using Microsoft.AspNetCore.SignalR;
using Hi.Geom;
using Hi.Native;
using System.IO.Compression;
using Hi.Webapi.Services;

namespace Hi.Webapi.Hubs
{
    /// <summary>
    /// SignalR Hub 用於處理渲染畫布的實時通信
    /// </summary>
    public class RenderingHub : Hub
    {
        private readonly RenderingService _renderingService;
        private readonly ILogger<RenderingHub> _logger;
        private readonly Dictionary<string, byte[]> _lastFrameCache = [];
        private readonly Dictionary<string, DateTime> _lastFrameTime = [];
        private readonly Dictionary<string, Mat4d> _sketchViewCache = [];

        public RenderingHub(RenderingService renderingService, ILogger<RenderingHub> logger)
        {
            _renderingService = renderingService;
            _logger = logger;
        }

        /// <summary>
        /// 客戶端連接時初始化渲染引擎
        /// </summary>
        public async Task InitializeCanvas(int width, int height)
        {
            var sessionId = Context.ConnectionId;
            _logger.LogInformation($"InitializeCanvas called - SessionId: {sessionId}, Width: {width}, Height: {height}");
            
            var engine = _renderingService.GetOrCreateEngine(sessionId);
            _logger.LogInformation($"Engine created/retrieved - SessionId: {sessionId}");
            
            // 啟動引擎（必須在設置回調之前）
            engine.Start(width, height);
            _logger.LogInformation($"Engine started with size {width}x{height} - SessionId: {sessionId}");
            
            // 在設置回調之前，先捕獲客戶端代理
            var clientProxy = Clients.Caller;
            var logger = _logger;
            var frameCount = 0;
            byte[] preImageRgba = null;
            
            // 設置渲染回調
            unsafe
            {
                engine.ImageRequestAfterBufferSwapped += (byte* bgra, int w, int h) =>
                {
                    if (bgra == null)
                        return;
                        
                    // 幀率限制 - 最多每秒30幀
                    if (_lastFrameTime.TryGetValue(sessionId, out var lastTime))
                    {
                        var elapsed = DateTime.Now - lastTime;
                        if (elapsed.TotalMilliseconds < 33) // 30 FPS
                        {
                            return;
                        }
                    }
                    _lastFrameTime[sessionId] = DateTime.Now;
                    
                    frameCount++;
                    if (frameCount <= 5) // 只記錄前5幀
                    {
                        logger.LogInformation($"Frame {frameCount} rendered - Size: {w}x{h}, SessionId: {sessionId}");
                    }
                    
                    // 檢查寬度和高度是否有效
                    if (w <= 0 || h <= 0)
                    {
                        logger.LogWarning($"Invalid image size: {w}x{h} - SessionId: {sessionId}");
                        return;
                    }
                    
                    try
                    {
                        // 在回調中同步處理圖像數據，轉換為 byte[]
                        int wh = w * h;
                        byte[] rgba = new byte[wh * 4];
                        for (int i = 0; i < wh; i++)
                        {
                            rgba[i * 4] = bgra[i * 4 + 2];
                            rgba[i * 4 + 1] = bgra[i * 4 + 1];
                            rgba[i * 4 + 2] = bgra[i * 4];
                            rgba[i * 4 + 3] = bgra[i * 4 + 3];
                        }
                        
                        // 檢查圖像是否有變化
                        if (preImageRgba != null && preImageRgba.SequenceEqual(rgba))
                            return;
                        preImageRgba = rgba;

                        if (frameCount <= 5)
                        {
                            logger.LogInformation($"Frame {frameCount} sending - Size: {w}x{h}, Data: {rgba.Length} bytes");
                        }

                        // 壓縮數據
                        using MemoryStream dstMemoryStream = new MemoryStream();
                        using GZipStream gZipStream = new GZipStream(dstMemoryStream, CompressionMode.Compress);
                        using MemoryStream srcMemoryStream = new MemoryStream(rgba);
                        srcMemoryStream.CopyTo(gZipStream);
                        gZipStream.Close();
                        byte[] compressedRgbaArray = dstMemoryStream.ToArray();
                        
