# Foundation review

## Verdict

The package boundaries are useful foundations: casino game logic is separate
from game presentation, multiplayer games share a small `tableGame` interface,
and tick system order has an explicit testable contract. Keep those boundaries;
a wholesale rewrite or a larger plugin framework is not needed yet.

However, this is **not yet a safe foundation for expanding persistent casino
activity or live world editing**. Ownership and transaction boundaries matter
more than further extraction of command files.

This review inspected session/tick entry points, account lifecycle and storage,
casino configuration/runtime/wallet integration, shutdown, and room rename/undo.
It is not a full audit of every combat, crafting, networking, or admin endpoint.

## Fixed in this pass

- **Account/character single-file saves:** replace direct truncating writes with
  a same-directory temporary file, file sync, atomic rename, and directory sync
  (`internal/persistence/atomic.go`, `internal/player/store.go`). Existing modes
  are preserved; new player/account files use 0600. Account/character discovery
  ignores non-YAML files, including leftover temporary files. This does not make
  multi-file operations or concurrent read-modify-write cycles transactional.
- **Save-time live mutation:** god-mode serialization uses a value snapshot
  instead of temporarily changing the live player's skills and HP. Maps still
  require caller ownership during serialization; this is not a deep snapshot.
- **Casino RNG ownership:** the manager creates independent random streams for
  each game under its own lock. Previously, different table/machine locks
  protected the same `rand.Rand`, permitting concurrent access to its state.
- **Slot profile isolation:** `ScaleToRTP` copies the symbols/paytables it changes,
  so scaling a reused profile no longer retunes other machines or its source.
- **Stale machine commands:** betting, spinning, or enabling autobet after a
  disconnect rejects the requesting player without dereferencing a missing
  occupant or messaging a replacement occupant.
- **Casino configuration:** validate raw values before defaulting; reject
  invalid game/variant/ID/range/finite-value configurations; detect room-local
  duplicate IDs. The room create/update API checks before writes, startup
  validation reports errors, and runtime lookup rejects invalid definitions.
  Legacy slots table entries remain supported. See `rooms.md` for bounds.
- **Tick lifecycle:** repeated `Stop` calls no longer close a closed channel;
  ticker goroutines retain their own run's resources across quick restarts;
  concurrent tick executions are serialized. `Stop` still does not wait for an
  in-flight callback and is explicitly not a final-save barrier.

## Remaining work, in recommended order

### 1. High: make live game/session state single-owner

Evidence: `internal/net/server.go` invokes `Game.HandleSession` from each
connection goroutine; `internal/engine/tick.go` invokes game callbacks from the
ticker goroutine. Disconnect callbacks also mutate players/game maps, while
admin callbacks such as `Game.RewriteRoomIDs` mutate online players directly.

`Hub.AllSessions` copies a list of pointers, not immutable session snapshots.
Store/map locks similarly do not grant ownership over all pointed-to state.
The casino wallet mutates player inventory and credits under a casino lock,
which does not exclude other player commands or saves. Serializing tick
callbacks alone does not solve these cross-entry-point races.

Recommended design:

1. One owner loop executes session input, connect/disconnect transitions, all
   tick callbacks (including dynamically registered ones), and admin mutations.
2. Network/admin goroutines submit bounded requests; they do not mutate live
   player/session/world objects. Admin reads consume snapshots.
3. Preserve the documented tick order. Do not wrap only `RunTickSystems` and
   assume dynamic callbacks or instant commands are covered.
4. Add bounded outbound queues/write deadlines before concentrating execution
   in one owner: current session writes perform synchronous network I/O, so one
   slow client could otherwise stall the entire world.
5. Put saves behind an explicit owned snapshot boundary. Avoid holding Hub
   membership locks across filesystem work; `hardRemoveLocked` currently calls
   the removal callback while holding the Hub mutex.

Acceptance: concurrent login/input/disconnect/admin-mutation integration tests
under `-race`, plus a slow-client test proving other players keep progressing.

### 2. High: transactional account lifecycle and authoritative membership

The two outstanding account issues are still present:

- `characterOnline` releases `charsMu` before rename/delete/purge touches files;
  `connectCharacter` can load/register the character during that gap.
- Account rename changes only the initiating `sess.Account.Name`. Other
  authenticated sessions retain old account objects. Character lists and
  pending menu selections can also become stale after rename/delete/create.

This is not just a cosmetic broadcast issue. A stale character name can be
reused by another account; cached membership must not authorize a later
connect/rename/delete against that reassigned name.

Use the owner/lifecycle boundary for lookup, canonical-name resolution,
current membership validation, online check, mutation, and session publication.
Refresh or invalidate all affected authenticated sessions, including pending
menu selections. Do not simply broadcast pointer mutations from a connection
 goroutine. Revalidate membership at operation commit, not only menu selection.

Account creation, character creation, character rename/delete, and purge also
span multiple files and contain ignored save/remove errors in
`core_login_account.go` and `core_login_char.go`. Single-file atomic replacement
cannot prevent orphaned characters, stale ownership lists, or partial purges.
Choose a journaled lifecycle transaction or transactional player database.
Stable account/character IDs would decouple identity from renameable filenames.

