/whatever/ is 10 characters, so the 9th char onward should give me the rest of the path
foo.example.com -> example.org/?id=foo. Was tinkering with moving over some Page Rules but having a hard time with this bit of the puzzle 


concat("/", substring(http.request.uri, 9))/whatever/foo.example.comexample.org/?id=fooconcat("https://", "chaika.me/?id=", substring(http.host, 0, -9))
// where -10 is the character count of the domain + 1 to remove the .