Domain Entities: Unit 3 — Focus & Immersion

struct FocusModeState: Equatable {
    var isEnabled: Bool
    var activeBlockID: EditorNode.ID?
    var dimmingConfiguration: DimmingConfiguration
    var transitionStyle: TransitionStyle
}

enum TransitionStyle: Equatable {
    case animated(duration: TimeInterval)   // Default: 0.2s fade
    case immediate                          // Used when "Reduce motion" is enabled
}

struct DimmingConfiguration: Equatable {
    var inactiveAlpha: CGFloat              // Alpha for non-active blocks (default: 0.3)
    var activeAlpha: CGFloat                // Alpha for the active block (default: 1.0)
    var dimmingGranularity: DimmingGranularity
}

enum DimmingGranularity: Equatable {
    case paragraph                          // Dim all blocks except the one containing the cursor
}

struct TypewriterScrollState: Equatable {
    var isEnabled: Bool
    var centerOffset: CGFloat?              // Computed: vertical center of the visible rect
    var activeLineRect: CGRect?             // Layout rect of the line containing the cursor
    var scrollBehavior: ScrollBehavior
}

enum ScrollBehavior: Equatable {
    case smooth(duration: TimeInterval)     // Default: 0.15s animation
    case immediate                          // Used when "Reduce motion" is enabled
    case suppressed                         // Short document — no scroll needed
}

struct FullScreenState: Equatable {
    var isFullScreen: Bool
    var toolbarPolicy: ToolbarPolicy
    var sidebarPolicy: SidebarPolicy
}

enum ToolbarPolicy: Equatable {
    case alwaysVisible                      // Normal windowed mode
    case autoHide                           // Full-screen: hide after inactivity
}

enum SidebarPolicy: Equatable {
    case visible                            // Normal windowed mode
    case hidden                             // Full-screen: sidebar collapsed
    case autoHide                           // Full-screen: show on hover near edge
}

extension EditorSettings {
    // Already declared in EditorSettings (Unit 2):
    var defaultFocusMode: Bool              // Persist focus mode on/off (default: false)
    var defaultTypewriterScroll: Bool       // Persist typewriter scroll on/off (default: false)

    // Dimming preferences (new):
    var focusDimmingAlpha: CGFloat          // Inactive block alpha (default: 0.3)
}

struct ActiveBlockRange: Equatable {
    var blockID: EditorNode.ID
    var textRange: NSRange                  // Range in the NSTextStorage
    var layoutRect: CGRect                  // Bounding rect from NSTextLayoutManager
}

enum FocusImmersionShortcut {
    case toggleFocusMode                    // Cmd+Shift+F
    case toggleTypewriterScroll             // Cmd+Ctrl+T
    case toggleFullScreen                   // Ctrl+Cmd+F (macOS standard)
}