LT_Janitorial_Quality_Control/CLAUDE.md

# Claude.md — JQC Developer Reference

> **Audience:** AI assistants and developers working on this codebase.  
> **Purpose:** Authoritative reference for architecture, conventions, gotchas, and decisions.  
> **Last reviewed:** April 2026 (Phase 12 complete + post-review hardening + UX improvements)

---

## Table of Contents

1. [Project Overview](#1-project-overview)
2. [Tech Stack](#2-tech-stack)
3. [Repository Layout](#3-repository-layout)
4. [Environment & Configuration](#4-environment--configuration)
5. [Database Models](#5-database-models)
6. [Role & Permission Matrix](#6-role--permission-matrix)
7. [Blueprint Prefixes & Route Inventory](#7-blueprint-prefixes--route-inventory)
8. [Utility Modules](#8-utility-modules)
9. [Mobile API (Phase 7)](#9-mobile-api-phase-7)
10. [Notification System](#10-notification-system)
11. [SLA Engine](#11-sla-engine)
12. [Audit Trail](#12-audit-trail)
13. [PDF Export](#13-pdf-export)
14. [Scheduled Reports](#14-scheduled-reports)
15. [Rate Limiting](#15-rate-limiting)
16. [Alembic Migration Chain](#16-alembic-migration-chain)
17. [Frontend Conventions](#17-frontend-conventions)
18. [Infrastructure](#18-infrastructure)
19. [Known Constraints & Hard Rules](#19-known-constraints--hard-rules)
20. [Change Philosophy](#20-change-philosophy)

---

## 1. Project Overview

**JQC (Janitorial Quality Control)** is a production-grade, full-stack web application that manages:

- Janitorial service contracts organised as **Contracts (Projects) → Facilities → Areas**
- **Inspection** execution against configurable templates with dynamic form builder
- **Issue** tracking with SLA enforcement, follower subscriptions, and verification workflow
- **Customer portal** with scoped facility visibility and invitation-based onboarding
- **Notification** system (in-app + email) driven by an admin-controlled matrix
- **Reports** — on-demand PDF/CSV scorecards and scheduled email digests
- **Audit trail** — immutable log of every create/update/delete action
- **Mobile API** — JWT-authenticated REST layer (Phase 7) for a React Native / Expo mobile app

The application is actively deployed in production and maintained by a single developer/administrator.

---

## 2. Tech Stack

| Layer | Technology |
|---|---|
| Language | Python 3.11+ |
| Web framework | Flask (application factory pattern) |
| ORM | Flask-SQLAlchemy (SQLAlchemy 2.x) |
| Database | MySQL (via PyMySQL driver) |
| Auth (web) | Flask-Login + Flask-WTF CSRF |
| Auth (API) | JWT access tokens + opaque refresh tokens (PyJWT) |
| Rate limiting | Flask-Limiter (Redis-backed in production via `REDIS_URL`; falls back to in-process memory for dev) |
| Migrations | Flask-Migrate / Alembic |
| Email | Flask-Mail (SMTP, background threading) |
| PDF generation | ReportLab |
| Forms | WTForms + Flask-WTF |
| Templating | Jinja2 |
| Frontend | Bootstrap 5, Chart.js, vanilla JS |
| Server | Gunicorn (sync workers) behind Nginx |
| OS | Ubuntu Linux |
| Mobile client | React Native + Expo (Expo Go for dev; cloud Mac for iOS builds) |
| Timezone | All datetimes stored as US/Eastern (naive, via `now_eastern()`) |

