#nullable enable
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Threading;
using Housing.Services;

namespace Housing.Login
{
    public sealed class StartupLoginWindowResult
    {
        public string Maker { get; set; } = string.Empty;
        public string Model { get; set; } = string.Empty;
        public string Variant1 { get; set; } = string.Empty;
        public string Variant2 { get; set; } = string.Empty;
        public string Operator { get; set; } = string.Empty;
        public string Password { get; set; } = string.Empty;
        public string LineNo { get; set; } = string.Empty;
        public string LotNo { get; set; } = string.Empty;
        public string JigNo { get; set; } = string.Empty;
    }

    public partial class StartupLoginWindow : Window
    {
        private const string OperatorHistoryFieldName = "Operator";
        private const string SuppressedOperatorHistoryValue = "su";
        private readonly LoginHistoryStore _loginHistoryStore;
        private readonly LoginSelectionOptions _loginOptions;
        private Popup? _openHistoryPopup;

        public StartupLoginWindowResult Result { get; private set; } = new();

        public StartupLoginWindow()
        {
            _loginHistoryStore = LoginHistoryStore.Load(GetLoginHistoryPath());
            _loginOptions = LoginSelectionOptions.Load(GetLoginOptionsPath());
            RemoveSuppressedOperatorHistory();
            InitializeComponent();
            ApplyLoginOptions();
            AttachLoginHistoryMenus();
            AttachSelectionDropDowns();
            PasswordBox.GotKeyboardFocus += (_, _) => CloseHistoryPopup();
            LoginButton.GotKeyboardFocus += (_, _) => CloseHistoryPopup();
            PasswordBox.KeyDown += (s, e) => { if (e.Key == System.Windows.Input.Key.Enter) LogInButton_Click(LoginButton, e); };
            OperatorTextBox.KeyDown += (s, e) => { if (e.Key == System.Windows.Input.Key.Enter) LogInButton_Click(LoginButton, e); };
            MakerComboBox.Focus();
        }

        private enum LoginCheckStatus
        {
            Success,
            InvalidCredentials,
            DbTimeoutOrError
        }

        private async void LogInButton_Click(object sender, RoutedEventArgs e)
        {
            CloseHistoryPopup();

            if (!TryReadRequiredFields(out var loginResult, out var password))
            {
                return;
            }

            string originalButtonText = "ACCESS / LOG IN";
            if (sender is Button button)
            {
                originalButtonText = button.Content?.ToString() ?? "ACCESS / LOG IN";
                button.IsEnabled = false;
                button.Content = "⏳ DB 접속 확인 중...";
                button.UpdateLayout();
                // WPF Dispatcher 렌더링 강제 갱신으로 클릭 즉시 화면 피드백 표기
                Dispatcher.Invoke(() => { }, System.Windows.Threading.DispatcherPriority.Render);
            }

            System.Windows.Input.Mouse.OverrideCursor = System.Windows.Input.Cursors.Wait;

            try
            {
                var checkResult = await CheckLoginAsync(loginResult.Operator, password);

                if (checkResult == LoginCheckStatus.InvalidCredentials)
                {
                    MessageBox.Show(this, "등록되지 않은 ID/PW입니다.", "Login", MessageBoxButton.OK, MessageBoxImage.Error);
                    PasswordBox.Clear();
                    PasswordBox.Focus();
                    return;
                }
                else if (checkResult == LoginCheckStatus.DbTimeoutOrError)
                {
                    MessageBox.Show(this, "DB 연결 상태 또는 ID/PW를 확인해 주십시오.", "로그인 오류", MessageBoxButton.OK, MessageBoxImage.Warning);
                    PasswordBox.Clear();
                    PasswordBox.Focus();
                    return;
                }

