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Understand session statuses

When you open a session in Polaris Express, the badge at the top of the page tells you where that charge sits in its life cycle. The status is not a free-form label — it’s derived from two signals: whether the session has been finalized on the back end, and whether its final meter reading has been received. Understanding the model makes it easier to tell a normal in-progress charge from one that needs attention.

The model

Section titled “The model”

A session in Polaris Express is anchored to a SteVe transaction. As you charge, SteVe emits MeterValues, Polaris syncs them as syncedTransactionEvents, and a sibling transactionSyncState row tracks whether SteVe has marked the transaction as closed.

The status badge on /sessions/[id] is computed from those two rows:

stateDiagram-v2
  [*] --> InProgress: First MeterValue synced
  InProgress --> InProgress: New MeterValue (kWh ticks up)
  InProgress --> Completed: syncState.isFinalized = true<br/>AND final meter value received
  InProgress --> [*]: Session closed without final reading<br/>(still shown as in-progress)
  Completed --> [*]

Two flags drive the badge:

FlagSourceMeaning
isLivetransactionSyncState.isFinalized is falseSteVe still considers the transaction active.
isFinalThe latest event row has isFinal = trueThe final MeterValue has been recorded.

The rendered status follows a simple rule:

  • isLive → In progress
  • not live and isFinal → Completed
  • not live and not isFinal → still rendered as In progress until the final reading lands

That last case is the important one. A session only flips to Completed once both the closing signal and the closing meter reading have been reconciled.

What each status surfaces

Section titled “What each status surfaces”

The status doesn’t just change a badge — it changes what the page shows.

flowchart LR
  A[Open /sessions/id] --> B{isLive?}
  B -->|yes| C[LiveSessionCard<br/>+ ChargerIdentityStrip<br/>+ live kW from SSE]
  B -->|no| D[Summary tiles only<br/>kWh / Duration / Cost / Avg kW]
  C --> E[Meter timeline]
  D --> E

For live sessions, Polaris also makes a best-effort call to SteVe to fetch the ChargeBox, connector, and start timestamp so the LiveSessionCard can render. If that call fails, the rest of the page still renders — you just won’t see the live charger strip.

Why it works this way

Section titled “Why it works this way”

Two design choices fall out of this model:

Status is derived, not stored. There is no status column on a session. The badge is computed at request time from the underlying sync state. That means a session can transition from “In progress” to “Completed” simply because a final MeterValue arrived — without any write to the session row itself. It also means a stale sync state can’t lie about whether a session is really done.

404, not 403, on sessions you don’t own. The loader runs assertOwnership before reading anything else, and any ownership failure returns Not Found. This prevents enumeration of session IDs that belong to other drivers.

Estimated cost is computed per-event. A session that straddles two billing periods, or crosses a tier boundary on a tiered plan, would report the wrong cost if Polaris just multiplied total kWh by a single rate. Instead, each event is priced against the period and tier it falls into, then summed. The result carries a coverage flag:

  • included — the session is covered by your subscription
  • billed — the session will appear on your invoice
  • unknown — pricing could not be resolved (rare; usually a tariff lookup failure)

What this means for you

Section titled “What this means for you”
  • A session that says In progress but hasn’t ticked up in a while is most likely waiting for SteVe to send its final MeterValue. The badge will flip once that lands — you don’t need to refresh aggressively.
  • The live tile (kW, elapsed time) only renders while isLive is true. Once the session completes, you’ll see the summary tiles instead, with the final totals.
  • Cost shown on a live session is an estimate based on kWh synced so far. The number on your invoice is the source of truth.
  • If you opened a session URL and got a “Not Found” page, the session either doesn’t exist or isn’t linked to one of your EV cards.
Section titled “Related”