ]
        )
    ]


pageAbout : Model -> List (Html Msg)
pageAbout model =
    [ Element.layout
        [ width fill
        ]
        (column [ width fill ]
            [ column
                [ width fill
                , height fill
                , spacing (vh2pt model -100)
                , id "zero"
                ]
                [ el
                    [ width fill
                    , height (vh2px model 100)
                    , Background.color black
                    ]
                    Element.none
                , animatedEl crossfadeIn
                    [ width fill
                    , height (vh2px model 100)
                    , Background.gradient { angle = 45, steps = [ rgb255 255 0 140, rgb255 40 0 255 ] }
                    ]
                    Element.none
                , animatedEl crossfadeOut
                    [ width fill
                    , height (vh2px model 100)
                    , Background.gradient { angle = 0, steps = [ rgb255 0 140 255, rgb255 0 150 25 ] }
                    ]
                    Element.none
                , el
                    ([ alignLeft
                     , alignTop
                     , width (vw2px model 50)
                     , height (vh2px model 100)
                     , paddingEach
                        { top = vh2pt model 20 - 96
                        , bottom = 0
                        , left = vw2pt model 10
                        , right = 0
                        }
                     ]
                        ++ heading
                    )
                    (column
                        [ spacing 35
                        ]
                        [ menu model
                        , text "Access"
                        , column [ spacing 15 ]
                            [ row
                                [ spacing 15 ]
                                [ linkBtnInt "← Back" model.path
                                , btn "Directions" (Scroll "one")
                                ]
                            , row [ spacing 15 ]
                                [ btn "Facilities" (Scroll "two")
                                , btn "Web Accessibility" (Scroll "three")
                                ]
                            ]
                        ]
                    )
                , el
                    [ alignRight
                    , alignTop
                    , width (vw2px model 60)
                    , height (vh2px model 100)
                    , paddingEach
                        { top = vh2pt model 25
                        , bottom = vh2pt model 25
                        , left = 0
                        , right = 0
                        }
                    ]
                    (view3DWalk model)
                ]
            , column
                (page model ++ [ id "one" ])
                [ image (fullImage model)
                    { src = model.path ++ "../assets/img/map.png"
                    , description = "mit campus map with pin at macgregor house"
                    }
                , column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (Scroll "zero")
                        , btn "↓" (Scroll "two")
                        ]
                    , paragraph
                        subheading
                        [ text "Directions" ]
                    , paragraph bodyText
                        [ text "MacGregor's address is "
                        , paragraph [ Font.bold ] [ text "450 Memorial Drive, Cambridge, MA 02139" ]
                        , text ". It is building number "
                        , paragraph [ Font.bold ] [ text "W61" ]
                        , text " on the "
                        , inlineLink "MIT campus" "https://whereis.mit.edu/?go=W61"
                        , text ". See the "
                        , inlineLink "OpenStreetMaps identifier" "https://www.openstreetmap.org/way/1246607679"
                        , text " for directions and more information. If you are mailing a package to a MacGregor resident, follow the directions listed on the "
                        , inlineLink "MIT DSL site" "https://studentlife.mit.edu/housing/undergraduate-housing/mailing-shipping-information"
                        , text "."
                        ]
                    ]
                ]
            , column
                (page model ++ [ id "two" ])
                [ image (fullImage model)
                    { src = "../assets/img/night.jpg"
                    , description = "looking out into the starry night from the second floor patio"
                    }
                , column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (Scroll "one")
                        , btn "↓" (Scroll "three")
                        ]
                    , paragraph subheading [ text "Facilities and Information" ]
                    , paragraph bodyText
                        [ text "MacGregor's main facilities are all located on the ground floor. They include a central courtyard, conference/seminar room, music practice room, two laundry rooms, gym, ice machine, game room with a black and white and color printer and an Athena computing cluster, study room, and dining room with a dance studio. All of these facilities are available to residents at any time except when they are being used for "
                        , inlineLink "events" "https://calendar.google.com/calendar/embed?src=c_c9fb13003264d5becb74cf9ba42a087d8a4a180d927441994458a07ac146eb88%40group.calendar.google.com&ctz=America%2FNew_York"
                        , text "."
                        ]
                    , paragraph bodyText
                        [ text "You can ask the front desk for a key to access the music practice room. Printers in MacGregor can be located "
                        , inlineLink "here" "https://print.mit.edu"
                        , text " (search for W61). Laundry uses the "
                        , inlineLink "CSCGo app" "https://mycscgo.com/laundry"
                        , text " for payments (approximately $1.25 for a single wash or dry cycle). You can learn more about MacGregor "
                        , inlineLink "here" "https://mitguidetoresidences.mit.edu/residences/macgregor-house"
                        , text "."
                        ]
                    ]
                ]
            , column
                (page model ++ [ id "three" ])
                [ image (fullImage model)
                    { src = "../assets/img/sunrise.jpg"
                    , description = "sunrise over back bay, boston, as seen from macgregor south side entrance"
                    }
                , column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (Scroll "two")
                        , btn "Top" (Scroll "zero")
                        ]
                    , paragraph subheading [ text "Accessibility is our highest priority." ]
                    , paragraph bodyText
                        [ text "If you're experiencing issues viewing or interacting with parts of this website, please do not hesitate to "
                        , inlineLink "contact the webmaster" "mailto:ananthv@mit.edu"
                        , text " at any time. We strive to make the story of MacGregor widely accessible to the general public, and we value your input and community support in achieving that goal."
                        ]
                    ]
                ]
            ]
        )
    ]


