using System;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Threading;
using AxCopilot.Services;

namespace AxCopilot.Views;

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

    /// <summary>열려 있는 프리뷰 탭 목록 (파일 경로 기준).</summary>
    private readonly List<string> _previewTabs = new();
    private string? _activePreviewTab;
    private bool _webViewInitialized;
    private Popup? _previewTabPopup;

    private static readonly string WebView2DataFolder =
        Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
                     "AxCopilot", "WebView2");

    private void TryShowPreview(string filePath)
    {
        if (string.IsNullOrEmpty(filePath) || !File.Exists(filePath))
            return;

        PreviewWindow.ShowPreview(filePath, _selectedMood);
    }

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

        _activePreviewTab = filePath;

        if (PreviewColumn.Width.Value < 100)
        {
            PreviewColumn.Width = new GridLength(420);
            SplitterColumn.Width = new GridLength(5);
        }

        PreviewPanel.Visibility = Visibility.Visible;
        PreviewSplitter.Visibility = Visibility.Visible;
        BtnPreviewToggle.Visibility = Visibility.Visible;

        RebuildPreviewTabs();
        LoadPreviewContent(filePath);
    }

    private void RebuildPreviewTabs()
    {
        PreviewTabPanel.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 _previewTabs)
        {
            var fileName = Path.GetFileName(tabPath);
            var isActive = string.Equals(tabPath, _activePreviewTab, StringComparison.OrdinalIgnoreCase);

            var tabBorder = new Border
            {
                Background = isActive
                    ? new SolidColorBrush(Color.FromArgb(0x15, 0xFF, 0xFF, 0xFF))
                    : Brushes.Transparent,
                BorderBrush = isActive ? accentBrush : Brushes.Transparent,
                BorderThickness = new Thickness(0, 0, 0, isActive ? 2 : 0),
                Padding = new Thickness(8, 6, 4, 6),
                Cursor = Cursors.Hand,
                MaxWidth = _previewTabs.Count <= 3 ? 200 : (_previewTabs.Count <= 5 ? 140 : 100),
            };

            var tabContent = new StackPanel { Orientation = Orientation.Horizontal };
            tabContent.Children.Add(new TextBlock
            {
                Text = fileName,
                FontSize = 11,
                Foreground = isActive ? primaryText : secondaryText,
                FontWeight = isActive ? FontWeights.SemiBold : FontWeights.Normal,
                VerticalAlignment = VerticalAlignment.Center,
                TextTrimming = TextTrimming.CharacterEllipsis,
                MaxWidth = tabBorder.MaxWidth - 30,
                ToolTip = tabPath,
            });

            var closeFg = isActive ? primaryText : secondaryText;
            var closeBtnText = new TextBlock
            {
                Text = "\uE711",
                FontFamily = new FontFamily("Segoe MDL2 Assets"),
                FontSize = 10,
                Foreground = closeFg,
                VerticalAlignment = VerticalAlignment.Center,
            };
            var closeBtn = new Border
            {
                Background = Brushes.Transparent,
                CornerRadius = new CornerRadius(3),
                Padding = new Thickness(3, 2, 3, 2),
                Margin = new Thickness(5, 0, 0, 0),
                Cursor = Cursors.Hand,
                VerticalAlignment = VerticalAlignment.Center,
                Visibility = isActive ? Visibility.Visible : Visibility.Hidden,
                Child = closeBtnText,
                Tag = "close",
            };

            var closePath = tabPath;
            closeBtn.MouseEnter += (s, _) =>
            {
                if (s is Border b)
                {
                    b.Background = new SolidColorBrush(Color.FromArgb(0x40, 0xFF, 0x50, 0x50));
                    if (b.Child is TextBlock tb)
                        tb.Foreground = new SolidColorBrush(Color.FromRgb(0xFF, 0x60, 0x60));
                }
            };
            closeBtn.MouseLeave += (s, _) =>
            {
                if (s is Border b)
                {
                    b.Background = Brushes.Transparent;
                    if (b.Child is TextBlock tb)
                        tb.Foreground = closeFg;
                }
            };
            closeBtn.MouseLeftButtonUp += (_, e) =>
            {
                e.Handled = true;
                ClosePreviewTab(closePath);
            };

