Sesame-iOS/Sesame/SettingsView.swift

import SwiftUI

struct SettingsView: View {

    @Binding
    var keyManager: KeyManagement
    
    @Binding
    var serverAddress: String
    
    @Binding
    var localAddress: String
    
    @Binding
    var deviceID: Int
    
    @Binding
    var nextMessageCounter: Int

    @Binding
    var isCompensatingDaylightTime: Bool
    
    @Binding
    var useLocalConnection: Bool
    
    @State
    private var showDeviceIdInput = false
    
    @State
    private var deviceIdText = ""
    
    @State
    private var showCounterInput = false
    
    @State
    private var counterText = ""
    
    
    var body: some View {
        NavigationView {
            ScrollView {
                VStack(alignment: .leading, spacing: 8) {
                    VStack(alignment: .leading) {
                        Text("Server address")
                            .bold()
                        TextField("Server address", text: $serverAddress)
                            .foregroundColor(.secondary)
                            .padding(.leading, 8)
                    }.padding(.vertical, 8)
                    VStack(alignment: .leading) {
                        Text("Local address")
                            .bold()
                        TextField("Local address", text: $localAddress)
                            .foregroundColor(.secondary)
                            .padding(.leading, 8)
                    }.padding(.vertical, 8)
                    Toggle(isOn: $useLocalConnection) {
                        Text("Use direct connection to device")
                    }
                    Text("Attempt to communicate directly with the device. This is useful if the server is unavailable. Requires a WiFi connection on the same network as the device.")
                        .font(.caption)
                        .foregroundColor(.secondary)
                    VStack(alignment: .leading) {
                        Text("Device id")
                            .bold()
                        HStack(alignment: .bottom) {
                            Text("\(deviceID)")
                                .font(.system(.body, design: .monospaced))
                                .foregroundColor(.secondary)
                                .padding([.trailing, .bottom])
                            Button("Edit", action: showAlertToChangeDeviceID)
                                .padding([.horizontal, .bottom])
                                .padding(.top, 4)
                        }
                    }.padding(.vertical, 8)
                    VStack(alignment: .leading) {
                        Text("Message counter")
                            .bold()
                        HStack(alignment: .bottom) {
                            Text("\(nextMessageCounter)")
                                .font(.system(.body, design: .monospaced))
                                .foregroundColor(.secondary)
                                .padding([.trailing, .bottom])
                            Button("Edit", action: showAlertToChangeCounter)
                                .padding([.horizontal, .bottom])
                                .padding(.top, 4)
                        }
                    }.padding(.vertical, 8)
                    ForEach(KeyManagement.KeyType.allCases) { keyType in
                        SingleKeyView(
                            keyManager: $keyManager,
                            type: keyType)
                    }
                    Toggle(isOn: $isCompensatingDaylightTime) {
                        Text("Compensate daylight savings time")
                    }
                    Text("If the remote has daylight savings time wrongly set, then the time validation will fail. Use this option to send messages with adjusted timestamps. Warning: Incorrect use of this option will allow replay attacks.")
                        .font(.caption)
                        .foregroundColor(.secondary)
                }.padding()
            }.onDisappear {
                if !localAddress.hasSuffix("/") {
                    localAddress += "/"
                }
            }
            .navigationTitle("Settings")
            .alert("Update device ID", isPresented: $showDeviceIdInput, actions: {
                TextField("Device ID", text: $deviceIdText)
                    .keyboardType(.decimalPad)
                    .font(.system(.body, design: .monospaced))
                    .foregroundColor(.black)
                Button("Save", action: saveDeviceID)
                Button("Cancel", role: .cancel, action: {})
            }, message: {
                Text("Enter the device ID")
            })
            .alert("Update message counter", isPresented: $showCounterInput, actions: {
                TextField("Message counter", text: $counterText)
                    .keyboardType(.decimalPad)
                    .font(.system(.body, design: .monospaced))
                    .foregroundColor(.black)
                Button("Save", action: saveCounter)
                Button("Cancel", role: .cancel, action: {})
            }, message: {
                Text("Enter the message counter")
            })
        }
    }
    
    private func showAlertToChangeDeviceID() {
        deviceIdText = "\(deviceID)"
        showDeviceIdInput = true
    }
    
    private func saveDeviceID() {
        guard let id = UInt8(deviceIdText) else {
            print("Invalid device id '\(deviceIdText)'")
            return
        }
        self.deviceID = Int(id)
    }
    
    private func showAlertToChangeCounter() {
        counterText = "\(nextMessageCounter)"
        showCounterInput = true
    }
    
    private func saveCounter() {
        guard let id = UInt32(counterText) else {
            print("Invalid message counter '\(counterText)'")
            return
        }
        self.nextMessageCounter = Int(id)
    }
}

struct SettingsView_Previews: PreviewProvider {
    static var previews: some View {
        SettingsView(
            keyManager: .constant(KeyManagement()),
            serverAddress: .constant("https://example.com"),
            localAddress: .constant("192.168.178.42"),
            deviceID: .constant(0),
            nextMessageCounter: .constant(12345678),
            isCompensatingDaylightTime: .constant(true),
            useLocalConnection: .constant(false))
    }
}