pageEntries : Model -> List (Html Msg)
pageEntries model =
    [ Element.layout
        [ width fill
        ]
        (column [ width fill ]
            [ column
                [ width fill
                , height fill
                , spacing (vh2pt model -100)
                , id "zero"
                ]
                [ el
                    [ width fill
                    , height (vh2px model 100)
                    , Background.color black
                    ]
                    Element.none
                , animatedEl crossfadeIn
                    [ width fill
                    , height (vh2px model 100)
                    , Background.gradient { angle = 360 - 45, steps = [ rgb255 100 125 50, rgb255 125 50 100 ] }
                    ]
                    Element.none
                , animatedEl crossfadeOut
                    [ width fill
                    , height (vh2px model 100)
                    , Background.gradient { angle = 360 - 45, steps = [ rgb255 100 50 175, rgb255 100 175 50 ] }
                    ]
                    Element.none
                , el
                    ([ alignLeft
                     , alignTop
                     , width (vw2px model 50)
                     , height (vh2px model 100)
                     , paddingEach
                        { top = vh2pt model 20 - 96
                        , bottom = 0
                        , left = vw2pt model 10
                        , right = 0
                        }
                     ]
                        ++ heading
                    )
                    (column
                        [ spacing 35
                        ]
                        [ menu model
                        , text "Meet the entries"
                        , paragraph bodyText
                            [ entryLink "A entry" "A"
                            , text ", "
                            , entryLink "Bentry" "B"
                            , text ", "
                            , entryLink "Centry" "C"
                            , text " (the C is silent), "
                            , entryLink "Dentry" "D"
                            , text ", "
                            , entryLink "E entry" "E"
                            , text ", "
                            , entryLink "Fentry" "F"
                            , text ", "
                            , entryLink "Gentry" "G"
                            , text " (hard G), "
                            , entryLink "Hentry" "H"
                            , text ", 𝑖 entry (imaginary),"
                            , image [ height (px 24), padding 10 ] { description = "flag of j entry", src = "../assets/img/jentry.png" }
                            , entryLink "Jentry" "J"
                            ]
                        , column [ spacing 15 ]
                            [ row
                                [ spacing 15
                                ]
                                [ linkBtnInt "← Back" model.path
                                , btn "Explore ↓" (ScrollToEntry "J")
                                ]
                            ]
                        ]
                    )
                , el
                    [ alignRight
                    , alignTop
                    , width (vw2px model 60)
                    , height (vh2px model 100)
                    , paddingEach
                        { top = vh2pt model 25
                        , bottom = vh2pt model 25
                        , left = 0
                        , right = 0
                        }
                    ]
                    (if model.entry == "zero" then
                        view3DColors model

                     else
                        Element.none
                    )
                ]
            , column
                (page model ++ [ id "J", Background.color (rgb255 76 76 254) ])
                [ column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (ScrollToEntry "zero")
                        , btn "↓" (ScrollToEntry "A")
                        ]
                    , paragraph
                        subheading
                        [ text "Welcome to the Jentry."
                        , image [ width (px 80), padding 12 ] { description = "flag of j entry", src = "../assets/img/jentry.png" }
                        ]
                    , paragraph (bodyText ++ [ Font.size 32 ])
                        [ text "(J Entry) The heart of MacGregor. Historic culture, big lore. Jentry memes. J is for Jamily. We're an eclectic community, filled with everyone from introverts to extroverts, crazy vibes, chill vibes, and everything in between."
                        ]
                    ]
                , el
                    [ alignRight
                    , alignTop
                    , width (vw2px model 60)
                    , height (vh2px model 100)
                    , paddingEach
                        { top = vh2pt model 25
                        , bottom = vh2pt model 25
                        , left = 0
                        , right = 0
                        }
                    ]
                    (if model.entry == "J" then
                        view3DEntries "J" model

