macOS: Manage tunnels: Export tunnels pulldown menu implementation

Signed-off-by: Roopesh Chander <roop@roopc.net>

WireGuard/WireGuard/UI/macOS/ViewController/TunnelsListTableViewController.swift

@@ -146,8 +146,27 @@ class TunnelsListTableViewController: NSViewController {
     @objc func exportLogClicked() {
         print("exportLogClicked")
     }
+
     @objc func exportTunnelsClicked() {
-        print("exportTunnelsClicked")
+        guard let window = view.window else { return }
+        let savePanel = NSSavePanel()
+        savePanel.allowedFileTypes = ["zip"]
+        savePanel.prompt = "Save"
+        savePanel.nameFieldLabel = "Export tunnels to"
+        savePanel.nameFieldStringValue = "wireguard-export.zip"
+        savePanel.beginSheetModal(for: window) { [weak tunnelsManager] response in
+            guard let tunnelsManager = tunnelsManager else { return }
+            guard response == .OK else { return }
+            guard let destinationURL = savePanel.url else { return }
+            let count = tunnelsManager.numberOfTunnels()
+            let tunnelConfigurations = (0 ..< count).compactMap { tunnelsManager.tunnel(at: $0).tunnelConfiguration }
+            ZipExporter.exportConfigFiles(tunnelConfigurations: tunnelConfigurations, to: destinationURL) { [weak self] error in
+                if let error = error {
+                    ErrorPresenter.showErrorAlert(error: error, from: self)
+                    return
+                }
+            }
+        }
     }
 
     @discardableResult