structure AppUpdate =
struct
  open AppType

  open DrawMessage
  open FileMessage
  open InputMessage
  open UpdateMessage

  fun getDotVecFromIndices (model: app_type, hIdx, vIdx) =
    let
      val {windowWidth, windowHeight, xClickPoints, yClickPoints, ...} = model
      val xpos = Vector.sub (xClickPoints, hIdx)
      val ypos = Vector.sub (yClickPoints, vIdx)

      val endXpos =
        if hIdx + 1 = Vector.length xClickPoints then
          xpos
        else
          Vector.sub (xClickPoints, hIdx + 1)

      val endYpos =
        if vIdx + 1 = Vector.length yClickPoints then
          ypos
        else
          Vector.sub (yClickPoints, vIdx + 1)

      val tl =
        ClickPoints.getDrawDotRgb
          (xpos, ypos, 1.0, 0.0, 0.0, windowWidth, windowHeight)
      val tr =
        ClickPoints.getDrawDotRgb
          (endXpos, ypos, 1.0, 0.0, 0.0, windowWidth, windowHeight)
      val bl =
        ClickPoints.getDrawDotRgb
          (xpos, endYpos, 1.0, 0.0, 0.0, windowWidth, windowHeight)
      val br =
        ClickPoints.getDrawDotRgb
          (endXpos, endYpos, 1.0, 0.0, 0.0, windowWidth, windowHeight)
    in
      Vector.concat [tl, tr, bl, br]
    end

end