                loginResult.Password = password; // 비밀번호를 결과 객체에도 담아둠
                Result = loginResult;
                SaveLoginHistory(loginResult);
                DialogResult = true;
                Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show(this, $"로그인 확인 실패: {ex.Message}", "Login", MessageBoxButton.OK, MessageBoxImage.Error);
                OperatorTextBox.Focus();
                OperatorTextBox.SelectAll();
            }
            finally
            {
                System.Windows.Input.Mouse.OverrideCursor = null;
                if (sender is Button loginButton)
                {
                    loginButton.IsEnabled = true;
                    loginButton.Content = originalButtonText;
                }
            }
        }

        private async Task<LoginCheckStatus> CheckLoginAsync(string loginId, string password)
        {
            // 1. LoginOptions.json의 로컬 계정 정보에서 먼저 찾기
            if (_loginOptions.LoginAccounts != null && _loginOptions.LoginAccounts.Count > 0)
            {
                var matched = _loginOptions.LoginAccounts.Any(account =>
                    string.Equals(account.Id, loginId, StringComparison.OrdinalIgnoreCase) &&
                    string.Equals(account.Password, password, StringComparison.Ordinal));
                
                if (matched)
                {
                    return LoginCheckStatus.Success;
                }
            }

            // 2. 오프라인 모드일 경우 통과
            var loginSettings = LoginSettings.Load(GetDatabaseIniPath());
            if (loginSettings.OfflinePreview)
            {
                return LoginCheckStatus.Success;
            }

            // 3. DB 접속 및 계정 조회 (3초 하드 제한)
            try
            {
                var repository = new LoginAccountRepository(
                    DatabaseSettings.Load(GetDatabaseIniPath()),
                    loginSettings);

                var dbCheckTask = repository.ExistsAsync(loginId, password);
                var timeoutTask = Task.Delay(3000); // 3초 하드 제한

                var completedTask = await Task.WhenAny(dbCheckTask, timeoutTask);
                if (completedTask == dbCheckTask)
                {
                    bool isExist = await dbCheckTask;
                    return isExist ? LoginCheckStatus.Success : LoginCheckStatus.InvalidCredentials;
                }
                else
                {
                    System.Diagnostics.Debug.WriteLine("[로그인 타임아웃] DB 응답 3초 초과 -> 타임아웃/DB연결안내 팝업 표출");
                    return LoginCheckStatus.DbTimeoutOrError;
                }
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine($"[로그인 오류] DB 연결 예외 발생: {ex.Message}");
                return LoginCheckStatus.DbTimeoutOrError;
            }
        }

        private bool TryReadRequiredFields(out StartupLoginWindowResult result, out string password)
        {
            result = new StartupLoginWindowResult();
            password = string.Empty;

            if (!TryReadRequiredComboBox(MakerComboBox, "Maker", out var maker) ||
                !TryReadRequiredComboBox(ModelComboBox, "Model", out var model) ||
                !TryReadTextBox(OperatorTextBox, "ID", out var loginId) ||
                !TryReadPasswordBox(PasswordBox, "PW", out password) ||
                !TryReadRequiredComboBox(LineNoComboBox, "Line", out var lineNo) ||
                !TryReadTextBox(LotNoTextBox, "Lot No", out var lotNo) ||
                !TryReadRequiredComboBox(JigNoComboBox, "Jig No", out var jigNo))
            {
                return false;
            }

            if (!string.IsNullOrWhiteSpace(lotNo) && lotNo.Length < 2)
            {
                lotNo = lotNo.PadLeft(2, '0');
            }

            var variant1 = ReadOptionalComboBox(Variant1ComboBox);
            var variant2 = ReadOptionalComboBox(Variant2ComboBox);

            result = new StartupLoginWindowResult
            {
                Maker = maker,
                Model = model,
                Variant1 = variant1,
                Variant2 = variant2,
                Operator = loginId,
                LineNo = lineNo,
                LotNo = lotNo,
                JigNo = jigNo
            };

