using System;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Input;
using System.Windows.Media;
using AxCopilot.Models;
using AxCopilot.Services;

namespace AxCopilot.Views;

public partial class ChatWindow
{
    // ── A-1: TopicButtonPanel 이벤트 위임 ──
    private Border? _lastHoveredTopicBorder;
    private bool _topicPanelDelegationInitialized;

    /// <summary>프리셋 카드 Border.Tag에 저장하는 메타 데이터.</summary>
    private sealed class TopicCardTag
    {
        public required string Action { get; init; } // "preset" | "etc" | "add" | "custom_preset"
        public TopicPreset? Preset { get; init; }
        public required Brush NormalBackground { get; init; }
        public required Brush HoverBackground { get; init; }
        public Brush? NormalBorderBrush { get; init; }
    }

    /// <summary>TopicButtonPanel에 이벤트 위임 핸들러를 1회 등록합니다.</summary>
    private void InitTopicPanelDelegation()
    {
        if (_topicPanelDelegationInitialized || TopicButtonPanel == null)
            return;
        _topicPanelDelegationInitialized = true;

        TopicButtonPanel.Background = Brushes.Transparent; // 갭 영역도 히트테스트 대상으로 등록
        TopicButtonPanel.MouseMove += TopicPanel_DelegatedMouseMove;
        TopicButtonPanel.MouseLeave += TopicPanel_DelegatedMouseLeave;
        TopicButtonPanel.PreviewMouseLeftButtonDown += TopicPanel_DelegatedLeftButtonDown;
        TopicButtonPanel.PreviewMouseRightButtonUp += TopicPanel_DelegatedRightButtonUp;
    }

    private void TopicPanel_DelegatedMouseMove(object sender, MouseEventArgs e)
    {
        var border = FindAncestorWithTag<Border>(e.OriginalSource as DependencyObject);
        if (ReferenceEquals(border, _lastHoveredTopicBorder))
            return;

        // 이전 호버 해제
        if (_lastHoveredTopicBorder?.Tag is TopicCardTag prevTag)
        {
            _lastHoveredTopicBorder.Background = prevTag.NormalBackground;
            if (prevTag.NormalBorderBrush != null)
                _lastHoveredTopicBorder.BorderBrush = prevTag.NormalBorderBrush;
        }

        _lastHoveredTopicBorder = border;

        // 새 호버 적용
        if (border?.Tag is TopicCardTag tag)
        {
            border.Background = tag.HoverBackground;
            border.BorderBrush = TryFindResource("AccentColor") as Brush ?? tag.NormalBorderBrush ?? border.BorderBrush;
        }
    }

    private void TopicPanel_DelegatedMouseLeave(object sender, MouseEventArgs e)
    {
        if (_lastHoveredTopicBorder?.Tag is TopicCardTag prevTag)
        {
            _lastHoveredTopicBorder.Background = prevTag.NormalBackground;
            if (prevTag.NormalBorderBrush != null)
                _lastHoveredTopicBorder.BorderBrush = prevTag.NormalBorderBrush;
        }
        _lastHoveredTopicBorder = null;
    }

    private void TopicPanel_DelegatedLeftButtonDown(object sender, MouseButtonEventArgs e)
    {
        var border = FindAncestorWithTag<Border>(e.OriginalSource as DependencyObject);
        if (border?.Tag is not TopicCardTag tag)
            return;

        e.Handled = true;
        switch (tag.Action)
        {
            case "preset" or "custom_preset" when tag.Preset != null:
                SelectTopic(tag.Preset);
                break;
            case "etc":
                EmptyState.Visibility = Visibility.Collapsed;
                InputBox.Focus();
                break;
            case "add":
                ShowCustomPresetDialog();
                break;
        }
    }

    private void TopicPanel_DelegatedRightButtonUp(object sender, MouseButtonEventArgs e)
    {
        var border = FindAncestorWithTag<Border>(e.OriginalSource as DependencyObject);
        if (border?.Tag is not TopicCardTag tag)
            return;

        if (tag.Action == "custom_preset" && tag.Preset != null)
        {
            e.Handled = true;
            ShowCustomPresetContextMenu(border, tag.Preset);
        }
    }

