using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Windows.Forms;
using AGVMapEditor.Models;

namespace AGVMapEditor.Controls
{
    /// <summary>
    /// 맵 편집을 위한 그래픽 캔버스 컨트롤
    /// </summary>
    public partial class MapCanvas : UserControl
    {
        #region Constants

        private const int NODE_SIZE = 20;
        private const int NODE_RADIUS = NODE_SIZE / 2;
        private const int GRID_SIZE = 20;
        private const float CONNECTION_WIDTH = 2.0f;

        #endregion

        #region Fields

        private List<MapNode> _nodes;
        private MapNode _selectedNode;
        private MapNode _hoveredNode;
        private bool _isDragging;
        private Point _dragOffset;
        private Point _lastMousePosition;

        // 그리드 및 줌 관련
        private bool _showGrid = true;
        private float _zoomFactor = 1.0f;
        private Point _panOffset = Point.Empty;

        // 브러쉬 및 펜
        private Brush _normalNodeBrush;
        private Brush _rotationNodeBrush;
        private Brush _dockingNodeBrush;
        private Brush _chargingNodeBrush;
        private Brush _selectedNodeBrush;
        private Brush _hoveredNodeBrush;
        private Pen _connectionPen;
        private Pen _gridPen;

        #endregion

        #region Events

        /// <summary>
        /// 노드가 선택되었을 때 발생하는 이벤트
        /// </summary>
        public event EventHandler<MapNode> NodeSelected;

        /// <summary>
        /// 노드가 이동되었을 때 발생하는 이벤트
        /// </summary>
        public event EventHandler<MapNode> NodeMoved;

        /// <summary>
        /// 배경이 클릭되었을 때 발생하는 이벤트
        /// </summary>
        public event EventHandler<Point> BackgroundClicked;

        #endregion

        #region Constructor

        public MapCanvas() : this(new List<MapNode>())
        {
        }

        public MapCanvas(List<MapNode> nodes)
        {
            InitializeComponent();
            InitializeGraphics();
            SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.DoubleBuffer | ControlStyles.ResizeRedraw, true);
            
            _nodes = nodes ?? new List<MapNode>();
            
            // 이벤트 연결
            this.MouseDown += MapCanvas_MouseDown;
            this.MouseMove += MapCanvas_MouseMove;
            this.MouseUp += MapCanvas_MouseUp;
            this.MouseWheel += MapCanvas_MouseWheel;
            this.KeyDown += MapCanvas_KeyDown;
            
            // 포커스를 받을 수 있도록 설정
            this.TabStop = true;
        }

        #endregion

        #region Graphics Initialization

        private void InitializeGraphics()
        {
            _normalNodeBrush = new SolidBrush(Color.Blue);
            _rotationNodeBrush = new SolidBrush(Color.Orange);
            _dockingNodeBrush = new SolidBrush(Color.Green);
            _chargingNodeBrush = new SolidBrush(Color.Red);
            _selectedNodeBrush = new SolidBrush(Color.Yellow);
            _hoveredNodeBrush = new SolidBrush(Color.LightBlue);
            
            _connectionPen = new Pen(Color.Gray, CONNECTION_WIDTH);
            _gridPen = new Pen(Color.LightGray, 1.0f) { DashStyle = DashStyle.Dot };
        }

        #endregion

        #region Properties

        /// <summary>
        /// 그리드 표시 여부
        /// </summary>
        public bool ShowGrid
        {
            get { return _showGrid; }
            set
            {
                _showGrid = value;
                Invalidate();
            }
        }

        /// <summary>
        /// 줌 팩터
        /// </summary>
        public float ZoomFactor
        {
            get { return _zoomFactor; }
            set
            {
                _zoomFactor = Math.Max(0.1f, Math.Min(5.0f, value));
                Invalidate();
            }
        }

        /// <summary>
        /// 선택된 노드
        /// </summary>
        public MapNode SelectedNode
        {
            get { return _selectedNode; }
            set
            {
                if (_selectedNode != value)
                {
                    _selectedNode = value;
                    Invalidate();
                }
            }
        }