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

            var clickPath = tabPath;
            tabBorder.MouseLeftButtonUp += (_, e) =>
            {
                if (e.Handled)
                    return;

                e.Handled = true;
                _activePreviewTab = clickPath;
                RebuildPreviewTabs();
                LoadPreviewContent(clickPath);
            };

            var ctxPath = tabPath;
            tabBorder.MouseRightButtonUp += (_, e) =>
            {
                e.Handled = true;
                ShowPreviewTabContextMenu(ctxPath);
            };

            var dblPath = tabPath;
            tabBorder.MouseLeftButtonDown += (_, e) =>
            {
                if (e.Handled)
                    return;

                if (e.ClickCount == 2)
                {
                    e.Handled = true;
                    OpenPreviewPopupWindow(dblPath);
                }
            };

            var capturedIsActive = isActive;
            var capturedCloseBtn = closeBtn;
            tabBorder.MouseEnter += (s, _) =>
            {
                if (s is Border b && !capturedIsActive)
                    b.Background = new SolidColorBrush(Color.FromArgb(0x10, 0xFF, 0xFF, 0xFF));
                if (!capturedIsActive)
                    capturedCloseBtn.Visibility = Visibility.Visible;
            };
            tabBorder.MouseLeave += (s, _) =>
            {
                if (s is Border b && !capturedIsActive)
                    b.Background = Brushes.Transparent;
                if (!capturedIsActive)
                    capturedCloseBtn.Visibility = Visibility.Hidden;
            };

            PreviewTabPanel.Children.Add(tabBorder);

            if (!string.Equals(tabPath, _previewTabs[^1], StringComparison.OrdinalIgnoreCase))
            {
                PreviewTabPanel.Children.Add(new Border
                {
                    Width = 1,
                    Height = 14,
                    Background = borderBrush,
                    Margin = new Thickness(0, 4, 0, 4),
                    VerticalAlignment = VerticalAlignment.Center,
                });
            }
        }
    }

    private void ClosePreviewTab(string filePath)
    {
        _previewTabs.Remove(filePath);

        if (_previewTabs.Count == 0)
        {
            HidePreviewPanel();
            return;
        }

        if (string.Equals(filePath, _activePreviewTab, StringComparison.OrdinalIgnoreCase))
        {
            _activePreviewTab = _previewTabs[^1];
            LoadPreviewContent(_activePreviewTab);
        }

        RebuildPreviewTabs();
    }

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

        PreviewWebView.Visibility = Visibility.Collapsed;
        PreviewTextScroll.Visibility = Visibility.Collapsed;
        PreviewDataGrid.Visibility = Visibility.Collapsed;
        PreviewEmpty.Visibility = Visibility.Collapsed;

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

        try
        {
            switch (ext)
            {
                case ".html":
                case ".htm":
                    await EnsureWebViewInitializedAsync();
                    PreviewWebView.Source = new Uri(filePath);
                    PreviewWebView.Visibility = Visibility.Visible;
                    break;

                case ".csv":
                    LoadCsvPreview(filePath);
                    PreviewDataGrid.Visibility = Visibility.Visible;
                    break;

                case ".md":
                    await EnsureWebViewInitializedAsync();
                    var mdText = File.ReadAllText(filePath);
                    if (mdText.Length > 50000)
                        mdText = mdText[..50000];
                    var mdHtml = Services.Agent.TemplateService.RenderMarkdownToHtml(mdText, _selectedMood);
                    PreviewWebView.NavigateToString(mdHtml);
                    PreviewWebView.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)";
                    PreviewTextBlock.Text = text;
                    PreviewTextScroll.Visibility = Visibility.Visible;
                    break;

                default:
                    SetPreviewHeaderState("지원되지 않는 형식");
                    PreviewEmpty.Text = "미리보기할 수 없는 파일 형식입니다";
                    PreviewEmpty.Visibility = Visibility.Visible;
                    break;
            }
        }
        catch (Exception ex)
        {
            SetPreviewHeaderState("미리보기 오류");
            PreviewTextBlock.Text = $"미리보기 오류: {ex.Message}";
            PreviewTextScroll.Visibility = Visibility.Visible;
        }
    }

