This is a small thing we (well mostly I) did in World Editor, so it's almost pure GUI, but it has some jass functions as well.
It's still in progress, so there may be some bugs, and I'm going to fix most of the leaks when I have time.
Here is how the player numbers work;
Red = 1
Blue = 2 etc.
failure to use these correctly will crash the game !
-rickroll uses JASS type players so in that specific trigger red is 0 and blue is 1 etc.
note that you need to import astley.blp and epiclolz.mp3 to the map, else -rickroll will crash target player.
Create a folder called war3mapimported (if there is no such folder) on the root of the map and place the files there.
A command with 2 variables, x and y, requires extra care;
you must type two spaces if the first number is 1-9, for example -ownall 1<space><space>2
if you fail at this part, the game will crash.