# State Management

> How state is managed in this project.

---

## Overview

This WPF application uses view models as both UI state containers and command
workflow coordinators. Some view model methods are reused by interactive UI
paths and startup/headless capability checks, so state that triggers UI prompts
or file writes must be explicitly controlled by the caller.

---

## State Categories

### View Model Workflow Flags

Use explicit boolean workflow flags when the same view model method can run in
different interaction contexts.

Example:

```csharp
var viewModel = new MainWindowViewModel
{
    ShouldCheckSortFileOnLoad = false
};
```

`MainWindowViewModel.LoadToolsFromDrillTape` can parse a drill tape for the main
window, startup menu capability checks, and headless startup actions. Only the
main window adjustment workflow should allow load-time sort seed prompts.

---

## When to Use Global State

<!-- Criteria for promoting state to global -->

(To be filled by the team)

---

## Server State

<!-- How server data is cached and synchronized -->

(To be filled by the team)

---

## Common Mistakes

### Triggering Interactive Side Effects During Capability Checks

Capability checks such as startup menu button visibility should not trigger
interactive prompts, file saves, Explorer windows, or reorder operations.

Wrong:

```csharp
var viewModel = new MainWindowViewModel
{
    IsStartupDrillTapeFile = true,
    OriginalFilePath = filePath
};

viewModel.LoadToolsFromDrillTape(content);
```

Correct:

```csharp
var viewModel = new MainWindowViewModel
{
    IsStartupDrillTapeFile = true,
    OriginalFilePath = filePath,
    ShouldCheckSortFileOnLoad = false
};

viewModel.LoadToolsFromDrillTape(content);
```

Before reusing a view model method in a startup, preview, export, or background
path, check whether it reads state that can show dialogs or mutate files.