docs: add AGENTS.md for agentic coding guidelines (#142)

Author: okwasniewski

AGENTS.md

@@ -0,0 +1,201 @@
+# MiniSim - Agent Guidelines
+
+MiniSim is a macOS menu bar utility for launching iOS simulators and Android emulators. Written in Swift and AppKit.
+
+## Build Commands
+
+```bash
+# Build the project
+xcodebuild -scheme MiniSim -configuration Debug build
+
+# Build for release
+xcodebuild -scheme MiniSim -configuration Release build
+
+# Clean build
+xcodebuild -scheme MiniSim clean build
+```
+
+## Testing
+
+```bash
+# Run all tests
+xcodebuild test -scheme MiniSim -destination 'platform=macOS'
+
+# Run a single test file
+xcodebuild test -scheme MiniSim -destination 'platform=macOS' \
+  -only-testing:MiniSimTests/DeviceParserTests
+
+# Run a single test method
+xcodebuild test -scheme MiniSim -destination 'platform=macOS' \
+  -only-testing:MiniSimTests/DeviceParserTests/testIOSSimulatorParser
+```
+
+## Linting
+
+SwiftLint is integrated via SPM. Config in `.swiftlint.yml`.
+
+```bash
+# Run SwiftLint
+swiftlint
+
+# Auto-fix issues
+swiftlint --fix
+```
+
+## Project Structure
+
+```
+MiniSim/
+├── Model/           # Data models (Device, Command, Platform, etc.)
+├── Service/         # Business logic and services
+│   ├── CustomErrors/   # Custom error types
+│   └── Terminal/       # Terminal integration
+├── Views/           # SwiftUI views
+│   ├── Onboarding/     # Onboarding flow
+│   ├── CustomCommands/ # Custom commands UI
+│   └── ParametersTable/ # Parameters management
+├── Extensions/      # Swift extensions
+├── MenuItems/       # NSMenu item implementations
+├── Components/      # Reusable UI components
+└── AppleScript Commands/ # AppleScript integration
+```
+
+## Code Style Guidelines
+
+### Imports
+- Sort imports alphabetically (enforced by SwiftLint `sorted_imports`)
+- Group Foundation/AppKit imports first, then third-party
+
+```swift
+import AppKit
+import Foundation
+import UserNotifications
+```
+
+### Naming Conventions
+- Types: `PascalCase` (e.g., `DeviceService`, `ActionFactory`)
+- Variables/functions: `camelCase`
+- Enums: `PascalCase` for type, `camelCase` for cases
+- Protocols: Suffix with `Protocol` for dependency injection (e.g., `ShellProtocol`, `ADBProtocol`)
+- `id` and `ID` are allowed as identifier names
+
+### Types and Protocols
+- Use protocols for dependency injection and testability
+- Prefer `struct` for data models, `class` for services with state
+- Use `final class` when inheritance is not needed
+
+```swift
+protocol DeviceServiceCommon {
+  var shell: ShellProtocol { get set }
+  var device: Device { get }
+  func deleteDevice() throws
+}
+
+struct Device: Hashable, Codable {
+  var name: String
+  var identifier: String?
+  var booted: Bool
+}
+```
+
+### Error Handling
+- Define custom errors as enums conforming to `Error` and `LocalizedError`
+- Group related errors in `Service/CustomErrors/`
+- Provide meaningful `errorDescription` for user-facing messages
+
+```swift
+enum DeviceError: Error, Equatable {
+  case deviceNotFound
+  case xcodeError
+  case unexpected(code: Int)
+}
+
+extension DeviceError: LocalizedError {
+  public var errorDescription: String? {
+    switch self {
+    case .deviceNotFound:
+      return NSLocalizedString("Selected device was not found...", comment: "")
+    }
+  }
+}
+```
+
+### SwiftUI Views
+- Use MVVM pattern with nested `ViewModel` class
+- ViewModels extend from view type (e.g., `CustomCommands.ViewModel`)
+- Use `@Published` for observable state
+
+```swift
+extension CustomCommands {
+  class ViewModel: ObservableObject {
+    @Published var commands: [Command] = []
+    @Published var showForm = false
+  }
+}
+```
+
+### Extensions
+- File naming: `TypeName+Feature.swift` (e.g., `UserDefaults+Configuration.swift`)
+- One extension purpose per file
+
+### Factory Pattern
+- Use factory classes for creating platform-specific implementations
+- Follow `ActionFactory` pattern for iOS/Android differentiation
+
+```swift
+class AndroidActionFactory: ActionFactory {
+  static func createAction(for tag: SubMenuItems.Tags, ...) -> any Action {
+    switch tag {
+    case .copyName: return CopyNameAction(device: device)
+    }
+  }
+}
+```
+
+### Testing
+- Test files mirror source structure in `MiniSimTests/`
+- Use `@testable import MiniSim`
+- Create stub/mock classes for dependencies (see `Mocks/ShellStub.swift`)
+- Override class methods in nested test classes for mocking
+
+```swift
+class ADBTests: XCTestCase {
+  var shellStub: ShellStub!
+
+  override func setUp() {
+    shellStub = ShellStub()
+    ADB.shell = shellStub
+  }
+}
+```
+
+### SwiftLint Rules (Key Enabled)
+- `sorted_imports` - alphabetical import ordering
+- `implicit_return` - omit return in single-expression closures
+- `trailing_closure` - use trailing closure syntax
+- `vertical_whitespace_closing_braces` - no blank lines before closing braces
+- `shorthand_optional_binding` - use `if let x` instead of `if let x = x`
+- `weak_delegate` - delegates should be weak
+
+### Disabled Rules
+- `nesting` - nested types are allowed
+
+### Documentation
+- Add JSDoc-style comments for new public functions
+- Focus on "why" not "what" for complex logic
+- No comments in JSX/SwiftUI describing what renders
+
+### Threading
+- Use `Thread.assertBackgroundThread()` for background-only operations
+- Main thread assertions available via `Thread+Asserts.swift`
+
+## Dependencies (SPM)
+- `KeyboardShortcuts` - Global keyboard shortcuts
+- `LaunchAtLogin` - Login item management
+- `Sparkle` - Auto-updates
+- `ShellOut` - Shell command execution
+- `CodeEditor` - Code editing in preferences
+- `SymbolPicker` - SF Symbol picker
+- `Settings` - Preferences window
+- `AcknowList` - Acknowledgements
+- `SwiftLint` - Linting (build plugin)