                        if (compressedRgbaArray == null)
                            return;
                            
                        var compressionRatio = (float)compressedRgbaArray.Length / rgba.Length * 100;
                        
                        if (frameCount <= 5)
                        {
                            logger.LogInformation($"Compressed: {compressedRgbaArray.Length} bytes ({compressionRatio:F1}% of original)");
                        }

                        // 發送壓縮數據到客戶端（注意：第二個參數應該是原始長度，不是壓縮後的長度）
                        _ = clientProxy.SendAsync("ImageUpdate", 
                            compressedRgbaArray,
                            rgba.Length,
                            w, 
                            h)
                            .ContinueWith(t =>
                            {
                                if (t.IsFaulted)
                                {
                                    logger.LogError($"Failed to send frame: {t.Exception?.GetBaseException().Message} - SessionId: {sessionId}");
                                }
                            });
                    }
                    catch (ObjectDisposedException)
                    {
                        // Hub 已經被釋放，忽略這個錯誤
                        logger.LogDebug($"Hub已釋放，忽略渲染回調 - SessionId: {sessionId}");
                    }
                    catch (Exception ex)
                    {
                        logger.LogError(ex, $"渲染回調錯誤 - SessionId: {sessionId}");
                    }
                };
            }
            
            // 設置初始視圖
            if (_sketchViewCache.TryGetValue(sessionId, out var cachedView))
            {
                engine.SketchView = cachedView;
            }
            else
            {
                engine.SetViewToHomeView();
                _sketchViewCache[sessionId] = engine.SketchView;
            }
            _logger.LogInformation($"View initialized - SessionId: {sessionId}");
            
            // 確保引擎可見並開始渲染
            engine.IsVisible = true;
            _logger.LogInformation($"Engine visibility set to true - SessionId: {sessionId}");
            
            await Clients.Caller.SendAsync("CanvasInitialized", sessionId);
            _logger.LogInformation($"Canvas initialized for session: {sessionId}");
        }

        /// <summary>
        /// 處理鼠標移動事件
        /// </summary>
        public Task HandleMouseMove(double x, double y, int buttonMask)
        {
            var sessionId = Context.ConnectionId;
            _logger.LogDebug($"HandleMouseMove - SessionId: {sessionId}, X: {x}, Y: {y}, ButtonMask: {buttonMask}");
            
            var engine = _renderingService.GetOrCreateEngine(sessionId);
            var p = new Vec2i((int)x, (int)y);
            
            // 移動鼠標
            engine.MouseMove(p.x, p.y);
            
            // 如果有按鈕按下，處理拖曳
            if (buttonMask > 0)
            {
                engine.MouseDragTransform(p.x, p.y,
                    new mouse_button_table__transform_view_by_mouse_drag_t()
                    {
                        LEFT_BUTTON = 0,
                        RIGHT_BUTTON = 2
                    });
                _sketchViewCache[sessionId] = engine.SketchView;
            }
            
            return Task.CompletedTask;
        }

        /// <summary>
        /// 處理鼠標按下事件
        /// </summary>
        public Task HandleMouseDown(double x, double y, int button)
        {
            var sessionId = Context.ConnectionId;
            _logger.LogInformation($"HandleMouseDown - SessionId: {sessionId}, X: {x}, Y: {y}, Button: {button}");
            
            var engine = _renderingService.GetOrCreateEngine(sessionId);
            engine.MouseButtonDown(button);
            return Task.CompletedTask;
        }

        /// <summary>
        /// 處理鼠標釋放事件
        /// </summary>
        public Task HandleMouseUp(double x, double y, int button)
        {
            var sessionId = Context.ConnectionId;
            _logger.LogInformation($"HandleMouseUp - SessionId: {sessionId}, X: {x}, Y: {y}, Button: {button}");
            
            var engine = _renderingService.GetOrCreateEngine(sessionId);
            engine.MouseButtonUp(button);
            return Task.CompletedTask;
        }

