using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Interop;
using System.Windows.Media;
using Microsoft.Web.WebView2.Core;

namespace AxCopilot.Views;

/// <summary>파일 미리보기 별도 창. WebView2 HWND airspace 문제를 근본적으로 회피합니다.</summary>
public partial class PreviewWindow : Window
{
    private static PreviewWindow? _instance;

    private readonly List<string> _tabs = new();
    private string? _activeTab;
    private bool _webViewInitialized;
    private string? _selectedMood;

    private static readonly string WebView2DataFolder =
        Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
                     "AxCopilot", "WebView2_Preview");

    private static readonly HashSet<string> PreviewableExtensions = new(StringComparer.OrdinalIgnoreCase)
    {
        ".html", ".htm", ".md", ".csv", ".txt", ".json", ".xml", ".log",
    };

    public PreviewWindow()
    {
        InitializeComponent();
        Loaded += OnLoaded;
        SourceInitialized += OnSourceInitialized;
        KeyDown += (_, e) => { if (e.Key == Key.Escape) Close(); };
        StateChanged += (_, _) =>
        {
            MaxBtnIcon.Text = WindowState == WindowState.Maximized ? "\uE923" : "\uE922";
        };
        Closed += (_, _) => _instance = null;
    }

    // ─── 상하좌우 리사이즈 (WindowStyle=None 대응) ─────────────
    [DllImport("user32.dll")]
    private static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

    private const int WM_NCHITTEST = 0x0084;
    private const int HTLEFT = 10, HTRIGHT = 11, HTTOP = 12, HTTOPLEFT = 13, HTTOPRIGHT = 14;
    private const int HTBOTTOM = 15, HTBOTTOMLEFT = 16, HTBOTTOMRIGHT = 17;

    private void OnSourceInitialized(object? sender, EventArgs e)
    {
        var hwndSource = (HwndSource)PresentationSource.FromVisual(this);
        hwndSource?.AddHook(WndProc);
    }

    private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
    {
        if (msg == WM_NCHITTEST)
        {
            var pt = PointFromScreen(new Point(
                (short)(lParam.ToInt32() & 0xFFFF),
                (short)((lParam.ToInt32() >> 16) & 0xFFFF)));
            const double grip = 8; // 리사이즈 가능 영역 (px)
            var w = ActualWidth;
            var h = ActualHeight;

            if (pt.X < grip && pt.Y < grip) { handled = true; return (IntPtr)HTTOPLEFT; }
            if (pt.X > w - grip && pt.Y < grip) { handled = true; return (IntPtr)HTTOPRIGHT; }
            if (pt.X < grip && pt.Y > h - grip) { handled = true; return (IntPtr)HTBOTTOMLEFT; }
            if (pt.X > w - grip && pt.Y > h - grip) { handled = true; return (IntPtr)HTBOTTOMRIGHT; }
            if (pt.X < grip) { handled = true; return (IntPtr)HTLEFT; }
            if (pt.X > w - grip) { handled = true; return (IntPtr)HTRIGHT; }
            if (pt.Y < grip) { handled = true; return (IntPtr)HTTOP; }
            if (pt.Y > h - grip) { handled = true; return (IntPtr)HTBOTTOM; }
        }
        return IntPtr.Zero;
    }

    // ─── 싱글턴 팩토리 ──────────────────────────────────────────

    /// <summary>파일을 미리보기 창에 표시합니다. 이미 열려 있으면 탭을 추가합니다.</summary>
    public static void ShowPreview(string filePath, string? mood = null)
    {
        if (string.IsNullOrEmpty(filePath) || !File.Exists(filePath))
            return;

        var ext = Path.GetExtension(filePath).ToLowerInvariant();
        if (!PreviewableExtensions.Contains(ext))
            return;

        Application.Current.Dispatcher.Invoke(() =>
        {
            if (_instance == null || !_instance.IsLoaded)
            {
                _instance = new PreviewWindow();
                // 부모 창의 테마 리소스 전달
                var mainWindow = Application.Current.MainWindow;
                if (mainWindow != null)
                {
                    foreach (var dict in mainWindow.Resources.MergedDictionaries)
                        _instance.Resources.MergedDictionaries.Add(dict);
                }
                _instance._selectedMood = mood;
                _instance.Show();
            }

