Presence Ledger

Presence Ledger is the avalonia-mobile product in src/PresenceLedger. Its durable output is a small local ledger of confirmed arrival and departure events at user-defined locations, plus UTC-daily raw samples used to explain and replay each displayed day.

Composition

The app composes general-purpose platform libraries rather than putting Android or map concerns into the domain:

Novolis.Math.Geometry
  -> PresenceLedger.Core
  -> PresenceLedger.Storage
  -> PresenceLedger.App
  -> PresenceLedger.Desktop / PresenceLedger.Android

Novolis.Avalonia.Map owns provider-neutral map viewport behavior, tiles, markers, radius and track overlays, selection, accessible zoom, loading/error state, and attribution. The app owns the Kartverket adapter. Novolis.Avalonia.Mobile owns neutral location and connected-Wi-Fi reading contracts; its Android package owns Android API adapters. Presence inference, observation retention, and day projection remain in the app's testable core.

Data boundary

Platform readings are accepted into local versioned NDJSON files under observations/YYYY-MM-DD.ndjson, partitioned by UTC date. The core also persists configured location revisions, inference state needed across process death, and semantic PresenceEvent records. NDJSON is the current store; the contracts leave room for a later SQLite implementation without changing the engine or day projection.

Map tiles and explicit address searches may use Kartverket/Geonorge over HTTPS. No ledger data is uploaded.

See the product-level details in src/PresenceLedger/README.md.