cpas/AGENTS.md

# AGENTS.md — CPAS Violation Tracker

Developer and AI agent guidance for working on this codebase. Read this before making changes.

---

## Project Purpose

CPAS (Corrective & Progressive Accountability System) is an internal HR tool for documenting employee violations, managing disciplinary tier escalation via a rolling 90-day point system, and producing auditable PDF records. It is a single-container Docker app deployed on a trusted internal network.

**This is a compliance tool.** Data integrity, auditability, and reversibility are first-class concerns. Every architectural decision below exists for a reason.

---

## Stack at a Glance

| Layer | Tech |
|---|---|
| Frontend | React 18 + Vite (SPA, served statically by Express) |
| Backend | Node.js + Express (REST API, `server.js`) |
| Database | SQLite via `better-sqlite3` (synchronous, WAL mode, FK enforcement) |
| PDF | Puppeteer + system Chromium (Alpine-bundled in Docker) |
| Styling | Inline React style objects; `client/src/styles/mobile.css` for breakpoints only |
| Deploy | Docker multi-stage build (Alpine); single container + volume mount at `/data` |

---

## Repository Layout

```
cpas/
├── Dockerfile                      # Multi-stage: builder (Node+React) → production (Alpine+Chromium)
├── server.js                       # All API routes + audit helper; single Express entry point
├── auth.js                         # scrypt hashing, sessions, bootstrap admin, requireAuth/requireAdmin
├── lib/
│   └── rolloff.js                  # Clean-cycle point roll-off model (computeStanding); SoT for scores
├── db/
│   ├── schema.sql                  # Base table + view definitions (CREATE TABLE IF NOT EXISTS)
│   └── database.js                 # DB connection, WAL/FK pragmas, auto-migrations on startup
├── pdf/
│   ├── generator.js                # Puppeteer launcher; --no-sandbox for Docker
│   └── template.js                 # HTML template builder; loads logo from disk
├── demo/                           # Static stakeholder demo page served at /demo
│   └── index.html                  # Synthetic data, no live API calls; registered before SPA catch-all
├── client/
│   ├── vite.config.js
│   ├── src/
│   │   ├── App.jsx                 # Root component + AppFooter
│   │   ├── main.jsx                # React DOM mount
│   │   ├── data/
│   │   │   ├── violations.js       # Canonical violation type registry (type key → metadata)
│   │   │   └── departments.js      # DEPARTMENTS constant; single source of truth
│   │   ├── hooks/
│   │   │   └── useEmployeeIntelligence.js  # Score + history fetch hook
│   │   ├── components/             # One file per component; no barrel index
│   │   └── styles/
│   │       └── mobile.css          # Media query overrides only; all other styles are inline
└── README.md                      # Install (local + Unraid), features, API reference, schema, roadmap
```

---

## Data Model & Compliance Rules

### Tables

| Table | Purpose |
|---|---|
| `employees` | id, name, department, supervisor, notes |
| `violations` | Full incident record; contains immutable scoring fields |
| `violation_resolutions` | Soft-delete records (resolution type, reason, resolver) |
| `violation_amendments` | Field-level diff per amendment (old → new, changed_by, timestamp) |
| `audit_log` | Append-only write action log; never delete from this table |
| `violation_types` | Persisted custom violation type definitions (UI-created; `type_key` prefixed `custom_`) |
| `users` | Auth accounts: username, scrypt `password_hash`, role (`admin`/`user`) |
| `sessions` | Bearer-token login sessions: token, user_id, expires_at (7-day TTL) |

> **Historical note:** an `active_cpas_scores` SQL view once computed a naive per-violation 90-day sum. It has been **dropped** (see `db/database.js`). CPAS standing is now computed in JavaScript by the clean-cycle roll-off model in `lib/rolloff.js` — see the CPAS Tier System section below.