    /// <summary>프리셋 대화 주제 버튼을 동적으로 생성합니다.</summary>
    private void BuildTopicButtons()
    {
        _lastHoveredTopicBorder = null;
        TopicButtonPanel.Children.Clear();
        TopicButtonPanel.Visibility = Visibility.Visible;
        if (TopicPresetScrollViewer != null)
            TopicPresetScrollViewer.Visibility = Visibility.Visible;

        if (_activeTab == "Cowork" || _activeTab == "Code")
        {
            if (EmptyStateTitle != null)
                EmptyStateTitle.Text = _activeTab == "Code" ? "코드 작업을 입력하세요" : "작업 유형을 선택하세요";
            if (EmptyStateDesc != null)
                EmptyStateDesc.Text = _activeTab == "Code"
                    ? "코딩 에이전트가 코드 분석, 수정, 빌드, 테스트를 수행합니다"
                    : "에이전트가 상세한 데이터를 작성합니다";
        }
        else
        {
            if (EmptyStateTitle != null)
                EmptyStateTitle.Text = "대화 주제를 선택하세요";
            if (EmptyStateDesc != null)
                EmptyStateDesc.Text = "주제에 맞는 전문 프리셋이 자동 적용됩니다";
        }

        if (_activeTab == "Code")
        {
            TopicButtonPanel.Visibility = Visibility.Collapsed;
            if (TopicPresetScrollViewer != null)
                TopicPresetScrollViewer.Visibility = Visibility.Collapsed;
            return;
        }

        var presets = Services.PresetService.GetByTabWithCustom(_activeTab, _settings.Settings.Llm.CustomPresets);
        var cardBackground = TryFindResource("ItemBackground") as Brush ?? Brushes.Transparent;
        var cardHoverBackground = TryFindResource("ItemHoverBackground") as Brush ?? Brushes.Transparent;
        var cardBorder = TryFindResource("BorderColor") as Brush ?? BrushFromHex("#E5E7EB");
        var primaryText = TryFindResource("PrimaryText") as Brush ?? Brushes.White;
        var secondaryText = TryFindResource("SecondaryText") as Brush ?? Brushes.Gray;

        foreach (var preset in presets)
        {
            var buttonColor = BrushFromHex(preset.Color);

            var border = new Border
            {
                Background = cardBackground,
                BorderBrush = cardBorder,
                BorderThickness = new Thickness(1),
                CornerRadius = new CornerRadius(14),
                Padding = new Thickness(14, 14, 14, 12),
                Margin = new Thickness(6, 6, 6, 8),
                Cursor = Cursors.Hand,
                Width = 148,
                Height = 124,
                ClipToBounds = true,
            };

            var contentGrid = new Grid();
            var stack = new StackPanel
            {
                HorizontalAlignment = HorizontalAlignment.Center,
                VerticalAlignment = VerticalAlignment.Center,
            };

            var iconCircle = new Border
            {
                Width = 34,
                Height = 34,
                CornerRadius = new CornerRadius(17),
                Background = new SolidColorBrush(((SolidColorBrush)buttonColor).Color) { Opacity = 0.15 },
                HorizontalAlignment = HorizontalAlignment.Center,
                Margin = new Thickness(0, 0, 0, 9),
            };
            var iconBlock = new TextBlock
            {
                Text = preset.Symbol,
                FontFamily = new FontFamily("Segoe MDL2 Assets"),
                FontSize = 15,
                Foreground = buttonColor,
                HorizontalAlignment = HorizontalAlignment.Center,
                VerticalAlignment = VerticalAlignment.Center,
            };
            iconCircle.Child = iconBlock;
            stack.Children.Add(iconCircle);

            stack.Children.Add(new TextBlock
            {
                Text = preset.Label,
                FontSize = 15,
                FontWeight = FontWeights.SemiBold,
                Foreground = primaryText,
                HorizontalAlignment = HorizontalAlignment.Center,
                TextAlignment = TextAlignment.Center,
                TextWrapping = TextWrapping.Wrap,
                MaxWidth = 112,
            });

            contentGrid.Children.Add(stack);