Acceptance: simultaneous same-account operations, stale menu selections, and
injected failure at each filesystem step must preserve identity/membership.

### 3. High: durable money and graceful shutdown

Evidence:

- `internal/game/casino.go`: `casinoWallet.Wager` and `PayCredits` mutate balances
  and ignore `SaveCharacter` errors. A successful wager can therefore exist only
  in memory, and a reported win can be lost on restart.
- `internal/casino/types.go`: `Wallet.PayCredits` cannot report failure.
- Round/wager/free-spin state exists only in memory. A crash after a saved wager
  debit but before settlement loses the player's stake without recovery.
- Currency uses machine-sized `int`, unchecked additions/multiplications, and
  floating-point payout conversion. Unlimited bets remain supported. Large
  balances or payout multipliers can overflow; finite config validation is not
  sufficient protection.
- `cmd/thoi/main.go` exits on signals after requesting tick stop;
  `internal/game/cmd_shutdown.go` calls `os.Exit` directly. Neither path drains
  work or saves all online characters. Tick stop does not join running callbacks.
  The countdown also reads a replaceable `g.shutdownCancel` field from its
  goroutine; cancellation/restart needs a captured per-run channel.

Recommended design:

- Give each round/wager/settlement a stable transaction ID; debit plus wager
  record, and payout plus settlement record, must be durable and idempotent.
  A small transactional player/economy database is worth considering while
  retaining YAML for authored world content.
- Define checked currency arithmetic and explicit rounding/balance limits.
  Distinguish insufficient funds from persistence failure. A failed write must
  not silently count as successful gameplay.
- Unify signals and the shutdown command into one shutdown request handled by
  main. Stop admissions/admin mutations; quiesce input and autobet; drain the
  owner and callbacks; resolve or persist outstanding wagers; save owned state;
  then close transports and return. Surface save failures to the operator.
- Decide server-shutdown/crash policy separately from deliberate player
  disconnect forfeiture. Do not blindly run disconnect-forfeit callbacks for a
  server-initiated shutdown.

Acceptance: fail saves during wager/payout; restart at each debit/settlement
boundary; test overflow boundaries; SIGTERM and scheduled shutdown must produce
identical recoverable state, without duplicate credits or lost settlements.

### 4. High for live building: complete room-ID migration and undo

`handleRoomRename` in `internal/admin/api_rooms.go` rewrites referencing rooms
and invokes player migration, but records only the renamed room in `ChangeDesc`.
Its `NewContent` is the original bytes, not necessarily the rewritten self-loop
content. Undo/redo therefore cannot restore all references or player state.
The reference loop also ignores some load/write failures.

`Game.RewriteRoomIDs` changes player fields but does not remap Hub room buckets
or casino manager room keys. Live room-ID changes can therefore leave gameplay
and broadcasts attached to old locations. Other runtime room-keyed state must
be inventoried before declaring migration complete.

`UndoStack` also ignores extra-file operation errors, so it can report success
with only part of a multi-file change restored. Restoring file snapshots alone
cannot update live players or runtime registries.

Implement one mutation plan containing all file before/after images and explicit
runtime mappings, executed under the owner boundary. Undo/redo must use that
same transaction and propagate failures. A naive inverse ID map is not enough
when the destination had pre-existing stale references. Avoid live renumbering
until this is complete; back up player and world data together.

Acceptance: rename/self-loop/external exits/triggers/offline and online player
state, Hub membership, active casino games, undo, redo, and injected partial
write failures all agree after execution and restart.

### 5. Medium: explicit casino reconfiguration and profile contracts

Manager `EnsureTable`/`EnsureMachine` returns the existing object for a room/ID.
Changing valid room config does not replace its live rules. Deleted/renumbered
rooms can leave cached games behind. Define whether changes take effect only
when idle, after draining rounds, or on restart; never replace an active game
and silently discard its wagers.

Before custom slot profiles are exposed, validate their geometry and weights.
The current implementation has a fixed 3x5 grid despite configurable profile
fields. Public profile math/validation is not a general slot engine. Fractional
slot credits are discarded on leaving a seat, and crash recovery does not
preserve them. Keep these limits explicit rather than promising arbitrary
profiles or exact realized RTP for short sessions.

## Verification and limits

Added regression coverage for complete-file visibility, failed-rename cleanup,
permissions, read-only god-mode saves, file discovery, config rejection and API
non-mutation, independent concurrent casino activity, profile isolation, stale
machine commands, and repeated/concurrent tick lifecycle operations.

Commands run successfully after the fixes:

- `go test ./...`
- `go test -race ./...`
- `go vet ./...`

The original suite also passed race mode before this work. Passing it is not
proof of safe live state ownership: it did not exercise the competing runtime
entry points described above. No production login/load test, process-kill
recovery test, or filesystem power-loss simulation was performed.