### Immutable Fields (DO NOT allow amendment of these)

The following fields on `violations` are locked after submission. They are the basis for tier calculation and PDF accuracy. **Never expose them to amendment endpoints:**

- `points`
- `violation_type`
- `violation_name`
- `category`
- `incident_date`
- `prior_active_points` (snapshot at insert time)
- `prior_tier_label`

Amendable fields (non-scoring): `incident_time`, `location`, `details`, `submitted_by`, `witness_name`, `acknowledged_by`, `acknowledged_date`, `amount`

### Soft-Delete Pattern

Violations are **never hard-deleted** in normal workflow. Use the `negated` flag + `violation_resolutions` record. Hard delete is reserved for confirmed data-entry errors and requires explicit user confirmation in the UI.

### Prior-Points Snapshot

Every `INSERT` into `violations` must compute and store `prior_active_points` (the employee's current active score before this violation is added). This snapshot ensures PDFs always reflect the accurate historical tier state regardless of subsequent negate/restore actions.

**There are exactly two sanctioned paths that may modify `prior_active_points` after insert; both are audit-logged as `violation_snapshots_recomputed`:**

1. **Back-dated insert (automatic).** If a new violation's `incident_date` precedes existing violations within the 90-day window, those existing violations' snapshots are recomputed via `recomputeSnapshotsAfter()` inside the same transaction as the insert. Logged with `reason: "backdated_insert"`. A back-dated insert is a *timeline rewrite* — the prior violations genuinely had an earlier event in their 90-day window — so their PDFs must reflect that.

2. **Manual backfill (admin-triggered).** `POST /api/employees/:id/recompute-snapshots` calls `recomputeAllSnapshotsForEmployee()` and rewrites every row for that employee from current data. Logged with `reason: "manual_backfill"`. This exists to repair drift from back-dated inserts that happened under older code (before path #1 existed) or any other case where the snapshot diverged from current truth. It is exposed in the UI as the **↻ Backfill Snapshots** button in the Employee Profile Modal next to the Active Violations header. Treat it as a targeted repair tool, not a routine maintenance step.

Negate/restore/amend/hard-delete are NOT timeline rewrites and must never recompute snapshots — PDFs remain stable through those operations by design.

### Audit Log

Every write action (employee created/edited/merged, violation logged/amended/negated/restored/deleted) must call the `audit()` helper in `server.js`. Never skip audit calls on write routes. The audit log is append-only — no UPDATE or DELETE against `audit_log`.

---

## CPAS Tier System

These thresholds are the authoritative values. Any feature touching tiers must use them.

| Points | Tier | Label |
|---|---|---|
| 0–4 | 0-1 | Elite Standing |
| 5–9 | 1 | Realignment |
| 10–14 | 2 | Administrative Lockdown |
| 15–19 | 3 | Verification |
| 20–24 | 4 | Risk Mitigation |
| 25–29 | 5 | Final Decision |
| 30+ | 6 | Separation |

The canonical tier logic lives in `client/src/components/CpasBadge.jsx` (`TIERS` array, `getTier()`, `getNextTier()`). Do not duplicate this logic elsewhere — import from `CpasBadge`.

### Point roll-off model (clean-cycle)

Active-point math lives in **`lib/rolloff.js`** (`computeStanding()`), not in SQL. The rule is a **clean-cycle roll-off**, NOT a per-violation 90-day window:

- Points retire only after the employee goes a full **90 consecutive days with no new non-negated violation**.
- **Any new violation resets that 90-day clock for the employee's entire balance.**
- Each completed clean cycle removes **5 points, oldest violation first**; each further roll-off requires another fresh 90-day clean stretch.

This is deliberately not "each violation expires 90 days after its own incident date" — one new violation pushes roll-off back for everything. Because the model is order-dependent, it is computed in JS and is the single source of truth for point totals. Do not reintroduce a SQL view or sum points client-side.

---

## Violation Type Registry

All violation types are defined in `client/src/data/violations.js` as `violationData`. Each entry includes:

```js
{
  name: string,         // Display name
  category: string,     // Grouping for UI display
  minPoints: number,    // Slider minimum
  maxPoints: number,    // Slider maximum (min === max means fixed, no slider)
  chapter: string,      // Policy chapter reference
  fields: string[],     // Which context fields to show ('time', 'minutes', 'amount', 'location', 'description')
  description: string,  // Plain-language definition shown in UI
}
```

To add a new violation type: add an entry to `violationData` with a unique camelCase key. Do not add new categories without confirming with the project owner — categories appear in UI groupings.