            if (preset.IsCustom)
            {
                var badge = new Border
                {
                    Width = 16,
                    Height = 16,
                    CornerRadius = new CornerRadius(4),
                    Background = new SolidColorBrush(Color.FromArgb(0x60, 0xFF, 0xFF, 0xFF)),
                    HorizontalAlignment = HorizontalAlignment.Left,
                    VerticalAlignment = VerticalAlignment.Top,
                    Margin = new Thickness(2, 2, 0, 0),
                };
                badge.Child = new TextBlock
                {
                    Text = "\uE710",
                    FontFamily = new FontFamily("Segoe MDL2 Assets"),
                    FontSize = 8,
                    Foreground = buttonColor,
                    HorizontalAlignment = HorizontalAlignment.Center,
                    VerticalAlignment = VerticalAlignment.Center,
                };
                contentGrid.Children.Add(badge);
            }

            border.Child = contentGrid;

            // A-1: 이벤트 위임 — 개별 람다 대신 Tag에 메타 저장
            border.Tag = new TopicCardTag
            {
                Action = preset.IsCustom ? "custom_preset" : "preset",
                Preset = preset,
                NormalBackground = cardBackground,
                HoverBackground = cardHoverBackground,
                NormalBorderBrush = cardBorder,
            };

            TopicButtonPanel.Children.Add(border);
        }

        var etcColor = BrushFromHex("#6B7280");
        var etcBorder = new Border
        {
            Background = cardBackground,
            BorderBrush = cardBorder,
            BorderThickness = new Thickness(1),
            CornerRadius = new CornerRadius(14),
            Padding = new Thickness(14, 14, 14, 12),
            Margin = new Thickness(6, 6, 6, 8),
            Cursor = Cursors.Hand,
            Width = 148,
            Height = 124,
            ClipToBounds = true,
        };

        var etcGrid = new Grid();
        var etcStack = new StackPanel
        {
            HorizontalAlignment = HorizontalAlignment.Center,
            VerticalAlignment = VerticalAlignment.Center,
        };

        var etcIconCircle = new Border
        {
            Width = 34,
            Height = 34,
            CornerRadius = new CornerRadius(17),
            Background = new SolidColorBrush(((SolidColorBrush)etcColor).Color) { Opacity = 0.15 },
            HorizontalAlignment = HorizontalAlignment.Center,
            Margin = new Thickness(0, 0, 0, 9),
        };
        etcIconCircle.Child = new TextBlock
        {
            Text = "\uE70F",
            FontFamily = new FontFamily("Segoe MDL2 Assets"),
            FontSize = 15,
            Foreground = etcColor,
            HorizontalAlignment = HorizontalAlignment.Center,
            VerticalAlignment = VerticalAlignment.Center,
        };
        etcStack.Children.Add(etcIconCircle);
        etcStack.Children.Add(new TextBlock
        {
            Text = "기타",
            FontSize = 15,
            FontWeight = FontWeights.SemiBold,
            Foreground = primaryText,
            HorizontalAlignment = HorizontalAlignment.Center,
            TextAlignment = TextAlignment.Center,
        });
        etcGrid.Children.Add(etcStack);
        etcBorder.Child = etcGrid;
        etcBorder.Tag = new TopicCardTag
        {
            Action = "etc",
            NormalBackground = cardBackground,
            HoverBackground = cardHoverBackground,
            NormalBorderBrush = cardBorder,
        };
        TopicButtonPanel.Children.Add(etcBorder);

        var addBorder = new Border
        {
            Background = Brushes.Transparent,
            BorderBrush = cardBorder,
            BorderThickness = new Thickness(1),
            CornerRadius = new CornerRadius(14),
            Padding = new Thickness(14, 14, 14, 12),
            Margin = new Thickness(6, 6, 6, 8),
            Cursor = Cursors.Hand,
            Width = 148,
            Height = 124,
            ClipToBounds = true,
        };

        var addGrid = new Grid();
        var addStack = new StackPanel
        {
            HorizontalAlignment = HorizontalAlignment.Center,
            VerticalAlignment = VerticalAlignment.Center,
        };

        addStack.Children.Add(new TextBlock
        {
            Text = "\uE710",
            FontFamily = new FontFamily("Segoe MDL2 Assets"),
            FontSize = 18,
            Foreground = secondaryText,
            HorizontalAlignment = HorizontalAlignment.Center,
            Margin = new Thickness(0, 8, 0, 8),
        });
        addStack.Children.Add(new TextBlock
        {
            Text = "프리셋 추가",
            FontSize = 14,
            FontWeight = FontWeights.SemiBold,
            Foreground = secondaryText,
            HorizontalAlignment = HorizontalAlignment.Center,
        });

