//
//  ContentView.swift
//  StosVPN
//
//  Created by Stossy11 on 28/03/2025.
//

import SwiftUI
import Foundation
import NetworkExtension


// MARK: - Logging Utility
class VPNLogger: ObservableObject {
    @Published var logs: [String] = []
    
    static var shared = VPNLogger()
    
    private init() {}
    
    func log(_ message: Any, file: String = #file, function: String = #function, line: Int = #line) {
        #if DEBUG
        let fileName = (file as NSString).lastPathComponent
        print("[\(fileName):\(line)] \(function): \(message)")
        #endif
        
        logs.append("\(message)")
    }
}

// MARK: - Tunnel Manager
class TunnelManager: ObservableObject {
    @Published var hasLocalDeviceSupport = false
    @Published var tunnelStatus: TunnelStatus = .disconnected
    
    static var shared = TunnelManager()
    
    private var vpnManager: NETunnelProviderManager?
    private var vpnObserver: NSObjectProtocol?
    
    private var tunnelDeviceIp: String {
        UserDefaults.standard.string(forKey: "TunnelDeviceIP") ?? "10.7.0.0"
    }
    
    private var tunnelFakeIp: String {
        UserDefaults.standard.string(forKey: "TunnelFakeIP") ?? "10.7.0.1"
    }
    
    private var tunnelSubnetMask: String {
        UserDefaults.standard.string(forKey: "TunnelSubnetMask") ?? "255.255.255.0"
    }
    
    private var tunnelBundleId: String {
        Bundle.main.bundleIdentifier!.appending(".TunnelProv")
    }
    
    enum TunnelStatus: String {
        case disconnected = "Disconnected"
        case connecting = "Connecting"
        case connected = "Connected"
        case disconnecting = "Disconnecting"
        case error = "Error"
        
        var color: Color {
            switch self {
            case .disconnected: return .gray
            case .connecting: return .orange
            case .connected: return .green
            case .disconnecting: return .orange
            case .error: return .red
            }
        }
        
        var systemImage: String {
            switch self {
            case .disconnected: return "network.slash"
            case .connecting: return "network.badge.shield.half.filled"
            case .connected: return "checkmark.shield.fill"
            case .disconnecting: return "network.badge.shield.half.filled"
            case .error: return "exclamationmark.shield.fill"
            }
        }
    }
    
    private init() {
        loadTunnelPreferences()
        setupStatusObserver()
    }
    
    // MARK: - Private Methods
    private func loadTunnelPreferences() {
        NETunnelProviderManager.loadAllFromPreferences { [weak self] (managers, error) in
            guard let self = self else { return }
            
            DispatchQueue.main.async {
                if let error = error {
                    VPNLogger.shared.log("Error loading preferences: \(error.localizedDescription)")
                    self.tunnelStatus = .error
                    return
                }
                
                self.hasLocalDeviceSupport = true
                
                if let managers = managers, !managers.isEmpty {
                    // Look specifically for StosVPN manager
                    for manager in managers {
                        if let proto = manager.protocolConfiguration as? NETunnelProviderProtocol,
                           proto.providerBundleIdentifier == self.tunnelBundleId {
                            self.vpnManager = manager
                            self.updateTunnelStatus(from: manager.connection.status)
                            VPNLogger.shared.log("Loaded existing StosVPN tunnel configuration")
                            break
                        }
                    }
                } else {
                    VPNLogger.shared.log("No existing tunnel configuration found")
                }
            }
        }
    }
    
    private func setupStatusObserver() {
        vpnObserver = NotificationCenter.default.addObserver(
            forName: .NEVPNStatusDidChange,
            object: nil,
            queue: .main
        ) { [weak self] notification in
            guard let self = self,
                  let connection = notification.object as? NEVPNConnection else {
                return
            }
            
            // Only update status if it's our VPN connection
            if let manager = self.vpnManager,
               connection == manager.connection {
                self.updateTunnelStatus(from: connection.status)
            }
        }
    }
    
    private func updateTunnelStatus(from connectionStatus: NEVPNStatus) {
        DispatchQueue.main.async {
            switch connectionStatus {
            case .invalid, .disconnected:
                self.tunnelStatus = .disconnected
            case .connecting:
                self.tunnelStatus = .connecting
            case .connected:
                self.tunnelStatus = .connected
            case .disconnecting:
                self.tunnelStatus = .disconnecting
            case .reasserting:
                self.tunnelStatus = .connecting
            @unknown default:
                self.tunnelStatus = .error
            }
            
