macos: quick terminal restores focus to previous application

macos/Sources/Features/QuickTerminal/QuickTerminalController.swift

@@ -13,6 +13,11 @@ class QuickTerminalController: BaseTerminalController {
     /// The current state of the quick terminal
     private(set) var visible: Bool = false
 
+    /// The previously running application when the terminal is shown. This is NEVER Ghostty.
+    /// If this is set then when the quick terminal is animated out then we will restore this
+    /// application to the front.
+    private var previousApp: NSRunningApplication? = nil
+
     init(_ ghostty: Ghostty.App,
          position: QuickTerminalPosition = .top,
          baseConfig base: Ghostty.SurfaceConfiguration? = nil,
@@ -58,10 +63,23 @@ class QuickTerminalController: BaseTerminalController {
     override func windowDidResignKey(_ notification: Notification) {
         super.windowDidResignKey(notification)
 
+        // If we're not visible then we don't want to run any of the logic below
+        // because things like resetting our previous app assume we're visible.
+        // windowDidResignKey will also get called after animateOut so this
+        // ensures we don't run logic twice.
+        guard visible else { return }
+
         // We don't animate out if there is a modal sheet being shown currently.
         // This lets us show alerts without causing the window to disappear.
         guard window?.attachedSheet == nil else { return }
 
+        // If our app is still active, then it means that we're switching
+        // to another window within our app, so we remove the previous app
+        // so we don't restore it.
+        if NSApp.isActive {
+            self.previousApp = nil
+        }
+
         animateOut()
     }
 
@@ -103,6 +121,14 @@ class QuickTerminalController: BaseTerminalController {
         // If our application is not active, then we grab focus. The quick terminal
         // always grabs focus on animation in.
         if !NSApp.isActive {
+            // If we have a previously focused application and it isn't us, then
+            // we want to store it so we can restore state later.
+            if let previousApp = NSWorkspace.shared.frontmostApplication,
+               previousApp.bundleIdentifier != Bundle.main.bundleIdentifier
+            {
+                self.previousApp = previousApp
+            }
+
             NSApp.activate(ignoringOtherApps: true)
         }
 
@@ -178,6 +204,18 @@ class QuickTerminalController: BaseTerminalController {
             // This causes the window to be removed from the screen list and macOS
             // handles what should be focused next.
             window.orderOut(self)
+
+            // If we have a previously active application, restore focus to it.
+            if let previousApp = self.previousApp {
+                // Make sure we unset the state no matter what
+                self.previousApp = nil
+
+                // If the app is terminated to nothing
+                guard !previousApp.isTerminated else { return }
+
+                // Ignore the result, it doesn't change our behavior.
+                _ = previousApp.activate(options: [])
+            }
         })
     }