        addGrid.Children.Add(addStack);
        addBorder.Child = addGrid;
        addBorder.Tag = new TopicCardTag
        {
            Action = "add",
            NormalBackground = Brushes.Transparent,
            HoverBackground = cardHoverBackground,
            NormalBorderBrush = cardBorder,
        };
        TopicButtonPanel.Children.Add(addBorder);

        UpdateTopicPresetScrollMode();
    }

    private void UpdateTopicPresetScrollMode()
    {
        if (TopicPresetScrollViewer == null || TopicButtonPanel == null)
            return;

        Dispatcher.BeginInvoke(new Action(() =>
        {
            if (TopicPresetScrollViewer == null || TopicButtonPanel == null)
                return;

            TopicPresetScrollViewer.UpdateLayout();
            var shouldScroll = TopicPresetScrollViewer.ExtentHeight > TopicPresetScrollViewer.ViewportHeight + 1;
            TopicPresetScrollViewer.VerticalScrollBarVisibility = shouldScroll
                ? ScrollBarVisibility.Auto
                : ScrollBarVisibility.Disabled;
            TopicPresetScrollViewer.Padding = shouldScroll
                ? new Thickness(0, 2, 6, 0)
                : new Thickness(0, 2, 0, 0);
        }), System.Windows.Threading.DispatcherPriority.Loaded);
    }

    private void ShowCustomPresetDialog(CustomPresetEntry? existing = null)
    {
        var dialog = new CustomPresetDialog(
            existingName: existing?.Label ?? "",
            existingDesc: existing?.Description ?? "",
            existingPrompt: existing?.SystemPrompt ?? "",
            existingColor: existing?.Color ?? "#6366F1",
            existingSymbol: existing?.Symbol ?? "\uE713",
            existingTab: existing?.Tab ?? _activeTab)
        {
            Owner = this,
        };

        if (dialog.ShowDialog() != true)
            return;

        if (existing != null)
        {
            existing.Label = dialog.PresetName;
            existing.Description = dialog.PresetDescription;
            existing.SystemPrompt = dialog.PresetSystemPrompt;
            existing.Color = dialog.PresetColor;
            existing.Symbol = dialog.PresetSymbol;
            existing.Tab = dialog.PresetTab;
        }
        else
        {
            _settings.Settings.Llm.CustomPresets.Add(new CustomPresetEntry
            {
                Label = dialog.PresetName,
                Description = dialog.PresetDescription,
                SystemPrompt = dialog.PresetSystemPrompt,
                Color = dialog.PresetColor,
                Symbol = dialog.PresetSymbol,
                Tab = dialog.PresetTab,
            });
        }

        _settings.Save();
        BuildTopicButtons();
    }

    private void ShowCustomPresetContextMenu(Border? anchor, Services.TopicPreset preset)
    {
        if (anchor == null || preset.CustomId == null)
            return;

        var popup = new Popup
        {
            PlacementTarget = anchor,
            Placement = PlacementMode.Bottom,
            StaysOpen = false,
            AllowsTransparency = true,
        };

        var menuBackground = TryFindResource("LauncherBackground") as Brush ?? Brushes.Black;
        var primaryText = TryFindResource("PrimaryText") as Brush ?? Brushes.White;
        var borderBrush = TryFindResource("BorderColor") as Brush ?? Brushes.Gray;

        var menuBorder = new Border
        {
            Background = menuBackground,
            CornerRadius = new CornerRadius(10),
            BorderBrush = borderBrush,
            BorderThickness = new Thickness(1),
            Padding = new Thickness(4),
            MinWidth = 120,
            Effect = new System.Windows.Media.Effects.DropShadowEffect
            {
                BlurRadius = 12,
                ShadowDepth = 2,
                Opacity = 0.3,
                Color = Colors.Black,
            },
        };

        var stack = new StackPanel();

