feat: add status notifications for server monitoring

- Add notification preferences (Status Notifications and Alert Notifications toggles)
- Implement ping failure/recovery notifications when servers go offline/online
- Track individual service status changes and notify when services fail
- Request notification permissions on app launch
- Services like DNS, FTP, SSH, etc. now trigger alerts when status changes
- Notifications only sent when settings are enabled

Changes:
- PreferencesView: Add NotificationsPreferencesView with two toggles
- PingService: Add notification support with state tracking for ping events
- MainView: Add service status monitoring with change detection
- Track previous service states to detect transitions

Sources/Model/API/PingService.swift

@@ -1,7 +1,10 @@
 import Foundation
+import UserNotifications
 
 enum PingService {
-    static func ping(hostname: String, apiKey: String) async -> Bool {
+    private static var previousPingStates: [String: Bool] = [:]
+
+    static func ping(hostname: String, apiKey: String, notificationsEnabled: Bool = true) async -> Bool {
         guard let url = URL(string: "https://\(hostname)/api/v2/ping") else {
             print("❌ [PingService] Invalid URL for \(hostname)")
             return false
@@ -18,17 +21,49 @@ enum PingService {
                 if let responseString = String(data: data, encoding: .utf8) {
                     print("❌ [PingService] HTTP \(httpResponse.statusCode): \(responseString)")
                 }
+                handlePingFailure(for: hostname, notificationsEnabled: notificationsEnabled)
                 return false
             }
 
             if let result = try? JSONDecoder().decode([String: String].self, from: data), result["response"] == "pong" {
+                handlePingSuccess(for: hostname, notificationsEnabled: notificationsEnabled)
                 return true
             } else {
+                handlePingFailure(for: hostname, notificationsEnabled: notificationsEnabled)
                 return false
             }
         } catch {
             print("❌ [PingService] Error pinging \(hostname): \(error)")
+            handlePingFailure(for: hostname, notificationsEnabled: notificationsEnabled)
             return false
         }
     }
+
+    private static func handlePingSuccess(for hostname: String, notificationsEnabled: Bool) {
+        let wasPreviouslyDown = previousPingStates[hostname] == false
+        previousPingStates[hostname] = true
+
+        if wasPreviouslyDown && notificationsEnabled {
+            sendNotification(title: "Server Online", body: "\(hostname) is now online")
+        }
+    }
+
+    private static func handlePingFailure(for hostname: String, notificationsEnabled: Bool) {
+        let wasPreviouslyUp = previousPingStates[hostname] != false
+        previousPingStates[hostname] = false
+
+        if wasPreviouslyUp && notificationsEnabled {
+            sendNotification(title: "Server Offline", body: "\(hostname) is offline")
+        }
+    }
+
+    private static func sendNotification(title: String, body: String) {
+        let content = UNMutableNotificationContent()
+        content.title = title
+        content.body = body
+        content.sound = .default
+
+        let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: nil)
+        UNUserNotificationCenter.current().add(request)
+    }
 }

Sources/Views/MainView.swift

@@ -7,6 +7,7 @@
 
 import SwiftUI
 import Combine
+import UserNotifications
 
 struct MainView: View {
     
@@ -20,9 +21,13 @@ struct MainView: View {
     @State private var isFetchingInfo: Bool = false
     @AppStorage("pingInterval") private var pingInterval: Int = 10
     @AppStorage("refreshInterval") private var refreshInterval: Int = 60
+    @AppStorage("enableStatusNotifications") private var enableStatusNotifications: Bool = true
+    @AppStorage("enableAlertNotifications") private var enableAlertNotifications: Bool = true
     @State private var refreshTimer: Timer.TimerPublisher?
     @State private var refreshSubscription: AnyCancellable?
     @State private var pingTimer: Timer?
+    @State private var lastRefreshInterval: Int?
+    @State private var previousServiceStates: [String: String] = [:]
     private let serverOrderKey = MainView.serverOrderKeyStatic
     private let storedServersKey = MainView.storedServersKeyStatic
 
