# Nexus Windows Replacement Layer 1.0 — Summary

**Date:** 2026-06-05  
**Build target:** `dotnet build NexusShell -c Release`

---

## Objective

Phase 1 of gradual Windows replacement: audit dependencies, plan replacements, and ship UI foundation for Nexus-branded dialogs and default-app preferences (JSON only, no registry).

---

## Completed

| Acceptance criterion | Status |
|---------------------|--------|
| Dependency audit complete | ✅ `WINDOWS-DEPENDENCY-AUDIT.md` |
| Replacement plan | ✅ `REPLACEMENT-PLAN.md` |
| `NexusOpenFileDialog` | ✅ |
| `NexusSaveFileDialog` | ✅ |
| `NexusOpenWithDialog` | ✅ |
| Default apps model + JSON service | ✅ `NexusDefaultAppsService`, `NexusFileAssociations` |
| Settings section "Nexus Default Apps" | ✅ |
| Proof migrations | ✅ Wallpaper picker, Files open routing |
| Build PASS | See build status below |

---

## Changed files

### New — Controls/Dialogs

- `Controls/Dialogs/NexusOpenFileDialog.cs`
- `Controls/Dialogs/NexusOpenFileDialogWindow.xaml`
- `Controls/Dialogs/NexusOpenFileDialogWindow.xaml.cs`
- `Controls/Dialogs/NexusSaveFileDialog.cs`
- `Controls/Dialogs/NexusSaveFileDialogWindow.xaml`
- `Controls/Dialogs/NexusSaveFileDialogWindow.xaml.cs`
- `Controls/Dialogs/NexusOpenWithDialog.cs`
- `Controls/Dialogs/NexusOpenWithDialogWindow.xaml`
- `Controls/Dialogs/NexusOpenWithDialogWindow.xaml.cs`

### New — Models & Services

- `Models/NexusDefaultAppsModels.cs`
- `Services/NexusFileAssociations.cs`
- `Services/NexusDefaultAppsService.cs`
- `Services/NexusFileOpenService.cs`

### New — Documentation

- `docs/evidence/nexus-windows-replacement-v1/WINDOWS-DEPENDENCY-AUDIT.md`
- `docs/evidence/nexus-windows-replacement-v1/REPLACEMENT-PLAN.md`
- `docs/evidence/nexus-windows-replacement-v1/SUMMARY.md`

### Modified

- `Models/NexusSettingsModels.cs` — `DefaultApps` section enum
- `ViewModels/NexusSettingsViewModel.cs` — Default Apps section, `NexusOpenFileDialog` migration
- `Views/NexusSettingsView.xaml` — Default Apps UI
- `ViewModels/NexusFilesViewModel.cs` — `NexusFileOpenService` routing, `SelectFile`
- `ViewModels/NexusPhotosViewModel.cs` — `OpenFilePath`
- `ViewModels/NexusMediaViewModel.cs` — `OpenFilePath`
- `Services/NexusMediaLibraryService.cs` — `TryBuildItemFromPath`
- `MainWindow.xaml.cs` — `INexusFileOpenRouter`
- `App.xaml.cs` — DI wiring, `AppServices` properties

---

## Audit highlights

- **Still Windows:** Process.Start for shutdown/update/catalog apps; registry reads for hardware info; Win32 browse inside Nexus dialog shells (v1 minimum).
- **Now Nexus:** Files, Photos, Media, Settings, Calculator; Nexus dialogs; JSON default apps; Files no longer uses ShellExecute for double-click open.
- **Next sprint:** Pure WPF picker, remove ShellExecute fallback, Files "Open with" menu, extension override UI.

---

## Build status

**PASS** — `dotnet build NexusShell -c Release` (2026-06-05)

```
Build succeeded.
    2 Warning(s)  (NU1510 package prune — pre-existing)
    0 Error(s)
```

---

## Git status

Uncommitted changes only (no commit per mission). Run from repo root:

```
git status --short "Ninja Nexus/"
```

Key paths: `source/nexus-shell/NexusShell/` (new Controls/Dialogs, Services, Models) and `docs/evidence/nexus-windows-replacement-v1/`.