---

## Authentication

All auth logic lives in **`auth.js`** (backend) and **`client/src/auth.js`** (token storage + axios interceptors). It is intentionally lightweight for a trusted-LAN deployment.

- **Password hashing**: scrypt, no external dependency. Stored format `scrypt$<saltHex>$<hashHex>`; verified with `crypto.timingSafeEqual`.
- **Sessions**: opaque 32-byte bearer tokens in the `sessions` table, **7-day TTL**. The client stores the token in `localStorage` (`cpas_token`) and an axios request interceptor attaches `Authorization: Bearer <token>`; a response interceptor clears the token and bounces to the login screen on any `401`.
- **Route guard**: `app.use('/api', auth.requireAuth)` protects every `/api/*` route registered after it. The only public routes are `GET /api/health` and `POST /api/auth/login`, registered *before* the guard. Admin-only routes add `auth.requireAdmin`.
- **Bootstrap admin**: created/re-synced every startup from `ADMIN_USERNAME` / `ADMIN_PASSWORD` env vars. Its password is owned by the environment — it cannot be changed from the UI (a UI change is overwritten on next restart). Rotate by changing `ADMIN_PASSWORD` and restarting. The Docker image ships a placeholder `changeme` that **must** be overridden at deploy time.
- **UI-managed users**: admins create/delete users and reset passwords via `/api/users*` (min 6-char passwords, `admin`/`user` roles). These accounts are unaffected by restarts.
- **Audit**: `login_success`, `login_failed`, `user_created`, `user_password_reset`, and `user_deleted` are all written to `audit_log`.

Do not weaken or bypass the global guard, and do not persist tokens anywhere but the existing `localStorage` key.

---

## Coding Standards

### Backend (`server.js`)

- Use `better-sqlite3` synchronous API. No async DB calls. This is intentional — it simplifies route handlers and matches Express's sync error handling.
- All prepared statements use positional `?` parameters. Never interpolate user input into SQL strings.
- Every POST/PUT/PATCH/DELETE route must:
  1. Validate required inputs and return `400` with a descriptive `{ error: '...' }` body on failure.
  2. Call `audit()` on success.
  3. Return `{ error: '...' }` (not HTML) on all error paths.
- Group routes by resource (Employees, Violations, Dashboard, Audit). Match the existing comment banner style: `// ── Resource Name ───`.
- **Auth is global, not per-route.** `app.use('/api', auth.requireAuth)` guards every `/api/*` route registered after it in `server.js`. The only public routes are `GET /api/health` and `POST /api/auth/login`, both registered *before* the guard. Admin-only routes add `auth.requireAdmin` as a second middleware. When adding a route, register it after the guard and let it inherit auth — do not add ad-hoc token checks. See the Authentication section below.

### Frontend (React)

- **Styling**: Use inline style objects defined as a `const s = { ... }` block at the top of each component file. Do not add CSS classes or CSS modules — except for responsive breakpoints which go in `mobile.css`.
- **Data constants**: Import violation types from `../data/violations`, departments from `../data/departments`, tier logic from `./CpasBadge`. Do not hardcode these values in components.
- **Toasts**: Use `useToast()` from `ToastProvider` for all user-facing feedback. Do not use `alert()` or `console.log` for user messages.
- **HTTP**: Use `axios` (already imported in form/modal components). Do not introduce `fetch` unless there is a compelling reason — keep it consistent.
- **State**: Prefer local `useState` over lifting state unless data is needed by multiple unrelated components. The only global context is `ToastProvider`.
- **Component files**: One component per file. Name the file to match the export. No barrel `index.js` files.