---

## 3. Repository Layout

```
lt_janitorial_quality_control/
├── app/
│   ├── __init__.py              # Application factory — limiter, csrf, db, mail, login_manager
│   ├── add_form_schema.py       # One-off migration helper (safe re-run)
│   ├── api/                     # Mobile REST API (Phase 7)
│   │   ├── __init__.py          # api_bp parent blueprint + register_api()
│   │   ├── auth.py              # /api/v1/auth/* and /api/v1/devices/*; rate-limited login/refresh
│   │   ├── decorators.py        # @jwt_required
│   │   ├── errors.py            # JSON error helpers + error handler registration
│   │   └── jwt_utils.py         # generate_access_token()
│   ├── models/
│   │   ├── __init__.py
│   │   ├── api_token.py         # RefreshToken, DeviceToken
│   │   ├── audit.py             # AuditLog
│   │   ├── facility.py          # Facility, Area
│   │   ├── inspection.py        # InspectionTemplate, ChecklistItem, Inspection, InspectionResult
│   │   ├── issue.py             # Issue, IssueComment, IssueFollower
│   │   ├── notification.py      # Notification, NotificationPreference + event constants
│   │   ├── notification_matrix.py
│   │   ├── project.py           # Project, CustomerAssignment
│   │   ├── scheduled_report.py  # ScheduledReport
│   │   └── user.py              # User (password-setup workflow, display_name)
│   ├── routes/
│   │   ├── auth.py              # /auth/* — login rate-limited; _safe_next() open-redirect guard
│   │   ├── customers.py         # /customers/* — _safe_referrer() helper; expired invitation banner
│   │   ├── dashboard.py         # / — single open_issues query (len() not .count())
│   │   ├── facilities.py        # /facilities/*
│   │   ├── inspections.py       # /inspections/* — passes now=now_eastern() for stale badge
│   │   ├── issues.py            # /issues/* — quick-assign AJAX; facility filter; SLA column
│   │   ├── notifications.py     # /notifications/* — send-digest, check-sla, cleanup-tokens
│   │   ├── projects.py          # /projects/*
│   │   ├── reports.py           # /reports/*
│   │   ├── scheduled_reports.py # /scheduled-reports/*
│   │   ├── templates.py         # /templates/*
│   │   └── audit.py             # /audit/*
│   ├── static/
│   │   ├── css/ipad_responsive.css
│   │   └── uploads/
│   ├── templates/
│   │   ├── base.html            # Active nav tab styling; request.endpoint-based active detection
│   │   ├── _sla_badge.html
│   │   └── ...
│   └── utils/
│       ├── audit.py             # log_action() + ACTION_* constants
│       ├── decorators.py        # @admin_required, @supervisor_required, @project_manager_required, @customer_required
│       ├── forms.py             # All WTForms (AreaForm includes 'floor' type)
│       ├── notifications.py     # notify(), notify_by_matrix(), send_pending_digests()
│       ├── pdf_export.py        # ReportLab PDF generation
│       ├── scope.py             # get_customer_scope()
│       ├── sla.py               # sla_status(), sla_deadline(), sla_hours_remaining(), send_sla_alerts()
│       └── time_utils.py        # now_eastern()
├── migrations/
│   └── versions/
│       ├── phase1_projects_roles.py
│       ├── phase6_features.py
│       ├── phase7_mobile_api.py
│       ├── phase8_notification_matrix.py
│       ├── phase9_user_full_name.py
│       ├── phase10_customer_password_setup.py
│       ├── phase11_director_role.py
│       └── phase12_performance_indexes.py   ← HEAD
├── config.py
├── gunicorn_config.py
├── requirements.txt             # Includes Flask-Limiter
├── run.py
└── wsgi.py
```

---

## 4. Environment & Configuration

### Required Environment Variables

| Variable | Notes |
|---|---|
| `SECRET_KEY` | Flask secret — no fallback; startup fails if absent |
| `DATABASE_URL` | e.g. `mysql+pymysql://user:pass@localhost/jqc` |
| `MAIL_SERVER` | SMTP hostname |
| `MAIL_USERNAME` | SMTP login |
| `MAIL_PASSWORD` | SMTP password |
| `MAIL_PORT` | 465 (SSL) or 587 (STARTTLS) — auto-selects flags |
| `APP_BASE_URL` | Full URL for email links |
| `MAIL_DEFAULT_SENDER` | From address |
| `DIGEST_SECRET` | Authenticates all cron endpoints: `send-digest`, `check-sla`, `cleanup-tokens`, `scheduled-reports/run` |
| `REDIS_URL` | Optional. e.g. `redis://127.0.0.1:6379/0`. When set, Flask-Limiter uses Redis for shared rate-limit counters across Gunicorn workers. Falls back to in-process memory if absent. |

### Email SSL Auto-Detection

```python
MAIL_USE_SSL  = _mail_port == 465
MAIL_USE_TLS  = not MAIL_USE_SSL
```

**Critical:** Never set both to `True` — Flask-Mail breaks silently.

### File Uploads

- `UPLOAD_FOLDER` = `app/static/uploads/`
- `MAX_CONTENT_LENGTH` = 50 MB
- Allowed: `png`, `jpg`, `jpeg`, `gif`

---

## 5. Database Models

### User

```
users: id, username (unique, indexed), full_name, email (unique, indexed),
       password_hash, role (ENUM), created_at, active,
       password_set, set_password_token (indexed), set_password_token_expires
```

**Role ENUM:** `admin`, `director`, `inspector`, `project_manager`, `customer`

**Key property:** `display_name` → `full_name.strip()` or falls back to `username`. Use this everywhere in templates — never use `.username` for display.

