property hexChrs : "0123456789abcdef"

tell application "Numbers"
	tell front document
		tell active sheet
			tell (first table whose class of selection range is range)
				set outList to {}
				repeat with aCell in cells of (get selection range)
					set v to value of aCell
					if text 1 of v is "#" then set v to text 2 thru -1 of v
					set hexColor to my hexColorToRGB(v)
					set inverseColor to {}
					repeat with i from 1 to 3
						copy (65535 - (item i of hexColor)) to end of inverseColor
					end repeat
					if v is "808080" then set inverseColor to {65535, 65535, 65535} -- hack to adjust gray
					set background color of aCell to hexColor
					set text color of aCell to inverseColor
				end repeat
			end tell
		end tell
	end tell
end tell

return outList

on hexColorToRGB(h) -- convert 
	if (count h) < 6 then my badColor(h)
	set rgbColor to {}
	try
		repeat with i from 1 to 6 by 2
			set end of rgbColor to ((my getHexVal(text i of h)) * 16 + (my getHexVal(text (i + 1) of h))) * 257
		end repeat
	end try
	if (count rgbColor) < 3 then my badColor(h)
	return rgbColor
end hexColorToRGB

on getHexVal(c)
	if c is not in hexChrs then error
	set text item delimiters to c
	return (count text item 1 of hexChrs)
end getHexVal

on badColor(n)
	display alert n & " is not a valid hex color" buttons {"OK"} cancel button "OK"
end badColor