Add check for last switch <1s

[yspreen]

fixes #1089

[nikitabobko]

Merged with the following stylistic patch:

diff --git a/Sources/AppBundle/focus.swift b/Sources/AppBundle/focus.swift
index 8d87e259..a5216a06 100644
--- a/Sources/AppBundle/focus.swift
+++ b/Sources/AppBundle/focus.swift
@@ -106,7 +106,7 @@ private var _lastKnownFocus: FrozenFocus = _focus
 // Used by workspace-back-and-forth
 var _prevFocusedWorkspaceName: String? = nil {
     didSet {
-        prevFocusedWorkspaceDate = Date()
+        prevFocusedWorkspaceDate = .now
     }
 }
 var prevFocusedWorkspaceDate: Date = .distantPast
diff --git a/Sources/AppBundle/tree/MacWindow.swift b/Sources/AppBundle/tree/MacWindow.swift
index fcf10cbc..c3e626cf 100644
--- a/Sources/AppBundle/tree/MacWindow.swift
+++ b/Sources/AppBundle/tree/MacWindow.swift
@@ -73,10 +73,10 @@ final class MacWindow: Window, CustomStringConvertible {
             AXObserverRemoveNotification(obs.obs, obs.ax, obs.notif)
         }
         axObservers = []
-        // todo the if is an approximation to filter out cases when window just closed itself (or was killed remotely)
-        // we check if the workspace switch was <1s ago
         let focus = focus
-        if let deadWindowWorkspace, deadWindowWorkspace == focus.workspace || (deadWindowWorkspace == prevFocusedWorkspace && -prevFocusedWorkspaceDate.timeIntervalSinceNow < 1) {
+        if let deadWindowWorkspace, deadWindowWorkspace == focus.workspace ||
+            deadWindowWorkspace == prevFocusedWorkspace && prevFocusedWorkspaceDate.distance(to: .now) < 1
+        {
             switch parent.cases {
                 case .tilingContainer, .workspace, .macosHiddenAppsWindowsContainer, .macosFullscreenWindowsContainer:
                     let deadWindowFocus = deadWindowWorkspace.toLiveFocus()