        /// <summary>
        /// 處理鼠標滾輪事件
        /// </summary>
        public Task HandleMouseWheel(double x, double y, double deltaX, double deltaY, string browserBrand = "chrome")
        {
            var sessionId = Context.ConnectionId;
            _logger.LogInformation($"HandleMouseWheel - SessionId: {sessionId}, X: {x}, Y: {y}, DeltaX: {deltaX}, DeltaY: {deltaY}, Browser: {browserBrand}");
            
            var engine = _renderingService.GetOrCreateEngine(sessionId);
            
            // 根據瀏覽器類型獲取縮放比例
            double scale = GetWheelScaling(browserBrand);
            
            engine.MouseWheel((int)(deltaX * scale), -(int)(deltaY * scale));
            
            // 使用 MouseWheelTransform 進行視圖變換
            engine.MouseWheelTransform(
                (int)(deltaX * scale * 1000), -(int)(deltaY * scale * 1000), 0.1 / 1000);
            
            _sketchViewCache[sessionId] = engine.SketchView;
            
            return Task.CompletedTask;
        }

        /// <summary>
        /// 處理窗口大小變化
        /// </summary>
        public Task HandleResize(int width, int height)
        {
            var sessionId = Context.ConnectionId;
            _logger.LogInformation($"HandleResize - SessionId: {sessionId}, Width: {width}, Height: {height}");
            
            var engine = _renderingService.GetOrCreateEngine(sessionId);
            
            // 重置圖像緩存以強制重新渲染
            if (_lastFrameCache.ContainsKey(sessionId))
            {
                _lastFrameCache.Remove(sessionId);
            }
            
            engine.Resize(width, height);
            
            _logger.LogInformation($"Resize completed - SessionId: {sessionId}");
            return Task.CompletedTask;
        }

        /// <summary>
        /// 處理可見性變化
        /// </summary>
        public Task HandleVisibilityChange(string visibilityState)
        {
            var sessionId = Context.ConnectionId;
            _logger.LogInformation($"HandleVisibilityChange - SessionId: {sessionId}, State: {visibilityState}");
            
            var engine = _renderingService.GetOrCreateEngine(sessionId);
            engine.IsVisible = visibilityState == "visible";
            
            return Task.CompletedTask;
        }

        /// <summary>
        /// 設置視圖
        /// </summary>
        public Task SetView(string viewType)
        {
            var sessionId = Context.ConnectionId;
            _logger.LogInformation($"SetView called - SessionId: {sessionId}, ViewType: {viewType}");
            
            var engine = _renderingService.GetOrCreateEngine(sessionId);
            
            switch (viewType.ToLower())
            {
                case "front":
                    engine.SetViewToFrontView();
                    break;
                case "back":
                    engine.SetViewToFrontView();
                    engine.TurnBackView();
                    break;
                case "left":
                    engine.SetViewToRightView();
                    engine.TurnBackView();
                    break;
                case "right":
                    engine.SetViewToRightView();
                    break;
                case "top":
                    engine.SetViewToTopView();
                    break;
                case "bottom":
                    engine.SetViewToTopView();
                    engine.TurnBackView();
                    break;
                case "isometric":
                    engine.SetViewToIsometricView();
                    break;
                case "home":
                    engine.SetViewToHomeView();
                    break;
                default:
                    _logger.LogWarning($"Unknown view type: {viewType} - SessionId: {sessionId}");
                    break;
            }
            
            _sketchViewCache[sessionId] = engine.SketchView;
            
            return Task.CompletedTask;
        }

        /// <summary>
        /// 處理鍵盤按下事件
        /// </summary>
        public Task HandleKeyDown(string key, string code, bool ctrlKey, bool shiftKey, bool altKey)
        {
            var sessionId = Context.ConnectionId;
            _logger.LogInformation($"HandleKeyDown - SessionId: {sessionId}, Key: {key}, Code: {code}, Ctrl: {ctrlKey}, Shift: {shiftKey}, Alt: {altKey}");
            
            var engine = _renderingService.GetOrCreateEngine(sessionId);
            
            // 使用 key 的 HashCode（與 Blazor 版本一致）
            long keyCode = key.ToLower().GetHashCode();
            engine.KeyDown(keyCode);
            
