using AuroraDesk.Core.Entities;
using AuroraDesk.Core.Interfaces;
using AuroraDesk.Presentation.ViewModels.Base;
using ReactiveUI;
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.Reactive;
using System.Reactive.Disposables;
using System.Reactive.Linq;
using System.Linq;
using Microsoft.Extensions.Logging;

namespace AuroraDesk.Presentation.ViewModels.Pages;

/// <summary>
/// 节点画布页面 ViewModel
/// </summary>
public class NodeCanvasPageViewModel : RoutableViewModel
{
    private readonly INodeCanvasService _nodeCanvasService;
    private readonly ILogger<NodeCanvasPageViewModel>? _logger;
    private Node? _selectedNode;
    private IDisposable? _selectedNodeSubscription;
    private ConnectionPoint? _connectingSourcePoint;
    private bool _isConnecting;
    private double _canvasOffsetX;
    private double _canvasOffsetY;
    private double _canvasZoom = 1.0;
    private int _selectedLeftConnectorCount;
    private int _selectedRightConnectorCount;

    public ObservableCollection<Node> Nodes => _nodeCanvasService.Nodes;
    public ObservableCollection<Connection> Connections => _nodeCanvasService.Connections;
    
    private ObservableCollection<NodeTemplate> _nodeTemplates = new();
    public ObservableCollection<NodeTemplate> NodeTemplates
    {
        get => _nodeTemplates;
        set => this.RaiseAndSetIfChanged(ref _nodeTemplates, value);
    }

    public IReadOnlyList<int> ConnectorCountOptions => _connectorCountOptions;

    /// <summary>
    /// 选中的节点
    /// </summary>
    private const double DefaultConnectorSize = 10d;
    private const int MinConnectorCount = 0;
    private const int MaxConnectorCount = 4;
    private const int DefaultConnectorCount = 3;
    private const string DefaultLeftConnectorColor = "#2D9CDB";
    private const string DefaultRightConnectorColor = "#EB5757";
    private readonly IReadOnlyList<int> _connectorCountOptions = Enumerable.Range(MinConnectorCount, MaxConnectorCount - MinConnectorCount + 1).ToList();

    public Node? SelectedNode
    {
        get => _selectedNode;
        set
        {
            if (ReferenceEquals(_selectedNode, value))
            {
                return;
            }

            this.RaiseAndSetIfChanged(ref _selectedNode, value);

            _selectedNodeSubscription?.Dispose();
            _selectedNodeSubscription = null;

            RefreshSelectedConnectorCounts();

            if (value != null)
            {
                var disposables = new CompositeDisposable();

                NotifyCollectionChangedEventHandler? handler = null;
                handler = (_, __) =>
                {
                    RefreshSelectedConnectorCounts();
                    this.RaisePropertyChanged(nameof(SelectedLeftConnectorCount));
                    this.RaisePropertyChanged(nameof(SelectedRightConnectorCount));
                    this.RaisePropertyChanged(nameof(SelectedConnectorMode));
                };

                value.ConnectionPoints.CollectionChanged += handler;
                disposables.Add(Disposable.Create(() => value.ConnectionPoints.CollectionChanged -= handler));

                _selectedNodeSubscription = disposables;
            }

            this.RaisePropertyChanged(nameof(SelectedConnectorMode));
            this.RaisePropertyChanged(nameof(SelectedLeftConnectorCount));
            this.RaisePropertyChanged(nameof(SelectedRightConnectorCount));
        }
    }

    public ConnectorAttachmentMode SelectedConnectorMode
    {
        get
        {
            if (SelectedNode == null)
            {
                return ConnectorAttachmentMode.None;
            }

            var hasLeft = _selectedLeftConnectorCount > 0;
            var hasRight = _selectedRightConnectorCount > 0;

            return (hasLeft, hasRight) switch
            {
                (false, false) => ConnectorAttachmentMode.None,
                (true, false) => ConnectorAttachmentMode.LeftOnly,
                (false, true) => ConnectorAttachmentMode.RightOnly,
                _ => ConnectorAttachmentMode.Both
            };
        }
        set
        {
            if (SelectedNode == null)
            {
                return;
            }

            if (SelectedConnectorMode == value)
            {
                return;
            }

