using System;
using System.Windows.Forms;
using System.Drawing;
using System.Drawing.Imaging;
using Hi.Native;
using Hi.Disp;
using System.Collections.Generic;
using Hi.Geom;
using System.Linq;
using System.Runtime.InteropServices;

namespace Hi.WinForm.Disp
{
    /// <summary>
    /// Window Form Displayer.
    /// </summary>
    public partial class RenderingCanvas : UserControl
    {
        #region Core_Properties
        /// <summary>
        /// <see cref="DispEngine"/>.
        /// </summary>
        public DispEngine DispEngine { get; }

        // Constants and structures for WM_TOUCH
        private const int WM_TOUCH = 0x0240;
        private const int TOUCHEVENTF_MOVE = 0x0001;
        private const int TOUCHEVENTF_DOWN = 0x0002;
        private const int TOUCHEVENTF_UP = 0x0004;

        [StructLayout(LayoutKind.Sequential)]
        private struct TOUCHINPUT
        {
            public int x;
            public int y;
            public IntPtr hSource;
            public int dwID;
            public int dwFlags;
            public int dwMask;
            public int dwTime;
            public IntPtr dwExtraInfo;
            public int cxContact;
            public int cyContact;
        }

        [DllImport("user32.dll")]
        private static extern bool RegisterTouchWindow(IntPtr hWnd, uint ulFlags);

        [DllImport("user32.dll")]
        private static extern bool GetTouchInputInfo(IntPtr hTouchInput, int cInputs, [In, Out] TOUCHINPUT[] pInputs, int cbSize);

        [DllImport("user32.dll")]
        private static extern void CloseTouchInputHandle(IntPtr lParam);
        #endregion

        #region Initialization
        /// <summary>
        /// Ctor.
        /// </summary>
        /// <param name="displayees">displayees</param>
        public unsafe RenderingCanvas(params IDisplayee[] displayees)
        {
            // Configure the control's visual styles
            SetStyle(ControlStyles.Selectable, true);
            SetStyle(ControlStyles.OptimizedDoubleBuffer, false);
            SetStyle(ControlStyles.ContainerControl, false);
            SetStyle(ControlStyles.ResizeRedraw, false);
            DoubleBuffered = true;

            InitializeComponent();
            Dock = DockStyle.Fill;

            // Connect event handlers for user input and window events
            this.Resize += RenderingCanvas_Resize;
            this.VisibleChanged += RenderingCanvas_VisibleChanged;
            this.MouseMove += RenderingCanvas_MouseMove;
            this.MouseDown += RenderingCanvas_MouseDown;
            this.MouseUp += RenderingCanvas_MouseUp;
            this.MouseWheel += RenderingCanvas_MouseWheel;
            this.KeyDown += RenderingCanvas_KeyDown;
            this.KeyUp += RenderingCanvas_KeyUp;

            // Add focus event handler
            this.GotFocus += RenderingCanvas_GotFocus;
            this.HandleCreated += OnHandleCreated;

            // Enable touch input and click events for the control
            this.SetStyle(ControlStyles.StandardClick, true);
            this.SetStyle(ControlStyles.StandardDoubleClick, true);
            this.TabStop = true;

            // Initialize the DispEngine with provided displayees
            DispEngine = new DispEngine(displayees);
            DispEngine.BackgroundColor = new Vec3d(0.1, 0.1, 0.5);
            DispEngine.BackgroundOpacity = 0.1;
            DispEngine.SetViewToHomeView();
            DispEngine.ImageRequestAfterBufferSwapped += DispEngine_ImageRequestAfterBufferSwapped;

            // Set initial size and start the rendering engine
            this.Size = new System.Drawing.Size(500, 300);
            DispEngine.Start(this.ClientSize.Width, this.ClientSize.Height);
        }
        #endregion

        #region Win32_Message_Handling
        protected override void WndProc(ref Message m)
        {
            if (m.Msg == WM_TOUCH)
            {
                HandleTouchInput(m.WParam, m.LParam);
                return;
            }

            base.WndProc(ref m);
        }

        private void OnHandleCreated(object sender, EventArgs e)
        {
            // Register window to receive touch messages
            RegisterTouchWindow(this.Handle, 0);
        }

        private void HandleTouchInput(IntPtr wParam, IntPtr lParam)
        {
            int inputCount = wParam.ToInt32();
            TOUCHINPUT[] inputs = new TOUCHINPUT[inputCount];

            if (!GetTouchInputInfo(lParam, inputCount, inputs, Marshal.SizeOf(typeof(TOUCHINPUT))))
                return;

            try
            {
                for (int i = 0; i < inputCount; i++)
                {
                    TOUCHINPUT ti = inputs[i];
                    int touchId = ti.dwID;

