[Local catalog] Hide cellular toggle on non-cellular devices (#16412)

Author: joshheald

Modules/Sources/PointOfSale/Presentation/Settings/POSSettingsLocalCatalogDetailView.swift

@@ -18,7 +18,9 @@ struct POSSettingsLocalCatalogDetailView: View {
                 ScrollView {
                     VStack(spacing: POSSpacing.medium) {
                         catalogStatus
-                        managingDataUsage
+                        if viewModel.deviceHasCellularCapability {
+                            managingDataUsage
+                        }
                         manualCatalogUpdate
                     }
                     .padding(.horizontal, POSPadding.medium)

Modules/Sources/PointOfSale/Presentation/Settings/POSSettingsLocalCatalogViewModel.swift

@@ -2,6 +2,7 @@ import CocoaLumberjackSwift
 import Yosemite
 import Foundation
 import Storage
+import WooFoundation
 
 @Observable
 final class POSSettingsLocalCatalogViewModel {
@@ -11,6 +12,7 @@ final class POSSettingsLocalCatalogViewModel {
 
     private(set) var isLoading: Bool = false
     private(set) var isRefreshingCatalog: Bool = false
+    let deviceHasCellularCapability: Bool = CellularCapabilityChecker.deviceHasCellularCapability()
 
     var catalogRefreshError: POSIdentifiableErrorState? = nil
 

Modules/Sources/WooFoundation/Utilities/Connectivity/CellularCapabilityChecker.swift

@@ -0,0 +1,26 @@
+import Darwin
+
+public struct CellularCapabilityChecker {
+    public static func deviceHasCellularCapability() -> Bool {
+        var addrs: UnsafeMutablePointer<ifaddrs>?
+        guard getifaddrs(&addrs) == 0 else { return false }
+        defer { freeifaddrs(addrs) }
+
+        var cursor = addrs
+        while let addr = cursor {
+            guard let namePtr = addr.pointee.ifa_name else {
+                cursor = addr.pointee.ifa_next
+                continue
+            }
+
+            let name = String(cString: namePtr)
+            // This isn't a great check, but the alternatives are deprecated, and apparently it's commonly used.
+            // pdp_ip0 is the first cellular interface – it's not present if there's no cellular hardware.
+            if name == "pdp_ip0" {
+                return true
+            }
+            cursor = addr.pointee.ifa_next
+        }
+        return false
+    }
+}