            VPNLogger.shared.log("StosVPN status updated: \(self.tunnelStatus.rawValue)")
        }
    }
    
    private func createStosVPNConfiguration(completion: @escaping (NETunnelProviderManager?) -> Void) {
        let manager = NETunnelProviderManager()
        manager.localizedDescription = "StosVPN"
        
        let proto = NETunnelProviderProtocol()
        proto.providerBundleIdentifier = self.tunnelBundleId
        proto.serverAddress = "StosVPN's Local Network Tunnel"
        manager.protocolConfiguration = proto
        
        let onDemandRule = NEOnDemandRuleEvaluateConnection()
        onDemandRule.interfaceTypeMatch = .any
        onDemandRule.connectionRules = [NEEvaluateConnectionRule(
            matchDomains: ["10.7.0.0", "10.7.0.1"],
            andAction: .connectIfNeeded
        )]
        
        manager.onDemandRules = [onDemandRule]
        manager.isOnDemandEnabled = true
        manager.isEnabled = true
        
        manager.saveToPreferences { error in
            DispatchQueue.main.async {
                if let error = error {
                    VPNLogger.shared.log("Error creating StosVPN configuration: \(error.localizedDescription)")
                    completion(nil)
                    return
                }
                
                VPNLogger.shared.log("StosVPN configuration created successfully")
                completion(manager)
            }
        }
    }
    
    private func getActiveVPNManager(completion: @escaping (NETunnelProviderManager?) -> Void) {
        NETunnelProviderManager.loadAllFromPreferences { managers, error in
            if let error = error {
                VPNLogger.shared.log("Error loading VPN configurations: \(error.localizedDescription)")
                completion(nil)
                return
            }
            
            guard let managers = managers else {
                completion(nil)
                return
            }
            
            let activeManager = managers.first { manager in
                return manager.connection.status == .connected ||
                       manager.connection.status == .connecting
            }
            
            completion(activeManager)
        }
    }
    
    // MARK: - Public Methods
    
    func toggleVPNConnection() {
        if tunnelStatus == .connected || tunnelStatus == .connecting {
            stopVPN()
        } else {
            startVPN()
        }
    }
    
    func startVPN() {
        getActiveVPNManager { [weak self] activeManager in
            guard let self = self else { return }
            
            if let activeManager = activeManager,
               (activeManager.protocolConfiguration as? NETunnelProviderProtocol)?.providerBundleIdentifier != self.tunnelBundleId {
                VPNLogger.shared.log("Disconnecting existing VPN connection before starting StosVPN")
                
                // Set a flag to start StosVPN after disconnection
                UserDefaults.standard.set(true, forKey: "ShouldStartStosVPNAfterDisconnect")
                activeManager.connection.stopVPNTunnel()
                return
            }
            
            
            self.initializeAndStartStosVPN()
        }
    }
    
    private func initializeAndStartStosVPN() {
        if let manager = vpnManager {
            startExistingVPN(manager: manager)
        } else {
            createStosVPNConfiguration { [weak self] manager in
                guard let self = self, let manager = manager else { return }
                
                self.vpnManager = manager
                self.startExistingVPN(manager: manager)
            }
        }
    }
    
    private func startExistingVPN(manager: NETunnelProviderManager) {
        guard tunnelStatus != .connected else {
            VPNLogger.shared.log("StosVPN tunnel is already connected")
            return
        }
        
        manager.isEnabled = true
        manager.saveToPreferences { error in
            if let error = error {
                VPNLogger.shared.log(error.localizedDescription)
                return
            }
            
