Centroid

module Centroid exposing (main)


import Array exposing (Array)
import Color exposing (Color)
import Path
import Shape exposing (Arc, defaultPieConfig)
import TypedSvg exposing (circle, g, svg)
import TypedSvg.Attributes exposing (fill, stroke, transform, viewBox)
import TypedSvg.Attributes.InPx exposing (cx, cy, r)
import TypedSvg.Core exposing (Svg)
import TypedSvg.Types exposing (Paint(..), Transform(..))


w : Float
w =
    990


h : Float
h =
    504


rgba255 : Int -> Int -> Int -> Float -> Color
rgba255 r g b a =
    Color.fromRgba { red = toFloat r / 255, green = toFloat g / 255, blue = toFloat b / 255, alpha = a }


colors : Array Color
colors =
    Array.fromList
        [ rgba255 31 119 180 0.5
        , rgba255 255 127 14 0.5
        , rgba255 44 159 44 0.5
        , rgba255 214 39 40 0.5
        , rgba255 148 103 189 0.5
        , rgba255 140 86 75 0.5
        , rgba255 227 119 194 0.5
        , rgba255 128 128 128 0.5
        , rgba255 188 189 34 0.5
        , rgba255 23 190 207 0.5
        ]


radius : Float
radius =
    min (w / 2) h / 2 - 10


circular : List Arc -> Svg msg
circular arcs =
    let
        makeSlice index datum =
            Path.element (Shape.arc datum)
                [ fill <| Paint <| Maybe.withDefault Color.black <| Array.get index colors
                , stroke <| Paint Color.black
                ]

        makeDot datum =
            let
                ( x, y ) =
                    Shape.centroid datum
            in
            circle [ cx x, cy y, r 5 ] []
    in
    g [ transform [ Translate radius radius ] ]
        [ g [] <| List.indexedMap makeSlice arcs
        , g [] <| List.map makeDot arcs
        ]


annular : List Arc -> Svg msg
annular arcs =
    let
        makeSlice index datum =
            Path.element (Shape.arc { datum | innerRadius = radius - 60 })
                [ fill <| Paint <| Maybe.withDefault Color.black <| Array.get index colors
                , stroke <| Paint Color.black
                ]

        makeDot datum =
            let
                ( x, y ) =
                    Shape.centroid { datum | innerRadius = radius - 60 }
            in
            circle [ cx x, cy y, r 5 ] []
    in
    g [ transform [ Translate (3 * radius + 20) radius ] ]
        [ g [] <| List.indexedMap makeSlice arcs
        , g [] <| List.map makeDot arcs
        ]


view : List Float -> Svg msg
view model =
    let
        pieData =
            model |> Shape.pie { defaultPieConfig | outerRadius = radius }
    in
    svg [ viewBox 0 0 w h ]
        [ circular pieData
        , annular pieData
        ]


data : List Float
data =
    [ 1, 1, 2, 3, 5, 8, 13 ]


main : Svg msg
main =
    view data