Yattee v2 rewrite

Yattee/Services/Navigation/ConnectivityMonitor.swift

@@ -0,0 +1,58 @@
+//
+//  ConnectivityMonitor.swift
+//  Yattee
+//
+//  Network connectivity monitoring for offline mode support.
+//
+
+import Foundation
+import Network
+
+/// Monitors network connectivity status.
+@Observable
+final class ConnectivityMonitor: @unchecked Sendable {
+    /// Whether the device is currently online.
+    private(set) var isOnline: Bool = true
+
+    /// Whether we're on a cellular connection.
+    private(set) var isCellular: Bool = false
+
+    /// Whether the connection is considered expensive (cellular or hotspot).
+    private(set) var isExpensive: Bool = false
+
+    /// Whether the connection is constrained (low data mode).
+    private(set) var isConstrained: Bool = false
+
+    private let monitor = NWPathMonitor()
+    private let queue = DispatchQueue(label: "stream.yattee.connectivity")
+
+    // MARK: - Lifecycle
+
+    init() {
+        startMonitoring()
+    }
+
+    deinit {
+        stopMonitoring()
+    }
+
+    // MARK: - Monitoring
+
+    /// Start monitoring network connectivity.
+    func startMonitoring() {
+        monitor.pathUpdateHandler = { [weak self] path in
+            Task { @MainActor [weak self] in
+                self?.isOnline = path.status == .satisfied
+                self?.isCellular = path.usesInterfaceType(.cellular)
+                self?.isExpensive = path.isExpensive
+                self?.isConstrained = path.isConstrained
+            }
+        }
+        monitor.start(queue: queue)
+    }
+
+    /// Stop monitoring network connectivity.
+    func stopMonitoring() {
+        monitor.cancel()
+    }
+}