        var editItem = CreateContextMenuItem("\uE70F", "편집", primaryText);
        editItem.MouseLeftButtonDown += (_, _) =>
        {
            popup.IsOpen = false;
            var entry = _settings.Settings.Llm.CustomPresets.FirstOrDefault(item => item.Id == preset.CustomId);
            if (entry != null)
                ShowCustomPresetDialog(entry);
        };
        stack.Children.Add(editItem);

        var deleteItem = CreateContextMenuItem("\uE74D", "삭제", new SolidColorBrush(Color.FromRgb(0xEF, 0x44, 0x44)));
        deleteItem.MouseLeftButtonDown += (_, _) =>
        {
            popup.IsOpen = false;
            var result = CustomMessageBox.Show(
                $"'{preset.Label}' 프리셋을 삭제하시겠습니까?",
                "프리셋 삭제",
                MessageBoxButton.YesNo,
                MessageBoxImage.Question);
            if (result != MessageBoxResult.Yes)
                return;

            _settings.Settings.Llm.CustomPresets.RemoveAll(item => item.Id == preset.CustomId);
            _settings.Save();
            BuildTopicButtons();
        };
        stack.Children.Add(deleteItem);

        menuBorder.Child = stack;
        popup.Child = menuBorder;
        popup.IsOpen = true;
    }

    private Border CreateContextMenuItem(string icon, string label, Brush foreground)
    {
        var item = new Border
        {
            Background = Brushes.Transparent,
            CornerRadius = new CornerRadius(6),
            Padding = new Thickness(10, 6, 14, 6),
            Cursor = Cursors.Hand,
        };

        var stack = new StackPanel { Orientation = Orientation.Horizontal };
        stack.Children.Add(new TextBlock
        {
            Text = icon,
            FontFamily = new FontFamily("Segoe MDL2 Assets"),
            FontSize = 13,
            Foreground = foreground,
            VerticalAlignment = VerticalAlignment.Center,
            Margin = new Thickness(0, 0, 8, 0),
        });
        stack.Children.Add(new TextBlock
        {
            Text = label,
            FontSize = 13,
            Foreground = foreground,
            VerticalAlignment = VerticalAlignment.Center,
        });
        item.Child = stack;

        var hoverBackground = TryFindResource("ItemHoverBackground") as Brush ?? Brushes.Transparent;
        item.MouseEnter += (sender, _) =>
        {
            if (sender is Border hovered)
                hovered.Background = hoverBackground;
        };
        item.MouseLeave += (sender, _) =>
        {
            if (sender is Border hovered)
                hovered.Background = Brushes.Transparent;
        };

        return item;
    }

    private Border CreateContextMenuItem(string icon, string label, Brush foreground, Brush secondaryForeground)
        => CreateContextMenuItem(icon, label, foreground);

    private void SelectTopic(Services.TopicPreset preset)
    {
        bool hasConversation;
        bool hasMessages;
        lock (_convLock)
        {
            hasConversation = _currentConversation != null;
            hasMessages = _currentConversation?.Messages.Count > 0;
        }

        var hasInput = !string.IsNullOrEmpty(InputBox.Text);
        if (!hasConversation)
            StartNewConversation();

        lock (_convLock)
        {
            if (_currentConversation == null)
                return;

            var session = ChatSession;
            if (session != null)
            {
                _currentConversation = session.UpdateConversationMetadata(_activeTab, conversation =>
                {
                    conversation.SystemCommand = preset.SystemPrompt;
                    conversation.Category = preset.Category;
                }, _storage);
            }
            else
            {
                _currentConversation.SystemCommand = preset.SystemPrompt;
                _currentConversation.Category = preset.Category;
            }
        }

        UpdateCategoryLabel();
        SaveConversationSettings();
        RefreshConversationList();
        UpdateSelectedPresetGuide();
        if (EmptyState != null)
            EmptyState.Visibility = Visibility.Collapsed;

        InputBox.Focus();

        if (!string.IsNullOrEmpty(preset.Placeholder))
        {
            _promptCardPlaceholder = preset.Placeholder;
            if (!hasMessages && !hasInput)
                ShowPlaceholder();
        }

        if (hasMessages || hasInput)
            ShowToast($"프리셋 변경 · {preset.Label}");

        if (_activeTab == "Cowork")
            BuildBottomBar();
    }
}