Paste & set color with a single button (for palettes)

Question

I need to use some colors frequently so I decided to make a palette for this. This is an example palette button that inserts a color:

CreatePalette[PasteButton[RGBColor[.5, .6, .7], RGBColor[.5, .6, .7]]]

But I may also want to set some text inside a non input cell to that color. So for that this works:

CreatePalette[
  Button[RGBColor[.5, .6, .7], 
    FrontEndExecute[{FrontEndToken[
                       SelectedNotebook[],
                       FontColor, 
                       RGBColor[.5, .6, .7]]}]]]

or

CreatePalette[
  Button[RGBColor[.5, .6, .7], 
    CurrentValue[NotebookSelection[InputNotebook[]], FontColor] = RGBColor[.5, .6, .7]]]

But I don't want two create two buttons for each color. I prefer to have a single button that inserts a color if nothing is selected (1st case) or styles some text is there is a selection.

This is what I have tried to do (but it does not work):

CreatePalette[
  Button[RGBColor[.5, .6, .7],
    If[CurrentValue["SelectionData"] == $Failed,
       NotebookWrite[ButtonNotebook[], RGBColor[.5, .6, .7]],
       FrontEndExecute[{FrontEndToken[InputNotebook[], FontColor, RGBColor[.5, .6, .7]]}]]]]

Can this be solved?

Answer 1

This works for me:

CreatePalette[Button["Crazy Color Palette",
  ib := InputNotebook[];
  If[NotebookRead[ib] === {},
     NotebookWrite[ib, "RGBColor[.5,.6,.7]"], 
     FrontEndExecute[{FrontEndToken[ib, FontColor, RGBColor[.5, .6, .7]]}]]]]