using Hi.Disp;
using Hi.Native;
using Hi.PanelModels;
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Collections.Generic;
using Hi.Geom;

namespace Hi.Wpf.Disp
{
    #region WPF Rendering Canvas
    /// <summary>
    /// Provides a WPF rendering canvas for 3D visualization of HiAPI components.
    /// Handles user interactions, rendering, and integration with the DispEngine system.
    /// </summary>
    /// <remarks>
    /// This canvas provides the core rendering capabilities for WPF applications using HiAPI.
    /// It manages mouse, keyboard, and touch events, and transforms them into appropriate
    /// actions in the 3D environment.
    /// </remarks>
    public class RenderingCanvas : UserControl, IDisposable
    {
        #region Core_Properties
        /// <summary>
        /// The DispEngine instance that handles rendering and user interactions
        /// </summary>
        public DispEngine DispEngine { get; } = new DispEngine();
        
        /// <summary>
        /// Internal container for rendering content
        /// </summary>
        private UserControl DisplayerPane { get; }
        
        /// <summary>
        /// Dictionary to store touch point information
        /// </summary>
        private Dictionary<int, Point> TouchingPointsMap { get; } = new Dictionary<int, Point>();
        
        /// <summary>
        /// Dictionary to store previous positions of touch points
        /// </summary>
        private Dictionary<int, Point> PreviousTouchingPointsMap { get; } = new Dictionary<int, Point>();
        #endregion
        
        #region Initialization
        /// <summary>
        /// Initializes a new instance of the RenderingCanvas
        /// </summary>
        public RenderingCanvas()
        {
            DispEngine.BackgroundColor = new Vec3d(0.1, 0.1, 0.5);
            DispEngine.BackgroundOpacity = 0.1;

            // Configure the main control properties
            HorizontalAlignment = HorizontalAlignment.Stretch;
            VerticalAlignment = VerticalAlignment.Stretch;
            Focusable = true;
            KeyboardNavigation.SetDirectionalNavigation(this, KeyboardNavigationMode.Cycle);
            DataContextChanged += CanvasDataContextChanged;

            // Create and configure the display pane
            DisplayerPane = new UserControl();
            DisplayerPane.HorizontalAlignment = HorizontalAlignment.Stretch;
            DisplayerPane.VerticalAlignment = VerticalAlignment.Stretch;
            DisplayerPane.Focusable = true;
            DisplayerPane.IsTabStop = true;

            // Connect event handlers for user input and window events
            DisplayerPane.SizeChanged += RenderingCanvas_SizeChanged;
            DisplayerPane.MouseMove += RenderingCanvas_MouseMove;
            DisplayerPane.MouseDown += RenderingCanvas_MouseDown;
            DisplayerPane.MouseUp += RenderingCanvas_MouseUp;
            DisplayerPane.MouseWheel += RenderingCanvas_MouseWheel;
            DisplayerPane.KeyDown += RenderingCanvas_KeyDown;
            DisplayerPane.KeyUp += RenderingCanvas_KeyUp;
            DisplayerPane.Loaded += RenderingCanvas_Loaded;
            DisplayerPane.Unloaded += RenderingCanvas_Unloaded;
            DisplayerPane.IsVisibleChanged += DisplayerPane_IsVisibleChanged;

            // Add touch event handlers
            DisplayerPane.TouchDown += RenderingCanvas_TouchDown;
            DisplayerPane.TouchMove += RenderingCanvas_TouchMove;
            DisplayerPane.TouchUp += RenderingCanvas_TouchUp;
            
            // Enable touch support
            this.IsManipulationEnabled = true;

            // Add the display pane to this control's content
            Content = DisplayerPane;
        }
        #endregion
        
        #region Touch_Events
        /// <summary>
        /// Handles the touch down event
        /// </summary>
        private void RenderingCanvas_TouchDown(object sender, TouchEventArgs e)
        {
            // Add touch point to dictionary
            Point touchPoint = e.GetTouchPoint(DisplayerPane).Position;
            DispEngine.TouchDown(e.TouchDevice.Id,
                (int)touchPoint.X, (int)touchPoint.Y);

            // Ensure control gets focus
            DisplayerPane.Focus();
            e.TouchDevice.Capture(DisplayerPane);
            
            e.Handled = true;
        }
        
        /// <summary>
        /// Handles the touch move event
        /// </summary>
        private void RenderingCanvas_TouchMove(object sender, TouchEventArgs e)
        {
            Point touchPoint = e.GetTouchPoint(DisplayerPane).Position;
            DispEngine.TouchMove(e.TouchDevice.Id,
                (int)touchPoint.X, (int)touchPoint.Y);
            e.Handled = true;
        }
        