            // Reload it to apply
            manager.loadFromPreferences { error in
                if let error = error {
                    VPNLogger.shared.log(error.localizedDescription)
                    return
                }
                
                self.tunnelStatus = .connecting
                
                let options: [String: NSObject] = [
                    "TunnelDeviceIP": self.tunnelDeviceIp as NSObject,
                    "TunnelFakeIP": self.tunnelFakeIp as NSObject,
                    "TunnelSubnetMask": self.tunnelSubnetMask as NSObject
                ]
                
                do {
                    try manager.connection.startVPNTunnel(options: options)
                    VPNLogger.shared.log("StosVPN tunnel start initiated")
                } catch {
                    self.tunnelStatus = .error
                    VPNLogger.shared.log("Failed to start StosVPN tunnel: \(error.localizedDescription)")
                }
            }
        }
    }
    
    func stopVPN() {
        guard let manager = vpnManager else { return }
        
        tunnelStatus = .disconnecting
        manager.connection.stopVPNTunnel()
        VPNLogger.shared.log("StosVPN tunnel stop initiated")
        
        UserDefaults.standard.removeObject(forKey: "ShouldStartStosVPNAfterDisconnect")
    }
    
    func handleVPNStatusChange(notification: Notification) {
        guard let connection = notification.object as? NEVPNConnection else { return }
        
        if let manager = vpnManager, connection == manager.connection {
            updateTunnelStatus(from: connection.status)
            return
        }
        
        if connection.status == .disconnected &&
           UserDefaults.standard.bool(forKey: "ShouldStartStosVPNAfterDisconnect") {
            UserDefaults.standard.removeObject(forKey: "ShouldStartStosVPNAfterDisconnect")
            
            DispatchQueue.main.asyncAfter(deadline: .now() + 1.0) { [weak self] in
                self?.initializeAndStartStosVPN()
            }
        }
    }
    
    deinit {
        if let observer = vpnObserver {
            NotificationCenter.default.removeObserver(observer)
        }
    }
}

// MARK: - Views

struct ContentView: View {
    @StateObject private var tunnelManager = TunnelManager.shared
    @State private var showSettings = false
    @State var tunnel = false
    @AppStorage("autoConnect") private var autoConnect = false
    @AppStorage("hasNotCompletedSetup") private var hasNotCompletedSetup = true
    
    var body: some View {
        NavigationStack {
            VStack(spacing: 30) {
                Spacer()
                
                StatusIndicatorView()
                
                ConnectionButton(
                    action: {
                        tunnelManager.tunnelStatus == .connected ? tunnelManager.stopVPN() : tunnelManager.startVPN()
                    }
                )
                
                Spacer()
                
                if tunnelManager.tunnelStatus == .connected {
                    ConnectionStatsView()
                }
            }
            .padding()
            .navigationTitle("StosVPN")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .topBarTrailing) {
                    Button {
                        showSettings = true
                    } label: {
                        Image(systemName: "gear")
                            .foregroundColor(.primary)
                    }
                }
            }
            .onAppear() {
                if tunnelManager.tunnelStatus != .connected && autoConnect {
                    tunnelManager.startVPN()
                }
            }
            .sheet(isPresented: $showSettings) {
                SettingsView()
            }
            .sheet(isPresented: $hasNotCompletedSetup) {
                SetupView()
            }
        }
    }
}


struct StatusIndicatorView: View {
    @StateObject private var tunnelManager = TunnelManager.shared
    @State private var animationAmount = 1.0
    @State private var isAnimating = false
    
    var body: some View {
        VStack(spacing: 20) {
            ZStack {
                Circle()
                    .stroke(tunnelManager.tunnelStatus.color.opacity(0.2), lineWidth: 20)
                    .frame(width: 200, height: 200)
                
                Circle()
                    .stroke(tunnelManager.tunnelStatus.color, lineWidth: 10)
                    .frame(width: 200, height: 200)
                    .scaleEffect(animationAmount)
                    .opacity(2 - animationAmount)
                    .animation(isAnimating ? Animation.easeOut(duration: 1.5).repeatForever(autoreverses: false) : .default, value: animationAmount)
                
                VStack(spacing: 10) {
                    Image(systemName: tunnelManager.tunnelStatus.systemImage)
                        .font(.system(size: 50))
                        .foregroundColor(tunnelManager.tunnelStatus.color)
                    
                    Text(tunnelManager.tunnelStatus.rawValue)
                        .font(.headline)
                        .foregroundColor(.primary)
                }
            }
            .onAppear {
                updateAnimation()
            }
            .onChange(of: tunnelManager.tunnelStatus) { _ in
                updateAnimation()
            }
            