            switch (value)
            {
                case ConnectorAttachmentMode.None:
                    SetConnectorCount(SelectedNode, ConnectionPointType.Input, 0);
                    SetConnectorCount(SelectedNode, ConnectionPointType.Output, 0);
                    break;
                case ConnectorAttachmentMode.LeftOnly:
                    if (SelectedLeftConnectorCount == 0)
                    {
                        SetConnectorCount(SelectedNode, ConnectionPointType.Input, 1);
                    }
                    SetConnectorCount(SelectedNode, ConnectionPointType.Output, 0);
                    break;
                case ConnectorAttachmentMode.RightOnly:
                    SetConnectorCount(SelectedNode, ConnectionPointType.Input, 0);
                    if (SelectedRightConnectorCount == 0)
                    {
                        SetConnectorCount(SelectedNode, ConnectionPointType.Output, 1);
                    }
                    break;
                case ConnectorAttachmentMode.Both:
                    if (SelectedLeftConnectorCount == 0)
                    {
                        SetConnectorCount(SelectedNode, ConnectionPointType.Input, 1);
                    }
                    if (SelectedRightConnectorCount == 0)
                    {
                        SetConnectorCount(SelectedNode, ConnectionPointType.Output, 1);
                    }
                    break;
                default:
                    return;
            }

            this.RaisePropertyChanged(nameof(SelectedConnectorMode));
        }
    }

    public int SelectedLeftConnectorCount
    {
        get => _selectedLeftConnectorCount;
        set
        {
            if (SelectedNode == null)
            {
                return;
            }

            SetConnectorCount(SelectedNode, ConnectionPointType.Input, value);
        }
    }

    public int SelectedRightConnectorCount
    {
        get => _selectedRightConnectorCount;
        set
        {
            if (SelectedNode == null)
            {
                return;
            }

            SetConnectorCount(SelectedNode, ConnectionPointType.Output, value);
        }
    }

    /// <summary>
    /// 正在连接的源连接点
    /// </summary>
    public ConnectionPoint? ConnectingSourcePoint
    {
        get => _connectingSourcePoint;
        set => this.RaiseAndSetIfChanged(ref _connectingSourcePoint, value);
    }

    /// <summary>
    /// 是否正在连接模式
    /// </summary>
    public bool IsConnecting
    {
        get => _isConnecting;
        set => this.RaiseAndSetIfChanged(ref _isConnecting, value);
    }

    /// <summary>
    /// 画布偏移X
    /// </summary>
    public double CanvasOffsetX
    {
        get => _canvasOffsetX;
        set => this.RaiseAndSetIfChanged(ref _canvasOffsetX, value);
    }

    /// <summary>
    /// 画布偏移Y
    /// </summary>
    public double CanvasOffsetY
    {
        get => _canvasOffsetY;
        set => this.RaiseAndSetIfChanged(ref _canvasOffsetY, value);
    }

    /// <summary>
    /// 画布缩放
    /// </summary>
    public double CanvasZoom
    {
        get => _canvasZoom;
        set => this.RaiseAndSetIfChanged(ref _canvasZoom, value);
    }

    // 命令
    public ReactiveCommand<Unit, Unit> ClearCanvasCommand { get; }
    public ReactiveCommand<Node, Unit> DeleteNodeCommand { get; }
    public ReactiveCommand<ConnectionPoint, Unit> StartConnectionCommand { get; }
    public ReactiveCommand<ConnectionPoint, Unit> CompleteConnectionCommand { get; }
    public ReactiveCommand<Connection, Unit> DeleteConnectionCommand { get; }
    public ReactiveCommand<(double x, double y), Unit> AddNodeCommand { get; }
    public ReactiveCommand<(NodeTemplate template, double x, double y), Unit> AddNodeFromTemplateCommand { get; }
    public ReactiveCommand<NodeTemplate, Unit> AddNodeFromTemplateAtCenterCommand { get; }
    public ReactiveCommand<NodeTemplate, Unit> AddNodeToCanvasCommand { get; }
    public ReactiveCommand<Unit, Unit> ZoomInCommand { get; }
    public ReactiveCommand<Unit, Unit> ZoomOutCommand { get; }
    public ReactiveCommand<Unit, Unit> ResetZoomCommand { get; }
    public ReactiveCommand<double, Unit> SetZoomCommand { get; }

    public NodeCanvasPageViewModel(
        IScreen screen,
        INodeCanvasService nodeCanvasService,
        ILogger<NodeCanvasPageViewModel>? logger = null) : base(screen, "node-canvas")
    {
        _nodeCanvasService = nodeCanvasService;
        _logger = logger;