        /// <summary>
        /// Handles the touch up event
        /// </summary>
        private void RenderingCanvas_TouchUp(object sender, TouchEventArgs e)
        {
            DispEngine.TouchUp(e.TouchDevice.Id);
            e.Handled = true;
        }
        #endregion
        
        #region Window_Events
        /// <summary>
        /// Handles window state changes (maximize, minimize, etc.)
        /// </summary>
        private unsafe void RenderingCanvas_StateChanged(object sender, EventArgs e)
        {
            switch ((sender as Window).WindowState)
            {
                case WindowState.Maximized:
                    DispEngine.IsVisible = true;
                    break;
                case WindowState.Minimized:
                    DispEngine.IsVisible = false;
                    break;
                case WindowState.Normal:
                    DispEngine.IsVisible = true;
                    break;
            }
        }

        /// <summary>
        /// Handles data context changes
        /// </summary>
        private unsafe void CanvasDataContextChanged(object sender, DependencyPropertyChangedEventArgs e)
        {
            DispEngine pre = e.OldValue as DispEngine;
            DispEngine cur = e.NewValue as DispEngine;

            //child's binding event is triggered after IsVisible event and Load event.
            if (pre != null)    //this section will never occur if the datacontext not set twice.
            {
                pre.Terminate();
                pre.ImageRequestAfterBufferSwapped -= RenderingCanvas_BufferSwapped;
            }
            if (cur != null)
            {
                cur.ImageRequestAfterBufferSwapped += RenderingCanvas_BufferSwapped;
                cur.Start((int)DisplayerPane.RenderSize.Width, (int)DisplayerPane.RenderSize.Height);

                cur.IsVisible = IsVisible;
            }
        }
        
        /// <summary>
        /// Reference to the current window containing this control
        /// </summary>
        private Window currentWindow;
        
        /// <summary>
        /// Gets or sets the current window, connecting or disconnecting state change events
        /// </summary>
        Window CurrentWindow
        {
            get => currentWindow; set
            {
                if (currentWindow != null)
                    currentWindow.StateChanged -= RenderingCanvas_StateChanged;
                currentWindow = value;
                if (currentWindow != null)
                    currentWindow.StateChanged += RenderingCanvas_StateChanged;
            }
        }
        
        /// <summary>
        /// Handles the loaded event
        /// </summary>
        private unsafe void RenderingCanvas_Loaded(object sender, RoutedEventArgs e)
        {
            // Get the window containing this control
            CurrentWindow = Window.GetWindow(this);
            
            // Set up DispEngine rendering
            DispEngine.ImageRequestAfterBufferSwapped -= RenderingCanvas_BufferSwapped;
            DispEngine.ImageRequestAfterBufferSwapped += RenderingCanvas_BufferSwapped;
            DispEngine.Start((int)DisplayerPane.RenderSize.Width, (int)DisplayerPane.RenderSize.Height);
            DispEngine.IsVisible = IsVisible;
        }
        
        /// <summary>
        /// Handles the unloaded event
        /// </summary>
        private unsafe void RenderingCanvas_Unloaded(object sender, RoutedEventArgs e)
        {
            DispEngine.IsVisible = IsVisible;
            DispEngine.ImageRequestAfterBufferSwapped -= RenderingCanvas_BufferSwapped;
            CurrentWindow = null;
        }
        #endregion
        
        #region DispEngine_Rendering
        /// <summary>
        /// Handles the buffer swapped event from DispEngine
        /// </summary>
        private unsafe void RenderingCanvas_BufferSwapped(byte* data, int w, int h)
        {
            if (data == null)
                return;
                
            // Copy pixel data from DispEngine
            int n = w * h * 4;
            byte[] arr = new byte[n];
            for (int i = 0; i < n; i++)
                arr[i] = data[i];
            
            // Update UI on the UI thread
            DisplayerPane.Dispatcher.InvokeAsync(() =>
            {
                BitmapSource bitmap = BitmapSource.Create(w, h, 1, 1, PixelFormats.Bgra32, null, arr, w * 4);
                DisplayerPane.Background = new ImageBrush(bitmap);
            });
        }
        
        /// <summary>
        /// Handles the size changed event
        /// </summary>
        private void RenderingCanvas_SizeChanged(object sender, SizeChangedEventArgs e)
        {
            // Notify DispEngine of size changes
            DispEngine.Resize((int)DisplayerPane.RenderSize.Width, (int)DisplayerPane.RenderSize.Height);
        }
        
        /// <summary>
        /// Handles visibility changes
        /// </summary>
        private unsafe void DisplayerPane_IsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
        {
            // Update visibility state in DispEngine
            DispEngine.IsVisible = IsVisible;
        }
        #endregion
        