**Expired invitations:** Customer accounts with `password_set=False` and `set_password_token_expires < now_eastern()` are flagged on the `/customers` index with an inline Resend button.

**Customer self-service setup:** When a customer clicks their invitation link, `set_password.html` prompts them to choose their own **username** (replacing the auto-generated placeholder) and set a **password**. The `set_password` route saves `form.username.data` to `user.username` before committing. The `SetPasswordForm` validates username uniqueness inline via `validate_username()`.

**Token verification:** `User.verify_set_password_token()` guards in order: token present → DB lookup → `password_set=False` check → expiry check → `hmac.compare_digest()` constant-time comparison. The `password_set=False` guard ensures accounts already activated cannot be re-used via a stale token. `compare_digest` is wrapped in `try/except` to safely handle type mismatches.

### Facility / Area

```
facilities: id, name, address, contact_person, contact_phone, active, project_id (FK)
areas:      id, facility_id (FK), name, area_type
```

**`area_type` choices:** `restroom`, `lobby`, `hallway`, `office`, `kitchen`, `storage`, `floor`, `outdoor`, `other`

### Project / CustomerAssignment

```
projects: id, name, description, project_manager_id, active, created_at
customer_assignments: id, user_id, project_id, facility_id (nullable)
    UniqueConstraint(user_id, project_id, facility_id)
```

**UI terminology:** "Project" is displayed as **"Contract"** throughout the UI. All backend identifiers (`project_id`, class `Project`, routes `projects.*`) are unchanged.

`facility_id = NULL` → access to all active facilities in that project.

### Inspection

```
inspections: id, template_id, facility_id, area_id, inspector_id, inspection_date,
             overall_score, status (in_progress/completed/flagged), notes, form_data (JSON),
             completed_at, parent_inspection_id (self-FK), follow_up_required, follow_up_note
```

**Indexed columns (Phase 12):** `status`, `facility_id`, `inspector_id`, `inspection_date`

**Score rule:** Items with `score = 0` mean "unanswered" — excluded from calculation entirely.

**Status display:** `completed` renders as **"Submitted"** in the UI. DB value unchanged.

**Stale badge:** In-progress inspections older than 24 hours show a `⚠ Stale` badge. Route passes `now=now_eastern()` to the list template.

### Issue

```
issues: id, inspection_id (nullable), area_id, severity (low/medium/high/critical),
        description, photo_path, status (open/in_progress/resolved/pending_verification),
        assigned_to, reported_at, resolved_at, result_notes, result_photos (JSON),
        verified_by, verified_at, verification_note, sla_notified
```

**Indexed columns (Phase 12):** `status`, `severity`, `assigned_to`, `reported_at`

**Issue status flow:** `open` → `in_progress` → `pending_verification` → `resolved`

**Quick-assign:** `POST /issues/<id>/quick-assign` — AJAX endpoint for admin/director. Returns JSON. Sends assignment notification. Logs to audit trail.

**Assignable staff roles:** `admin`, `director`, `inspector` — all three appear in the assignment dropdown on the issue view, create, and list quick-assign forms. `admin` was previously absent from the view/create dropdowns; corrected.

### Notification / NotificationPreference

```
notifications: id, user_id, title, body, link, is_read, created_at, issue_id, event_type
notification_preferences: id, user_id, event_type, email_enabled, digest_mode, digest_frequency
```

**Pause all emails:** Preferences page has a "Pause All Emails" toggle that bulk-disables all email toggles client-side.

### NotificationMatrix

```
notification_matrix: id, event_type, role_key, enabled, custom_emails (JSON)
    UniqueConstraint(event_type, role_key)
```

### AuditLog

```
audit_logs: id, user_id (nullable, SET NULL on delete), username (snapshot), user_role (snapshot),
            action, entity_type, entity_id, entity_label, details, created_at (indexed), ip_address
```

