using System.Collections.ObjectModel;
using System.Linq;
using System.Threading.Tasks;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using DMS.Core.Enums;
using DMS.Helper;
using DMS.Models;
using Opc.Ua;
using Opc.Ua.Client;
using Opc.Ua.Configuration;

namespace DMS.ViewModels.Dialogs;

public partial class OpcUaImportDialogViewModel : ObservableObject
{
    [ObservableProperty]
    private string _endpointUrl = "opc.tcp://127.0.0.1:4855"; // 默认值

    [ObservableProperty]
    private ObservableCollection<OpcUaNode> _opcUaNodes;

    [ObservableProperty]
    private ObservableCollection<Variable> _selectedNodeVariables;

    public List<Variable> SelectedVariables { get; set; }=new List<Variable>();

    [ObservableProperty]
    private bool _selectAllVariables;

    [ObservableProperty]
    private bool _isConnected;

    private Session _session;

    public OpcUaImportDialogViewModel()
    {
        OpcUaNodes = new ObservableCollection<OpcUaNode>();
        SelectedNodeVariables = new ObservableCollection<Variable>();
        // Automatically connect when the ViewModel is created
        ConnectCommand.Execute(null);
        
    }

    [RelayCommand]
    private async Task Connect()
    {
        try
        {
            // 断开现有连接
            if (_session != null && _session.Connected)
            {
                await _session.CloseAsync();
                _session.Dispose();
                _session = null;
            }

            IsConnected = false;
            OpcUaNodes.Clear();
            SelectedNodeVariables.Clear();

            _session = await ServiceHelper.CreateOpcUaSessionAsync(EndpointUrl);

            NotificationHelper.ShowSuccess($"已连接到 OPC UA 服务器: {EndpointUrl}");
            IsConnected = true;

            // 浏览根节点
            await BrowseNodes(OpcUaNodes, ObjectIds.ObjectsFolder);
        }
        catch (Exception ex)
        {
            IsConnected = false;
            NotificationHelper.ShowError($"连接 OPC UA 服务器失败: {EndpointUrl} - {ex.Message}", ex);
        }
    }

    /// <summary>
    /// 处理来自服务器的数据变化通知
    /// </summary>
    private static void OnNotification(MonitoredItem item, MonitoredItemNotificationEventArgs e)
    {
        foreach (var value in item.DequeueValues())
        {
            Console.WriteLine(
                $"[通知] {item.DisplayName}: {value.Value} | 时间戳: {value.SourceTimestamp.ToLocalTime()} | 状态: {value.StatusCode}");
        }
    }

    private async Task BrowseNodes(ObservableCollection<OpcUaNode> nodes, NodeId parentNodeId)
    {
        try
        {
            Opc.Ua.ReferenceDescriptionCollection references;
            byte[] continuationPoint = null;

            _session.Browse(
                null, // RequestHeader
                new ViewDescription(),
                parentNodeId,
                0u,
                BrowseDirection.Forward,
                Opc.Ua.ReferenceTypeIds.HierarchicalReferences,
                true,
                (uint)Opc.Ua.NodeClass.Object | (uint)Opc.Ua.NodeClass.Variable,
                out continuationPoint,
                out references
            );

            foreach (var rd in references)
            {
                NodeType nodeType = NodeType.Folder; // 默认是文件夹
                if ((rd.NodeClass & NodeClass.Variable) != 0)
                {
                    nodeType = NodeType.Variable;
                }
                else if ((rd.NodeClass & NodeClass.Object) != 0)
                {
                    nodeType = NodeType.Object;
                }

                var opcUaNode = new OpcUaNode(rd.DisplayName.Text, (NodeId)rd.NodeId, nodeType);
                nodes.Add(opcUaNode);