                     else
                        Element.none
                    )
                ]
            , column
                (page model ++ [ id "A", Background.color (rgb255 5 93 243) ])
                [ column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (ScrollToEntry "J")
                        , btn "↓" (ScrollToEntry "B")
                        ]
                    , paragraph
                        subheading
                        [ text "Welcome to A Entry." ]
                    , paragraph (bodyText ++ [ Font.size 32 ])
                        [ text "Top floor. Top dog. Alpha wolf. Unity and strength. Positive, above average."
                        ]
                    ]
                , el
                    [ alignRight
                    , alignTop
                    , width (vw2px model 60)
                    , height (vh2px model 100)
                    , paddingEach
                        { top = vh2pt model 25
                        , bottom = vh2pt model 25
                        , left = 0
                        , right = 0
                        }
                    ]
                    (if model.entry == "A" then
                        view3DEntries "A" model

                     else
                        Element.none
                    )
                ]
            , column
                (page model ++ [ id "B", Background.color (rgb255 5 180 93) ])
                [ column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (ScrollToEntry "A")
                        , btn "↓" (ScrollToEntry "C")
                        ]
                    , paragraph
                        subheading
                        [ text "Welcome to Bentry." ]
                    , paragraph (bodyText ++ [ Font.size 32 ])
                        [ text "(B Entry) Bentry is loud and fun and very social. We like to hang out with each other and check in, catch up, and go out. We banter a lot too but we are always there for each other. We’re a family for sure."
                        ]
                    ]
                , el
                    [ alignRight
                    , alignTop
                    , width (vw2px model 60)
                    , height (vh2px model 100)
                    , paddingEach
                        { top = vh2pt model 25
                        , bottom = vh2pt model 25
                        , left = 0
                        , right = 0
                        }
                    ]
                    (if model.entry == "B" then
                        view3DEntries "B" model

                     else
                        Element.none
                    )
                ]
            , column
                (page model ++ [ id "C", Background.color (rgb255 5 140 40) ])
                [ column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (ScrollToEntry "B")
                        , btn "↓" (ScrollToEntry "D")
                        ]
                    , paragraph
                        subheading
                        [ text "Welcome to Centry." ]
                    , paragraph (bodyText ++ [ Font.size 32 ])
                        [ text "(C Entry) Chill. Calmer. Sloths."
                        ]
                    ]
                , el
                    [ alignRight
                    , alignTop
                    , width (vw2px model 60)
                    , height (vh2px model 100)
                    , paddingEach
                        { top = vh2pt model 25
                        , bottom = vh2pt model 25
                        , left = 0
                        , right = 0
                        }
                    ]
                    (if model.entry == "C" then
                        view3DEntries "C" model

                     else
                        Element.none
                    )
                ]
            , column
                (page model ++ [ id "D", Background.color (rgb255 40 140 240) ])
                [ column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (ScrollToEntry "C")
                        , btn "↓" (ScrollToEntry "E")
                        ]
                    , paragraph
                        subheading
                        [ text "Welcome to Dentry." ]
                    , paragraph (bodyText ++ [ Font.size 32 ])
                        [ text "(D Entry) D is for doing. Whether we stay in or go out (mostly go out), we have fun! D is also for degenerate. We are up the latest of all entries."
                        ]
                    ]
                , el
                    [ alignRight
                    , alignTop
                    , width (vw2px model 60)
                    , height (vh2px model 100)
                    , paddingEach
                        { top = vh2pt model 25
                        , bottom = vh2pt model 25
                        , left = 0
                        , right = 0
                        }
                    ]
                    (if model.entry == "D" then
                        view3DEntries "D" model

                     else
                        Element.none
                    )
                ]
            , column
                (page model ++ [ id "E", Background.color (rgb255 221 162 126) ])
                [ column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (ScrollToEntry "D")
                        , btn "↓" (ScrollToEntry "F")
                        ]
                    , paragraph
                        subheading
                        [ text "Welcome to E entry." ]
                    , paragraph (bodyText ++ [ Font.size 32 ])
                        [ text "We're a really cozy and friendly entry! We love having baking/cooking nights, watching movies, playing games, and just hanging out to chat. We also go out for dinners occasionally!"
                        ]
                    ]
                , el
                    [ alignRight
                    , alignTop
                    , width (vw2px model 60)
                    , height (vh2px model 100)
                    , paddingEach
                        { top = vh2pt model 25
                        , bottom = vh2pt model 25
                        , left = 0
                        , right = 0
                        }
                    ]
                    (if model.entry == "E" then
                        view3DEntries "E" model