        // 初始化节点模板
        InitializeNodeTemplates();

        // 初始化命令
        ClearCanvasCommand = ReactiveCommand.Create(ClearCanvas);
        DeleteNodeCommand = ReactiveCommand.Create<Node>(DeleteNode);
        StartConnectionCommand = ReactiveCommand.Create<ConnectionPoint>(StartConnection);
        CompleteConnectionCommand = ReactiveCommand.Create<ConnectionPoint>(CompleteConnection);
        DeleteConnectionCommand = ReactiveCommand.Create<Connection>(DeleteConnection);
        AddNodeCommand = ReactiveCommand.Create<(double x, double y)>(AddNode);
        AddNodeFromTemplateCommand = ReactiveCommand.Create<(NodeTemplate template, double x, double y)>(AddNodeFromTemplate);
        AddNodeFromTemplateAtCenterCommand = ReactiveCommand.Create<NodeTemplate>(template => AddNodeFromTemplateAtCenter(template));
        AddNodeToCanvasCommand = ReactiveCommand.Create<NodeTemplate>(AddNodeToCanvas);
        ZoomInCommand = ReactiveCommand.Create(ZoomIn);
        ZoomOutCommand = ReactiveCommand.Create(ZoomOut);
        ResetZoomCommand = ReactiveCommand.Create(ResetZoom);
        SetZoomCommand = ReactiveCommand.Create<double>(SetZoom);

        // 监听选中节点变化
        this.WhenAnyValue(x => x.SelectedNode)
            .Subscribe(node =>
            {
                // 取消其他节点的选中状态
                foreach (var n in Nodes)
                {
                    n.IsSelected = n == node;
                }
            });

        _logger?.LogInformation("NodeCanvasPageViewModel 已创建");
    }
    
    /// <summary>
    /// 初始化节点模板
    /// </summary>
    private void InitializeNodeTemplates()
    {
        NodeTemplates.Clear();

        NodeTemplates.Add(new NodeTemplate
        {
            Name = "rectangle-vertical",
            DisplayName = "竖向矩形",
            Description = "高>宽的矩形组件",
            Content = string.Empty,
            InputCount = 3,
            OutputCount = 3,
            Width = 90,
            Height = 160,
            LeftConnectorSize = DefaultConnectorSize,
            RightConnectorSize = DefaultConnectorSize,
            LeftConnectorColor = "#2D9CDB",
            RightConnectorColor = "#EB5757",
            LeftConnectorPlacement = ConnectorPlacementMode.Outside,
            RightConnectorPlacement = ConnectorPlacementMode.Outside
        });

        NodeTemplates.Add(new NodeTemplate
        {
            Name = "rectangle-horizontal",
            DisplayName = "横向矩形",
            Description = "宽>高的矩形组件",
            Content = string.Empty,
            InputCount = 3,
            OutputCount = 3,
            Width = 200,
            Height = 90,
            LeftConnectorSize = DefaultConnectorSize,
            RightConnectorSize = DefaultConnectorSize,
            LeftConnectorColor = "#2D9CDB",
            RightConnectorColor = "#EB5757",
            LeftConnectorPlacement = ConnectorPlacementMode.Outside,
            RightConnectorPlacement = ConnectorPlacementMode.Outside
        });
    }

    /// <summary>
    /// 添加节点到画布
    /// </summary>
    private void AddNode((double x, double y) position)
    {
        // 确保位置在合理范围内（至少为正数）
        var x = Math.Max(0, position.x);
        var y = Math.Max(0, position.y);
        
        var node = new Node
        {
            X = x,
            Y = y,
            Title = $"矩形 {Nodes.Count + 1}",
            Content = string.Empty,
            Width = 200,
            Height = 90,
            LeftConnectorSize = DefaultConnectorSize,
            RightConnectorSize = DefaultConnectorSize,
            LeftConnectorColor = "#2D9CDB",
            RightConnectorColor = "#EB5757",
            LeftConnectorPlacement = ConnectorPlacementMode.Outside,
            RightConnectorPlacement = ConnectorPlacementMode.Outside
        };

