Substage's flippy out command bar

PromptWindowController.swift

import AppKit
import SwiftUI

class PromptWindowController: NSWindowController, NSWindowDelegate {
    
    // Essential properties
    private var promptWindowContext: PromptWindowContext
    private let finderContext: FinderContext
    
    init() {
        self.finderContext = FinderContext()
        self.promptWindowContext = PromptWindowContext()
        
        super.init(window: nil)
        
        // Initialize the prompt window context
        self.promptWindowContext = PromptWindowContext(
            window: nil,
            onDidAnimateClosed: { self.close() },
            onUseWithoutSubscription: {}
        )
        
        // Create and configure the window
        let window = NSWindow(
            contentRect: NSRect(x: 100, y: 400, width: 800, height: promptBarHeight),
            styleMask: [.titled, .closable, .miniaturizable, .resizable],
            backing: .buffered,
            defer: false
        )
        window.delegate = self
        
        // Set up the SwiftUI view
        let promptWindowControllerView = PromptWindowControllerView()
            .environment(\.finderContext, finderContext)
            .environment(\.promptWindowContext, promptWindowContext)
        
        // Configure the hosting controller
        let hostingController = NSHostingController(rootView: promptWindowControllerView)
        hostingController.sizingOptions = NSHostingSizingOptions.maxSize
        hostingController.view.translatesAutoresizingMaskIntoConstraints = false
        window.contentViewController = hostingController
        
        // Style the window
        window.hasShadow = true
        window.backgroundColor = .clear
        window.isOpaque = false
        
        // Hide standard window buttons
        window.standardWindowButton(.closeButton)?.isHidden = true
        window.standardWindowButton(.miniaturizeButton)?.isHidden = true
        window.standardWindowButton(.zoomButton)?.isHidden = true
        window.styleMask.remove(.resizable)
        window.titleVisibility = .hidden
        window.titlebarAppearsTransparent = true
        
        window.setContentSize(NSSize(width: 800, height: promptBarHeight))
        
        self.window = window
        
        // Show the window and position it
        window.makeKeyAndOrderFront(nil)
        updatePosition()
        
        // Start monitoring Finder windows
        finderContext.startRefreshLoop()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    // MARK: - Window Positioning
    
    func updatePosition() {
        if let bounds = FinderWindowTracker.topFinderWindowBounds() {
            attachWindow(belowFinderWindowWithBounds: bounds)
        }
    }
    
    func attachWindow(belowFinderWindowWithBounds bounds: CGRect) {
        guard let window = self.window else { return }
        
        if let targetFrame = calculateTargetWindowFrame(window: window, belowFinderWindowWithBounds: bounds) {
            window.setFrame(targetFrame, display: false)
            promptWindowContext.windowWidth = targetFrame.width
        }
        
        // Set window level based on whether Finder is active
        if let activeApp = NSWorkspace.shared.frontmostApplication {
            window.level = activeApp.bundleIdentifier == "com.apple.finder" ? .floating : .normal
        } else {
            window.level = .normal
        }
    }
    
    func calculateTargetWindowFrame(window: NSWindow, belowFinderWindowWithBounds bounds: CGRect) -> NSRect? {
        // Find the primary screen
        let primaryScreen = NSScreen.screens.first { $0.frame.origin == .zero }
        guard let primaryScreen else { return nil }
        
        // Convert Finder window bounds to NSWindow coordinate system (origin at bottom left)
        let finderWindowBounds = CGRect(
            x: bounds.origin.x,
            y: primaryScreen.frame.height - bounds.origin.y - bounds.height,
            width: bounds.width,
            height: bounds.height
        )
        
        // Find which screen the Finder window is on
        let finderWindowCenterX = finderWindowBounds.origin.x + finderWindowBounds.width / 2
        let pointBelowTopEdge = finderWindowBounds.origin.y + finderWindowBounds.height - 100
        let anchorPoint = CGPoint(x: finderWindowCenterX, y: pointBelowTopEdge)
        
        let screenContainingCenter = NSScreen.screens.first { screen in
            return screen.frame.contains(anchorPoint)
        }
        
        let targetScreen = screenContainingCenter ?? primaryScreen
        
        // Position just below the finder window
        let padding: CGFloat = 2
        let hiddenTitleBarHeight: CGFloat = 14
        let yPosition = finderWindowBounds.origin.y - promptBarHeight - padding + hiddenTitleBarHeight
        
        let targetFrame = NSRect(
            x: finderWindowBounds.origin.x,
            y: yPosition,
            width: bounds.width,
            height: promptBarHeight
        )
        
        // Ensure window is not obscured by the dock
        let targetVisibleFrame = targetScreen.visibleFrame
        let clampedFrame = NSRect(
            x: targetFrame.minX - transparentMarginWidth,
            y: max(targetVisibleFrame.minY, targetFrame.minY),
            width: targetFrame.width + 2*transparentMarginWidth,
            height: targetFrame.height
        )
        
        return clampedFrame
    }
    
    // MARK: - Window Delegate Methods
    
    func windowWillClose(_ notification: Notification) {
        finderContext.stopRefreshLoop()
    }
}

PromptWindowControllerView.swift

import SwiftUI

struct PromptWindowControllerView: View {    
    @State var flippedOpen: Bool = false

    @Environment(\.promptWindowContext) var promptWindowContext

    var body: some View {
        VStack(spacing:0) {
            HStack(spacing:0) {
                PromptWindowContentView()
                .frame(width:promptWindowContext.windowWidth - 2*transparentMarginWidth)
                .clipped()
                .background(
                    UnevenRoundedRectangle(topLeadingRadius: 11,
                                        bottomLeadingRadius: 18,
                                        bottomTrailingRadius: 18,
                                        topTrailingRadius: 11)
                    .fill(Material.thickMaterial)
                )
                .rotation3DEffect(
                    .degrees(flippedOpen ? 0 : -90),
                    axis: (x: 1.0, y: 0.0, z: 0.0),
                    anchor:.top
                )
                .opacity(flippedOpen ? 1.0 : 0.0)
                .onAppear {
                    withAnimation(.bouncy(duration: 0.4, extraBounce: 0.4)) {
                        flippedOpen = true
                    }
                }
                .onChange(of: promptWindowContext.shouldAnimateClosed) {
                    if promptWindowContext.shouldAnimateClosed {
                        withAnimation(.easeIn(duration: 0.2)) {
                            flippedOpen = false
                        }
                    }
                }
                .padding(.horizontal, transparentMarginWidth)
            }
            
            Spacer().frame(height: 20)
        }
        .frame(height: promptBarHeight)
    }
}