                     else
                        Element.none
                    )
                ]
            , column
                (page model ++ [ id "F", Background.color (rgb255 200 125 150) ])
                [ column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (ScrollToEntry "E")
                        , btn "↓" (ScrollToEntry "G")
                        ]
                    , paragraph
                        subheading
                        [ text "Welcome to the Fentry." ]
                    , paragraph (bodyText ++ [ Font.size 32 ])
                        [ text "(F entry) Typical nights for us look like playing poker, watching a movie, or just chilling and doing homework."
                        ]
                    ]
                , el
                    [ alignRight
                    , alignTop
                    , width (vw2px model 60)
                    , height (vh2px model 100)
                    , paddingEach
                        { top = vh2pt model 25
                        , bottom = vh2pt model 25
                        , left = 0
                        , right = 0
                        }
                    ]
                    (if model.entry == "F" then
                        view3DEntries "F" model

                     else
                        Element.none
                    )
                ]
            , column
                (page model ++ [ id "G", Background.color (rgb255 250 150 50) ])
                [ column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (ScrollToEntry "F")
                        , btn "↓" (ScrollToEntry "H")
                        ]
                    , paragraph
                        subheading
                        [ text "Welcome to the Gentry." ]
                    , paragraph (bodyText ++ [ Font.size 32 ])
                        [ text "(G entry) Chill but welcoming. The G in Gentry stands for Goofy, Gamers, and Good Times."
                        ]
                    ]
                , el
                    [ alignRight
                    , alignTop
                    , width (vw2px model 60)
                    , height (vh2px model 100)
                    , paddingEach
                        { top = vh2pt model 25
                        , bottom = vh2pt model 25
                        , left = 0
                        , right = 0
                        }
                    ]
                    (if model.entry == "G" then
                        view3DEntries "G" model

                     else
                        Element.none
                    )
                ]
            , column
                (page model ++ [ id "H", Background.color (rgb255 50 175 50) ])
                [ column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (ScrollToEntry "G")
                        , btn "Top" (ScrollToEntry "zero")
                        ]
                    , paragraph
                        subheading
                        [ text "Welcome to the Hentry." ]
                    , paragraph (bodyText ++ [ Font.size 32 ])
                        [ text "(H entry) Where the walls are hexagonal (not really), the vibes are chaotic-good, and the only thing more structured than our beehive of activity is our legendary group chats."
                        ]
                    ]
                , el
                    [ alignRight
                    , alignTop
                    , width (vw2px model 60)
                    , height (vh2px model 100)
                    , paddingEach
                        { top = vh2pt model 25
                        , bottom = vh2pt model 25
                        , left = 0
                        , right = 0
                        }
                    ]
                    (if model.entry == "H" then
                        view3DEntries "H" model

                     else
                        Element.none
                    )
                ]
            ]
        )
    ]


notFound : Model -> List (Html Msg)
notFound model =
    [ Element.layout
        [ width fill ]
        (column [ width fill ]
            [ column
                [ width fill
                , height fill
                , spacing (vh2pt model -100)
                ]
                [ el
                    [ width fill
                    , height (vh2px model 100)
                    , Background.color black
                    ]
                    Element.none
                , animatedEl crossfadeIn
                    [ width fill
                    , height (vh2px model 100)
                    , Background.gradient { angle = 45, steps = [ rgb255 100 200 0, rgb255 200 100 0 ] }
                    ]
                    Element.none
                , animatedEl crossfadeOut
                    [ width fill
                    , height (vh2px model 100)
                    , Background.gradient { angle = 45, steps = [ rgb255 0 150 50, rgb255 0 50 150 ] }
                    ]
                    Element.none
                , el
                    ([ alignLeft
                     , alignTop
                     , width (vw2px model 50)
                     , height (vh2px model 100)
                     , paddingEach
                        { top = vh2pt model 35 - 96
                        , bottom = 0
                        , left = vw2pt model 10
                        , right = 0
                        }
                     ]
                        ++ heading
                    )
                    (column
                        [ spacing 35
                        ]
                        [ text "Error! 404."
                        , paragraph (bodyText ++ [ Font.size 24 ])
                            [ text "We went all the way up to A entry, then back down and around to J, yet no trace of this page could be found. Perhaps it's in 𝑖 entry?" ]
                        , paragraph (bodyText ++ [ width (vw2px model 33) ])
                            [ text "You were likely redirected here by a link to a page on the old website, the last known archive of which can be found "
                            , inlineLink "here" "https://web.archive.org/web/20170529064230/http://macgregor.mit.edu/"
                            , text ". Unless you want to conduct research on ancient MIT traditions, you can probably find what you're looking for on the new "
                            , inlineLinkInt "main page" (model.path ++ "/src")
                            , text ". If you believe this page really is missing, "
                            , inlineLink "contact the webmaster" "mailto:ananthv@mit.edu"
                            , text "."
                            ]
                        ]
                    )
                , el
                    [ alignRight
                    , alignTop
                    , width (vw2px model 60)
                    , height (vh2px model 100)
                    , paddingEach
                        { top = vh2pt model 25
                        , bottom = vh2pt model 25
                        , left = 0
                        , right = 0
                        }
                    ]
                    (view3DTower model)
                ]
            ]
        )
    ]