            return true;
        }

        private void ApplyLoginOptions()
        {
            SetComboBoxOptions(MakerComboBox, _loginOptions.Makers, allowBlank: false, historyFieldName: "Maker");
            SetComboBoxOptions(ModelComboBox, _loginOptions.Models, allowBlank: false, historyFieldName: "Model");
            SetComboBoxOptions(Variant1ComboBox, _loginOptions.Variant1Values, allowBlank: true, historyFieldName: "Variant1");
            SetComboBoxOptions(Variant2ComboBox, _loginOptions.Variant2Values, allowBlank: true, historyFieldName: "Variant2");
            SetComboBoxOptions(LineNoComboBox, _loginOptions.LineValues, allowBlank: false, historyFieldName: "LineNo");
            SetComboBoxOptions(JigNoComboBox, _loginOptions.JigNoValues, allowBlank: false, historyFieldName: "JigNo");
        }

        private void SetComboBoxOptions(
            ComboBox comboBox,
            IReadOnlyList<string> values,
            bool allowBlank,
            string historyFieldName)
        {
            var items = new List<LoginOptionItem>();
            if (allowBlank)
            {
                items.Add(new LoginOptionItem("(None)", string.Empty));
            }

            foreach (var value in values.Where(value => !string.IsNullOrWhiteSpace(value)))
            {
                if (items.Any(item => string.Equals(item.Value, value, StringComparison.OrdinalIgnoreCase)))
                {
                    continue;
                }

                items.Add(new LoginOptionItem(value, value));
            }

            // 옵션 항목 개수를 최대 3개로 제한
            items = items.Take(3).ToList();

            comboBox.ItemsSource = items;
            comboBox.DisplayMemberPath = nameof(LoginOptionItem.DisplayText);

            var rememberedValue = _loginHistoryStore.GetValues(historyFieldName).FirstOrDefault();
            if (!string.IsNullOrWhiteSpace(rememberedValue) &&
                TrySelectComboBoxValue(comboBox, rememberedValue))
            {
                return;
            }

            if (allowBlank)
            {
                comboBox.SelectedIndex = 0;
            }
            else if (items.Count == 1)
            {
                comboBox.SelectedIndex = 0;
            }
        }

        private static bool TrySelectComboBoxValue(ComboBox comboBox, string value)
        {
            for (var index = 0; index < comboBox.Items.Count; index++)
            {
                if (comboBox.Items[index] is LoginOptionItem item &&
                    string.Equals(item.Value, value, StringComparison.OrdinalIgnoreCase))
                {
                    comboBox.SelectedIndex = index;
                    return true;
                }
            }

            return false;
        }

        private void AttachSelectionDropDowns()
        {
            foreach (var comboBox in new[]
                     {
                         MakerComboBox,
                         ModelComboBox,
                         Variant1ComboBox,
                         Variant2ComboBox,
                         LineNoComboBox,
                         JigNoComboBox
                     })
            {
                comboBox.GotKeyboardFocus += (_, _) => CloseHistoryPopup();
                comboBox.DropDownOpened += (_, _) => CloseHistoryPopup();
            }
        }

        private void AttachLoginHistoryMenus()
        {
            AttachHistoryMenu(OperatorTextBox, OperatorHistoryFieldName, PasswordBox);
            AttachHistoryMenu(LotNoTextBox, "LotNo", JigNoComboBox);
        }

        private void AttachHistoryMenu(TextBox textBox, string fieldName, Control nextFocusControl)
        {
            textBox.GotKeyboardFocus += (_, _) => ShowHistoryMenu(textBox, fieldName, nextFocusControl);
            textBox.PreviewMouseLeftButtonDown += (_, _) =>
            {
                if (textBox.IsKeyboardFocusWithin)
                {
                    ShowHistoryMenu(textBox, fieldName, nextFocusControl);
                }
            };
        }

        private void ShowHistoryMenu(TextBox textBox, string fieldName, Control nextFocusControl)
        {
            // 최근 기록 히스토리 항목 개수 최대 3개로 제한
            var values = _loginHistoryStore.GetValues(fieldName).Take(3).ToList();
            if (values.Count == 0)
            {
                CloseHistoryPopup();
                return;
            }