            Text(tunnelManager.tunnelStatus == .connected ? "Local tunnel active" : "Local tunnel inactive")
                .font(.subheadline)
                .foregroundColor(tunnelManager.tunnelStatus == .connected ? .green : .secondary)
        }
    }
    
    private func updateAnimation() {
        switch tunnelManager.tunnelStatus {
        case .disconnecting:
            isAnimating = false
            withAnimation {
                animationAmount = 1.0
            }
        case .disconnected:
            isAnimating = false
            animationAmount = 1.0
        default:
            isAnimating = true
            animationAmount = 1.0
            DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
                withAnimation {
                    animationAmount = 2.0
                }
            }
        }
    }
}


struct ConnectionButton: View {
    @StateObject private var tunnelManager = TunnelManager.shared
    let action: () -> Void
    
    var body: some View {
        Button(action: action) {
            HStack {
                Text(buttonText)
                    .font(.headline)
                    .fontWeight(.semibold)
                
                if tunnelManager.tunnelStatus == .connecting || tunnelManager.tunnelStatus == .disconnecting {
                    ProgressView()
                        .progressViewStyle(CircularProgressViewStyle())
                        .padding(.leading, 5)
                }
            }
            .frame(width: 200, height: 50)
            .background(buttonBackground)
            .foregroundColor(.white)
            .clipShape(Capsule())
            .shadow(color: Color.black.opacity(0.15), radius: 10, x: 0, y: 5)
        }
        .disabled(tunnelManager.tunnelStatus == .connecting || tunnelManager.tunnelStatus == .disconnecting)
    }
    
    private var buttonText: String {
        if tunnelManager.tunnelStatus == .connected {
            return "Disconnect"
        } else if tunnelManager.tunnelStatus == .connecting {
            return "Connecting..."
        } else if tunnelManager.tunnelStatus == .disconnecting {
            return "Disconnecting..."
        } else {
            return "Connect"
        }
    }
    
    private var buttonBackground: some View {
        Group {
            if tunnelManager.tunnelStatus == .connected {
                LinearGradient(
                    gradient: Gradient(colors: [Color.red.opacity(0.8), Color.red]),
                    startPoint: .leading,
                    endPoint: .trailing
                )
            } else {
                LinearGradient(
                    gradient: Gradient(colors: [Color.blue.opacity(0.8), Color.blue]),
                    startPoint: .leading,
                    endPoint: .trailing
                )
            }
        }
    }
}

struct ConnectionStatsView: View {
    @State private var time = 0
    let timer = Timer.publish(every: 1, on: .main, in: .common).autoconnect()
    
    var body: some View {
        VStack(spacing: 25) {
            Text("Local Tunnel Details")
                .font(.headline)
                .foregroundColor(.primary)
            
            HStack(spacing: 30) {
                StatItemView(
                    title: "Time Connected",
                    value: formattedTime,
                    icon: "clock.fill"
                )
                
                StatItemView(
                    title: "Status",
                    value: "Active",
                    icon: "checkmark.circle.fill"
                )
            }
            
            HStack(spacing: 30) {
                StatItemView(
                    title: "Network Interface",
                    value: "Local",
                    icon: "network"
                )
                
                StatItemView(
                    title: "Assigned IP",
                    value: "10.7.0.1",
                    icon: "number"
                )
            }
        }
        .padding()
        .background(
            RoundedRectangle(cornerRadius: 20)
                .fill(Color(UIColor.darkGray))
                .shadow(color: Color.black.opacity(0.05), radius: 10, x: 0, y: 5)
        )
        .onReceive(timer) { _ in
            time += 1
        }
    }
    
    var formattedTime: String {
        let minutes = (time / 60) % 60
        let hours = time / 3600
        let seconds = time % 60
        
        if hours > 0 {
            return String(format: "%02d:%02d:%02d", hours, minutes, seconds)
        } else {
            return String(format: "%02d:%02d", minutes, seconds)
        }
    }
}

struct StatItemView: View {
    let title: String
    let value: String
    let icon: String
    
    var body: some View {
        VStack(alignment: .leading, spacing: 10) {
            HStack {
                Image(systemName: icon)
                    .foregroundColor(.blue)
                
                Text(title)
                    .font(.caption)
                    .foregroundColor(.secondary)
            }
            
            Text(value)
                .font(.system(size: 16, weight: .semibold))
                .foregroundColor(.primary)
        }
        .frame(maxWidth: .infinity, alignment: .leading)
    }
}