### RefreshToken / DeviceToken

```
api_refresh_tokens: id, user_id, token_hash (SHA-256, unique), device_id, device_name,
                    created_at, expires_at, revoked
api_device_tokens:  id, user_id, device_id, apns_token, device_name, app_version, registered_at
    UniqueConstraint(user_id, device_id)
```

**Token cleanup:**
1. **Passive** — on every successful API login, expired/revoked tokens for that user are deleted
2. **Cron** — `POST /notifications/cleanup-tokens?token=<DIGEST_SECRET>` deletes all globally

---

## 6. Role & Permission Matrix

| Area | admin | director | project_manager | inspector | customer |
|---|---|---|---|---|---|
| Dashboard | ✅ full | ✅ full | ✅ full | ✅ limited | ✅ scoped |
| Users | ✅ | ✅ | ❌ | ❌ | ❌ |
| Notification Matrix | ✅ only | ❌ | ❌ | ❌ | ❌ |
| Customers | ✅ | ✅ | ❌ | ❌ | ❌ |
| Facilities | ✅ | ✅ | ✅ | read | scoped |
| Contracts | ✅ | ✅ | ✅ | read | scoped |
| Templates | ✅ | ✅ | ❌ | ❌ | ❌ |
| Inspections (execute) | ✅ | ✅ | ✅ | ✅ | read |
| Issues (create/assign) | ✅ | ✅ | ✅ | ✅ | read |
| Issues (quick-assign) | ✅ | ✅ | ❌ | ❌ | ❌ |
| Issue verification | ✅ | ✅ | ❌ | ❌ | ❌ |
| Reports | ✅ | ✅ | ✅ | ✅ | scoped |
| Scheduled Reports | ✅ | ✅ | ✅ | ❌ | ❌ |
| Audit Trail | ✅ only | ❌ | ❌ | ❌ | ❌ |
| Mobile API | ✅ | ✅ | ✅ | ✅ | ❌ |

### Decorator Map

```python
@admin_required            # role == 'admin' only
@supervisor_required       # role in ('admin', 'director') — name kept to avoid touching 30+ routes
@project_manager_required  # role in ('admin', 'director', 'project_manager')
@customer_required         # role == 'customer' only
```

---

## 7. Blueprint Prefixes & Route Inventory

| Blueprint | Prefix | Notable routes |
|---|---|---|
| `auth` | `/auth` | `/login` (rate-limited 20/min), `/logout`, `/profile`, `/users/*`, `/notification-matrix` |
| `dashboard` | `/` | `GET /`, `/facility-trend` (AJAX) |
| `facilities` | `/facilities` | CRUD + area management; list grouped by Contract with collapsible sections; detail page has Back button |
| `projects` | `/projects` | CRUD + customer assignment management |
| `customers` | `/customers` | list (expired invitation banner), invite (name + email only), set-password (customer chooses username + password), manage, import CSV |
| `inspections` | `/inspections` | list (stale badge, `now` passed from route), start (template + facility only — area and notes removed), execute, view, PDF export, flag-issue, save-draft (AJAX), flag-followup, reinspect |
| `templates` | `/templates` | list, create, edit, delete, form editor, preview |
| `issues` | `/issues` | list (SLA column, facility filter, quick-assign dropdown), view, create, update, verify, comment, follow/unfollow, verification queue, delete |
| `issues` | `/issues` | `POST /<id>/quick-assign` — JSON AJAX, admin/director only |
| `notifications` | `/notifications` | list, mark-read, mark-all-read, preferences (pause-all toggle), `send-digest` (cron), `check-sla` (cron), `cleanup-tokens` (cron) |
| `audit` | `/audit` | list (admin only), view, purge |
| `reports` | `/reports` | index, facility report, scorecard, CSV/PDF export |
| `scheduled_reports` | `/scheduled-reports` | CRUD + manual trigger |
| `api` | `/api/v1` | parent blueprint |
| `api_auth` | `/api/v1` | `/auth/login` (10/min), `/auth/refresh` (30/min), `/auth/logout`, `/auth/me`, `/devices/register` |

---

## 8. Utility Modules

### `time_utils.py`
`now_eastern()` — always use this, never `datetime.utcnow()`.

### `audit.py`
`log_action(action, entity_type, entity_id, entity_label, details)` — call **after** `db.session.commit()`.

### `scope.py`
`get_customer_scope(user)` — returns `list[int]` facility IDs for customers, `None` for staff. Uses a single bulk `Facility.project_id.in_(...)` query for project-scoped assignments — never N+1.