colophon : Model -> List (Html Msg)
colophon model =
    [ Element.layout
        [ width fill ]
        (column [ width fill ]
            [ column
                [ width fill
                , height fill
                , spacing (vh2pt model -100)
                ]
                [ el
                    [ width fill
                    , height (vh2px model 100)
                    , Background.color black
                    ]
                    Element.none
                , animatedEl crossfadeIn
                    [ width fill
                    , height (vh2px model 100)
                    , Background.gradient { angle = 45, steps = [ rgb255 100 200 0, rgb255 200 100 0 ] }
                    ]
                    Element.none
                , animatedEl crossfadeOut
                    [ width fill
                    , height (vh2px model 100)
                    , Background.gradient { angle = 45, steps = [ rgb255 0 150 50, rgb255 0 50 150 ] }
                    ]
                    Element.none
                , el
                    ([ alignLeft
                     , alignTop
                     , width (vw2px model 50)
                     , height (vh2px model 100)
                     , paddingEach
                        { top = vh2pt model 25 - 96
                        , bottom = 0
                        , left = vw2pt model 10
                        , right = 0
                        }
                     , id "zero"
                     ]
                        ++ heading
                    )
                    (column
                        [ spacing 35
                        ]
                        [ text "Colophon."
                        , row [ spacing 15 ]
                            [ linkBtnInt "← Back" model.path
                            , linkBtn "Source" "https://forgejo.mit.edu/ananthv/macgregor"
                            , btn "Literature" (Scroll "one")
                            ]
                        , paragraph (bodyText ++ [ Font.size 24, width (vw2px model 70) ])
                            [ text "You may be wondering why a website (especially this one) has a colophon, which is typically reserved for books and other seemingly serious publications." ]
                        , paragraph (bodyText ++ [ width (vw2px model 70) ])
                            [ text "This section exists to highlight our principles of development. This entire site, and most software components that it relies on ("
                            , inlineLink "Elm" "https://seas.harvard.edu/news/2015/10/alumni-profile-evan-czaplicki-ab-12"
                            , text ", "
                            , inlineLink "MIT Forgejo instance" "https://forgejo.mit.edu/"
                            , text ", "
                            , inlineLink "Athena servers" "https://ist.mit.edu/athena"
                            , text ", "
                            , inlineLink "software licensing" "https://en.wikipedia.org/wiki/MIT_License"
                            , text ", among others) was built in "
                            , paragraph [ Font.bold ] [ text "Cambridge, MA" ]
                            , text ". We make every effort possible to source "
                            , paragraph [ Font.bold ] [ text "local, free, and open-source software" ]
                            , text " and other infrastructure. We adhere strictly to the principles of "
                            , paragraph [ Font.bold ] [ inlineLink "free software" "https://www.gnu.org/philosophy/free-sw.html" ]
                            , text " (\"free\" as in \"freedom\"). This entire website is designed in a "
                            , inlineLink "purely functional" "https://en.wikipedia.org/wiki/Functional_programming"
                            , text " language and built using a purely functional "
                            , inlineLink "build tool" "https://nixos.org/"
                            , text " with provable reproducibility. In doing so, we build on decades of academic research to create a website that will survive the next generation of the internet. You can review some of the relevant literature involved in designing this website below."
                            ]
                        ]
                    )
                ]
            , column
                (page model ++ [ id "one", Background.color (rgb255 173 111 101) ])
                [ column (pageText model)
                    [ row [ spacing 10 ]
                        [ btn "↑" (Scroll "zero")
                        , btn "↓" (Scroll "two")
                        ]
                    , paragraph
                        subheading
                        [ text "Relevant literature" ]
                    , paragraph bodyText
                        [ text "Here is a sampling of the most relevant papers referenced in the most recent redesign of this website: (1) "
                        , inlineLink "\"Elm: Concurrent FRP for Functional GUIs\"" "https://elm-lang.org/assets/papers/concurrent-frp.pdf"
                        , text ", (2) "
                        , inlineLink "\"NeRF: Representing Scenes as Neural Radiance Fields for View Synthesis\"" "https://arxiv.org/abs/2003.08934"
                        , text ", (3) "
                        , inlineLink "\"The Purely Functional Software Deployment Model\"" "https://edolstra.github.io/pubs/phd-thesis.pdf"
                        , text ", (4) "
                        , inlineLink "\"Asynchronous Functional Reactive Programming for GUIs\"" "https://people.seas.harvard.edu/~chong/pubs/pldi13-elm.pdf"
                        , text ". Note that all these papers are "
                        , paragraph [ Font.bold ] [ text "open access" ]
                        , text " because we refuse to compromise our fundamental principles."
                        ]
                    ]
                ]
            , column
                [ id "two", Background.color (rgb255 200 50 150), width fill, height (vh2px model 100) ]
                [ el
                    [ alignLeft
                    , alignTop
                    , width (vw2px model 100)
                    , height (vh2px model 100)
                    , padding 0
                    ]
                    (spin3D model)
                ]
            ]
        )
    ]