### Mobile / responsive

The UI targets phones **375px and up** with no external CSS framework. Durable rules:

- **Breakpoints**: `768px` (phones → card layouts, stacked nav), `480px` (small phones → single-column stats), `375px` (minimum supported width). Tablet tweaks at `1024px`. Put breakpoint rules in `mobile.css`, not inline styles.
- **Layout switch**: at ≤768px the dashboard table swaps to a card layout — desktop renders `<table>` in `Dashboard.jsx`; mobile renders `DashboardMobile.jsx`. Gate with the `isMobile` media-query pattern.
- **Touch & iOS**: tap targets ≥ **44px**; form inputs use **16px** font to stop iOS focus-zoom; use `-webkit-overflow-scrolling: touch` for momentum scroll.
- **`useMediaQuery` hook**: currently defined inline in both `App.jsx` and `Dashboard.jsx` (see TODO #8 to extract to `src/hooks/useMediaQuery.js`). Reuse the extracted hook once it lands rather than copying it a third time.
- Test on a real device — Chrome DevTools device mode does not exercise touch behavior.

### Database Migrations

New columns are added via the auto-migration pattern in `database.js`. Do not modify `schema.sql` for columns that already exist in production. Instead:

```js
// Example: adding a new column to violations
const cols = db.prepare('PRAGMA table_info(violations)').all().map(c => c.name);
if (!cols.includes('new_column')) db.exec("ALTER TABLE violations ADD COLUMN new_column TEXT");
```

Add a comment describing the feature the column enables. `schema.sql` is only for base tables — use it only for brand-new tables.

---

## Schema Changes: Decision Checklist

Before adding a column or table, answer:

1. **Does it affect scoring?** If yes, it must be immutable after insert and included in `prior_active_points` computation logic.
2. **Does it need audit trail?** If it tracks a change to an existing record, add a corresponding entry pattern to `violation_amendments` or `audit_log`.
3. **Is it soft-deletable?** Prefer `negated`/flag patterns over hard deletes for anything HR might need to reverse.
4. **Does it appear on PDFs?** Update `pdf/template.js` to reflect it. Test PDF output after schema changes.
5. **Does it affect point calculations?** If so, update `computeStanding()` in `lib/rolloff.js` — that function is the single source of truth for active-point totals. (There is no longer a SQL scoring view.)

---

## PDF Generation

- PDFs are generated on-demand via `GET /api/violations/:id/pdf`. No pre-caching.
- Template is built in `pdf/template.js`. It receives the full violation + employee record. Logo is loaded from disk at startup and embedded as base64.
- Puppeteer launches with `--no-sandbox --disable-setuid-sandbox` (required for Docker; safe in this deployment context).
- Acknowledgment rendering: if `acknowledged_by` is set, show name + date in signature block. If not, render blank wet-ink signature lines.
- After any schema change that adds user-visible fields, update the template to include the new field where appropriate.

---

## Development Workflow

### Local Development (without Docker)

```bash
# Terminal 1 — backend
npm install
node server.js          # Serves API on :3001 and client/dist statically

# Terminal 2 — frontend (hot reload)
cd client
npm install
npm run dev             # Vite dev server on :5173 (proxy to :3001 configured in vite.config.js)
```

### Build & Deploy

```bash
# Build Docker image (compiles React inside container)
docker build -t cpas .

# Run (local)
docker run -d --name cpas -p 3001:3001 -v cpas-data:/data cpas

# Unraid: build → save → transfer → load → run with --pids-limit 2048
# See the "Deploying on Unraid" section of README.md for full instructions
```

**Unraid PID limit is critical.** Chromium spawns many child processes for PDF generation. Always include `--pids-limit 2048` on Unraid containers or PDF generation will fail silently.

### Health Check

`GET /api/health` returns `{ status: 'ok', timestamp, version }`. The `version` field is populated by the Dockerfile at build time from git commit SHA. In local dev it returns `{ sha: 'dev' }` — this is expected.