    private void SetPreviewHeader(string filePath)
    {
        if (PreviewHeaderTitle == null || PreviewHeaderSubtitle == null || PreviewHeaderMeta == null)
            return;

        var fileName = Path.GetFileName(filePath);
        var extension = Path.GetExtension(filePath).TrimStart('.').ToUpperInvariant();
        var fileInfo = new FileInfo(filePath);
        var sizeText = fileInfo.Exists
            ? fileInfo.Length >= 1024 * 1024
                ? $"{fileInfo.Length / 1024d / 1024d:F1} MB"
                : $"{Math.Max(1, fileInfo.Length / 1024d):F0} KB"
            : "파일 없음";

        PreviewHeaderTitle.Text = string.IsNullOrWhiteSpace(fileName) ? "미리보기" : fileName;
        PreviewHeaderSubtitle.Text = filePath;
        PreviewHeaderMeta.Text = string.IsNullOrWhiteSpace(extension)
            ? sizeText
            : $"{extension} · {sizeText}";
    }

    private void SetPreviewHeaderState(string state)
    {
        if (PreviewHeaderMeta != null && !string.IsNullOrWhiteSpace(state))
            PreviewHeaderMeta.Text = state;
    }

    private async Task EnsureWebViewInitializedAsync()
    {
        if (_webViewInitialized)
            return;

        try
        {
            var env = await Microsoft.Web.WebView2.Core.CoreWebView2Environment.CreateAsync(
                userDataFolder: WebView2DataFolder);
            await PreviewWebView.EnsureCoreWebView2Async(env);
            _webViewInitialized = true;
        }
        catch (Exception ex)
        {
            LogService.Warn($"WebView2 초기화 실패: {ex.Message}");
        }
    }

    private void LoadCsvPreview(string filePath)
    {
        try
        {
            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 (var i = 1; i < maxRows; i++)
            {
                var vals = ParseCsvLine(lines[i]);
                var row = dt.NewRow();
                for (var j = 0; j < Math.Min(vals.Length, headers.Length); j++)
                    row[j] = vals[j];
                dt.Rows.Add(row);
            }

            PreviewDataGrid.ItemsSource = dt.DefaultView;
        }
        catch (Exception ex)
        {
            PreviewTextBlock.Text = $"CSV 로드 오류: {ex.Message}";
            PreviewTextScroll.Visibility = Visibility.Visible;
            PreviewDataGrid.Visibility = Visibility.Collapsed;
        }
    }

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

        for (var i = 0; i < line.Length; i++)
        {
            var 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();
    }

    private void HidePreviewPanel()
    {
        _previewTabs.Clear();
        _activePreviewTab = null;
        if (PreviewHeaderTitle != null) PreviewHeaderTitle.Text = "미리보기";
        if (PreviewHeaderSubtitle != null) PreviewHeaderSubtitle.Text = "선택한 파일이 여기에 표시됩니다";
        if (PreviewHeaderMeta != null) PreviewHeaderMeta.Text = "파일 메타";
        PreviewColumn.Width = new GridLength(0);
        SplitterColumn.Width = new GridLength(0);
        PreviewPanel.Visibility = Visibility.Collapsed;
        PreviewSplitter.Visibility = Visibility.Collapsed;
        PreviewWebView.Visibility = Visibility.Collapsed;
        PreviewTextScroll.Visibility = Visibility.Collapsed;
        PreviewDataGrid.Visibility = Visibility.Collapsed;
        try
        {
            if (_webViewInitialized)
                PreviewWebView.CoreWebView2?.NavigateToString("<html></html>");
        }
        catch
        {
        }
    }

    private void PreviewTabBar_PreviewMouseDown(object sender, MouseButtonEventArgs e)
    {
        if (PreviewWebView.IsFocused || PreviewWebView.IsKeyboardFocusWithin)
        {
            var border = sender as Border;
            border?.Focus();
        }
    }

