Solo and Crew modes

A server decides whether a player may practise every profession or only one. The setting is professionMode, in the world's serverconfig/akumalib-server.toml:

Value	Behaviour
AUTO (default)	SOLO in singleplayer and on LAN, CREW on a dedicated server
SOLO	every profession can be practised and levelled
CREW	one profession per player. XP for any other is dropped

Read the mode in force with AkumaProfessions.getMode(player) (or getMode(server)), never from the config: AUTO is resolved there, and the client gets the resolved value with the rest of the sync.

canPractice: the one check

if (AkumaProfessions.canPractice(player, MyProfessions.COOK.get())) {
    // let the player craft at the kitchen
}

canPractice is true in Solo mode, and in Crew mode only for the player's chosen profession. It works on both sides. addXp already applies it, so an XP source needs no check of its own. A workstation, a tool or a screen does.

Choosing and changing

Method	Does
getChosen(player)	the chosen profession, if any
choose(ServerPlayer, Profession)	makes it the chosen one
reset(ServerPlayer)	clears the choice

A change resets every profession

choose and reset both set every profession's XP back to zero, the first choice included. Both fire the cancelable ProfessionChangeEvent first (old and new profession, either may be null): cancel it to make a change cost something, such as an item or a visit to an NPC.

In Crew mode, Mine Mine no Mi's character creator gets a fourth tab, Profession, under Faction, Race and Style: its arrows cycle the registered professions (and Random), and finishing the creation makes the choice (chooseFirst). A player who already chose sees theirs, locked.

The choice is saved with the player in both modes, so a server moving from Solo to Crew keeps it. A player with no choice in Crew mode practises nothing until they pick one.