# Quickstart: Quick HP Input

## What this feature does

Adds an inline damage/heal numeric input to each combatant row. Instead of editing the absolute HP value, the game master types a number (e.g., "7") and the system applies it as damage (subtract) or healing (add) to the combatant's current HP.

## Key files to modify

1. **`apps/web/src/components/quick-hp-input.tsx`** (NEW) -- The main component: numeric input + damage/heal mode toggle.
2. **`apps/web/src/components/combatant-row.tsx`** (MODIFY) -- Integrate `QuickHpInput` into the combatant row layout alongside existing HP display.

## Key files to understand (read-only)

- `packages/domain/src/adjust-hp.ts` -- Domain function that applies signed deltas (negative = damage, positive = heal)
- `packages/domain/src/types.ts` -- `Combatant` type with optional `maxHp`/`currentHp`
- `apps/web/src/hooks/use-encounter.ts` -- `adjustHp(id, delta)` hook already exposed
- `apps/web/src/components/ui/input.tsx` -- Base input component for consistent styling
- `apps/web/src/components/ui/button.tsx` -- Base button component for toggle

## How the pieces connect

```
QuickHpInput (new component)
  |-- User types "7" in damage mode, presses Enter
  |-- Calls onAdjustHp(combatantId, -7)
  |
CombatantRow
  |-- Passes onAdjustHp prop to QuickHpInput
  |
useEncounter hook
  |-- adjustHp(id, delta) -> adjustHpUseCase -> domain adjustHp()
  |-- Domain clamps result to [0, maxHp]
  |-- State updates, localStorage persists
```

## Running the feature locally

```bash
pnpm --filter web dev    # Start Vite dev server at localhost:5173
```

## Running tests

```bash
pnpm check               # Full quality gate (format + lint + typecheck + test)
pnpm test                # All tests
```

No new domain tests needed -- `adjustHp` is already fully tested. New tests (if any) would be component-level tests for `QuickHpInput` keyboard behavior and mode toggling.