feat(progression): Attempt ledger with terminal-outcome guard (slice 2)

Attempt carries its LevelId so settlement decides First Clear vs Replay
without trusting the caller. Outcome is terminal and refuses to change:
one death costs one life, one completion banks once.

Coins.Zero/Add driven out by the ledger rather than added up front.
21 tests. ADR-0005: Playthrough settles Attempts, has no LoseLife.
This commit is contained in:
2026-07-28 18:40:20 +02:00
parent 9767941c65
commit 40bd5c1d86
6 changed files with 232 additions and 4 deletions

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# Playthrough has no LoseLife; it settles Attempts
Playthrough and Attempt are separate aggregate roots (ADR-0002), but "one death costs exactly one life" requires
ending the Attempt and decrementing lives *together*. Rather than expose bare mutators and rely on the caller to
sequence them, Playthrough exposes only what happened — `Commit(attempt)`, `SettleDeath(attempt)`,
`SettleReplay(attempt)` — each of which calls the Attempt's own `TryEnd…` internally and does nothing when it
returns false. Every operation is therefore atomic and idempotent, and there is no `LoseLife` to call from
somewhere else.
The alternative shape, `if (attempt.TryEndInDeath()) playthrough.LoseLife();`, puts the idempotency in the domain
but leaves the sequencing to the caller. A public `LoseLife` is an invitation: the code being replaced has two
paths to exactly that operation — `LivesStateHandler.RemoveLife` and `ConsoleManager` writing `Player.Lives`
directly, unclamped — because the operation existed to be called.
## Considered options
Collapsing the two into one aggregate with Attempt as an inner entity, making the atomicity structural. Rejected:
`Commit(Attempt)` already gave the shape we needed, and passing one root into another's method is a transient
reference rather than a stored association, so ADR-0002 stands unchanged.
## Consequences
- Overlapping hazards in a kill zone, or a hazard re-firing during the two seconds before `DeathScreen` reloads,
cost one life rather than two.
- `ExitDoorComponent` and `ConsoleManager.GoToNextLevelCommand` can both request completion; only the first banks.
- The application layer holds the active Attempt and passes it in. The Attempt carries its own `LevelId`, so
`Commit` decides First Clear versus Replay from the Attempt itself rather than trusting a level supplied
alongside it — finishing a Replay stops being a way to corrupt campaign position.

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@@ -73,12 +73,19 @@ Invariants to drive out with tests:
The ledger from ADR-0002: `CoinsFound`, `CoinsSpent`, `SkillsBought`, plus an outcome.
- `RecordCoinsFound(Coins)`
- `RecordPurchase(SkillId, Coins cost)`
- `Attempt(LevelId level)` and `LevelId Level` — the Attempt knows which Level it is an attempt at, so
`Commit` decides First Clear versus Replay from the Attempt rather than from a level the caller passes alongside
- `Outcome` — `InProgress | Died | Cleared`
- `void RecordCoinsFound(Coins)` — silently ignores late coins once ended
- `bool TryRecordPurchase(SkillId, SkillLevel resulting, Coins cost)` — records where the skill ended up, since
one Attempt can both unlock and upgrade the same skill
- `bool TryEndInDeath()` / `bool TryEndInCompletion()` — return false if the Attempt already ended
- No `Discard` method: discarding is throwing the object away.
The recording methods are deliberately asymmetric. A coin pickup firing after death is a real event — the player
node survives for two seconds before `DeathScreen` reloads — and its caller has nothing useful to do with a
`false`, so it returns nothing. A purchase's caller does care.
`CoinsFound` and `CoinsSpent` are both non-negative. There is no signed net value — settlement is
`bank.Add(found).TrySubtract(spent)` in `Playthrough.Commit`, which in that order cannot go negative given
affordability was checked at purchase time.
@@ -111,8 +118,12 @@ incidental and `Health` is a public `[Export]` setter that bypasses it. Do not r
Aggregate root. `PlaythroughId`, `Lives`, `Bank`, `OwnedSkills : SkillId → SkillLevel`, `CurrentLevel : LevelId`,
`ClearedLevels`.
Operations: `LoseLife`, `Commit(Attempt)`, `CanAfford(Attempt, Coins)`, `HasCleared(LevelId)`,
`ReachableLevels(order)`, `IsRunOver`.
Operations: `Commit(Attempt)`, `SettleDeath(Attempt)`, `SettleReplay(Attempt)`, `CanAfford(Attempt, Coins)`,
`HasCleared(LevelId)`, `ReachableLevels(order)`, `IsRunOver`.
**There is no `LoseLife`** — see ADR-0005. Each settle operation calls the Attempt's `TryEnd…` internally and does
nothing when it returns false, so it is atomic and idempotent, and no bare mutator exists to be called from a
second place.
Raises: `LifeLost(remaining)`, `RunEnded`, `BankChanged(total)`, `SkillSetChanged`.