### `forms.py`
All WTForms classes. `AreaForm.area_type` includes `floor`. `UserForm` excludes `customer` role.

### `notifications.py`
`notify()`, `notify_by_matrix()`, `notify_customers_for_facility()` — all email sent in background thread.

### `sla.py`
`sla_status(issue)` → `'ok'` | `'at_risk'` | `'breached'` | `None` (resolved).
`send_sla_alerts()` — called by cron, deduplicates via `issue.sla_notified`.

### `pdf_export.py`
ReportLab-based. 12-column grid must be preserved — never collapse in PDF views.

---

## 9. Mobile API (Phase 7)

### Auth Flow
1. `POST /api/v1/auth/login` → access token (60 min JWT) + refresh token (30 day opaque hex)
2. Bearer token on every request
3. `POST /api/v1/auth/refresh` → token rotation (old revoked, new issued)
4. `POST /api/v1/auth/logout` → revokes refresh token

### Rate Limits
| Endpoint | Limit |
|---|---|
| `POST /api/v1/auth/login` | 10/min, 3/sec |
| `POST /api/v1/auth/refresh` | 30/min, 5/sec |
| `POST /auth/login` (web) | 20/min, 5/sec |

### Refresh Token Cleanup
- Raw token never stored — SHA-256 hash only
- Passive: expired/revoked tokens purged per-user on each login
- Cron: `POST /notifications/cleanup-tokens`

### CSRF Exemption Pattern
```python
csrf.exempt(api_bp)   # BEFORE register_api(app) — order matters
register_api(app)
```

### Phase 2 (planned)
`api_facilities`, `api_inspections`, `api_issues`, `api_notifications`, `api_photos` — all stubbed in `app/api/__init__.py`.

---

## 10. Notification System

### Event Constants (`app/models/notification.py`)
```
inspection_completed, issue_assigned, issue_reassigned, issue_unassigned,
issue_status, issue_comment, issue_follow_update, issue_flagged, issue_created,
issue_updated_customer, verification_requested, sla_alert,
customer_inspection_completed
```

### Cron Endpoints (all require `token=DIGEST_SECRET`)

| Endpoint | Purpose | Schedule |
|---|---|---|
| `POST /notifications/send-digest` | Digest email delivery | `0 7 * * *` |
| `POST /notifications/check-sla` | SLA breach/at-risk alerts | `*/30 * * * *` |
| `POST /notifications/cleanup-tokens` | Purge expired API tokens | `0 3 * * *` |

### Implicit Notifications (always sent, not matrix-controlled)
- Issue **assignee** on assignment/status/comment
- Issue **followers** on any update
- SLA **assignee + followers** on SLA events

---

## 11. SLA Engine

| Severity | Window | At-Risk |
|---|---|---|
| critical | 4h | 3h |
| high | 24h | 18h |
| medium | 72h | 54h |
| low | 168h | 126h |

SLA column shown on issues list. `issue.sla_notified` prevents duplicate cron notifications.

**SLA filter on issues list:** When `?sla=` is active, the full matching result set is loaded and filtered in Python, then wrapped in `_SLAFilteredPage` (defined at the top of `routes/issues.py`). This satisfies the template's pagination interface (`.items`, `.page`, `.pages`, `.iter_pages()`) without any template changes. Pagination nav is automatically suppressed via the existing `{% if issues.pages > 1 %}` guard.

---

## 12. Audit Trail

- Admin-only at `/audit/` — director is excluded
- Actions: `CREATE`, `UPDATE`, `DELETE`, `LOGIN`, `LOGOUT`, `EXPORT`
- Immutable — never updated or deleted through the application (purge UI exists for old records)
- IP from `X-Forwarded-For` or `request.remote_addr`

**`ACTION_EXPORT` coverage:** Both `/reports/export/inspections` and `/reports/export/issues` call `log_action(ACTION_EXPORT, ...)` before streaming the CSV response.

**Logging coverage:** All route modules now import `logging` and define a module-level `logger = logging.getLogger(__name__)`. Previously missing from `facilities.py`, `templates.py`, `reports.py`, and `dashboard.py`.

---

## 13. PDF Export

ReportLab — `app/utils/pdf_export.py`. **12-column grid must be preserved** — do not collapse in print/PDF.

