Hub server

CREATE TABLE orders (
  pos_reference TEXT PRIMARY KEY,
  version       INTEGER NOT NULL DEFAULT 1,
  snapshot      TEXT NOT NULL,       -- JSON OrderSnapshot
  table_id      INTEGER,
  terminal_id   TEXT,
  created_at    TEXT DEFAULT (datetime('now')),
  updated_at    TEXT DEFAULT (datetime('now'))
);

CREATE TABLE leases (
  pos_reference TEXT PRIMARY KEY,
  terminal_id   TEXT NOT NULL,
  uid           INTEGER,
  role          TEXT,
  version       INTEGER NOT NULL DEFAULT 0,
  granted_at    TEXT DEFAULT (datetime('now')),
  expires_at    TEXT NOT NULL
);

CREATE TABLE events (
  id            INTEGER PRIMARY KEY AUTOINCREMENT,
  type          TEXT NOT NULL,
  pos_reference TEXT,
  terminal_id   TEXT,
  payload       TEXT,                -- JSON
  forwarded     INTEGER DEFAULT 0,
  created_at    TEXT DEFAULT (datetime('now'))
);
CREATE INDEX idx_events_forwarded ON events(forwarded, id);

CREATE TABLE tables (
  table_id      INTEGER PRIMARY KEY,
  status        TEXT DEFAULT 'available',
  pos_reference TEXT,
  terminal_id   TEXT,
  updated_at    TEXT DEFAULT (datetime('now'))
);

CREATE TABLE table_locks (
  table_id      INTEGER PRIMARY KEY,
  terminal_id   TEXT NOT NULL,
  uid           INTEGER,
  user_name     TEXT,
  granted_at    TEXT DEFAULT (datetime('now')),
  expires_at    TEXT NOT NULL
);

PRAGMA journal_mode = WAL;       -- Concurrent readers during writes
PRAGMA busy_timeout = 5000;      -- Wait 5s on lock contention
PRAGMA synchronous = NORMAL;     -- Balanced durability/performance
PRAGMA foreign_keys = ON;

interface TerminalInfo {
  terminalId: string;
  deviceId: string;
  uid: number;
  role: string;
  name: string;
  ws: WebSocket;
  lastSeen: number;
}

nu_pos_hub/src/
├── index.ts                  # Entry point, wires everything together
├── config.ts                 # Environment-based configuration
├── storage/
│   ├── db.ts                 # SQLite init, schema, WAL mode
│   ├── orderStore.ts         # Order CRUD with versioning
│   ├── leaseStore.ts         # Lease CRUD with expiry
│   ├── eventLog.ts           # Append-only event log
│   ├── tableStore.ts         # Table status CRUD
│   └── tableLockStore.ts     # Table lock CRUD with expiry
├── leasing/
│   ├── leaseManager.ts       # Lease business logic
│   └── tableLockManager.ts   # Table lock business logic
├── server/
│   ├── httpServer.ts         # Health, status, events, dashboard endpoints
│   ├── wsServer.ts           # WebSocket connection handler
│   ├── messageRouter.ts      # JSON parse, validate, route
│   └── terminalRegistry.ts   # In-memory terminal map
├── handlers/
│   ├── authHandler.ts        # AUTH message handler
│   ├── leaseHandler.ts       # LEASE_* message handler
│   ├── orderHandler.ts       # ORDER_SNAPSHOT handler
│   ├── tableHandler.ts       # TABLE_UPDATE handler
│   ├── tableLockHandler.ts   # TABLE_LOCK_* message handler
│   └── floorPlanHandler.ts   # FLOOR_PLAN_UPDATE handler
├── upstream/
│   ├── types.ts              # UpstreamAdapter interface
│   ├── odooAdapter.ts        # Odoo HTTP client
│   └── forwarder.ts          # Background event drain
├── discovery/
│   └── mdns.ts               # Bonjour/mDNS advertisement
├── dashboard/
│   └── html.ts               # Self-contained HTML dashboard
└── cli/
    └── index.ts              # CLI: stats, drain, events, reset-leases, reset-data