# Implementation Plan: HP Status Indicators

**Branch**: `013-hp-status-indicators` | **Date**: 2026-03-05 | **Spec**: [spec.md](./spec.md)
**Input**: Feature specification from `/specs/013-hp-status-indicators/spec.md`

## Summary

Add visual HP status indicators to combatant rows. A pure domain function derives the HP status ("healthy", "bloodied", "unconscious") from currentHp and maxHp. The UI applies color treatments: amber for bloodied HP text, red + muted row for unconscious/dead combatants. No new stored state -- status is computed on render.

## Technical Context

**Language/Version**: TypeScript 5.8 (strict mode, verbatimModuleSyntax)
**Primary Dependencies**: React 19, Vite 6, Tailwind CSS v4, shadcn/ui-style components, Lucide React (icons)
**Storage**: N/A (no storage changes -- purely derived state, existing localStorage persistence unchanged)
**Testing**: Vitest (unit tests for domain function, existing layer boundary test)
**Target Platform**: Modern browsers (Vite dev server, production build)
**Project Type**: Web application (monorepo: domain + application + web adapter)
**Performance Goals**: Synchronous render -- indicator updates in the same React render cycle as HP changes
**Constraints**: Domain layer must remain pure (no UI imports); adapter layer handles all visual presentation
**Scale/Scope**: Single new domain function + UI changes to one component (combatant-row)

## Constitution Check

*GATE: Must pass before Phase 0 research. Re-check after Phase 1 design.*

| Principle | Status | Notes |
|-----------|--------|-------|
| I. Deterministic Domain Core | PASS | `deriveHpStatus` is a pure function: same inputs always produce the same output. No I/O, randomness, or clocks. |
| II. Layered Architecture | PASS | Domain exports the pure function; UI adapter calls it in the component. No reverse dependency. |
| III. Agent Boundary | N/A | No agent involvement in this feature. |
| IV. Clarification-First | PASS | No ambiguity -- thresholds are defined in spec (bloodied = 0 < currentHp < maxHp/2, unconscious = currentHp <= 0). |
| V. Escalation Gates | PASS | All behavior is within spec scope. |
| VI. MVP Baseline Language | PASS | Assumptions section uses "MVP baseline does not include" language. |
| VII. No Gameplay Rules in Constitution | PASS | Bloodied/unconscious thresholds are in feature spec, not constitution. |
| Development Workflow | PASS | `pnpm check` must pass before commit. Domain testable via pure-function assertions. |

No violations. Complexity Tracking section not needed.

## Project Structure

### Documentation (this feature)

```text
specs/013-hp-status-indicators/
├── plan.md              # This file
├── research.md          # Phase 0 output
├── data-model.md        # Phase 1 output
├── quickstart.md        # Phase 1 output
└── tasks.md             # Phase 2 output (/speckit.tasks command)
```

### Source Code (repository root)

```text
packages/domain/src/
├── hp-status.ts                    # NEW: deriveHpStatus pure function + HpStatus type
├── __tests__/hp-status.test.ts     # NEW: unit tests for deriveHpStatus
├── index.ts                        # MODIFIED: export new function and type

apps/web/src/components/
├── combatant-row.tsx               # MODIFIED: apply status-based styling
```

**Structure Decision**: Follows existing monorepo layout. New domain function in its own module (consistent with adjust-hp.ts, set-hp.ts pattern). UI changes confined to the existing combatant-row component. No new application-layer code needed since status is derived at render time, not via a use case.