                // 如果是文件夹或对象，添加一个虚拟子节点，用于懒加载
                if (nodeType == NodeType.Folder || nodeType == NodeType.Object)
                {
                    opcUaNode.Children.Add(new OpcUaNode("Loading...", NodeId.Null, NodeType.Folder)); // 虚拟节点
                }
            }
        }
        catch (Exception ex)
        {
            NlogHelper.Error($"浏览 OPC UA 节点失败: {parentNodeId} - {ex.Message}", ex);
            NotificationHelper.ShowError($"浏览 OPC UA 节点失败: {parentNodeId} - {ex.Message}", ex);
        }
    }

    public async Task LoadNodeVariables(OpcUaNode node)
    {
        if (node.NodeType == NodeType.Variable)
        {
            // 如果是变量节点，直接显示它
            SelectedNodeVariables.Clear();
            SelectedNodeVariables.Add(new Variable
                                      {
                                          Name = node.DisplayName,
                                          NodeId = node.NodeId.ToString(),
                                          OpcUaNodeId = node.NodeId.ToString(),
                                          ProtocolType = ProtocolType.OpcUA,
                                          IsActive = true // 默认选中
                                      });
            return;
        }

        if (node.IsLoaded || node.IsLoading)
        {
            return; // 已经加载或正在加载
        }

        node.IsLoading = true;
        node.Children.Clear(); // 清除虚拟节点

        try
        {
            Opc.Ua.ReferenceDescriptionCollection references;
            byte[] continuationPoint = null;

            _session.Browse(
                null, // RequestHeader
                new ViewDescription(),
                node.NodeId,
                0u,
                BrowseDirection.Forward,
                Opc.Ua.ReferenceTypeIds.HierarchicalReferences,
                true,
                (uint)Opc.Ua.NodeClass.Object | (uint)Opc.Ua.NodeClass.Variable,
                out continuationPoint,
                out references
            );

            foreach (var rd in references)
            {
                NodeType nodeType = NodeType.Folder;
                if ((rd.NodeClass & NodeClass.Variable) != 0)
                {
                    nodeType = NodeType.Variable;
                }
                else if ((rd.NodeClass & NodeClass.Object) != 0)
                {
                    nodeType = NodeType.Object;
                }

                var opcUaNode = new OpcUaNode(rd.DisplayName.Text, (NodeId)rd.NodeId, nodeType);
                node.Children.Add(opcUaNode);

                if (nodeType == NodeType.Folder || nodeType == NodeType.Object)
                {
                    opcUaNode.Children.Add(new OpcUaNode("Loading...", NodeId.Null, NodeType.Folder)); // 虚拟节点
                }

                // 如果是变量，添加到右侧列表
                if (nodeType == NodeType.Variable)
                {
                    // Read the DataType attribute
                    ReadValueId readValueId = new ReadValueId
                                              {
                                                  NodeId = opcUaNode.NodeId,
                                                  AttributeId = Attributes.DataType,
                                                  // You might need to specify IndexRange and DataEncoding if dealing with arrays or specific encodings
                                              };

                    DataValueCollection results;
                    DiagnosticInfoCollection diagnosticInfos;

                    _session.Read(
                        null, // RequestHeader
                        0, // MaxAge
                        TimestampsToReturn.Source,
                        new ReadValueIdCollection { readValueId },
                        out results,
                        out diagnosticInfos
                    );

                    string dataType = string.Empty;

                    if (results != null && results.Count > 0 && results[0].Value != null)
                    {
                        // Convert the NodeId of the DataType to a readable string
                        NodeId dataTypeNodeId = (NodeId)results[0].Value;
                        dataType = _session.NodeCache.GetDisplayText(dataTypeNodeId);
                    }

                    SelectedNodeVariables.Add(new Variable
                                              {
                                                  Name = opcUaNode.DisplayName,
                                                  OpcUaNodeId = opcUaNode.NodeId.ToString(),
                                                  ProtocolType = ProtocolType.OpcUA,
                                                  IsActive = true, // Default selected
                                                  DataType = dataType // Assign the read DataType
                                              });
                }
            }

            node.IsLoaded = true;
        }
        catch (Exception ex)
        {
            NlogHelper.Error($"加载 OPC UA 节点变量失败: {node.NodeId} - {ex.Message}", ex);
            NotificationHelper.ShowError($"加载 OPC UA 节点变量失败: {node.NodeId} - {ex.Message}", ex);
        }
        finally
        {
            node.IsLoading = false;
        }
    }

    public ObservableCollection<Variable> GetSelectedVariables()
    {
        return new ObservableCollection<Variable>(SelectedVariables);
    }
}