// MARK: - Updated SettingsView
struct SettingsView: View {
    @Environment(\.dismiss) private var dismiss
    @AppStorage("TunnelDeviceIP") private var deviceIP = "10.7.0.0"
    @AppStorage("TunnelFakeIP") private var fakeIP = "10.7.0.1"
    @AppStorage("TunnelSubnetMask") private var subnetMask = "255.255.255.0"
    @AppStorage("autoConnect") private var autoConnect = false
    
    var body: some View {
        NavigationStack {
            List {
                Section(header: Text("Connection Settings")) {
                    Toggle("Auto-connect on Launch", isOn: $autoConnect)
                    
                    NavigationLink(destination: ConnectionLogView()) {
                        Label("Connection Logs", systemImage: "doc.text")
                    }
                }
                
                Section(header: Text("Network Configuration")) {
                    HStack {
                        Text("Device IP")
                        Spacer()
                        TextField("Device IP", text: $deviceIP)
                            .multilineTextAlignment(.trailing)
                            .foregroundColor(.secondary)
                            .keyboardType(.numbersAndPunctuation)
                    }
                    
                    HStack {
                        Text("Tunnel IP")
                        Spacer()
                        TextField("Tunnel IP", text: $fakeIP)
                            .multilineTextAlignment(.trailing)
                            .foregroundColor(.secondary)
                            .keyboardType(.numbersAndPunctuation)
                    }
                    
                    HStack {
                        Text("Subnet Mask")
                        Spacer()
                        TextField("Subnet Mask", text: $subnetMask)
                            .multilineTextAlignment(.trailing)
                            .foregroundColor(.secondary)
                            .keyboardType(.numbersAndPunctuation)
                    }
                }
                
                Section(header: Text("App Information")) {
                    Button {
                        UIApplication.shared.open(URL(string: "https://github.com/stossy11/PrivacyPolicy/blob/main/PrivacyPolicy.md")!, options: [:])
                    } label: {
                        Label("Privacy Policy", systemImage: "lock.shield")
                    }
                    
                    NavigationLink(destination: DataCollectionInfoView()) {
                        Label("Data Collection Policy", systemImage: "hand.raised.slash")
                    }
                    
                    HStack {
                        Text("App Version")
                        Spacer()
                        Text("1.1.0")
                            .foregroundColor(.secondary)
                    }
                    
                    NavigationLink(destination: HelpView()) {
                        Text("Help & Support")
                    }
                }
            }
            .navigationTitle("Settings")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .topBarTrailing) {
                    Button("Done") {
                        dismiss()
                    }
                }
            }
        }
    }
}

// MARK: - New Data Collection Info View
struct DataCollectionInfoView: View {
    var body: some View {
        ScrollView {
            VStack(alignment: .leading, spacing: 20) {
                Text("Data Collection Policy")
                    .font(.title)
                    .fontWeight(.bold)
                    .padding(.bottom, 10)
                
                GroupBox(label: Label("No Data Collection", systemImage: "hand.raised.slash").font(.headline)) {
                    Text("StosVPN does NOT collect any user data, traffic information, or browsing activity. This app creates a purely local network tunnel that stays entirely on your device.")
                        .padding(.vertical)
                }
                
                GroupBox(label: Label("Local Processing Only", systemImage: "iphone").font(.headline)) {
                    Text("All network traffic and configurations are processed locally on your device. No information ever leaves your device or is transmitted over the internet.")
                        .padding(.vertical)
                }
                
                GroupBox(label: Label("No Third-Party Sharing", systemImage: "person.2.slash").font(.headline)) {
                    Text("Since we collect no data, there is no data shared with third parties. We have no analytics, tracking, or data collection mechanisms in this app.")
                        .padding(.vertical)
                }
                
                GroupBox(label: Label("Why Use Network Permissions", systemImage: "network").font(.headline)) {
                    Text("StosVPN requires network extension permissions to create a local network interface on your device. This is used exclusively for local development and testing purposes, such as connecting to local web servers for development.")
                        .padding(.vertical)
                }
                
                GroupBox(label: Label("Our Promise", systemImage: "checkmark.seal").font(.headline)) {
                    Text("We're committed to privacy and transparency. This app is designed for developers to test and connect to local servers on their device without any privacy concerns.")
                        .padding(.vertical)
                }
            }
            .padding()
        }
        .navigationTitle("Data Collection")
        .navigationBarTitleDisplayMode(.inline)
    }
}