            _instance.AddTab(filePath);
            _instance.Activate();
        });
    }

    /// <summary>이미 열린 파일의 콘텐츠만 새로고침합니다. 활성 탭이 아닌 파일도 탭 목록에 있으면 활성 탭으로 전환 후 새로고침.</summary>
    public static void RefreshIfOpen(string filePath)
    {
        if (_instance == null || !_instance.IsLoaded) return;
        Application.Current.Dispatcher.Invoke(() =>
        {
            // 현재 활성 탭이면 즉시 새로고침
            if (_instance._activeTab != null &&
                string.Equals(_instance._activeTab, filePath, StringComparison.OrdinalIgnoreCase))
            {
                _instance.LoadContent(filePath);
                return;
            }

            // 탭 목록에 있으면 해당 탭으로 전환 후 새로고침
            var existing = _instance._tabs.FirstOrDefault(
                t => string.Equals(t, filePath, StringComparison.OrdinalIgnoreCase));
            if (existing != null)
            {
                _instance._activeTab = existing;
                _instance.LoadContent(existing);
                _instance.RebuildTabs();
            }
        });
    }

    /// <summary>현재 미리보기 창이 열려 있는지 반환합니다.</summary>
    public static bool IsOpen => _instance != null && _instance.IsLoaded;

    // ─── 초기화 ─────────────────────────────────────────────────

    private async void OnLoaded(object sender, RoutedEventArgs e)
    {
        try
        {
            var env = await CoreWebView2Environment.CreateAsync(
                userDataFolder: WebView2DataFolder);
            await PreviewBrowser.EnsureCoreWebView2Async(env);
            _webViewInitialized = true;

            // 대기 중인 콘텐츠 로드
            if (_activeTab != null)
                LoadContent(_activeTab);
        }
        catch (Exception ex)
        {
            Services.LogService.Warn($"PreviewWindow WebView2 초기화 실패: {ex.Message}");
        }
    }

    // ─── 탭 관리 ────────────────────────────────────────────────

    private void AddTab(string filePath)
    {
        if (!_tabs.Contains(filePath, StringComparer.OrdinalIgnoreCase))
            _tabs.Add(filePath);

        _activeTab = filePath;
        RebuildTabs();
        LoadContent(filePath);
    }

    private void CloseTab(string filePath)
    {
        _tabs.RemoveAll(t => string.Equals(t, filePath, StringComparison.OrdinalIgnoreCase));

        if (_tabs.Count == 0)
        {
            Close();
            return;
        }

        if (string.Equals(_activeTab, filePath, StringComparison.OrdinalIgnoreCase))
        {
            _activeTab = _tabs[^1];
            LoadContent(_activeTab);
        }

        RebuildTabs();
    }

    private void RebuildTabs()
    {
        TabPanel.Children.Clear();

        var accentBrush = TryFindResource("AccentColor") as Brush ?? Brushes.CornflowerBlue;
        var secondaryText = TryFindResource("SecondaryText") as Brush ?? Brushes.Gray;
        var primaryText = TryFindResource("PrimaryText") as Brush ?? Brushes.White;
        var borderBrush = TryFindResource("BorderColor") as Brush ?? Brushes.Gray;

        foreach (var tabPath in _tabs)
        {
            var fileName = Path.GetFileName(tabPath);
            var isActive = string.Equals(tabPath, _activeTab, StringComparison.OrdinalIgnoreCase);

            var tabBorder = new Border
            {
                Background = Brushes.Transparent,
                BorderBrush = isActive ? accentBrush : Brushes.Transparent,
                BorderThickness = new Thickness(0, 0, 0, isActive ? 2 : 0),
                Padding = new Thickness(10, 6, 6, 6),
                Cursor = Cursors.Hand,
                MaxWidth = _tabs.Count <= 3 ? 220 : (_tabs.Count <= 5 ? 160 : 110),
            };

            var tabContent = new StackPanel { Orientation = Orientation.Horizontal };

            tabContent.Children.Add(new TextBlock
            {
                Text = fileName,
                FontSize = 11.5,
                Foreground = isActive ? primaryText : secondaryText,
                FontWeight = isActive ? FontWeights.SemiBold : FontWeights.Normal,
                VerticalAlignment = VerticalAlignment.Center,
                TextTrimming = TextTrimming.CharacterEllipsis,
                MaxWidth = tabBorder.MaxWidth - 36,
                ToolTip = tabPath,
            });

