Sogon architecture — layers and call direction Diagram

Three principles

• State lives in AppState alone and every surface observes it — views read, and side effects go to injected closures
• RecordingCoordinator orchestrates the pipeline — a service does one job and does not know which stage follows it
• Whatever is swappable is a protocol — tests put a mock behind the same one

Isolation rules

• @MainActor is the default everywhere
• Only code running on a real-time thread, such as an audio callback, is pulled out as a nonisolated static pure function
• Apply the target state every time rather than comparing with the previous value — coalesced notifications make the comparison miss a real change

What the pure models hold

• SpeakerAlignment — anchor matching · speaker per sentence · line break on a pause
• SpeakerAttributionResult — speaker names, valid only inside their session
• TextChunking — splits long text by line
• UpdateCheckSchedule — decides on time since the last check, not a timer
• AppSettings — persists in UserDefaults and AppState propagates it