using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Input;
using System.Windows.Media;
using TeamAAS.Dialogs.Dialogs;

namespace TeamAAS.Logging.Controls
{
    /// <summary>
    /// 实时日志控件：订阅 <see cref="LogStream.Published"/> 联动显示 AppLogger / PluginLogger 的日志。
    /// - 类别筛选：Debug/Info/Warning/Error/Critical 多选开关；
    /// - 显示判定：公共日志恒显；插件日志由各节点「显示详细度」闸门决定是否进流（与是否落盘无关）；
    /// - 插件条目上的 L2/L4 为归一化档位标签，仅用于区分常规/详细，不参与显隐。
    /// </summary>
    public partial class LogView : UserControl
    {
        /// <summary>显示上限依赖属性的默认值（可在 XAML 用 MaxEntries 覆盖）。</summary>
        private const int DefaultMaxEntries = 500;

        /// <summary>显示上限：控件最多保留的最近条目数，超出移除最旧。可在 XAML 用 MaxEntries 设置。</summary>
        public static readonly DependencyProperty MaxEntriesProperty =
            DependencyProperty.Register(nameof(MaxEntries), typeof(int), typeof(LogView),
                new PropertyMetadata(DefaultMaxEntries, OnMaxEntriesChanged));

        /// <summary>显示上限（最近 N 条），默认 500，&lt;=0 视为 1。</summary>
        public int MaxEntries
        {
            get => (int)GetValue(MaxEntriesProperty);
            set => SetValue(MaxEntriesProperty, value);
        }

        private static void OnMaxEntriesChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
            => (d as LogView)?.TrimToMax();

        private readonly ObservableCollection<LogEntry> _items = new ObservableCollection<LogEntry>();
        private readonly ICollectionView _view;
        private ScrollViewer _scrollViewer;
        private bool _subscribed;

        public LogView()
        {
            InitializeComponent();

            _view = CollectionViewSource.GetDefaultView(_items);
            _view.Filter = o => IsCategoryEnabled(((LogEntry)o).Category);
            LogList.ItemsSource = _view;

            Loaded += OnLoaded;
            Unloaded += OnUnloaded;
        }

        private void OnLoaded(object sender, RoutedEventArgs e)
        {
            if (_subscribed) return;

            // 首次加载回填历史缓冲（新建控件实例时 _items 为空）
            if (_items.Count == 0)
            {
                foreach (var entry in LogStream.Snapshot())
                    AppendInternal(entry);
            }

            LogStream.Published += OnPublished;
            _subscribed = true;
            ScrollToEnd();
        }

        private void OnUnloaded(object sender, RoutedEventArgs e)
        {
            if (!_subscribed) return;
            LogStream.Published -= OnPublished;
            _subscribed = false;
        }

        private void OnPublished(LogEntry entry)
        {
            var dispatcher = Application.Current?.Dispatcher;
            if (dispatcher != null && !dispatcher.CheckAccess())
                dispatcher.BeginInvoke(new Action(() => Append(entry)));
            else
                Append(entry);
        }

        private void Append(LogEntry entry)
        {
            bool atBottom = IsScrolledToEnd();
            AppendInternal(entry);
            if (atBottom) ScrollToEnd();
        }

        private void AppendInternal(LogEntry entry)
        {
            _items.Add(entry);
            TrimToMax();
        }

        private void TrimToMax()
        {
            int max = MaxEntries <= 0 ? 1 : MaxEntries;
            while (_items.Count > max)
                _items.RemoveAt(0);
        }

        private void CategoryToggle_Changed(object sender, RoutedEventArgs e)
        {
            // 初始化阶段（ToggleButton 尚未就绪）不刷新
            if (_view != null && LogList != null)
                _view.Refresh();
        }

        private void BtnClear_Click(object sender, RoutedEventArgs e)
        {
            _items.Clear();
        }

        // 双击一条日志 → 弹出详情窗（含来源/时间/类别/完整内容，支持复制）
        private void LogList_MouseDoubleClick(object sender, MouseButtonEventArgs e)
        {
            var entry = FindEntry(e.OriginalSource as DependencyObject) ?? LogList.SelectedItem as LogEntry;
            if (entry == null) return;

            var window = new LogDetailWindow(entry) { Owner = Window.GetWindow(this) };
            window.ShowDialog();
        }

        // 从双击命中点沿（视觉/逻辑）树上溯，找到 DataContext 为 LogEntry 的元素
        private static LogEntry FindEntry(DependencyObject node)
        {
            while (node != null)
            {
                if (node is FrameworkElement fe && fe.DataContext is LogEntry entry)
                    return entry;
                node = node is Visual
                    ? VisualTreeHelper.GetParent(node)
                    : LogicalTreeHelper.GetParent(node);
            }
            return null;
        }

        private bool IsCategoryEnabled(LogLevel category)
        {
            switch (category)
            {
                case LogLevel.Warning: return TgWarning == null || TgWarning.IsChecked == true;
                case LogLevel.Error: return TgError == null || TgError.IsChecked == true;
                default: return TgInfo == null || TgInfo.IsChecked == true;   // Info
            }
        }

        private bool IsScrolledToEnd()
        {
            if (_scrollViewer == null) _scrollViewer = FindScrollViewer(LogList);
            if (_scrollViewer == null) return true;
            return _scrollViewer.VerticalOffset >= _scrollViewer.ScrollableHeight - 4;
        }

        private void ScrollToEnd()
        {
            if (LogList.Items.Count > 0)
                LogList.ScrollIntoView(LogList.Items[LogList.Items.Count - 1]);
        }

        private static ScrollViewer FindScrollViewer(DependencyObject root)
        {
            if (root == null) return null;
            int count = VisualTreeHelper.GetChildrenCount(root);
            for (int i = 0; i < count; i++)
            {
                var child = VisualTreeHelper.GetChild(root, i);
                if (child is ScrollViewer sv) return sv;
                var result = FindScrollViewer(child);
                if (result != null) return result;
            }
            return null;
        }
    }
}