TMS: in-transit tracking

The status chain picked_up → in_transit → out_for_delivery → delivered, GPS-stamped tracking events, driver updates from the mobile app, and POD sign-off.

Once the truck is loaded and rolling, the freight is "in transit". Tracking means watching where the goods are: statuses move forward step by step, each step writes a GPS-stamped tracking event automatically, and the driver taps a button in the mobile app to advance — no phone calls needed.

The in-transit status chain#

1. picked_up (picked up, 已提货): the driver arrived at the warehouse and loaded the freight. WMS gets a write-back.
2. in_transit (in transit, 在途中): the truck is on the road; GPS events keep recording its position.
3. out_for_delivery (out for delivery, 派送中): almost at the destination, starting the final delivery leg.
4. delivered (delivered, 已送达): the freight reached the customer. WMS gets a write-back.
5. exception (exception, 异常): something went wrong on the road (breakdown, traffic, damage) — the order is parked here until it is handled, then resumes from the previous status.

Drivers advance statuses in the mobile app#

1. The driver opens the TMS section of the mobile app and only sees orders assigned to them.
2. On the order detail page there is a "Next status" button that moves one way forward: dispatched → picked_up → in_transit → out_for_delivery → delivered.
3. Before each tap, the phone tries to grab GPS once (10-second timeout; if it fails, the status still moves — nothing is blocked).
4. Each step writes a tracking event automatically — events are append-only, so a wrong entry cannot be edited.

POD sign-off#

1. Only orders in out_for_delivery or delivered can be signed off.
2. The driver (or warehouse) taps "Upload POD": fill the recipient name, take photos, add a note, and flag any damage.
3. Photos go into the unified Documents center; one order allows exactly one POD record.