    private void BtnClosePreview_Click(object sender, RoutedEventArgs e)
    {
        HidePreviewPanel();
        BtnPreviewToggle.Visibility = Visibility.Collapsed;
    }

    private void BtnPreviewToggle_Click(object sender, RoutedEventArgs e)
    {
        if (PreviewPanel.Visibility == Visibility.Visible)
        {
            PreviewPanel.Visibility = Visibility.Collapsed;
            PreviewSplitter.Visibility = Visibility.Collapsed;
            PreviewColumn.Width = new GridLength(0);
            SplitterColumn.Width = new GridLength(0);
        }
        else if (_previewTabs.Count > 0)
        {
            PreviewPanel.Visibility = Visibility.Visible;
            PreviewSplitter.Visibility = Visibility.Visible;
            PreviewColumn.Width = new GridLength(420);
            SplitterColumn.Width = new GridLength(5);
            RebuildPreviewTabs();
            if (_activePreviewTab != null)
                LoadPreviewContent(_activePreviewTab);
        }
    }

    private void BtnOpenExternal_Click(object sender, RoutedEventArgs e)
    {
        if (string.IsNullOrEmpty(_activePreviewTab) || !File.Exists(_activePreviewTab))
            return;

        try
        {
            Process.Start(new ProcessStartInfo
            {
                FileName = _activePreviewTab,
                UseShellExecute = true,
            });
        }
        catch (Exception ex)
        {
            Debug.WriteLine($"외부 프로그램 실행 오류: {ex.Message}");
        }
    }

    private void ShowPreviewTabContextMenu(string filePath)
    {
        if (_previewTabPopup != null)
            _previewTabPopup.IsOpen = false;

        var primaryText = TryFindResource("PrimaryText") as Brush ?? Brushes.White;
        var secondaryText = TryFindResource("SecondaryText") as Brush ?? Brushes.Gray;

        var stack = new StackPanel();

        void AddItem(string icon, string iconColor, string label, Action action)
        {
            var iconBrush = string.IsNullOrEmpty(iconColor)
                ? secondaryText
                : new SolidColorBrush((Color)ColorConverter.ConvertFromString(iconColor));
            var itemBorder = CreateSurfacePopupMenuItem(icon, iconBrush, label, () =>
            {
                _previewTabPopup!.IsOpen = false;
                action();
            }, primaryText, 13);
            stack.Children.Add(itemBorder);
        }

        void AddSeparator()
        {
            stack.Children.Add(CreateSurfacePopupSeparator());
        }

        AddItem("\uE8A7", "#64B5F6", "외부 프로그램으로 열기", () =>
        {
            try
            {
                Process.Start(new ProcessStartInfo
                {
                    FileName = filePath,
                    UseShellExecute = true,
                });
            }
            catch
            {
            }
        });

        AddItem("\uE838", "#FFB74D", "파일 위치 열기", () =>
        {
            try
            {
                Process.Start("explorer.exe", $"/select,\"{filePath}\"");
            }
            catch
            {
            }
        });

        AddItem("\uE8A7", "#81C784", "별도 창에서 보기", () => OpenPreviewPopupWindow(filePath));

        AddSeparator();

        AddItem("\uE8C8", "", "경로 복사", () =>
        {
            try
            {
                Clipboard.SetText(filePath);
            }
            catch
            {
            }
        });

        AddSeparator();

        AddItem("\uE711", "#EF5350", "이 탭 닫기", () => ClosePreviewTab(filePath));

        if (_previewTabs.Count > 1)
        {
            AddItem("\uE8BB", "#EF5350", "다른 탭 모두 닫기", () =>
            {
                var keep = filePath;
                _previewTabs.RemoveAll(p => !string.Equals(p, keep, StringComparison.OrdinalIgnoreCase));
                _activePreviewTab = keep;
                RebuildPreviewTabs();
                LoadPreviewContent(keep);
            });
        }

        var popupBorder = CreateSurfacePopupContainer(stack, 180, new Thickness(4, 6, 4, 6));

