# Current Product Backlog

This document records the next agreed product improvements. It describes
requirements and intended sequencing, not proof of implementation.

## Circuit List Editor

- Collect the remaining editor interaction issues before changing additional
  behavior.

## Project History

- Every listed logical snapshot, including automatic snapshots, must be
  explicitly restorable from the project history UI.
- Show which project change produced a snapshot. Prefer immutable revision
  metadata over storing a second free-form description of the same change.
- Keep restoration auditable as a new project revision and preserve persistent
  undo/redo.

## Distribution Boards

- Assign an optional project floor to a distribution board.
- Store a supply classification for each distribution board:
  - `AV` (Allgemeine Stromversorgung)
  - `SV` (Sicherheitsstromversorgung)
  - `EV` (Ersatzstromversorgung)
  - `USV` (Unterbrechungsfreie Stromversorgung)
  - `MSR` (Mess-, Steuerungs- und Regelungstechnik)
  - `SiBe` (Sicherheitsbeleuchtung)
- Let project settings select which catalog supply types are used in a
  project. Distribution-board dialogs offer only that selection; a type in
  use cannot be disabled.
- Include both fields in project snapshots and portable project
  export/import.
- Persist changes through project commands so they remain undoable after a
  restart.

## Device Voltage Derivation

- Derive voltage from the selected phase type and the project settings:
  - single-phase uses the project's single-phase voltage;
  - three-phase uses the project's three-phase voltage.
- Voltage is not editable on global devices, project devices or circuits.
  Global devices store only their phase; copying one into a project derives
  the target project's voltage.
- Project-device voltage follows its phase. Circuit voltage follows the
  section phase; an unassigned circuit is three-phase only when all assigned
  device rows with a valid phase are three-phase.
- Changing project voltage settings updates all project devices and circuits
  atomically in the same persistent Undo/Redo step.
- Database migration `0019` and snapshot schema version `5` normalize older
  stored values. Version-four and older imports remain supported and are
  normalized while being upgraded.

## Recommended Sequence

1. Distribution-board floor and supply fields.
2. Device voltage derivation without overrides.
3. Snapshot-to-revision descriptions and history presentation.

The Revit/CSV/IFCGUID round-trip remains a separate jointly planned phase and
must not be inferred from these tasks.