ios_app/Shared/Views/LoginView.swift

//
//  LoginView.swift
//  VolnahubApp
//
//  Created by cheykrym on 09/06/2025.
//

import SwiftUI

struct LoginView: View {
    @ObservedObject var viewModel: LoginViewModel
    @AppStorage("isDarkMode") private var isDarkMode: Bool = true
    
    @State private var isShowingRegistration = false

    private var isUsernameValid: Bool {
        let pattern = "^[A-Za-z0-9_]{3,32}$"
        return viewModel.username.range(of: pattern, options: .regularExpression) != nil
    }

    private var isPasswordValid: Bool {
        return viewModel.password.count >= 6 && viewModel.password.count <= 32
    }
    
    var body: some View {

        VStack {
            HStack {

                Button(action: openLanguageSettings) {
                    Text("🌍 " + NSLocalizedString("LoginView_change_language", comment: ""))
                        .padding()
                }
                Spacer()
                Button(action: toggleTheme) {
                    Image(systemName: isDarkMode ? "moon.fill" : "sun.max.fill")
                        .padding()
                }
            }

            Spacer()

            
//            Text(NSLocalizedString("LoginView_title", comment: ""))
//                .font(.largeTitle)
//                .bold()

            TextField(NSLocalizedString("LoginView_login", comment: ""), text: $viewModel.username)
                .padding()
                .background(Color(.secondarySystemBackground))
                .cornerRadius(8)
                .autocapitalization(.none)
                .disableAutocorrection(true)
                .onChange(of: viewModel.username) { newValue in
                    if newValue.count > 32 {
                        viewModel.username = String(newValue.prefix(32))
                    }
                }

            // Показываем ошибку для логина
            if !isUsernameValid && !viewModel.username.isEmpty {
                Text(NSLocalizedString("LoginView_error_username_invalid", comment: "Неверный логин"))
                    .foregroundColor(.red)
                    .font(.caption)
            }

            // Показываем поле пароля (даже если оно невалидное) только если логин корректен
            if isUsernameValid {
                SecureField(NSLocalizedString("LoginView_password", comment: ""), text: $viewModel.password)
                    .padding()
                    .background(Color(.secondarySystemBackground))
                    .cornerRadius(8)
                    .autocapitalization(.none)
                    .onChange(of: viewModel.password) { newValue in
                        if newValue.count > 32 {
                            viewModel.password = String(newValue.prefix(32))
                        }
                    }

                // Показываем ошибку для пароля
                if !isPasswordValid && !viewModel.password.isEmpty {
                    Text(NSLocalizedString("LoginView_error_password_invalid", comment: "Неверный пароль"))
                        .foregroundColor(.red)
                        .font(.caption)
                }
            }
            
            if isUsernameValid && isPasswordValid {
                Button(action: {
                    viewModel.login()
                }) {
                    if viewModel.isLoading {
                        ProgressView()
                            .progressViewStyle(CircularProgressViewStyle())
                            .padding()
                            .frame(maxWidth: .infinity)
                            .background(Color.gray.opacity(0.6))
                            .cornerRadius(8)
                    } else {
                        Text(NSLocalizedString("LoginView_button_login", comment: ""))
                            .foregroundColor(.white)
                            .padding()
                            .frame(maxWidth: .infinity)
                            .background(Color.blue)
                            .cornerRadius(8)
                    }
                }
                .disabled(viewModel.isLoading)
            }

            Spacer()
            
            // Кнопка регистрации
            Button(action: {
                isShowingRegistration = true
            }) {
                Text(NSLocalizedString("LoginView_button_register", comment: "Регистрация"))
                    .foregroundColor(.blue)
            }
            .padding(.top, 10)
            .sheet(isPresented: $isShowingRegistration) {
                RegistrationView()
            }
            
        }
        .padding()
        .alert(isPresented: $viewModel.showError) {
            Alert(
                title: Text(NSLocalizedString("LoginView_error", comment: "")),
                message: Text(viewModel.errorMessage),
                dismissButton: .default(Text("ОК"))
            )
        }
    }
    
    private func toggleTheme() {
        isDarkMode.toggle()
    }
    
    private func openLanguageSettings() {
        guard let url = URL(string: UIApplication.openSettingsURLString) else { return }
        UIApplication.shared.open(url)
    }

}

struct LoginView_Previews: PreviewProvider {
    static var previews: some View {
        let viewModel = LoginViewModel()
        viewModel.isLoading = false // чтобы убрать спиннер
        return LoginView(viewModel: viewModel)
    }
}