                    // Convert touch coordinates to client coordinates
                    Point touchPoint = PointToClient(new Point(ti.x / 100, ti.y / 100));

                    if ((ti.dwFlags & TOUCHEVENTF_DOWN) != 0)
                    {
                        // Touch down event
                        DispEngine.TouchDown(touchId, touchPoint.X, touchPoint.Y);
                        this.Focus();
                    }
                    else if ((ti.dwFlags & TOUCHEVENTF_MOVE) != 0)
                    {
                        // Touch move event
                        DispEngine.TouchMove(touchId, touchPoint.X, touchPoint.Y);
                    }
                    else if ((ti.dwFlags & TOUCHEVENTF_UP) != 0)
                    {
                        // Touch up event
                        DispEngine.TouchUp(touchId);
                    }
                }
            }
            finally
            {
                CloseTouchInputHandle(lParam);
            }
        }
        #endregion

        #region Cleanup
        /// <summary> 
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                // Dispose the DispEngine to free resources
                DispEngine.Dispose();
                components.Dispose();
            }
            base.Dispose(disposing);
        }
        #endregion

        #region DispEngine_Rendering
        private unsafe void DispEngine_ImageRequestAfterBufferSwapped(byte* bgra_unsignedbyte_pixels, int w, int h)
        {
            // Create a bitmap from the raw pixel data provided by DispEngine
            Bitmap bitmap;
            bitmap = new Bitmap(new Bitmap(w, h, w * 4,
                PixelFormat.Format32bppArgb, new IntPtr(bgra_unsignedbyte_pixels)));

            // Update the background image and dispose the previous one
            Image pre = this.BackgroundImage;
            this.BackgroundImage = bitmap;
            pre?.Dispose();
        }
        #endregion

        #region Window_Events
        private void RenderingCanvas_Resize(object sender, EventArgs e)
        {
            // Notify DispEngine of size changes
            DispEngine.Resize(this.ClientSize.Width, this.ClientSize.Height);
        }

        private void RenderingCanvas_VisibleChanged(object sender, EventArgs e)
        {
            // Update visibility state in DispEngine
            DispEngine.IsVisible = this.Visible;
        }
        #endregion

        #region Mouse_Events
        private void RenderingCanvas_MouseMove(object sender, MouseEventArgs e)
        {
            // Update mouse position and handle drag transforms
            DispEngine.MouseMove(e.Location.X, e.Location.Y);
            DispEngine.MouseDragTransform(e.Location.X, e.Location.Y,
                new mouse_button_table__transform_view_by_mouse_drag_t()
                {
                    LEFT_BUTTON = (long)MouseButtons.Left,
                    RIGHT_BUTTON = (long)MouseButtons.Right
                });
        }

        private void RenderingCanvas_MouseDown(object sender, MouseEventArgs e)
        {
            // Handle mouse button press
            DispEngine.MouseButtonDown((long)e.Button);
            this.Focus();
        }

        private void RenderingCanvas_MouseUp(object sender, MouseEventArgs e)
        {
            // Handle mouse button release
            DispEngine.MouseButtonUp((long)e.Button);
        }

        private void RenderingCanvas_MouseWheel(object sender, MouseEventArgs e)
        {
            // Handle mouse wheel for zoom operations
            DispEngine.MouseWheel(0, e.Delta / 120);
            DispEngine.MouseWheelTransform(0, e.Delta / 120);
        }
        #endregion

        #region Keyboard_Events
        /// <inheritdoc/>
        protected override bool IsInputKey(Keys keyData)
        {
            //since in default, arrow does not trigger key event(keyDown and keyUp).
            return true;
        }

        private void RenderingCanvas_KeyDown(object sender, KeyEventArgs e)
        {
            Focus();
            DispEngine.KeyDown((long)e.KeyData);

            // Map specific keys for view transformation
            long key = (long)e.KeyData;
            if (key == (long)Keys.LShiftKey || key == (long)Keys.RShiftKey || key == (long)Keys.ShiftKey)
                key = (long)Keys.Shift;

            DispEngine.KeyDownTransform(key, new key_table__transform_view_by_key_pressing_t()
            {
                HOME = (long)Keys.Home,
                PAGE_UP = (long)Keys.PageUp,
                PAGE_DOWN = (long)Keys.PageDown,
                F1 = (long)Keys.F1,
                F2 = (long)Keys.F2,
                F3 = (long)Keys.F3,
                F4 = (long)Keys.F4,
                SHIFT = (long)Keys.Shift,
                ARROW_LEFT = (long)Keys.Left,
                ARROW_RIGHT = (long)Keys.Right,
                ARROW_DOWN = (long)Keys.Down,
                ARROW_UP = (long)Keys.Up
            });
        }

        private void RenderingCanvas_KeyUp(object sender, KeyEventArgs e)
        {
            DispEngine.KeyUp((long)e.KeyData);
        }
        #endregion

        #region Touch_Events
        private void RenderingCanvas_GotFocus(object sender, EventArgs e)
        {
            // Ensure touch input is enabled when control gets focus
            this.Capture = true;
        }
        #endregion
    }
}