using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Configuration;
using System.Linq;
using System.Threading;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Threading;
using CanSimulator;
using log4net;

namespace CanSimulatorServer.App
{
    /// <summary>
    /// 模拟器服务监控窗口：状态栏 + 连接节点树 + 实时帧表 + 日志区。
    /// 纯代码构建 UI（不走 XAML 标记编译链路）；帧表经 100ms 定时器批量刷新，上限 2000 行。
    /// </summary>
    public class MainWindow : Window
    {
        private static readonly ILog Log = LogManager.GetLogger(typeof(MainWindow));

        private const int MaxFrameRows = 2000;

        private readonly TcpSimulatorHost _host = new();
        private readonly ConcurrentQueue<FrameRow> _pendingRows = new();
        private readonly ObservableCollection<FrameRow> _rows = new();
        private readonly DispatcherTimer _uiTimer = new();
        private int _tickCount;

        private TextBlock _statusText = null!;
        private TextBlock _statsText = null!;
        private TreeView _nodeTree = null!;
        private ListView _frameList = null!;
        private TextBox _logBox = null!;
        private Button _startBtn = null!;
        private Button _stopBtn = null!;
        private CheckBox _echoChk = null!;
        private bool _echoWanted;
        private readonly int _port;
        private readonly bool _listenAll;

        private sealed class FrameRow
        {
            public string Time { get; set; } = "";
            public string Bus { get; set; } = "";
            public string Src { get; set; } = "";
            public string FrameId { get; set; } = "";
            public string Data { get; set; } = "";
            public string Kind { get; set; } = "TX";
        }

        public MainWindow()
        {
            _port = ReadIntConfig("ServerPort", 9000);
            _listenAll = string.Equals(ConfigurationManager.AppSettings["ListenOnAllInterfaces"],
                "true", StringComparison.OrdinalIgnoreCase);

            BuildUi();
            HookHostEvents();

            _uiTimer.Interval = TimeSpan.FromMilliseconds(100);
            _uiTimer.Tick += (s, e) => DrainPendingRows();
            _uiTimer.Start();

            Loaded += async (s, e) => await StartHostAsync();
            Closing += (s, e) => { _host.Dispose(); };
        }

        // ==================== 宿主生命周期 ====================

        private async Task StartHostAsync()
        {
            try
            {
                await _host.StartAsync(_port, _listenAll);
                _statusText.Text = $"监听中  {(_listenAll ? "0.0.0.0" : "127.0.0.1")}:{_port}";
                _statusText.Foreground = Brushes.ForestGreen;
                _startBtn.IsEnabled = false;
                _stopBtn.IsEnabled = true;
                AppendLog($"服务端已启动，监听 {_port}（{(_listenAll ? "全部接口" : "仅本机")}）");
            }
            catch (Exception ex)
            {
                _statusText.Text = "启动失败：端口被占用？";
                _statusText.Foreground = Brushes.Firebrick;
                AppendLog($"[FATAL] 启动失败: {ex.Message}");
                _startBtn.IsEnabled = true;
                Log.Error("宿主启动失败", ex);
            }
        }

        private void HookHostEvents()
        {
            _host.SessionAttached += session =>
            {
                Dispatcher.BeginInvoke(new Action(() =>
                {
                    AppendLog($"节点接入：{session.ClientTag}");
                    RefreshTree();
                }));
            };
        }

        /// <summary>总线帧事件挂接（宿主启动后总线才存在，故在定时器里惰性补挂）</summary>
        private void EnsureBusSubscriptions()
        {
            foreach (var bus in _host.Manager.AllBuses())
            {
                if (_subscribedBuses.Add(bus.BusName))
                {
                    bus.FrameTransmitted += (s, e) => EnqueueBusRow(bus.BusName, e.Frame, e.SourceNodeId);
                    bus.EchoResponderToSender = _echoWanted; // 新建总线继承当前应答器开关
                }
            }
        }
        private readonly HashSet<string> _subscribedBuses = new(StringComparer.OrdinalIgnoreCase);

        // ==================== UI 构建 ====================

        private void BuildUi()
        {
            var root = new Grid { Margin = new Thickness(10) };
            root.RowDefinitions.Add(new RowDefinition { Height = GridLength.Auto });
            root.RowDefinitions.Add(new RowDefinition { Height = new GridLength(1, GridUnitType.Star) });
            root.RowDefinitions.Add(new RowDefinition { Height = new GridLength(160) });

            // ── 顶部状态/按钮栏 ──
            var bar = new StackPanel { Orientation = Orientation.Horizontal };
            _statusText = new TextBlock
            {
                Text = "未启动",
                FontWeight = FontWeights.Bold,
                VerticalAlignment = VerticalAlignment.Center,
                Margin = new Thickness(0, 0, 16, 0)
            };
            _statsText = new TextBlock { VerticalAlignment = VerticalAlignment.Center, Margin = new Thickness(0, 0, 16, 0) };
            _startBtn = new Button { Content = "启动监听", Width = 90, Height = 28, Margin = new Thickness(0, 0, 6, 0) };
            _startBtn.Click += async (s, e) => await StartHostAsync();
            _stopBtn = new Button { Content = "停止监听", Width = 90, Height = 28, Margin = new Thickness(0, 0, 6, 0), IsEnabled = false };
            _stopBtn.Click += (s, e) =>
            {
                _host.Dispose();
                _statusText.Text = "已停止";
                _statusText.Foreground = Brushes.Gray;
                _startBtn.IsEnabled = true;
                _stopBtn.IsEnabled = false;
                AppendLog("服务端已停止（注意：已运行客户端将断线重连）");
            };
            var clearBtn = new Button { Content = "清空帧表", Width = 90, Height = 28 };
            clearBtn.Click += (s, e) => { _rows.Clear(); while (_pendingRows.TryDequeue(out _)) { } };
            _echoChk = new CheckBox
            {
                Content = "总线应答器(回显发送者)",
                VerticalAlignment = VerticalAlignment.Center,
                Margin = new Thickness(12, 0, 0, 0),
                IsChecked = false
            };
            _echoChk.Click += (s, e) =>
            {
                _echoWanted = _echoChk.IsChecked == true;
                foreach (var bus in _host.Manager.AllBuses())
                    bus.EchoResponderToSender = _echoWanted;
                AppendLog($"总线应答器已{(_echoWanted ? "开启" : "关闭")}（作用于当前所有总线）");
            };
            bar.Children.Add(_statusText);
            bar.Children.Add(_statsText);
            bar.Children.Add(_startBtn);
            bar.Children.Add(_stopBtn);
            bar.Children.Add(clearBtn);
            bar.Children.Add(_echoChk);
            Grid.SetRow(bar, 0);
            root.Children.Add(bar);

