Custom cmake targets completion

[MartyMcFlyInTheSky]

I want to write a custom ** bash completion expansion that shows me all configured cmake targets to build. The way I intend it to work is this:

cmake --build build --target **<ENTER>

should give me a list of cmake targets. I figure I'm quite close, so I intended to use the _fzf_complete setup helper as in the docs:

_fzf_complete_cmake() {
  _fzf_complete --multi --reverse --prompt="cmake ??? --targets> " -- "$@" < <(
     ..cmake listing the targets (this I know how to do)
  )
}

Then bind it with

complete -F _fzf_complete_cmake -o default -o bashdefault cmake

But the problem is that the completion should only trigger when the --targets option is specified before. But the other flags /arguments are not important and the user might specify a variable amount of them before and after --target . I'm not sure how filter that with the current helper API. I figure the prompt argument would somehow have to get this information, but how? Any ideas?