@@ -102,6 +107,8 @@ struct MainView: View {
             Button("Cancel", role: .cancel) {}
         }
         .onAppear {
+            requestNotificationPermissions()
+
             let initialID: UUID?
             if let storedID = UserDefaults.standard.string(forKey: "selectedServerID"),
                let uuid = UUID(uuidString: storedID),
@@ -128,8 +135,10 @@ struct MainView: View {
         .onChange(of: pingInterval) { _, _ in
             setupPingTimer()
         }
-        .onChange(of: refreshInterval) { _, _ in
-            setupRefreshTimer()
+        .onChange(of: refreshInterval) { oldValue, newValue in
+            if oldValue != newValue {
+                setupRefreshTimer()
+            }
         }
         .frame(minWidth: 800, minHeight: 450)
     }
@@ -161,6 +170,7 @@ struct MainView: View {
                         var updated = servers[index]
                         updated.info = info
                         servers[index] = updated
+                        checkServiceStatusChanges(for: server.hostname, newInfo: info)
                     }
                 }
             } catch {
@@ -221,7 +231,7 @@ struct MainView: View {
         for (index, server) in servers.enumerated() {
             Task {
                 let apiKey = KeychainHelper.loadApiKey(for: server.hostname)?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
-                let pingable = await PingService.ping(hostname: server.hostname, apiKey: apiKey)
+                let pingable = await PingService.ping(hostname: server.hostname, apiKey: apiKey, notificationsEnabled: enableStatusNotifications)
                 await MainActor.run {
                     servers[index].pingable = pingable
                 }
@@ -246,6 +256,7 @@ struct MainView: View {
     }
 
     private func setupRefreshTimer() {
+        refreshSubscription?.cancel()
         refreshSubscription = nil
         refreshTimer = Timer.publish(every: Double(refreshInterval), on: .main, in: .common)
         refreshSubscription = refreshTimer?.autoconnect().sink { _ in
@@ -281,6 +292,46 @@ struct MainView: View {
             return []
         }
     }
+
+    private func requestNotificationPermissions() {
+        Task {
+            do {
+                try await UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound])
+            } catch {
+                print("❌ [MainView] Failed to request notification permissions: \(error)")
+            }
+        }
+    }
+
+    private func checkServiceStatusChanges(for hostname: String, newInfo: ServerInfo) {
+        guard let ports = newInfo.ports else { return }
+
+        for port in ports {
+            let key = "\(hostname)-\(port.id)"
+            let previousStatus = previousServiceStates[key]
+            let currentStatus = port.status
+
+            previousServiceStates[key] = currentStatus
+
+            if let previousStatus, previousStatus != currentStatus {
+                if currentStatus == "offline" && enableStatusNotifications {
+                    sendServiceNotification(service: port.service, hostname: hostname, status: "offline")
+                } else if currentStatus == "online" && previousStatus == "offline" && enableStatusNotifications {
+                    sendServiceNotification(service: port.service, hostname: hostname, status: "online")
+                }
+            }
+        }
+    }
+
+    private func sendServiceNotification(service: String, hostname: String, status: String) {
+        let content = UNMutableNotificationContent()
+        content.title = "\(service) \(status.uppercased())"
+        content.body = "\(service) on \(hostname) is \(status)"
+        content.sound = .default
+
+        let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: nil)
+        UNUserNotificationCenter.current().add(request)
+    }
 }
 
 #Preview {

Sources/Views/PreferencesView.swift

@@ -260,19 +260,18 @@ private struct UpdatesPreferencesView: View {
 }
 
 private struct NotificationsPreferencesView: View {
-    var body: some View {
-        VStack(alignment: .leading, spacing: 12) {
-            Text("Notifications")
-                .font(.headline)
-                .padding(.bottom)
+    @AppStorage("enableStatusNotifications") private var enableStatusNotifications: Bool = true
+    @AppStorage("enableAlertNotifications") private var enableAlertNotifications: Bool = true
 
-            Text("Configure notification behavior here.")
-                .foregroundColor(.secondary)
+    var body: some View {
+        VStack(alignment: .leading, spacing: 18) {
+            Toggle("Status Notifications", isOn: $enableStatusNotifications)
+            Toggle("Alert Notifications", isOn: $enableAlertNotifications)
 
             Spacer()
         }
+        .toggleStyle(.switch)
         .frame(maxWidth: .infinity, alignment: .leading)
-        .padding()
     }
 }