        // 默认提供输入和输出连接点
        for (int i = 0; i < DefaultConnectorCount; i++)
        {
            node.ConnectionPoints.Add(new ConnectionPoint
            {
                Label = string.Empty,
                Type = ConnectionPointType.Input,
                Index = i,
                Node = node,
                Diameter = node.LeftConnectorSize,
                Color = node.LeftConnectorColor,
                Placement = node.LeftConnectorPlacement
            });
        }

        for (int i = 0; i < DefaultConnectorCount; i++)
        {
            node.ConnectionPoints.Add(new ConnectionPoint
            {
                Label = (i + 1).ToString(),
                Type = ConnectionPointType.Output,
                Index = i,
                Node = node,
                Diameter = node.RightConnectorSize,
                Color = node.RightConnectorColor,
                Placement = node.RightConnectorPlacement
            });
        }

        _nodeCanvasService.AddNode(node);
        SelectedNode = node;
        _logger?.LogDebug("添加节点: {NodeId} 在位置 ({X}, {Y})", node.Id, position.x, position.y);
    }

    private void SetConnectorCount(Node node, ConnectionPointType type, int desiredCount)
    {
        UpdateConnectorCount(node, type, desiredCount);
        RefreshSelectedConnectorCounts();

        if (type == ConnectionPointType.Input)
        {
            this.RaisePropertyChanged(nameof(SelectedLeftConnectorCount));
        }
        else
        {
            this.RaisePropertyChanged(nameof(SelectedRightConnectorCount));
        }

        this.RaisePropertyChanged(nameof(SelectedConnectorMode));
    }

    private void RefreshSelectedConnectorCounts()
    {
        if (SelectedNode == null)
        {
            _selectedLeftConnectorCount = 0;
            _selectedRightConnectorCount = 0;
            return;
        }

        _selectedLeftConnectorCount = SelectedNode.ConnectionPoints.Count(p => p.Type == ConnectionPointType.Input);
        _selectedRightConnectorCount = SelectedNode.ConnectionPoints.Count(p => p.Type == ConnectionPointType.Output);
    }

    private void UpdateConnectorCount(Node node, ConnectionPointType type, int desiredCount)
    {
        if (node == null)
        {
            return;
        }

        desiredCount = Math.Clamp(desiredCount, MinConnectorCount, MaxConnectorCount);

        var existing = node.ConnectionPoints
            .Where(p => p.Type == type)
            .OrderBy(p => p.Index)
            .ToList();

        if (existing.Count > desiredCount)
        {
            for (int i = existing.Count - 1; i >= desiredCount; i--)
            {
                node.ConnectionPoints.Remove(existing[i]);
            }
        }
        else if (existing.Count < desiredCount)
        {
            for (int i = existing.Count; i < desiredCount; i++)
            {
                node.ConnectionPoints.Add(CreateConnectionPoint(node, type, i));
            }
        }

        RenumberConnectionPoints(node, type);
    }

    private ConnectionPoint CreateConnectionPoint(Node node, ConnectionPointType type, int index)
    {
        var existingSameSide = node.ConnectionPoints
            .Where(p => p.Type == type)
            .OrderBy(p => p.Index)
            .LastOrDefault();

        var defaultDiameter = existingSameSide?.Diameter ?? (type == ConnectionPointType.Input ? node.LeftConnectorSize : node.RightConnectorSize);
        if (defaultDiameter <= 0)
        {
            defaultDiameter = DefaultConnectorSize;
        }

        var defaultColor = existingSameSide?.Color ?? (type == ConnectionPointType.Input ? node.LeftConnectorColor : node.RightConnectorColor);
        if (string.IsNullOrWhiteSpace(defaultColor))
        {
            defaultColor = type == ConnectionPointType.Input ? DefaultLeftConnectorColor : DefaultRightConnectorColor;
        }

        var defaultPlacement = existingSameSide?.Placement ?? (type == ConnectionPointType.Input ? node.LeftConnectorPlacement : node.RightConnectorPlacement);