        _previewTabPopup = new Popup
        {
            Child = popupBorder,
            Placement = PlacementMode.MousePoint,
            StaysOpen = false,
            AllowsTransparency = true,
            PopupAnimation = PopupAnimation.Fade,
        };
        _previewTabPopup.IsOpen = true;
    }

    private void OpenPreviewPopupWindow(string filePath)
    {
        if (!File.Exists(filePath))
            return;

        var ext = Path.GetExtension(filePath).ToLowerInvariant();
        var fileName = Path.GetFileName(filePath);
        var bg = TryFindResource("LauncherBackground") as Brush ?? new SolidColorBrush(Color.FromRgb(0x1E, 0x1E, 0x2E));
        var fg = TryFindResource("PrimaryText") as Brush ?? Brushes.White;

        var win = new Window
        {
            Title = $"미리보기 — {fileName}",
            Width = 900,
            Height = 700,
            WindowStartupLocation = WindowStartupLocation.CenterScreen,
            Background = bg,
        };

        FrameworkElement content;

        switch (ext)
        {
            case ".html":
            case ".htm":
                var wv = new Microsoft.Web.WebView2.Wpf.WebView2();
                wv.Loaded += async (_, _) =>
                {
                    try
                    {
                        var env = await Microsoft.Web.WebView2.Core.CoreWebView2Environment.CreateAsync(
                            userDataFolder: WebView2DataFolder);
                        await wv.EnsureCoreWebView2Async(env);
                        wv.Source = new Uri(filePath);
                    }
                    catch
                    {
                    }
                };
                content = wv;
                break;

            case ".md":
                var mdWv = new Microsoft.Web.WebView2.Wpf.WebView2();
                var mdMood = _selectedMood;
                mdWv.Loaded += async (_, _) =>
                {
                    try
                    {
                        var env = await Microsoft.Web.WebView2.Core.CoreWebView2Environment.CreateAsync(
                            userDataFolder: WebView2DataFolder);
                        await mdWv.EnsureCoreWebView2Async(env);
                        var mdSrc = File.ReadAllText(filePath);
                        if (mdSrc.Length > 100000)
                            mdSrc = mdSrc[..100000];
                        var html = Services.Agent.TemplateService.RenderMarkdownToHtml(mdSrc, mdMood);
                        mdWv.NavigateToString(html);
                    }
                    catch
                    {
                    }
                };
                content = mdWv;
                break;

            case ".csv":
                var dg = new DataGrid
                {
                    AutoGenerateColumns = true,
                    IsReadOnly = true,
                    Background = Brushes.Transparent,
                    Foreground = Brushes.White,
                    BorderThickness = new Thickness(0),
                    FontSize = 12,
                };
                try
                {
                    var lines = File.ReadAllLines(filePath);
                    if (lines.Length > 0)
                    {
                        var dt = new DataTable();
                        var headers = ParseCsvLine(lines[0]);
                        foreach (var h in headers)
                            dt.Columns.Add(h);
                        for (var i = 1; i < Math.Min(lines.Length, 1001); i++)
                        {
                            var vals = ParseCsvLine(lines[i]);
                            var row = dt.NewRow();
                            for (var j = 0; j < Math.Min(vals.Length, dt.Columns.Count); j++)
                                row[j] = vals[j];
                            dt.Rows.Add(row);
                        }

                        dg.ItemsSource = dt.DefaultView;
                    }
                }
                catch
                {
                }
                content = dg;
                break;

            default:
                var text = File.ReadAllText(filePath);
                if (text.Length > 100000)
                    text = text[..100000] + "\n\n... (이후 생략)";
                var sv = new ScrollViewer
                {
                    VerticalScrollBarVisibility = ScrollBarVisibility.Auto,
                    Padding = new Thickness(20),
                    Content = new TextBlock
                    {
                        Text = text,
                        TextWrapping = TextWrapping.Wrap,
                        FontFamily = new FontFamily("Consolas"),
                        FontSize = 13,
                        Foreground = fg,
                    },
                };
                content = sv;
                break;
        }

        win.Content = content;
        win.Show();
    }
}