// MARK: - Updated ConnectionLogView
struct ConnectionLogView: View {
    @StateObject var logger = VPNLogger.shared
    var body: some View {
        List(logger.logs, id: \.self) { log in
            Text(log)
                .font(.system(.body, design: .monospaced))
        }
        .navigationTitle("Logs")
        .navigationBarTitleDisplayMode(.inline)
    }
}

// MARK: - Updated HelpView
struct HelpView: View {
    var body: some View {
        List {
            Section(header: Text("Frequently Asked Questions")) {
                NavigationLink("What does this app do?") {
                    VStack(alignment: .leading, spacing: 15) {
                        Text("StosVPN creates a local network interface that can be used for development and testing purposes. It does not route traffic through any external servers - everything stays on your device.")
                            .padding(.bottom, 10)
                        
                        Text("Common use cases include:")
                            .fontWeight(.medium)
                        
                        Text("• Testing web applications with local web servers")
                        Text("• Developing and debugging network-related features")
                        Text("• Accessing locally hosted development environments")
                        Text("• Testing applications that require specific network configurations")
                    }
                    .padding()
                }
                
                NavigationLink("Is this a traditional VPN?") {
                    VStack(alignment: .leading, spacing: 15) {
                        Text("No, StosVPN is NOT a traditional VPN service. It does not:")
                            .padding(.bottom, 10)
                            .fontWeight(.medium)
                        
                        Text("• Route your traffic through external servers")
                        Text("• Provide privacy or anonymity for internet browsing")
                        Text("• Connect to remote VPN servers")
                        Text("• Encrypt or route your internet traffic")
                        
                        Text("StosVPN only creates a local network interface on your device to help developers connect to local services and servers for testing and development purposes.")
                            .padding(.top, 10)
                    }
                    .padding()
                }
                
                NavigationLink("Why does the connection fail?") {
                    VStack(alignment: .leading, spacing: 15) {
                        Text("Connection failures could be due to system permission issues, configuration errors, or iOS restrictions.")
                            .padding(.bottom, 10)
                        
                        Text("Troubleshooting steps:")
                            .fontWeight(.medium)
                        
                        Text("• Ensure you've approved the network extension permission")
                        Text("• Try restarting the app")
                        Text("• Check if your IP configuration is valid")
                        Text("• Restart your device if issues persist")
                    }
                    .padding()
                }
                
                NavigationLink("Who is this app for?") {
                    VStack(alignment: .leading, spacing: 15) {
                        Text("StosVPN is primarily designed for:")
                            .fontWeight(.medium)
                            .padding(.bottom, 10)
                        
                        Text("• Developers testing local web servers")
                        Text("• App developers testing network features")
                        Text("• QA engineers testing applications in isolated network environments")
                        Text("• Anyone who needs to access locally hosted services on their iOS device")
                        
                        Text("This app is available to the general public and is especially useful for developers who need to test applications with network features on iOS devices.")
                            .padding(.top, 10)
                    }
                    .padding()
                }
            }
            
            Section(header: Text("Business Model Information")) {
                NavigationLink("How does StosVPN work?") {
                    VStack(alignment: .leading, spacing: 15) {
                        Text("StosVPN is a completely free app available to the general public. There are no paid features, subscriptions, or in-app purchases.")
                            .padding(.bottom, 10)
                        
                        Text("Key points about our business model:")
                            .fontWeight(.medium)
                        
                        Text("• The app is not restricted to any specific company or group")
                        Text("• Anyone can download and use the app from the App Store")
                        Text("• No account creation is required to use the app")
                        Text("• All features are available to all users free of charge")
                        Text("• The app is developed and maintained as an open utility for the iOS development community")
                    }
                    .padding()
                }
            }
            
            Section(header: Text("App Information")) {
                HStack {
                    Image(systemName: "exclamationmark.shield")
                    Text("Requires iOS 16.0 or later")
                }
                
