# Tasks: enterprise-gaming-day-night

## 0. Pre-flight (non-negotiable)

- [ ] 0.1 Confirm clean working tree (`git status` reports nothing) and no in-flight worktrees with uncommitted work (`git worktree list` then `git status` in each)
- [ ] 0.2 If any worktrees exist under `.claude/worktrees/`, account for each one: still-active agent, work-pending-merge, or stale-and-prune. Stale worktrees MUST be removed (`git worktree remove`) before opening a new one — code that has been lost twice on main is the failure mode this guards against.
- [ ] 0.3 Confirm the package set in `MANIFEST.md` matches `find packages -maxdepth 3 -name package.json` count. Drift here means a prior change archived without regenerating the manifest.

## Phase 1 — Scaffold

- [ ] Create `gaming/world/day-night/` (`@suaveplan/day-night`, `0.1.0`, `sideEffects: false`)
- [ ] `tsconfig.json`, `vitest.config.ts`

## Phase 2 — Error codes & constants

- [ ] `src/error-codes.ts` + `src/constants/index.ts` — `DEFAULT_TIME_SCALE`, `HOURS_IN_DAY`

## Phase 3 — Types

- [ ] `src/types/common.ts` + `common.md`

## Phase 4 — Sky position utils

- [ ] `src/utils/sky-position.ts` — simplified celestial math: sun elevation peaks at noon, moon at midnight
- [ ] Tests + docs

## Phase 5 — Day/night clock

- [ ] `src/core/day-night-clock/day-night-clock.ts` — time scale, tick/pause/resume, dawn/dusk events, OTel gauge
- [ ] Tests (time scale, day boundary wrap, events)
- [ ] Docs

## Phase 6 — Light schedule

- [ ] `src/core/light-schedule/light-schedule.ts` — keyframe interpolation (lerp color/intensity between keyframes)
- [ ] Tests + docs

## Phase 7 — Gameplay modifiers

- [ ] `src/core/gameplay-modifiers/gameplay-modifiers.ts` — time-segment lookup + merge defaults
- [ ] Tests + docs

## Phase 8 — Integration tests

- [ ] `tests/integration.test.ts` — advance clock through full day, verify light + modifier evaluations

## Phase 9 — Pre-publish gate

- [ ] `bunx turbo lint typecheck test --filter=@suaveplan/day-night` green
- [ ] 100% coverage
- [ ] Publish: `bun scripts/publish.ts --package @suaveplan/day-night`