pyramidMesh : Mesh.Uniform coordinates
pyramidMesh =
    let
        -- Define the vertices of our pyramid
        frontLeft : Point3d Length.Meters coordinates
        frontLeft =
            Point3d.centimeters 250 500 0

        frontRight : Point3d Length.Meters coordinates
        frontRight =
            Point3d.centimeters 400 0 -500

        backLeft : Point3d Length.Meters coordinates
        backLeft =
            Point3d.centimeters -250 500 -500

        backRight : Point3d Length.Meters coordinates
        backRight =
            Point3d.centimeters -250 0 0

        tip : Point3d Length.Meters coordinates
        tip =
            Point3d.centimeters 0 0 500

        -- Create a TriangularMesh value from an array of vertices and list
        -- of index triples defining faces (see https://package.elm-lang.org/packages/ianmackenzie/elm-triangular-mesh/latest/TriangularMesh#indexed)
        triangularMesh : TriangularMesh (Point3d Length.Meters coordinates)
        triangularMesh =
            TriangularMesh.indexed
                (Array.fromList
                    [ frontLeft -- 0
                    , frontRight -- 1
                    , backLeft -- 2
                    , backRight -- 3
                    , tip -- 4
                    ]
                )
                [ ( 1, 0, 4 ) -- front
                , ( 0, 2, 4 ) -- left
                , ( 2, 3, 4 ) -- back
                , ( 3, 1, 4 ) -- right
                , ( 1, 3, 0 ) -- bottom
                , ( 0, 3, 2 ) -- bottom
                ]
    in
    -- Create a elm-3d-scene Mesh value from the TriangularMesh; we use
    -- Mesh.indexedFacets so that normal vectors will be generated for each face
    Mesh.indexedFacets triangularMesh


spin3D : Model -> Element msg
spin3D model =
    Element.html
        (let
            entity : Entity Obj.Decode.ObjCoordinates
            entity =
                case model.mesh of
                    Nothing ->
                        Scene3d.mesh (Material.matte (Color.rgb255 173 111 101)) pyramidMesh

                    Just mesh ->
                        case model.textures of
                            Nothing ->
                                Scene3d.mesh (Material.matte (Color.rgb255 173 111 101)) (Mesh.texturedFacets mesh)

                            Just textures ->
                                Scene3d.mesh textures (Mesh.texturedFacets mesh)

            camera : Camera3d.Camera3d Length.Meters coordinates
            camera =
                Camera3d.perspective
                    { viewpoint =
                        Viewpoint3d.lookAt
                            { focalPoint = Point3d.origin
                            , eyePoint =
                                let
                                    theta : Angle.Angle
                                    theta =
                                        Angle.degrees (3 * model.angle)
                                in
                                Point3d.meters (model.radius * Angle.cos theta) 7 (-model.radius * Angle.sin theta)
                            , upDirection = Direction3d.xy (Angle.degrees 90)
                            }
                    , verticalFieldOfView = Angle.degrees 90
                    }
         in
         Scene3d.sunny
            { entities = [ entity ]
            , camera = camera
            , upDirection = Direction3d.x
            , sunlightDirection = Direction3d.yz (Angle.degrees -120)
            , background = Scene3d.transparentBackground
            , clipDepth = Length.centimeters 1
            , shadows = False
            , dimensions = ( Pixels.int (round (vw model 100)), Pixels.int (round (vh model 100)) )
            }
        )


view3D : Model -> Element msg
view3D model =
    Element.html
        (let
            entity : Entity Obj.Decode.ObjCoordinates
            entity =
                case model.mesh of
                    Nothing ->
                        Scene3d.mesh (Material.matte (Color.rgb255 173 111 101)) pyramidMesh

                    Just mesh ->
                        case model.textures of
                            Nothing ->
                                Scene3d.mesh (Material.matte (Color.rgb255 173 111 101)) (Mesh.texturedFacets mesh)