            // ── 中部：左节点树 + 右帧表 ──
            var split = new Grid();
            split.ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(280) });
            split.ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(1, GridUnitType.Star) });

            _nodeTree = new TreeView();
            var treeBorder = new Border
            {
                Child = _nodeTree,
                BorderBrush = Brushes.LightGray,
                BorderThickness = new Thickness(1),
                Margin = new Thickness(0, 8, 8, 0)
            };
            Grid.SetColumn(treeBorder, 0);

            _frameList = new ListView { View = BuildGridView() };
            _frameList.ItemsSource = _rows;
            var listBorder = new Border
            {
                Child = _frameList,
                BorderBrush = Brushes.LightGray,
                BorderThickness = new Thickness(1),
                Margin = new Thickness(0, 8, 0, 0)
            };
            Grid.SetColumn(listBorder, 1);

            split.Children.Add(treeBorder);
            split.Children.Add(listBorder);
            Grid.SetRow(split, 1);
            root.Children.Add(split);

            // ── 底部日志 ──
            _logBox = new TextBox
            {
                IsReadOnly = true,
                VerticalScrollBarVisibility = ScrollBarVisibility.Auto,
                FontFamily = new FontFamily("Consolas"),
                FontSize = 11,
                Margin = new Thickness(0, 8, 0, 0)
            };
            Grid.SetRow(_logBox, 2);
            root.Children.Add(_logBox);

            Content = root;
        }

        private static GridView BuildGridView()
        {
            var gv = new GridView();
            AddCol(gv, "时间", 85, nameof(FrameRow.Time));
            AddCol(gv, "总线", 95, nameof(FrameRow.Bus));
            AddCol(gv, "源节点", 60, nameof(FrameRow.Src));
            AddCol(gv, "帧ID", 70, nameof(FrameRow.FrameId));
            AddCol(gv, "数据", 200, nameof(FrameRow.Data));
            AddCol(gv, "类型", 70, nameof(FrameRow.Kind));
            return gv;
        }

        private static void AddCol(GridView gv, string header, double width, string binding)
        {
            gv.Columns.Add(new GridViewColumn
            {
                Header = header,
                Width = width,
                DisplayMemberBinding = new System.Windows.Data.Binding(binding)
            });
        }

        // ==================== 帧表与树刷新 ====================

        /// <summary>总线级观察：路由发生即记一行（含自动响应帧）</summary>
        private void EnqueueBusRow(string busName, CanFrame frame, string srcNodeId)
        {
            _pendingRows.Enqueue(new FrameRow
            {
                Time = frame.Timestamp.ToString("HH:mm:ss.fff"),
                Bus = busName,
                Src = srcNodeId,
                FrameId = frame.FrameIdHex,
                Data = frame.DataHex,
                Kind = "TX路由"
            });
        }

        private void DrainPendingRows()
        {
            EnsureBusSubscriptions();

            int n = 0;
            while (_pendingRows.TryDequeue(out var row) && n < 50)
            {
                _rows.Insert(0, row);
                n++;
            }
            while (_rows.Count > MaxFrameRows)
                _rows.RemoveAt(_rows.Count - 1);

            RefreshStatsLine();

            // 每秒刷新一次节点树（反映断开会话，避免只在接入事件中刷新）
            if (++_tickCount % 10 == 0) RefreshTree();
        }

        private void RefreshStatsLine()
        {
            var buses = _host.Manager.AllBuses().ToList();
            long tx = buses.Sum(b => b.TotalFramesTransmitted);
            long rx = buses.Sum(b => b.TotalFramesReceived);
            _statsText.Text = $"会话={_host.ActiveSessionCount} 累计={_host.AcceptedCount} " +
                              $"总线={buses.Count} TX={tx} RX={rx}";
        }

        private void RefreshTree()
        {
            _nodeTree.Items.Clear();
            foreach (var bus in _host.Manager.AllBuses())
            {
                var busNode = new TreeViewItem { Header = bus.BusName + $"（{bus.State}）" };
                foreach (var node in bus.GetAllNodes())
                    busNode.Items.Add(new TreeViewItem { Header = $"节点 {node.NodeId} · {node.Name}" });
                _nodeTree.Items.Add(busNode);
                busNode.IsExpanded = true;
            }
        }

        private void AppendLog(string msg)
        {
            _logBox.AppendText($"{DateTime.Now:HH:mm:ss.fff} {msg}{Environment.NewLine}");
            _logBox.ScrollToEnd();
        }

        private static int ReadIntConfig(string key, int fallback)
            => int.TryParse(ConfigurationManager.AppSettings[key], out int v) ? v : fallback;
    }
}