        #endregion

        #region Mouse Events

        private void MapCanvas_MouseDown(object sender, MouseEventArgs e)
        {
            this.Focus(); // 키보드 이벤트를 받기 위해 포커스 설정

            var worldPoint = ScreenToWorld(e.Location);
            var hitNode = GetNodeAt(worldPoint);

            if (e.Button == MouseButtons.Left)
            {
                if (hitNode != null)
                {
                    // 노드 선택 및 드래그 시작
                    SelectNode(hitNode);
                    _isDragging = true;
                    _dragOffset = new Point(worldPoint.X - hitNode.Position.X, worldPoint.Y - hitNode.Position.Y);
                }
                else
                {
                    // 배경 클릭
                    SelectNode(null);
                    BackgroundClicked?.Invoke(this, worldPoint);
                }
            }
            else if (e.Button == MouseButtons.Right)
            {
                // 우클릭 메뉴 (추후 구현)
                ShowContextMenu(worldPoint, hitNode);
            }

            _lastMousePosition = e.Location;
        }

        private void MapCanvas_MouseMove(object sender, MouseEventArgs e)
        {
            var worldPoint = ScreenToWorld(e.Location);

            if (_isDragging && _selectedNode != null)
            {
                // 노드 드래그
                var newPosition = new Point(worldPoint.X - _dragOffset.X, worldPoint.Y - _dragOffset.Y);
                
                // 그리드에 맞춤 (Ctrl 키를 누르지 않은 경우)
                if (!ModifierKeys.HasFlag(Keys.Control))
                {
                    newPosition.X = (newPosition.X / GRID_SIZE) * GRID_SIZE;
                    newPosition.Y = (newPosition.Y / GRID_SIZE) * GRID_SIZE;
                }
                
                _selectedNode.Position = newPosition;
                Invalidate();
            }
            else if (e.Button == MouseButtons.Middle || (e.Button == MouseButtons.Left && ModifierKeys.HasFlag(Keys.Space)))
            {
                // 팬 (화면 이동)
                var deltaX = e.X - _lastMousePosition.X;
                var deltaY = e.Y - _lastMousePosition.Y;
                _panOffset.X += deltaX;
                _panOffset.Y += deltaY;
                Invalidate();
            }
            else
            {
                // 호버 효과
                var hitNode = GetNodeAt(worldPoint);
                if (_hoveredNode != hitNode)
                {
                    _hoveredNode = hitNode;
                    Invalidate();
                }
            }

            _lastMousePosition = e.Location;
        }

        private void MapCanvas_MouseUp(object sender, MouseEventArgs e)
        {
            if (_isDragging && _selectedNode != null)
            {
                NodeMoved?.Invoke(this, _selectedNode);
            }
            
            _isDragging = false;
        }

        private void MapCanvas_MouseWheel(object sender, MouseEventArgs e)
        {
            // 줌
            var delta = e.Delta > 0 ? 1.1f : 0.9f;
            ZoomFactor *= delta;
        }

        #endregion

        #region Keyboard Events

        private void MapCanvas_KeyDown(object sender, KeyEventArgs e)
        {
            switch (e.KeyCode)
            {
                case Keys.Delete:
                    // 선택된 노드 삭제 (메인 폼에서 처리하도록 이벤트 발생)
                    if (_selectedNode != null)
                    {
                        // 삭제 확인 후 처리는 메인 폼에서
                    }
                    break;

                case Keys.G:
                    // 그리드 토글
                    ShowGrid = !ShowGrid;
                    break;

                case Keys.Home:
                    // 뷰 리셋
                    ZoomFactor = 1.0f;
                    _panOffset = Point.Empty;
                    Invalidate();
                    break;
            }
        }

        #endregion

        #region Coordinate Conversion

        /// <summary>
        /// 스크린 좌표를 월드 좌표로 변환
        /// </summary>
        private Point ScreenToWorld(Point screenPoint)
        {
            var worldX = (int)((screenPoint.X - _panOffset.X) / _zoomFactor);
            var worldY = (int)((screenPoint.Y - _panOffset.Y) / _zoomFactor);
            return new Point(worldX, worldY);
        }

        /// <summary>
        /// 월드 좌표를 스크린 좌표로 변환
        /// </summary>
        private Point WorldToScreen(Point worldPoint)
        {
            var screenX = (int)(worldPoint.X * _zoomFactor + _panOffset.X);
            var screenY = (int)(worldPoint.Y * _zoomFactor + _panOffset.Y);
            return new Point(screenX, screenY);
        }

