signature APP_INIT =
sig
  val fromWindowWidthAndHeight: int * int * int * int * string
                                -> AppType.app_type
end

structure AppInit :> APP_INIT =
struct
  open AppType

  fun helpFromWidthAndHeight
    ( windowWidth
    , windowHeight
    , wStart
    , wFinish
    , hStart
    , hFinish
    , canvasWidth
    , canvasHeight
    , filepath
    ) : app_type =
    let
      val (xClickPoints, yClickPoints) =
        ClickPoints.generate
          (windowWidth, windowHeight, canvasWidth, canvasHeight)

      val maxPoints = Int.max (canvasWidth, canvasHeight)
      val layerTree = LayerTree.init maxPoints
    in
      { mode = AppType.NORMAL_MODE
      , canvasWidth = canvasWidth
      , canvasHeight = canvasHeight
      , windowWidth = windowWidth
      , windowHeight = windowHeight
      , xClickPoints = xClickPoints
      , yClickPoints = yClickPoints

      , mouseX = 0.0
      , mouseY = 0.0
      , showGraph = true
      , arrowX = 0
      , arrowY = 0
      , openFilePath = filepath
      , r = 0
      , g = 0
      , b = 0
      , a = 1
      , layer = LayerTree.minKey
      , layerTree = layerTree
      , modalNum = 0
      }
    end

  fun fromWindowWidthAndHeight
    (windowWidth, windowHeight, canvasWidth, canvasHeight, filepath) =
    if windowWidth > windowHeight then
      let
        val difference = windowWidth - windowHeight
        val wStart = difference div 2
        val wFinish = wStart + windowHeight
      in
        helpFromWidthAndHeight
          ( windowWidth
          , windowHeight
          , wStart
          , wFinish
          , 0
          , windowHeight
          , canvasWidth
          , canvasHeight
          , filepath
          )
      end
    else
      let
        val difference = windowHeight - windowWidth
        val hStart = difference div 2
        val hFinish = hStart + windowWidth
      in
        helpFromWidthAndHeight
          ( windowWidth
          , windowHeight
          , 0
          , windowWidth
          , hStart
          , hFinish
          , canvasWidth
          , canvasHeight
          , filepath
          )
      end
end