            CloseHistoryPopup();

            var menuWidth = Math.Max(160, textBox.ActualWidth);
            var stackPanel = new StackPanel();
            var popup = new Popup
            {
                PlacementTarget = textBox,
                Placement = PlacementMode.Bottom,
                HorizontalOffset = 0,
                StaysOpen = true,
                AllowsTransparency = true,
                Focusable = false
            };

            foreach (var value in values)
            {
                var rowGrid = new Grid
                {
                    Width = menuWidth - 2,
                    Background = textBox.Background
                };
                rowGrid.ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(1, GridUnitType.Star) });
                rowGrid.ColumnDefinitions.Add(new ColumnDefinition { Width = GridLength.Auto });

                var selectBtn = new Button
                {
                    Content = value,
                    Padding = new Thickness(10, 6, 10, 6),
                    BorderThickness = new Thickness(0),
                    Background = System.Windows.Media.Brushes.Transparent,
                    Foreground = textBox.Foreground,
                    HorizontalContentAlignment = HorizontalAlignment.Left
                };
                selectBtn.Click += (_, _) =>
                {
                    textBox.Text = value;
                    textBox.CaretIndex = textBox.Text.Length;
                    CloseHistoryPopup();
                    FocusControl(nextFocusControl);
                };
                Grid.SetColumn(selectBtn, 0);
                rowGrid.Children.Add(selectBtn);

                var deleteBtn = new Button
                {
                    Content = "✕",
                    Width = 28,
                    Height = 28,
                    Padding = new Thickness(0),
                    BorderThickness = new Thickness(0),
                    Background = System.Windows.Media.Brushes.Transparent,
                    Foreground = System.Windows.Media.Brushes.Red,
                    FontWeight = FontWeights.Bold,
                    ToolTip = "이력 삭제"
                };
                deleteBtn.Click += (s, e) =>
                {
                    _loginHistoryStore.Forget(fieldName, value);
                    _loginHistoryStore.Save();
                    ShowHistoryMenu(textBox, fieldName, nextFocusControl);
                };
                Grid.SetColumn(deleteBtn, 1);
                rowGrid.Children.Add(deleteBtn);

                stackPanel.Children.Add(rowGrid);
            }

            popup.Child = new Border
            {
                Width = menuWidth,
                MaxHeight = 180,
                Background = textBox.Background,
                BorderBrush = textBox.BorderBrush,
                BorderThickness = new Thickness(1),
                Child = new ScrollViewer
                {
                    MaxHeight = 180,
                    VerticalScrollBarVisibility = ScrollBarVisibility.Auto,
                    Content = stackPanel
                }
            };

            _openHistoryPopup = popup;
            popup.IsOpen = true;
        }

        private void CloseHistoryPopup()
        {
            if (_openHistoryPopup is not null)
            {
                _openHistoryPopup.IsOpen = false;
                _openHistoryPopup = null;
            }
        }

        private void FocusControl(Control control)
        {
            Dispatcher.BeginInvoke(new Action(() =>
            {
                control.Focus();

                if (control is TextBox textBox)
                {
                    textBox.CaretIndex = textBox.Text.Length;
                }
                else if (control is PasswordBox passwordBox)
                {
                    passwordBox.Focus();
                }
            }), DispatcherPriority.Input);
        }

        private void SaveLoginHistory(StartupLoginWindowResult result)
        {
            _loginHistoryStore.Remember("Maker", result.Maker);
            _loginHistoryStore.Remember("Model", result.Model);
            _loginHistoryStore.Remember("Variant1", result.Variant1);
            _loginHistoryStore.Remember("Variant2", result.Variant2);
            RememberOperatorHistory(result.Operator);
            _loginHistoryStore.Remember("LineNo", result.LineNo);
            _loginHistoryStore.Remember("LotNo", result.LotNo);
            _loginHistoryStore.Remember("JigNo", result.JigNo);
            _loginHistoryStore.Save();
        }

        private void RememberOperatorHistory(string operatorId)
        {
            if (IsSuppressedOperatorHistoryValue(operatorId))
            {
                _loginHistoryStore.Forget(OperatorHistoryFieldName, operatorId);
                return;
            }

