# pricegod-urovo-daemon (macOS)

The Mac counterpart to the Windows `daemon.cs`. Drives the **Urovo D812R+ (RFID)** over
raw USB — printing a label and encoding the UHF chip in one pass — and serves the same
`localhost:7790` HTTP contract, so it is a drop-in for the PriceGod extension's
`daemon.js` client.

**No vendor SDK required.** `ASSESSMENT.md` §7 assumed the RFID encode was locked inside
the Windows-only `GTSPL_SDK.dll` and would need a USB sniff or the Java jar to recover.
It doesn't: the DLL is a managed .NET assembly, and its IL shows every RFID call is a
one-line `String.Concat` → ASCII → `WritePrinter`. The wire format below was recovered
from `ldstr` order + argument order and independently confirmed by a second decompile.

```
UHF WRITE <fmt>,<start>,<len>,<bank>,"<data>"     # the RFID encode
UHF READ  <fmt>,<start>,<len>,<bank>
UHF QUERY <fmt>,<pcStatus>,<crcStatus>
UHF GEN2 EPC|TID|USER|ACCESS|KILL <action>,"<pw>"
SET RFID  <tagType>,<rw_pos>,<void_printout>,<tryEncode>,<errHandle>,<speed>,<retry>
&DEFAULT,i        # rfidSetupDefault      &CALIBRATE,A,R    # RFIDAutoCalibration
PRINT <set>, <copy>                                # note the space after the comma
```

All plain ASCII, one command per line, CRLF-terminated. `writeUHF("H",2,12,"E",epc)`
emits exactly `UHF WRITE H,2,12,E,"<24 hex chars>"`.

## Setup

```bash
./setup.sh          # brew install libusb + venv with pyusb/pillow/segno
```

Then double-click **`start-daemon.command`** (leave it open while you work).

## Files

| File | What |
|---|---|
| `urovo.py` | USB transport + the full GTSPL command set, status decoding, fault recovery, SKU↔EPC packing. Runs standalone as a connection test. |
| `label.py` | Renders the label to a 1-bit bitmap with PIL and emits TSPL `BITMAP`. Run standalone to dump previews to `/tmp`. |
| `daemon.py` | The `:7790` HTTP service. |

## Routes

| method | path | body / query | returns |
|---|---|---|---|
| GET | `/status` | — | `{ok,ready,status,statusText,printer}` |
| POST | `/print-encode` | `{sku,releaseId,artist?,title?,genre?,style?,info?,price?,condition?,size?,w?,h?,gap?}` | `{ok,epc,status,...}` |
| POST | `/write-tag` | alias of `/print-encode` | same |
| POST | `/print-test` | same body — **prints only, no RFID** (safe on chipless stock) | same |
| GET | `/read-tag` | — | `{ok,epc,sku,releaseId,recognized}` |
| GET | `/read-raw` | — | every memory bank |
| GET | `/preview?size=large&artist=…` | — | **PNG of the label, printing nothing** |
| GET | `/profiles` | — | the media profiles below |
| POST | `/calibrate` | — | RFID auto-calibration |
| POST | `/recover` | — | clear a latched fault |

Use `/preview` while tuning a layout — it costs no labels.

## Media profiles

Both shop stocks sit on a **24 mm web** and feed long-edge-first, so the landscape design
is rotated 90° onto the media. Names match the extension's size dropdown.

| profile | label face | pitch | notes |
|---|---|---|---|
| `small` | 51 × 19 mm | 51 mm | older stock; the rest of the 24 mm web is blank filler, design is centred across it |
| `large` | 55 × 24 mm | 55 mm | current stock (default) |
| `xlarge` | 64 × 34 mm | 64 mm | untested |

Each inherits `margin_mm` (default 1.5), a safe-area inset held back from every edge —
without it the design runs edge-to-edge and the least registration drift clips it.
Override per request with `size`, or `w`/`h`/`gap` directly.

## Gotchas confirmed on macOS

1. **`0x08` "out of ribbon" is a latch.** `SET RIBBON OFF` alone will *not* clear it — it
   also needs a `FORMFEED` (costs one blank label). `recover()` / `POST /recover` does this.
2. **The status byte lies for 1–3 s after a print** (transient `0x20`/`0x31`/`0x45`).
   Never judge a print by the immediate post-print byte; poll until it settles to `0x00`.
3. **`VOID0` stamps on chipless stock.** If RFID encoding is armed, every label without a
   chip gets voided. `SET RFID OFF` stops it; `/print-test` is the safe route on plain
   thermal. Note `&DEFAULT,i` appears to *arm* RFID, so don't send it casually.
4. **Bidirectional USB is required.** `UHF READ`/`QUERY` reply with raw bytes on the
   bulk-IN endpoint, so CUPS `lp -o raw` is not sufficient — hence libusb.
5. **After changing stock**, calibrate on the printer itself: hold **FEED** while powering
   on and wait for **5 beeps**.

## SKU ↔ EPC scheme (⚠ still unverified)

96-bit EPC = **6 bytes** 14-digit timestamp SKU + **4 bytes** release_id + **2 bytes**
`0xEC01` marker — ported byte-for-byte from `daemon.cs`. Confirm against an existing
Chafon-written tag before trusting it; if it differs, change **only** `epc_encode` /
`epc_decode` in `urovo.py`.