There's a little improv warm up game where you arrange yourselves in a circle and send zips, zaps, and zops around by pointing to a person and saying the next word in the sequence, then they do the same until all of you are warmed up or whatever.

Your task is to create a program that gives the next word in sequence given an input word. (Zip --> Zap --> Zop --> Zip) Since there's a lot of different ways to say these three words and flairs that can be added to them, your program should imitate case and letter duplication and carry suffixes.

To elaborate, your input will be one or more Zs, then one or more Is, As, or Os (all the same letter), then one or more Ps, (all letters up to this point may be in mixed case) followed by some arbitrary suffix (which may be empty). You should leave the runs of Zs and Ps, as well as the suffix exactly as received, but then change the Is to As, As to Os, or Os to Is, preserving case at each step.

Example Test Cases

zip         ==> zap

zAp         ==> zOp

ZOP         ==> ZIP

ZiiP        ==> ZaaP

ZZaapp      ==> ZZoopp

zzzzOoOPppP ==> zzzzIiIPppP

Zipperoni   ==> Zapperoni

ZAPsky      ==> ZOPsky

ZoPtOn      ==> ZiPtOn

zipzip      ==> zapzip

zapzopzip   ==> zopzopzip

zoopzaap    ==> ziipzaap

Rules and Notes

• You may use any convenient character encoding for input and output, provided that it supports all printable ASCII characters, provided that it was created prior to this challenge.


• You may assume the input word is some variant of Zip, Zap, or Zop. All other inputs result in undefined behavior.
  
  
  
  
  • Valid inputs will full-match the regex Z+(I+|A+|O+)P+.* (in mixed case)
  
  
  
  


• You may assume that the input word consists entirely of ASCII letters.

Happy Golfing!

Stax, 19 bytes

Ç╛√êΣ%,╖FP╚`=Lh←⌡·ƒ

Run and debug it

Perl 6, 41 bytes

{S:i{z+<(.+?)>p}=$/.&{TR/iaoIAO/aoiAOI/}}

Try it online!

Simple case-insensitive substitution to shift the vowel section.

Japt, 22 bytes

r"%v+"_d"i_oiao_a"pu}"

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JavaScript (Node.js), 69 bytes

s=>Buffer(s).map(p=c=>s|p-c&31?s=c:c&1?c-[6,-14,p=c,,8][c%16%5]:c)+''

Try it online!

Commented

s =>                        // s = input string

  Buffer(s)                 // convert it to a Buffer of ASCII codes

  .map(p =                  // initialize p to a non-numeric value

  c =>                      // for each ASCII code c in s:

    s |                     //   if s is numeric

    p - c & 31 ?            //   or p and c are not the same letter (case insensitive):

      s = c                 //     turn s into a numeric value and yield c

    :                       //   else:

      c & 1 ?               //     if c is a vowel:

        c -                 //       update c to either c - 6 ('o' -> 'i'), c + 14

        [6, -14, p = c,, 8] //       ('a' -> 'o') or c - 8 ('i' -> 'a'); and store c in p

        [c % 16 % 5]        //       small hash function to convert from ASCII code to index

      :                     //     else (c is either 'z' or 'Z'):

        c                   //       let it unchanged

  ) + ''                    // end of map(); coerce the Buffer back to a string