        return new ConnectionPoint
        {
            Type = type,
            Index = index,
            Label = type == ConnectionPointType.Output ? (index + 1).ToString() : string.Empty,
            Node = node,
            Diameter = defaultDiameter,
            Color = defaultColor,
            Placement = defaultPlacement
        };
    }

    private void RenumberConnectionPoints(Node node, ConnectionPointType type)
    {
        var points = node.ConnectionPoints
            .Where(p => p.Type == type)
            .OrderBy(p => p.Index)
            .ToList();

        for (int i = 0; i < points.Count; i++)
        {
            points[i].Index = i;
            if (type == ConnectionPointType.Output)
            {
                points[i].Label = (i + 1).ToString();
            }
        }
    }

    /// <summary>
    /// 删除节点
    /// </summary>
    private void DeleteNode(Node node)
    {
        if (node == null) return;

        _nodeCanvasService.RemoveNode(node);
        if (SelectedNode == node)
        {
            SelectedNode = null;
        }
        _logger?.LogDebug("删除节点: {NodeId}", node.Id);
    }

    /// <summary>
    /// 开始连接
    /// </summary>
    private void StartConnection(ConnectionPoint connectionPoint)
    {
        if (connectionPoint == null || connectionPoint.Type != ConnectionPointType.Output)
            return;

        ConnectingSourcePoint = connectionPoint;
        IsConnecting = true;
        _logger?.LogDebug("开始连接，源连接点: {PointId}", connectionPoint.Id);
    }

    /// <summary>
    /// 完成连接
    /// </summary>
    private void CompleteConnection(ConnectionPoint targetPoint)
    {
        if (targetPoint == null || ConnectingSourcePoint == null)
        {
            CancelConnection();
            return;
        }

        if (targetPoint.Type != ConnectionPointType.Input)
        {
            CancelConnection();
            return;
        }

        var success = _nodeCanvasService.CreateConnection(ConnectingSourcePoint, targetPoint);
        if (success)
        {
            _logger?.LogDebug("连接成功: {SourceId} -> {TargetId}", 
                ConnectingSourcePoint.Id, targetPoint.Id);
        }
        else
        {
            _logger?.LogWarning("连接失败: {SourceId} -> {TargetId}", 
                ConnectingSourcePoint.Id, targetPoint.Id);
        }

        CancelConnection();
    }

    /// <summary>
    /// 取消连接
    /// </summary>
    public void CancelConnection()
    {
        ConnectingSourcePoint = null;
        IsConnecting = false;
    }

    /// <summary>
    /// 删除连接
    /// </summary>
    private void DeleteConnection(Connection connection)
    {
        if (connection == null) return;

        _nodeCanvasService.RemoveConnection(connection);
        _logger?.LogDebug("删除连接: {ConnectionId}", connection.Id);
    }

    /// <summary>
    /// 清空画布
    /// </summary>
    private void ClearCanvas()
    {
        _nodeCanvasService.Clear();
        SelectedNode = null;
        _logger?.LogDebug("清空画布");
    }

    /// <summary>
    /// 更新节点位置
    /// </summary>
    public void UpdateNodePosition(Node node, double x, double y)
    {
        _nodeCanvasService.UpdateNodePosition(node, x, y);
    }

    /// <summary>
    /// 从模板添加节点到画布
    /// </summary>
    private void AddNodeFromTemplate((NodeTemplate template, double x, double y) args)
    {
        System.Diagnostics.Debug.WriteLine($"[ViewModel] AddNodeFromTemplate 被调用");
        System.Diagnostics.Debug.WriteLine($"[ViewModel] 模板: {args.template.Name}, 位置: ({args.x}, {args.y})");
        
        try
        {
            var node = args.template.CreateNode(args.x, args.y);
            System.Diagnostics.Debug.WriteLine($"[ViewModel] 节点创建成功: {node.Title}, ID: {node.Id}");
            
            _nodeCanvasService.AddNode(node);
            System.Diagnostics.Debug.WriteLine($"[ViewModel] 节点已添加到服务，当前节点数量: {Nodes.Count}");
            