---

## 14. Scheduled Reports

Types: `summary`, `facility`, `issues`. Frequencies: `daily`, `weekly`, `monthly`.
Cron: `POST /scheduled-reports/run?secret=<DIGEST_SECRET>`

---

## 15. Rate Limiting

Initialised in `app/__init__.py` as a module-level extension:

```python
limiter = Limiter(
    key_func       = get_remote_address,
    default_limits = [],
    storage_uri    = os.environ.get('REDIS_URL', 'memory://'),
)
limiter.init_app(app)
```

Import in routes: `from app import limiter`, then `@limiter.limit('N per period')`.

**Production:** Set `REDIS_URL=redis://127.0.0.1:6379/0` in the server environment. Counters are then shared across all Gunicorn workers and rate limits are correctly enforced.

**Development:** `REDIS_URL` absent → falls back to `memory://` (in-process, single-worker). No Redis install required locally.

> **`redis` package** is in `requirements.txt`. Install it with `pip install -r requirements.txt` before setting `REDIS_URL`.

---

## 16. Alembic Migration Chain

```
phase1_projects_roles → phase6_features → phase7_mobile_api → phase8_notification_matrix
    → phase9_user_full_name → phase10_customer_password_setup → phase11_director_role
        → phase12_performance_indexes   ← HEAD
```

### MySQL ENUM Change Protocol (3 steps — always follow)
```sql
-- 1. Expand to include both values
ALTER TABLE users MODIFY COLUMN role ENUM('admin','supervisor','director',...) NOT NULL;
-- 2. Migrate data
UPDATE users SET role = 'director' WHERE role = 'supervisor';
-- 3. Contract to remove old value
ALTER TABLE users MODIFY COLUMN role ENUM('admin','director',...) NOT NULL;
```

### MySQL Compatibility
`CREATE INDEX IF NOT EXISTS` requires MySQL ≥ 8.0.1. For 5.7 compatibility use `information_schema.statistics` existence checks — see `phase12_performance_indexes.py` for the reusable `_index_exists()` pattern.

### Deprecated SQLAlchemy Patterns
```python
# WRONG
Model.query.get(id)
Model.query.get_or_404(id)

# CORRECT
obj = db.session.get(Model, id)
if obj is None: abort(404)
```

> All `Model.query.get()` calls have been replaced — including `load_user()` in `models/user.py` and three calls in `utils/notifications.py`.

---

## 17. Frontend Conventions

### Active Nav Tab
```css
/* base.html <style> block */
.navbar-dark .navbar-nav .nav-link.active {
    background-color: rgba(255,255,255,0.18);
    color: #fff !important;
    border-radius: 6px;
    font-weight: 600;
    box-shadow: inset 0 -2px 0 rgba(255,255,255,0.6);
}
```
Active state detected via `request.endpoint.startswith('<blueprint>.')` in each nav `<a>` tag.

### Display Names
Always use `user.display_name` in templates — never `.username` for display purposes.

### Status Label Map
| DB value | Displayed as |
|---|---|
| `completed` | **Submitted** |
| `in_progress` | In Progress |
| `flagged` | Flagged |
| `open` | Open |
| `resolved` | Resolved |
| `pending_verification` | Pending Verification |

### Forms
- Flask-WTF CSRF auto-applied to all web forms
- Manual forms: `<input type="hidden" name="csrf_token" value="{{ csrf_token() }}">`
- **Never nest `<form>` tags** — browsers silently discard inner forms

### Real-Time
**SSE banned.** All "live" updates use polling.

---

## 18. Infrastructure

### Gunicorn
```python
bind = "127.0.0.1:8000"
workers = multiprocessing.cpu_count() * 2 + 1
worker_class = "sync"
timeout = 30
```
Logs: `/home/jqc/logs/gunicorn-error.log`, `/home/jqc/logs/gunicorn-access.log`

### Application Logging
- `RotatingFileHandler` → `logs/jqc.log` (5 × 5 MB)
- `StreamHandler` → stdout (journalctl)
- Format: `[YYYY-MM-DD HH:MM:SS] LEVEL in module: message`