                            Just textures ->
                                Scene3d.mesh textures (Mesh.texturedFacets mesh)

            camera : Camera3d.Camera3d Length.Meters coordinates
            camera =
                Camera3d.perspective
                    { viewpoint =
                        Viewpoint3d.lookAt
                            { focalPoint = Point3d.origin
                            , eyePoint =
                                let
                                    theta : Angle.Angle
                                    theta =
                                        Angle.degrees model.angle
                                in
                                Point3d.meters (10 * Angle.cos theta) 2 (10 * Angle.sin theta)
                            , upDirection = Direction3d.xy (Angle.degrees 90)
                            }
                    , verticalFieldOfView = Angle.degrees 100
                    }
         in
         Scene3d.sunny
            { entities = [ entity ]
            , camera = camera
            , upDirection = Direction3d.z
            , sunlightDirection = Direction3d.yz (Angle.degrees -120)
            , background = Scene3d.transparentBackground
            , clipDepth = Length.centimeters 1
            , shadows = False
            , dimensions = ( Pixels.int (round (vw model 60)), Pixels.int (round (vh model 100)) )
            }
        )


view3DColors : Model -> Element msg
view3DColors model =
    Element.html
        (let
            entity : Entity Obj.Decode.ObjCoordinates
            entity =
                case model.mesh of
                    Nothing ->
                        Scene3d.mesh (Material.matte model.mainColor) pyramidMesh

                    Just mesh ->
                        Scene3d.mesh (Material.matte model.mainColor) (Mesh.texturedFacets mesh)

            camera : Camera3d.Camera3d Length.Meters coordinates
            camera =
                Camera3d.perspective
                    { viewpoint =
                        Viewpoint3d.lookAt
                            { focalPoint = Point3d.origin
                            , eyePoint =
                                let
                                    theta : Angle.Angle
                                    theta =
                                        Angle.degrees (2 * model.angle)
                                in
                                Point3d.meters (10 * Angle.cos theta) 2 (10 * Angle.sin theta)
                            , upDirection = Direction3d.xy (Angle.degrees 90)
                            }
                    , verticalFieldOfView = Angle.degrees 100
                    }
         in
         Scene3d.sunny
            { entities = [ entity ]
            , camera = camera
            , upDirection = Direction3d.z
            , sunlightDirection = Direction3d.yz (Angle.degrees -120)
            , background = Scene3d.transparentBackground
            , clipDepth = Length.centimeters 1
            , shadows = False
            , dimensions = ( Pixels.int (round (vw model 60)), Pixels.int (round (vh model 100)) )
            }
        )


view3DEntries : String -> Model -> Element msg
view3DEntries entry model =
    Element.html
        (let
            entity : Entity Obj.Decode.ObjCoordinates
            entity =
                case model.mesh of
                    Nothing ->
                        Scene3d.mesh (Material.matte model.mainColor) pyramidMesh

                    Just mesh ->
                        case model.textures of
                            Nothing ->
                                Scene3d.mesh (Material.matte model.mainColor) (Mesh.texturedFacets mesh)

                            Just textures ->
                                if model.show then
                                    Scene3d.mesh (Material.matte model.mainColor) (Mesh.texturedFacets mesh)

                                else
                                    Scene3d.mesh textures (Mesh.texturedFacets mesh)

            camera : Camera3d.Camera3d Length.Meters coordinates
            camera =
                Camera3d.perspective
                    { viewpoint =
                        Viewpoint3d.lookAt
                            { focalPoint = Point3d.origin
                            , eyePoint =
                                let
                                    orbit : Float
                                    orbit =
                                        case entry of
                                            "A" ->
                                                4

                                            "B" ->
                                                6

                                            "C" ->
                                                6

                                            "D" ->
                                                10

                                            "F" ->
                                                12

                                            "G" ->
                                                10

                                            "J" ->
                                                12

                                            "H" ->
                                                11

                                            _ ->
                                                7

                                    perspective : Angle.Angle
                                    perspective =
                                        let
                                            phi : Float
                                            phi =
                                                180 * frac (model.angle / 180)

                                            winding : Float
                                            winding =
                                                360 * frac (model.angle / 360)

                                            direction : Float
                                            direction =
                                                abs (180 - winding) / (180 - winding)

                                            interp : Float -> Float -> Angle.Angle
                                            interp a b =
                                                Angle.degrees
                                                    (if direction > 0 then
                                                        a + (b - a) * phi / 180

                                                     else
                                                        b + (a - b) * phi / 180
                                                    )
                                        in
                                        case entry of
                                            "J" ->
                                                interp -45 30

                                            "E" ->
                                                interp 30 110

                                            "F" ->
                                                interp 140 230

                                            "G" ->
                                                interp 230 290

                                            "H" ->
                                                interp 290 315

                                            _ ->
                                                Angle.degrees model.angle

                                    height : Float
                                    height =
                                        case entry of
                                            "A" ->
                                                10