        #endregion

        #region Node Management

        /// <summary>
        /// 지정된 위치의 노드 검색
        /// </summary>
        private MapNode GetNodeAt(Point worldPoint)
        {
            foreach (var node in _nodes)
            {
                var distance = Math.Sqrt(Math.Pow(worldPoint.X - node.Position.X, 2) + Math.Pow(worldPoint.Y - node.Position.Y, 2));
                if (distance <= NODE_RADIUS)
                {
                    return node;
                }
            }
            return null;
        }

        /// <summary>
        /// 노드 선택
        /// </summary>
        private void SelectNode(MapNode node)
        {
            if (_selectedNode != node)
            {
                _selectedNode = node;
                NodeSelected?.Invoke(this, node);
                Invalidate();
            }
        }

        /// <summary>
        /// 우클릭 컨텍스트 메뉴 표시
        /// </summary>
        private void ShowContextMenu(Point worldPoint, MapNode node)
        {
            var contextMenu = new ContextMenuStrip();
            
            if (node != null)
            {
                contextMenu.Items.Add("노드 삭제", null, (s, e) => { /* 삭제 처리 */ });
                contextMenu.Items.Add(new ToolStripSeparator());
                contextMenu.Items.Add("일반 노드로 변경", null, (s, e) => ChangeNodeType(node, NodeType.Normal));
                contextMenu.Items.Add("회전 지점으로 변경", null, (s, e) => ChangeNodeType(node, NodeType.Rotation));
                contextMenu.Items.Add("도킹 스테이션으로 변경", null, (s, e) => ChangeNodeType(node, NodeType.Docking));
                contextMenu.Items.Add("충전 스테이션으로 변경", null, (s, e) => ChangeNodeType(node, NodeType.Charging));
            }
            else
            {
                contextMenu.Items.Add("새 노드 추가", null, (s, e) => { /* 노드 추가 처리 */ });
            }
            
            var screenPoint = WorldToScreen(worldPoint);
            contextMenu.Show(this, screenPoint);
        }

        /// <summary>
        /// 노드 타입 변경
        /// </summary>
        private void ChangeNodeType(MapNode node, NodeType newType)
        {
            node.Type = newType;
            node.SetDefaultColorByType(newType);
            Invalidate();
        }

        #endregion

        #region Painting

        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);

            var g = e.Graphics;
            g.SmoothingMode = SmoothingMode.AntiAlias;
            
            // 변환 매트릭스 적용
            g.ResetTransform();
            g.TranslateTransform(_panOffset.X, _panOffset.Y);
            g.ScaleTransform(_zoomFactor, _zoomFactor);

            // 배경 그리드 그리기
            if (_showGrid)
            {
                DrawGrid(g);
            }

            // 연결선 그리기
            DrawConnections(g);

            // 노드 그리기
            DrawNodes(g);

            // 선택된 노드의 연결 정보 강조 표시
            if (_selectedNode != null)
            {
                DrawSelectedNodeConnections(g);
            }
        }

        private void DrawGrid(Graphics g)
        {
            var bounds = GetVisibleWorldBounds();
            
            // 수직선
            for (int x = (bounds.Left / GRID_SIZE) * GRID_SIZE; x <= bounds.Right; x += GRID_SIZE)
            {
                g.DrawLine(_gridPen, x, bounds.Top, x, bounds.Bottom);
            }
            
            // 수평선
            for (int y = (bounds.Top / GRID_SIZE) * GRID_SIZE; y <= bounds.Bottom; y += GRID_SIZE)
            {
                g.DrawLine(_gridPen, bounds.Left, y, bounds.Right, y);
            }
        }

        private void DrawConnections(Graphics g)
        {
            foreach (var node in _nodes)
            {
                foreach (var connectedNodeId in node.ConnectedNodes)
                {
                    var connectedNode = _nodes.FirstOrDefault(n => n.NodeId == connectedNodeId);
                    if (connectedNode != null)
                    {
                        g.DrawLine(_connectionPen, node.Position, connectedNode.Position);
                    }
                }
            }
        }

        private void DrawNodes(Graphics g)
        {
            foreach (var node in _nodes)
            {
                DrawNode(g, node);
            }
        }

        private void DrawNode(Graphics g, MapNode node)
        {
            var brush = GetNodeBrush(node);
            var rect = new Rectangle(
                node.Position.X - NODE_RADIUS,
                node.Position.Y - NODE_RADIUS,
                NODE_SIZE,
                NODE_SIZE);