            SelectedNode = node;
            System.Diagnostics.Debug.WriteLine($"[ViewModel] 节点已设置为选中状态");
            
            _logger?.LogDebug("从模板添加节点: {TemplateName} 在位置 ({X}, {Y})", 
                args.template.Name, args.x, args.y);
            
            System.Diagnostics.Debug.WriteLine($"[ViewModel] AddNodeFromTemplate 完成");
        }
        catch (Exception ex)
        {
            System.Diagnostics.Debug.WriteLine($"[ViewModel] AddNodeFromTemplate 异常: {ex.Message}");
            System.Diagnostics.Debug.WriteLine($"[ViewModel] 堆栈: {ex.StackTrace}");
            _logger?.LogError(ex, "添加节点时发生错误");
        }
    }

    /// <summary>
    /// 从模板添加节点到画布中心
    /// </summary>
    private void AddNodeFromTemplateAtCenter(NodeTemplate template)
    {
        // 默认位置：画布中心区域
        double centerX = 400;
        double centerY = 300;
        
        var node = template.CreateNode(centerX, centerY);
        _nodeCanvasService.AddNode(node);
        SelectedNode = node;
        _logger?.LogDebug("从模板添加节点到中心: {TemplateName} 在位置 ({X}, {Y})", 
            template.Name, centerX, centerY);
    }

    /// <summary>
    /// 添加节点到画布（简化版本，默认位置）
    /// </summary>
    private void AddNodeToCanvas(NodeTemplate template)
    {
        System.Diagnostics.Debug.WriteLine($"[ViewModel] AddNodeToCanvas 被调用，模板: {template?.Name}");
        
        if (template == null)
        {
            System.Diagnostics.Debug.WriteLine($"[ViewModel] 错误: template为null");
            return;
        }

        try
        {
            // 默认位置：画布中心区域
            double centerX = 400;
            double centerY = 300;
            
            var node = template.CreateNode(centerX, centerY);
            System.Diagnostics.Debug.WriteLine($"[ViewModel] 节点创建成功: {node.Title}, ID: {node.Id}, 位置: ({centerX}, {centerY})");
            
            _nodeCanvasService.AddNode(node);
            System.Diagnostics.Debug.WriteLine($"[ViewModel] 节点已添加到服务，当前节点数量: {Nodes.Count}");
            
            SelectedNode = node;
            System.Diagnostics.Debug.WriteLine($"[ViewModel] 节点已设置为选中状态");
            
            _logger?.LogDebug("添加节点到画布: {TemplateName} 在位置 ({X}, {Y})", 
                template.Name, centerX, centerY);
            
            System.Diagnostics.Debug.WriteLine($"[ViewModel] AddNodeToCanvas 完成");
        }
        catch (Exception ex)
        {
            System.Diagnostics.Debug.WriteLine($"[ViewModel] AddNodeToCanvas 异常: {ex.Message}");
            System.Diagnostics.Debug.WriteLine($"[ViewModel] 堆栈: {ex.StackTrace}");
            _logger?.LogError(ex, "添加节点时发生错误");
        }
    }

    /// <summary>
    /// 放大
    /// </summary>
    private void ZoomIn()
    {
        var newZoom = Math.Min(_canvasZoom * 1.2, 3.0); // 最大3倍
        CanvasZoom = newZoom;
        _logger?.LogDebug("放大到: {Zoom}", newZoom);
    }

    /// <summary>
    /// 缩小
    /// </summary>
    private void ZoomOut()
    {
        var newZoom = Math.Max(_canvasZoom / 1.2, 0.1); // 最小0.1倍
        CanvasZoom = newZoom;
        _logger?.LogDebug("缩小到: {Zoom}", newZoom);
    }

    /// <summary>
    /// 重置缩放
    /// </summary>
    private void ResetZoom()
    {
        CanvasZoom = 1.0;
        _logger?.LogDebug("重置缩放到: 1.0");
    }

    /// <summary>
    /// 设置缩放
    /// </summary>
    private void SetZoom(double zoom)
    {
        var newZoom = Math.Max(0.1, Math.Min(zoom, 3.0)); // 限制在0.1到3.0之间
        CanvasZoom = newZoom;
        _logger?.LogDebug("设置缩放到: {Zoom}", newZoom);
    }
}