---

## Forward-Thinking Development Guidelines

### Adding New Features

- **Score-affecting logic belongs in `lib/rolloff.js`**, not scattered across route handlers or duplicated in SQL. `computeStanding()` is the single source of truth for point totals. If you need a new score variant (e.g., 30-day window, category-filtered), add it as an option/variant of the roll-off model — don't sum points ad hoc in a route.
- **New violation fields**: Add to `schema.sql` for fresh installs AND to the migration block in `database.js` for existing databases. Both are required.
- **Reporting features**: Future aggregate queries should call `computeStanding()` (or join against `audit_log`) rather than re-implementing point logic. Structure new API endpoints under `/api/reports/` namespace, registered after the auth guard.
- **Notifications/alerts**: Any future alerting feature (email, Slack) should read from `audit_log` or call `computeStanding()` — do not add side effects directly into violation insert routes.
- **Auth is already implemented** (see the Authentication section). It is global middleware (`app.use('/api', auth.requireAuth)`) applied before all `/api` routes, exactly as this guidance recommends — do not add per-route auth checks. When wiring identity into records, pass the signed-in user into `performed_by`/`changed_by` fields on audit and amendment records.
- **Multi-tenant / multi-site**: The schema is single-tenant. If site isolation is ever needed, add a `site_id` foreign key to `employees` and `violations` as a migration column, then scope all queries with a `WHERE site_id = ?` clause.

### What NOT to Do

- Do not compute active CPAS scores by summing violation points client-side. Always fetch the server-computed standing (`/api/employees/:id/score`, `/api/dashboard`, etc.), which runs the clean-cycle model in `lib/rolloff.js`. A naive client-side sum ignores roll-off and will be wrong.
- Do not modify `prior_active_points` after a violation is inserted, EXCEPT via one of the two sanctioned paths: automatic recompute on a back-dated insert (`recomputeSnapshotsAfter()`), or manual admin backfill (`recomputeAllSnapshotsForEmployee()` behind `POST /api/employees/:id/recompute-snapshots` and the **↻ Backfill Snapshots** UI button). Both are audit-logged as `violation_snapshots_recomputed`. Never recompute snapshots on negate, restore, amend, or hard delete.
- Do not add columns to `audit_log`. It is append-only with a fixed schema.
- Do not add a framework or ORM. Raw SQL with prepared statements is intentional — it keeps the query behavior explicit and the dependency surface small.
- Do not add a build step beyond `vite build`. The backend is plain CommonJS `require()`; do not transpile it.
- Do not use `alert()`, `console.log` for user messages, or `document.querySelector` inside React components.

---

## Documentation Standards

### Code Comments

- Comment **why**, not **what**. If the reason for a decision is not obvious from the code, explain it.
- Use the existing banner style for section groupings in `server.js`:
  ```js
  // ── Section Name ─────────────────────────────────────────────────────────────
  ```
- Mark non-obvious schema columns with inline SQL comments (see `schema.sql` for examples).
- When adding a migration block, include a comment naming the feature it enables.

### In-App Documentation

The `ReadmeModal.jsx` component renders an admin reference panel accessible via the `? Docs` button. When adding a significant new feature:
- Add it to the feature map section of the docs modal.
- Update the tier system table if thresholds change.
- Move completed roadmap items from the "Proposed" section to the "Completed" section.

### README

Update `README.md` when:
- A new environment variable is introduced.
- The Docker run command changes (new volume, port, or flag).
- A new top-level feature is added that HR administrators need to know about.

Do not add implementation details to README — that belongs in code comments or AGENTS.md.

---

## Constraints & Non-Goals

- **Authentication is intentionally minimal.** A login gate, scrypt-hashed passwords, bearer-token sessions, and an admin/user role split exist (see the Authentication section) — but the app still runs on a trusted LAN. Do not layer on OAuth, SSO, password-reset email flows, or finer-grained permission tiers without explicit direction from the project owner. There is no CSRF/rate-limiting hardening by design; keep it deployed behind the LAN.
- **No external dependencies beyond what's in `package.json`.** Avoid introducing new npm packages unless they solve a clearly scoped problem. Prefer using existing stack capabilities.
- **No client-side routing library.** Navigation between Violation Form, Dashboard, and modals is handled via `App.jsx` state (`view` prop). Do not introduce React Router unless the navigation model meaningfully grows beyond 3–4 views.
- **No test suite currently.** If adding tests, use Vitest for frontend and a lightweight assertion library for backend routes. Do not add a full testing framework without discussion.
- **SQLite only.** Do not introduce Postgres, Redis, or other datastores. The single-file DB on a Docker volume is the correct solution for this scale.