            // 노드 그리기
            switch (node.Type)
            {
                case NodeType.Normal:
                    g.FillEllipse(brush, rect);
                    break;
                case NodeType.Rotation:
                    g.FillRectangle(brush, rect);
                    break;
                case NodeType.Docking:
                    g.FillRectangle(brush, rect);
                    // 도킹 방향 표시
                    DrawDockingDirection(g, node);
                    break;
                case NodeType.Charging:
                    g.FillEllipse(brush, rect);
                    // 충전 표시 (+)
                    DrawChargingSymbol(g, node);
                    break;
            }

            // 노드 테두리
            g.DrawEllipse(Pens.Black, rect);

            // 노드 이름 표시
            if (_zoomFactor > 0.5f) // 줌이 충분히 큰 경우만 텍스트 표시
            {
                var font = new Font("Arial", 8 * _zoomFactor);
                var textRect = new RectangleF(
                    node.Position.X - 30,
                    node.Position.Y + NODE_RADIUS + 2,
                    60, 15);
                
                var format = new StringFormat
                {
                    Alignment = StringAlignment.Center,
                    LineAlignment = StringAlignment.Near
                };
                
                g.DrawString(node.Name, font, Brushes.Black, textRect, format);
            }
        }

        private Brush GetNodeBrush(MapNode node)
        {
            if (node == _selectedNode)
                return _selectedNodeBrush;
            
            if (node == _hoveredNode)
                return _hoveredNodeBrush;

            switch (node.Type)
            {
                case NodeType.Normal:
                    return _normalNodeBrush;
                case NodeType.Rotation:
                    return _rotationNodeBrush;
                case NodeType.Docking:
                    return _dockingNodeBrush;
                case NodeType.Charging:
                    return _chargingNodeBrush;
                default:
                    return _normalNodeBrush;
            }
        }

        private void DrawDockingDirection(Graphics g, MapNode node)
        {
            if (node.DockDirection == null)
                return;

            var arrowSize = 8;
            var arrowPen = new Pen(Color.White, 2);
            
            Point arrowStart, arrowEnd;
            
            if (node.DockDirection == DockingDirection.Forward)
            {
                arrowStart = new Point(node.Position.X - arrowSize/2, node.Position.Y);
                arrowEnd = new Point(node.Position.X + arrowSize/2, node.Position.Y);
            }
            else // Backward
            {
                arrowStart = new Point(node.Position.X + arrowSize/2, node.Position.Y);
                arrowEnd = new Point(node.Position.X - arrowSize/2, node.Position.Y);
            }
            
            g.DrawLine(arrowPen, arrowStart, arrowEnd);
            
            // 화살표 머리
            var headSize = 3;
            var headPoints = new Point[]
            {
                arrowEnd,
                new Point(arrowEnd.X - headSize, arrowEnd.Y - headSize),
                new Point(arrowEnd.X - headSize, arrowEnd.Y + headSize)
            };
            g.FillPolygon(Brushes.White, headPoints);
        }

        private void DrawChargingSymbol(Graphics g, MapNode node)
        {
            var symbolSize = 6;
            var symbolPen = new Pen(Color.White, 2);
            
            // + 모양
            g.DrawLine(symbolPen, 
                node.Position.X - symbolSize/2, node.Position.Y,
                node.Position.X + symbolSize/2, node.Position.Y);
            g.DrawLine(symbolPen,
                node.Position.X, node.Position.Y - symbolSize/2,
                node.Position.X, node.Position.Y + symbolSize/2);
        }

        private void DrawSelectedNodeConnections(Graphics g)
        {
            var highlightPen = new Pen(Color.Yellow, CONNECTION_WIDTH + 2);
            
            foreach (var connectedNodeId in _selectedNode.ConnectedNodes)
            {
                var connectedNode = _nodes.FirstOrDefault(n => n.NodeId == connectedNodeId);
                if (connectedNode != null)
                {
                    g.DrawLine(highlightPen, _selectedNode.Position, connectedNode.Position);
                }
            }
        }

        #endregion

        #region Helper Methods

        /// <summary>
        /// 현재 보이는 월드 영역 계산
        /// </summary>
        private Rectangle GetVisibleWorldBounds()
        {
            var topLeft = ScreenToWorld(new Point(0, 0));
            var bottomRight = ScreenToWorld(new Point(Width, Height));
            
            return new Rectangle(
                topLeft.X, topLeft.Y,
                bottomRight.X - topLeft.X,
                bottomRight.Y - topLeft.Y);
        }

        #endregion

    }
}