            _loginHistoryStore.Remember(OperatorHistoryFieldName, operatorId);
        }

        private void RemoveSuppressedOperatorHistory()
        {
            try
            {
                if (_loginHistoryStore.Forget(OperatorHistoryFieldName, SuppressedOperatorHistoryValue))
                {
                    _loginHistoryStore.Save();
                }
            }
            catch
            {
                // Login history cleanup is optional and should not block the login window.
            }
        }

        private static bool IsSuppressedOperatorHistoryValue(string value)
        {
            return string.Equals(value.Trim(), SuppressedOperatorHistoryValue, StringComparison.OrdinalIgnoreCase);
        }

        private bool TryReadRequiredComboBox(ComboBox comboBox, string fieldName, out string value)
        {
            value = ReadComboBoxValue(comboBox);
            if (!string.IsNullOrWhiteSpace(value))
            {
                return true;
            }

            MessageBox.Show(
                this,
                $"{fieldName} value is required. Edit LoginOptions.json and select a value.",
                "Login",
                MessageBoxButton.OK,
                MessageBoxImage.Warning);
            comboBox.Focus();
            comboBox.IsDropDownOpen = true;
            return false;
        }

        private static string ReadOptionalComboBox(ComboBox comboBox)
        {
            return ReadComboBoxValue(comboBox);
        }

        private static string ReadComboBoxValue(ComboBox comboBox)
        {
            return comboBox.SelectedItem is LoginOptionItem item
                ? item.Value.Trim()
                : comboBox.Text.Trim();
        }

        private bool TryReadTextBox(TextBox textBox, string fieldName, out string value)
        {
            value = textBox.Text.Trim();
            if (!string.IsNullOrWhiteSpace(value))
            {
                return true;
            }

            MessageBox.Show(this, $"{fieldName}을(를) 입력하세요.", "Login", MessageBoxButton.OK, MessageBoxImage.Warning);
            textBox.Focus();
            textBox.SelectAll();
            return false;
        }

        private bool TryReadPasswordBox(PasswordBox passwordBox, string fieldName, out string value)
        {
            value = passwordBox.Password;
            if (!string.IsNullOrWhiteSpace(value))
            {
                return true;
            }

            MessageBox.Show(this, $"{fieldName}을(를) 입력하세요.", "Login", MessageBoxButton.OK, MessageBoxImage.Warning);
            passwordBox.Focus();
            passwordBox.SelectAll();
            return false;
        }

        private static string GetDatabaseIniPath()
        {
            return Path.Combine(AppContext.BaseDirectory, "Database.ini");
        }

        private static string GetLoginOptionsPath()
        {
            // 1. 실행 파일과 동일한 디렉토리에 있는 LoginOptions.json을 최우선적으로 직접 사용
            var bundledPath = Path.Combine(AppContext.BaseDirectory, "LoginOptions.json");
            if (File.Exists(bundledPath))
            {
                return bundledPath;
            }

            // 2. 실행 디렉토리에 존재하지 않는 경우, 로컬 AppData 폴백 처리 (하위 호환성)
            var directory = Path.Combine(
                Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
                "Housing");
            var filePath = Path.Combine(directory, "LoginOptions.json");

            if (!File.Exists(filePath))
            {
                Directory.CreateDirectory(directory);
                LoginSelectionOptions.CreateDefaultFile(filePath);
            }

            return filePath;
        }

        private static string GetLoginHistoryPath()
        {
            return Path.Combine(
                Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
                "Housing",
                "LoginHistory.json");
        }

        private sealed class LoginOptionItem
        {
            public string DisplayText { get; }
            public string Value { get; }
            public LoginOptionItem(string displayText, string value)
            {
                DisplayText = displayText;
                Value = value;
            }
        }
    }
}