            // 使用 KeyDownTransform 進行視圖變換
            engine.KeyDownTransform(keyCode, new key_table__transform_view_by_key_pressing_t()
            {
                HOME = "home".ToLower().GetHashCode(),
                PAGE_UP = "pageup".ToLower().GetHashCode(),
                PAGE_DOWN = "pagedown".ToLower().GetHashCode(),
                F1 = "f1".ToLower().GetHashCode(),
                F2 = "f2".ToLower().GetHashCode(),
                F3 = "f3".ToLower().GetHashCode(),
                F4 = "f4".ToLower().GetHashCode(),
                SHIFT = "shift".ToLower().GetHashCode(),
                ARROW_LEFT = "arrowleft".ToLower().GetHashCode(),
                ARROW_RIGHT = "arrowright".ToLower().GetHashCode(),
                ARROW_DOWN = "arrowdown".ToLower().GetHashCode(),
                ARROW_UP = "arrowup".ToLower().GetHashCode()
            });
            
            _sketchViewCache[sessionId] = engine.SketchView;
            
            return Task.CompletedTask;
        }

        /// <summary>
        /// 處理鍵盤釋放事件
        /// </summary>
        public Task HandleKeyUp(string key, string code, bool ctrlKey, bool shiftKey, bool altKey)
        {
            var sessionId = Context.ConnectionId;
            _logger.LogInformation($"HandleKeyUp - SessionId: {sessionId}, Key: {key}, Code: {code}, Ctrl: {ctrlKey}, Shift: {shiftKey}, Alt: {altKey}");
            
            var engine = _renderingService.GetOrCreateEngine(sessionId);
            
            long keyCode = key.ToLower().GetHashCode();
            engine.KeyUp(keyCode);
            
            return Task.CompletedTask;
        }

        /// <summary>
        /// 處理觸摸按下事件
        /// </summary>
        public Task HandleTouchDown(int pointerId, double x, double y)
        {
            var sessionId = Context.ConnectionId;
            _logger.LogInformation($"HandleTouchDown - SessionId: {sessionId}, PointerId: {pointerId}, X: {x}, Y: {y}");
            
            var engine = _renderingService.GetOrCreateEngine(sessionId);
            engine.TouchDown(pointerId, (int)x, (int)y);
            
            return Task.CompletedTask;
        }

        /// <summary>
        /// 處理觸摸移動事件
        /// </summary>
        public Task HandleTouchMove(int pointerId, double x, double y)
        {
            var sessionId = Context.ConnectionId;
            _logger.LogDebug($"HandleTouchMove - SessionId: {sessionId}, PointerId: {pointerId}, X: {x}, Y: {y}");
            
            var engine = _renderingService.GetOrCreateEngine(sessionId);
            engine.TouchMove(pointerId, (int)x, (int)y);
            
            return Task.CompletedTask;
        }

        /// <summary>
        /// 處理觸摸釋放事件
        /// </summary>
        public Task HandleTouchUp(int pointerId)
        {
            var sessionId = Context.ConnectionId;
            _logger.LogInformation($"HandleTouchUp - SessionId: {sessionId}, PointerId: {pointerId}");
            
            var engine = _renderingService.GetOrCreateEngine(sessionId);
            engine.TouchUp(pointerId);
            
            return Task.CompletedTask;
        }

        /// <summary>
        /// 獲取瀏覽器滾輪縮放比例
        /// </summary>
        private double GetWheelScaling(string browserBrand)
        {
            switch (browserBrand.ToLower())
            {
                case "firefox":
                    return 1.0;
                case "chrome":
                case "edge":
                case "safari":
                default:
                    return 0.01;
            }
        }

        /// <summary>
        /// 客戶端斷開連接時清理資源
        /// </summary>
        public override async Task OnDisconnectedAsync(Exception exception)
        {
            var sessionId = Context.ConnectionId;
            
            // 清理緩存
            _lastFrameCache.Remove(sessionId);
            _lastFrameTime.Remove(sessionId);
            _sketchViewCache.Remove(sessionId);
            
            _renderingService.RemoveEngine(sessionId);
            _logger.LogInformation($"Client disconnected: {sessionId}");
            await base.OnDisconnectedAsync(exception);
        }
    }
}