            // 닫기 버튼
            var closePath = tabPath;
            var closeBtn = new Border
            {
                Background = Brushes.Transparent,
                CornerRadius = new CornerRadius(3),
                Padding = new Thickness(4, 2, 4, 2),
                Margin = new Thickness(6, 0, 0, 0),
                Cursor = Cursors.Hand,
                VerticalAlignment = VerticalAlignment.Center,
                Child = new TextBlock
                {
                    Text = "\uE711",
                    FontFamily = new FontFamily("Segoe MDL2 Assets"),
                    FontSize = 8,
                    Foreground = secondaryText,
                    VerticalAlignment = VerticalAlignment.Center,
                },
            };
            closeBtn.MouseEnter += (s, _) =>
            {
                if (s is Border b)
                    b.Background = new SolidColorBrush(Color.FromArgb(0x30, 0xFF, 0x50, 0x50));
            };
            closeBtn.MouseLeave += (s, _) =>
            {
                if (s is Border b) b.Background = Brushes.Transparent;
            };
            closeBtn.MouseLeftButtonUp += (_, me) =>
            {
                me.Handled = true;
                CloseTab(closePath);
            };

            tabContent.Children.Add(closeBtn);
            tabBorder.Child = tabContent;

            // 탭 클릭 → 활성화
            var clickPath = tabPath;
            tabBorder.MouseLeftButtonUp += (_, me) =>
            {
                if (me.Handled) return;
                me.Handled = true;
                _activeTab = clickPath;
                RebuildTabs();
                LoadContent(clickPath);
            };

            // 호버 효과
            tabBorder.MouseEnter += (s, _) =>
            {
                if (s is Border b && !string.Equals(clickPath, _activeTab, StringComparison.OrdinalIgnoreCase))
                    b.Background = new SolidColorBrush(Color.FromArgb(0x18, 0xFF, 0xFF, 0xFF));
            };
            tabBorder.MouseLeave += (s, _) =>
            {
                if (s is Border b) b.Background = Brushes.Transparent;
            };

            TabPanel.Children.Add(tabBorder);

            // 구분선
            if (tabPath != _tabs[^1])
            {
                TabPanel.Children.Add(new Border
                {
                    Width = 1, Height = 14,
                    Background = borderBrush,
                    Margin = new Thickness(2, 0, 2, 0),
                    VerticalAlignment = VerticalAlignment.Center,
                });
            }
        }

        // 타이틀 업데이트
        if (_activeTab != null)
            TitleText.Text = $"미리보기 — {Path.GetFileName(_activeTab)}";
    }

    // ─── 콘텐츠 로드 ────────────────────────────────────────────

    private async void LoadContent(string filePath)
    {
        var ext = Path.GetExtension(filePath).ToLowerInvariant();

        PreviewBrowser.Visibility = Visibility.Collapsed;
        TextScroll.Visibility = Visibility.Collapsed;
        DataGridContent.Visibility = Visibility.Collapsed;
        EmptyMessage.Visibility = Visibility.Collapsed;

        if (!File.Exists(filePath))
        {
            EmptyMessage.Text = "파일을 찾을 수 없습니다";
            EmptyMessage.Visibility = Visibility.Visible;
            return;
        }

        try
        {
            switch (ext)
            {
                case ".html":
                case ".htm":
                    if (!_webViewInitialized) return; // OnLoaded에서 재시도
                    PreviewBrowser.Source = new Uri(filePath);
                    PreviewBrowser.Visibility = Visibility.Visible;
                    break;

                case ".csv":
                    LoadCsvContent(filePath);
                    DataGridContent.Visibility = Visibility.Visible;
                    break;

                case ".md":
                    if (!_webViewInitialized) return;
                    var mdText = File.ReadAllText(filePath);
                    if (mdText.Length > 50000) mdText = mdText[..50000];
                    var mdHtml = Services.Agent.TemplateService.RenderMarkdownToHtml(
                        mdText, _selectedMood ?? "modern");
                    PreviewBrowser.NavigateToString(mdHtml);
                    PreviewBrowser.Visibility = Visibility.Visible;
                    break;