                                            "B" ->
                                                7

                                            "C" ->
                                                5

                                            "E" ->
                                                1

                                            _ ->
                                                2

                                    theta : Angle.Angle
                                    theta =
                                        perspective
                                in
                                Point3d.meters (orbit * Angle.cos theta) height (orbit * Angle.sin theta)
                            , upDirection = Direction3d.xy (Angle.degrees 90)
                            }
                    , verticalFieldOfView = Angle.degrees 60
                    }
         in
         Scene3d.sunny
            { entities = [ entity ]
            , camera = camera
            , upDirection = Direction3d.z
            , sunlightDirection = Direction3d.yz (Angle.degrees -120)
            , background = Scene3d.transparentBackground
            , clipDepth = Length.centimeters 1
            , shadows = False
            , dimensions = ( Pixels.int (round (vw model 60)), Pixels.int (round (vh model 100)) )
            }
        )


view3DTower : Model -> Element msg
view3DTower model =
    Element.html
        (let
            entity : Entity Obj.Decode.ObjCoordinates
            entity =
                case model.mesh of
                    Nothing ->
                        Scene3d.mesh (Material.matte (Color.rgb255 173 111 101)) pyramidMesh

                    Just mesh ->
                        case model.textures of
                            Nothing ->
                                Scene3d.mesh (Material.matte (Color.rgb255 173 111 101)) (Mesh.texturedFacets mesh)

                            Just textures ->
                                Scene3d.mesh textures (Mesh.texturedFacets mesh)

            camera : Camera3d.Camera3d Length.Meters coordinates
            camera =
                Camera3d.perspective
                    { viewpoint =
                        Viewpoint3d.lookAt
                            { focalPoint = Point3d.origin
                            , eyePoint =
                                let
                                    theta : Angle.Angle
                                    theta =
                                        Angle.degrees 90
                                in
                                Point3d.meters (model.radius * Angle.cos theta) model.elevation (model.radius * Angle.sin theta)
                            , upDirection = Direction3d.xy (Angle.degrees 90)
                            }
                    , verticalFieldOfView = Angle.degrees 60
                    }
         in
         Scene3d.sunny
            { entities = [ entity ]
            , camera = camera
            , upDirection = Direction3d.z
            , sunlightDirection = Direction3d.yz (Angle.degrees -120)
            , background = Scene3d.transparentBackground
            , clipDepth = Length.centimeters 1
            , shadows = False
            , dimensions = ( Pixels.int (round (vw model 60)), Pixels.int (round (vh model 100)) )
            }
        )


view3DWalk : Model -> Element msg
view3DWalk model =
    Element.html
        (let
            entity : Entity Obj.Decode.ObjCoordinates
            entity =
                case model.mesh of
                    Nothing ->
                        Scene3d.mesh (Material.matte (Color.rgb255 173 111 101)) pyramidMesh

                    Just mesh ->
                        case model.textures of
                            Nothing ->
                                Scene3d.mesh (Material.matte (Color.rgb255 173 111 101)) (Mesh.texturedFacets mesh)

                            Just textures ->
                                Scene3d.mesh textures (Mesh.texturedFacets mesh)

            camera : Camera3d.Camera3d Length.Meters coordinates
            camera =
                let
                    phi : Float
                    phi =
                        180 * frac (model.angle / 180)

                    winding : Float
                    winding =
                        360 * frac (model.angle / 360)

                    direction : Float
                    direction =
                        abs (180 - winding) / (180 - winding)

                    interp : Float -> Float -> Angle.Angle
                    interp a b =
                        Angle.degrees
                            (if direction > 0 then
                                a + (b - a) * phi / 180

                             else
                                b + (a - b) * phi / 180
                            )
                in
                Camera3d.perspective
                    { viewpoint =
                        Viewpoint3d.lookAt
                            { focalPoint = Point3d.origin
                            , eyePoint =
                                let
                                    theta : Angle.Angle
                                    theta =
                                        interp -90 90
                                in
                                Point3d.meters (model.radius * Angle.cos theta) model.elevation (model.radius * Angle.sin theta)
                            , upDirection = Direction3d.xy (interp (90 + 45) (90 - 45))
                            }
                    , verticalFieldOfView = Angle.degrees 60
                    }
         in
         Scene3d.sunny
            { entities = [ entity ]
            , camera = camera
            , upDirection = Direction3d.z
            , sunlightDirection = Direction3d.yz (Angle.degrees -120)
            , background = Scene3d.transparentBackground
            , clipDepth = Length.centimeters 1
            , shadows = False
            , dimensions = ( Pixels.int (round (vw model 60)), Pixels.int (round (vh model 100)) )
            }
        )


crossfadeIn : Animation
crossfadeIn =
    Animation.fromTo
        { duration = 2017
        , options = [ Animation.yoyo, Animation.loop ]
        }
        [ P.opacity 0 ]
        [ P.opacity 1 ]


crossfadeOut : Animation
crossfadeOut =
    Animation.fromTo
        { duration = 2027
        , options = [ Animation.yoyo, Animation.loop ]
        }
        [ P.opacity 1 ]
        [ P.opacity 0 ]