### Nginx
- `client_max_body_size 50M`
- Passes `X-Forwarded-For`

### Recommended Cron Schedule
```bash
0 7    * * * curl -s -X POST https://your-domain.com/notifications/send-digest \
                   -d "token=SECRET&frequency=daily"
*/30 * * * * curl -s -X POST https://your-domain.com/notifications/check-sla \
                   -d "token=SECRET"
0 3    * * * curl -s -X POST https://your-domain.com/notifications/cleanup-tokens \
                   -d "token=SECRET"
0 8    * * * curl -s -X POST https://your-domain.com/scheduled-reports/run \
                   -d "secret=SECRET"
```

---

## 19. Known Constraints & Hard Rules

| # | Rule | Rationale |
|---|---|---|
| 1 | **No SSE** | Exhausted Gunicorn sync worker pool |
| 2 | **`now_eastern()` always** | `utcnow()` caused incorrect SLA cutoffs |
| 3 | **3-step MySQL ENUM changes** | Skipping causes data loss |
| 4 | **Port 465 → SSL; 587 → STARTTLS** | Both True breaks Flask-Mail |
| 5 | **`CSRFProtect` as extension instance** | Flask-WTF 1.0+ removed per-route `@csrf_exempt` |
| 6 | **`supervisor_required` name preserved** | Renaming would touch 30+ route decorators |
| 7 | **Score 0 = unanswered** | Excluded from calculation — not the same as scoring zero |
| 8 | **12-column grid in PDF** | Must not collapse in print/PDF |
| 9 | **No nested `<form>` tags** | Browsers silently discard inner forms |
| 10 | **`log_action()` after `db.session.commit()`** | Entity ID must exist before audit capture |
| 11 | **`db.session.get(Model, id)` not `Model.query.get(id)`** | SQLAlchemy 2.x deprecation |
| 12 | **`filter()` before `limit()`** | SQLAlchemy ordering requirement |
| 13 | **Bulk queries in customer list** | Per-customer loops cause N+1 |
| 14 | **Email in background thread** | Never block HTTP response |
| 15 | **Open-redirect guards** | `_safe_next()` in auth.py; `_safe_referrer()` in customers.py |
| 16 | **`CREATE INDEX IF NOT EXISTS` not on MySQL < 8.0.1** | Use `information_schema` — see phase12 |
| 17 | **Set `REDIS_URL` in production** | `memory://` is per-process; multi-worker Gunicorn needs Redis for accurate shared counters |
| 18 | **"Project" → "Contract" is UI-only** | Backend identifiers unchanged |
| 19 | **`display_name` not `username` in templates** | Respects full_name; username is login identity only |
| 20 | **`open_issues` count derived from `len()` not `.count()`** | Avoids a second DB round-trip on the dashboard |
| 21 | **`supervisor` removed from Python-side ENUM** | Phase 11 migration complete — both DB and model ENUM must stay in sync |
| 22 | **SLA filter loads full result set (no paginate)** | SLA status is computed in Python; `_SLAFilteredPage` wrapper satisfies the template pagination interface |
| 23 | **`hmac.compare_digest()` for token comparison** | Prevents timing oracle attacks on `verify_set_password_token` |
| 24 | **`get_customer_scope()` uses bulk project query** | Single `Facility.project_id.in_(project_ids)` replaces per-assignment loop |
| 25 | **CSV exports always call `log_action(ACTION_EXPORT, ...)`** | Data exports are compliance-relevant audit events |
| 26 | **`StartInspectionForm` has no `area_id` or `notes` fields** | Both removed from the start page; `Inspection` constructor receives `area_id=None, notes=None` explicitly |
| 27 | **Customer set-password page collects username + password** | `SetPasswordForm` includes `username` field; route saves it to `user.username`, replacing the auto-generated placeholder |
| 28 | **`verify_set_password_token` requires `password_set=False`** | Prevents reuse of a stale token on an already-activated account |
| 29 | **Facilities list grouped by Contract in route, not template** | `list_facilities()` builds a `grouped` OrderedDict before rendering; template iterates `grouped`, not the flat `facilities` list |

---

## 20. Change Philosophy

1. **Surgical, additive patches** — smallest possible change to achieve the goal
2. **Preserve all routes, function names, variable names** unless explicitly directed otherwise
3. **Never remove existing functionality** unless explicitly directed
4. **Log all create/update/delete actions** via `log_action()`
5. **Migration existence checks** — all migrations safe to re-run
6. **Full file contents for 1–3 file changes**; deployment map for larger changesets
7. **Explicit deploy instructions** — migration steps separated from code steps
8. **Root cause analysis** on errors — never apply temporary workarounds