        #region Keyboard_Events
        /// <summary>
        /// Handles the key up event
        /// </summary>
        private void RenderingCanvas_KeyUp(object sender, KeyEventArgs e)
        {
            DispEngine.KeyUp((long)e.Key);
        }
        
        /// <summary>
        /// Handles the key down event
        /// </summary>
        private void RenderingCanvas_KeyDown(object sender, KeyEventArgs e)
        {
            DispEngine.KeyDown((long)e.Key);

            // Map specific keys for view transformation
            long key = (long)e.Key;
            if (key == (long)Key.RightShift)
                key = (long)Key.LeftShift;
                
            DispEngine.KeyDownTransform(key, new key_table__transform_view_by_key_pressing_t()
            {
                HOME = (long)Key.Home,
                PAGE_UP = (long)Key.PageUp,
                PAGE_DOWN = (long)Key.PageDown,
                F1 = (long)Key.F1,
                F2 = (long)Key.F2,
                F3 = (long)Key.F3,
                F4 = (long)Key.F4,
                SHIFT = (long)Key.LeftShift,
                ARROW_LEFT = (long)Key.Left,
                ARROW_RIGHT = (long)Key.Right,
                ARROW_DOWN = (long)Key.Down,
                ARROW_UP = (long)Key.Up
            });
        }
        #endregion
        
        #region Mouse_Events
        /// <summary>
        /// Helper method to get mouse button mask
        /// </summary>
        internal static HiMouseButtonMask GetMouseButtonMask(MouseDevice device)
        {
            HiMouseButtonMask mouseButtonMask = 0;
            mouseButtonMask.SetLeftPressed(device.LeftButton == MouseButtonState.Pressed);
            mouseButtonMask.SetMiddlePressed(device.MiddleButton == MouseButtonState.Pressed);
            mouseButtonMask.SetRightPressed(device.RightButton == MouseButtonState.Pressed);
            mouseButtonMask.SetXButton1Pressed(device.XButton1 == MouseButtonState.Pressed);
            mouseButtonMask.SetXButton2Pressed(device.XButton2 == MouseButtonState.Pressed);
            return mouseButtonMask;
        }

        /// <summary>
        /// Handles the mouse wheel event
        /// </summary>
        private void RenderingCanvas_MouseWheel(object sender, MouseWheelEventArgs e)
        {
            // Handle mouse wheel for zoom operations
            DispEngine.MouseWheel(0, e.Delta / 120);
            DispEngine.MouseWheelTransform(0, e.Delta / 120);
        }
        
        /// <summary>
        /// Handles the mouse up event
        /// </summary>
        private void RenderingCanvas_MouseUp(object sender, MouseButtonEventArgs e)
        {
            // Handle mouse button release
            DispEngine.MouseButtonUp((long)e.ChangedButton);
            (sender as UIElement)?.ReleaseMouseCapture();
        }
        
        /// <summary>
        /// Handles the mouse down event
        /// </summary>
        private void RenderingCanvas_MouseDown(object sender, MouseButtonEventArgs e)
        {
            // Handle mouse button press
            DispEngine.MouseButtonDown((long)e.ChangedButton);
            DisplayerPane.Focus();
            (sender as UIElement)?.CaptureMouse();
        }
        
        /// <summary>
        /// Handles the mouse move event
        /// </summary>
        private void RenderingCanvas_MouseMove(object sender, MouseEventArgs e)
        {
            // Update mouse position and handle drag transforms
            Point p = e.GetPosition(DisplayerPane);
            DispEngine.MouseMove((int)p.X, (int)p.Y);
            DispEngine.MouseDragTransform((int)p.X, (int)p.Y,
                new mouse_button_table__transform_view_by_mouse_drag_t()
                {
                    LEFT_BUTTON = (long)MouseButton.Left,
                    RIGHT_BUTTON = (long)MouseButton.Right
                });
        }
        #endregion
        
        #region Cleanup
        /// <summary>
        /// Flag to track disposed state
        /// </summary>
        private bool disposedValue;
        
        /// <summary>
        /// Disposes managed resources
        /// </summary>
        protected virtual void Dispose(bool disposing)
        {
            if (!disposedValue)
            {
                if (disposing)
                {
                    // Dispose the DispEngine to free resources
                    DispEngine.Dispose();
                }
                disposedValue = true;
            }
        }
        
        /// <summary>
        /// Public dispose method to free resources
        /// </summary>
        public void Dispose()
        {
            // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
            Dispose(disposing: true);
            GC.SuppressFinalize(this);
        }
        #endregion
    }
    #endregion
}