                HStack {
                    Image(systemName: "lock.shield")
                    Text("Uses Apple's Network Extension APIs")
                }
            }
        }
        .navigationTitle("Help & Support")
        .navigationBarTitleDisplayMode(.inline)
    }
}

struct SetupView: View {
    @Environment(\.dismiss) private var dismiss
    @AppStorage("hasNotCompletedSetup") private var hasNotCompletedSetup = true
    @State private var currentPage = 0
    
    let pages = [
        SetupPage(
            title: "Welcome to StosVPN",
            description: "A simple local network tunnel for developers",
            imageName: "checkmark.shield.fill",
            details: "StosVPN creates a local network interface on your device for development, testing, and accessing local servers. This app does NOT collect any user data or route traffic through external servers."
        ),
        SetupPage(
            title: "Why Use StosVPN?",
            description: "Perfect for iOS developers",
            imageName: "person.2.fill",
            details: "• Access local web servers and development environments\n• Test applications that require specific network configurations\n• Connect to local network services without complex setup\n• Create isolated network environments for testing"
        ),
        SetupPage(
            title: "Easy to Use",
            description: "Just one tap to connect",
            imageName: "hand.tap.fill",
            details: "StosVPN is designed to be simple and straightforward. Just tap the connect button to establish a local network tunnel with pre-configured settings that work for most developer testing needs."
        ),
        SetupPage(
            title: "Privacy Focused",
            description: "Your data stays on your device",
            imageName: "lock.shield.fill",
            details: "StosVPN creates a local tunnel that doesn't route traffic through external servers. All network traffic remains on your device, ensuring your privacy and security. No data is collected or shared with third parties."
        )
    ]
    
    var body: some View {
        NavigationStack {
            VStack {
                TabView(selection: $currentPage) {
                    ForEach(0..<pages.count, id: \.self) { index in
                        SetupPageView(page: pages[index])
                            .tag(index)
                    }
                }
                .tabViewStyle(PageTabViewStyle(indexDisplayMode: .always))
                
                Spacer()
                
                if currentPage == pages.count - 1 {
                    Button {
                        hasNotCompletedSetup = false
                        dismiss()
                    } label: {
                        Text("Get Started")
                            .font(.headline)
                            .fontWeight(.semibold)
                            .frame(height: 50)
                            .frame(maxWidth: .infinity)
                            .background(
                                LinearGradient(
                                    gradient: Gradient(colors: [Color.blue.opacity(0.8), Color.blue]),
                                    startPoint: .leading,
                                    endPoint: .trailing
                                )
                            )
                            .foregroundColor(.white)
                            .cornerRadius(10)
                            .padding(.horizontal)
                    }
                    .padding(.bottom)
                } else {
                    Button {
                        withAnimation {
                            currentPage += 1
                        }
                    } label: {
                        Text("Next")
                            .font(.headline)
                            .fontWeight(.semibold)
                            .frame(height: 50)
                            .frame(maxWidth: .infinity)
                            .background(
                                LinearGradient(
                                    gradient: Gradient(colors: [Color.blue.opacity(0.8), Color.blue]),
                                    startPoint: .leading,
                                    endPoint: .trailing
                                )
                            )
                            .foregroundColor(.white)
                            .cornerRadius(10)
                            .padding(.horizontal)
                    }
                    .padding(.bottom)
                }
            }
            .navigationTitle("Setup")
            .navigationBarTitleDisplayMode(.inline)
            .toolbar {
                ToolbarItem(placement: .topBarTrailing) {
                    Button("Skip") {
                        hasNotCompletedSetup = false
                        dismiss()
                    }
                }
            }
        }
    }
}

struct SetupPage {
    let title: String
    let description: String
    let imageName: String
    let details: String
}

struct SetupPageView: View {
    let page: SetupPage
    
    var body: some View {
        VStack(spacing: 30) {
            Image(systemName: page.imageName)
                .font(.system(size: 80))
                .foregroundColor(.blue)
                .padding(.top, 50)
            
            Text(page.title)
                .font(.title)
                .fontWeight(.bold)
                .multilineTextAlignment(.center)
            
            Text(page.description)
                .font(.headline)
                .foregroundColor(.secondary)
                .multilineTextAlignment(.center)
            
            ScrollView {
                Text(page.details)
                    .font(.body)
                    .multilineTextAlignment(.leading)
                    .padding(.horizontal)
            }
            
            Spacer()
        }
        .padding()
    }
}

#Preview {
    ContentView()
}