                case ".txt":
                case ".json":
                case ".xml":
                case ".log":
                    var text = File.ReadAllText(filePath);
                    if (text.Length > 50000) text = text[..50000] + "\n\n... (이후 생략)";
                    TextContent.Text = text;
                    TextScroll.Visibility = Visibility.Visible;
                    break;

                default:
                    EmptyMessage.Text = "미리보기할 수 없는 파일 형식입니다";
                    EmptyMessage.Visibility = Visibility.Visible;
                    break;
            }
        }
        catch (Exception ex)
        {
            TextContent.Text = $"미리보기 오류: {ex.Message}";
            TextScroll.Visibility = Visibility.Visible;
        }

        await System.Threading.Tasks.Task.CompletedTask; // async 경고 방지
    }

    private void LoadCsvContent(string filePath)
    {
        var lines = File.ReadAllLines(filePath);
        if (lines.Length == 0) return;

        var dt = new DataTable();
        var headers = ParseCsvLine(lines[0]);
        foreach (var h in headers)
            dt.Columns.Add(h);

        var maxRows = Math.Min(lines.Length, 501);
        for (int i = 1; i < maxRows; i++)
        {
            var vals = ParseCsvLine(lines[i]);
            var row = dt.NewRow();
            for (int j = 0; j < Math.Min(vals.Length, headers.Length); j++)
                row[j] = vals[j];
            dt.Rows.Add(row);
        }

        DataGridContent.ItemsSource = dt.DefaultView;
    }

    private static string[] ParseCsvLine(string line)
    {
        var fields = new List<string>();
        var current = new StringBuilder();
        bool inQuotes = false;

        for (int i = 0; i < line.Length; i++)
        {
            char c = line[i];
            if (inQuotes)
            {
                if (c == '"' && i + 1 < line.Length && line[i + 1] == '"')
                { current.Append('"'); i++; }
                else if (c == '"') inQuotes = false;
                else current.Append(c);
            }
            else
            {
                if (c == '"') inQuotes = true;
                else if (c == ',') { fields.Add(current.ToString()); current.Clear(); }
                else current.Append(c);
            }
        }
        fields.Add(current.ToString());
        return fields.ToArray();
    }

    // ─── 타이틀 바 ──────────────────────────────────────────────

    private void TitleBar_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        if (e.ClickCount == 2) { ToggleMaximize(); return; }
        DragMove();
    }

    private void OpenExternalBtn_Click(object sender, MouseButtonEventArgs e)
    {
        e.Handled = true;
        if (_activeTab == null || !File.Exists(_activeTab)) return;
        try
        {
            System.Diagnostics.Process.Start(new System.Diagnostics.ProcessStartInfo
            {
                FileName = _activeTab,
                UseShellExecute = true,
            });
        }
        catch (Exception ex)
        {
            Services.LogService.Warn($"외부 프로그램 열기 실패: {ex.Message}");
        }
    }

    private void MinBtn_Click(object sender, MouseButtonEventArgs e)
    {
        e.Handled = true;
        WindowState = WindowState.Minimized;
    }

    private void MaxBtn_Click(object sender, MouseButtonEventArgs e)
    {
        e.Handled = true;
        ToggleMaximize();
    }

    private void CloseBtn_Click(object sender, MouseButtonEventArgs e)
    {
        e.Handled = true;
        Close();
    }

    private void ToggleMaximize()
    {
        WindowState = WindowState == WindowState.Maximized
            ? WindowState.Normal
            : WindowState.Maximized;
    }

    private void TitleBtn_Enter(object sender, MouseEventArgs e)
    {
        if (sender is Border b)
            b.Background = TryFindResource("ItemHoverBackground") as Brush
                           ?? new SolidColorBrush(Color.FromArgb(0x18, 0xFF, 0xFF, 0xFF));
    }

    private void CloseBtnEnter(object sender, MouseEventArgs e)
    {
        if (sender is Border b)
            b.Background = new SolidColorBrush(Color.FromArgb(0x44, 0xFF, 0x40, 0x40));
    }

    private void TitleBtn_Leave(object sender, MouseEventArgs e)
    {
        if (sender is Border b)
            b.Background = Brushes.Transparent;
    }
}