using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Drawing;
using System.Windows.Forms;
using Microsoft.Win32;

namespace Common
{
    class ResizableControls
    {
        int dragSize = 16;
        Point mouseStartPos = Point.Empty;
        Control movedControl = null;
        Size movedControlSize;
        Size movedControlParentSize;
        Form form;
        Point lastMousePos;
        string RegSubKey = "ControlHeight";
        RegistryKey regKey;
        int richTextBoxMinHeight = 24;
        int listViewMinHeight = 48;
        int dataGridViewMinHeight = 24;

        public void InitForm(Form form)
        {
            this.form = form;
            InitControlsRecursive(form.Controls);

            LoadFromRegistry(form);
        }

        public void InitControlsRecursive(Control.ControlCollection coll)
        {
            foreach (Control c in coll)
            {
                if (c is ResizableListView) (c as ResizableListView).MouseDownEx += HandleMouseDownEx;
                else c.MouseDown += HandleMouseDown;
                if (c is ResizableListView) (c as ResizableListView).MouseUpEx += HandleMouseUpEx;
                else c.MouseUp += HandleMouseUp;
                if (c is ResizableListView) (c as ResizableListView).MouseMoveEx += HandleMouseMoveEx;
                else c.MouseMove += HandleMouseMove;
                c.MouseLeave += HandleMouseLeave;
                //c.MouseCaptureChanged += MouseCaptureChanged;
                InitControlsRecursive(c.Controls);
            }
        }

        public static Control FindControlAtPoint(Control container, Point pos)
        {
            Control child;
            foreach (Control c in container.Controls)
            {
                if (c.Visible && c.Bounds.Contains(pos))
                {
                    child = FindControlAtPoint(c, new Point(pos.X - c.Left, pos.Y - c.Top));
                    if (child == null) return c;
                    else return child;
                }
            }
            return null;
        }

        public static Control FindControlAtCursor(Form form)
        {
            Point pos = Cursor.Position;
            if (form.Bounds.Contains(pos))
                return FindControlAtPoint(form, form.PointToClient(pos));
            return null;
        }

        private void MouseCaptureChanged(object sender, EventArgs e)
        {
            mouseStartPos = Point.Empty;
            movedControl = null;
        }

        private void HandleMouseDown(object sender, MouseEventArgs e)
        {
            HandleMouseDownEx(sender, new MouseEventArgsEx(e.Button, e.Clicks, e.X, e.Y, e.Delta));
        }

        private void HandleMouseDownEx(object sender, MouseEventArgsEx e)
        {
            Point pos = Cursor.Position;
            mouseStartPos = pos;
            lastMousePos = pos;
            movedControl = FindControlAtPoint(form, form.PointToClient(pos));
            if (movedControl != null)
            {
                Rectangle dragArea = new Rectangle(movedControl.PointToScreen(new Point(0,
                    movedControl.Size.Height - dragSize)), new Size(movedControl.Size.Width, dragSize));
                if (dragArea.Contains(pos) &&
                    ((movedControl is RichTextBox) || (movedControl is ListView) || (movedControl is DataGridView)))
                {
                    movedControlSize = movedControl.Size;
                    movedControlParentSize = movedControl.Parent.Parent.Size;
                    e.Handled = true;
                }
                else movedControl = null;
            }
        }

        private void HandleMouseLeave(object sender, EventArgs e)
        {
            mouseStartPos = Point.Empty;
            movedControl = null;
        }

        private void HandleMouseUp(object sender, MouseEventArgs e)
        {
            HandleMouseUpEx(sender, new MouseEventArgsEx(e.Button, e.Clicks, e.X, e.Y, e.Delta));
        }

        private void HandleMouseUpEx(object sender, MouseEventArgsEx e)
        {
            mouseStartPos = Point.Empty;
            movedControl = null;
        }

        private void HandleMouseMove(object sender, MouseEventArgs e)
        {
            HandleMouseMoveEx(sender, new MouseEventArgsEx(e.Button, e.Clicks, e.X, e.Y, e.Delta));
        }

        private void HandleMouseMoveEx(object sender, MouseEventArgsEx e)
        {
            Point pos = Cursor.Position;

            // Show pan cursor for bottom right corner
            Control movableControl = FindControlAtPoint(form, form.PointToClient(pos));
            if (movableControl != null)
            {
                Rectangle dragArea = new Rectangle(movableControl.PointToScreen(new Point(0,
                    movableControl.Size.Height - dragSize)), new Size(movableControl.Size.Width, dragSize));
                if (dragArea.Contains(pos) &&
                    ((movableControl is RichTextBox) || (movableControl is ListView) || (movableControl is DataGridView)))
                {
                    if (Cursor.Current != Cursors.SizeNS) Cursor.Current = Cursors.SizeNS;
                }
                else if (Cursor.Current == Cursors.SizeNS) Cursor.Current = Cursors.Default;
            }

            if ((mouseStartPos != Point.Empty) && (movedControl != null) && (lastMousePos != pos))
            {
                Point posDiff = Point.Subtract(pos, (Size)lastMousePos);
                posDiff.X = 0; // Allow only resize of height
                //movedControl.Size = (Size)Point.Add(posDiff, movedControl.Size);
                Cursor.Current = Cursors.Arrow;
                
                Size newControlSize = (Size)Point.Add(posDiff, movedControl.Size);
                if ((movedControl is RichTextBox) && (newControlSize.Height < richTextBoxMinHeight)) posDiff.Y = movedControl.Height - richTextBoxMinHeight;
                else if ((movedControl is ListView) && (newControlSize.Height < listViewMinHeight)) posDiff.Y = movedControl.Height - listViewMinHeight;
                else if ((movedControl is DataGridView) && (newControlSize.Height < dataGridViewMinHeight)) posDiff.Y = movedControl.Height - dataGridViewMinHeight;
                ResizeParent(movedControl, posDiff);
                lastMousePos = pos;
                regKey.SetValue(movedControl.Name, movedControl.Height);
            }
        }

        private void ResizeParent(Control control, Point diff)
        {
            if ((control.Parent != null) && !diff.IsEmpty)
            {
                if ((control.Parent is Panel) && (control.Parent as Panel).AutoScroll) return;
                if (control.Parent is Panel)
                    control.Parent.Size = (Size)Point.Add(diff, control.Parent.Size);
                ResizeParent(control.Parent, diff);
            }
        }

        private void LoadFromRegistry(Form form)
        {
            regKey = Application.UserAppDataRegistry.OpenSubKey(RegSubKey + "\\" + form.Name, true);
            if (regKey == null) regKey = Application.UserAppDataRegistry.CreateSubKey(RegSubKey + "\\" + form.Name);
            LoadControlFromRegistry(form, regKey);
        }

        private void LoadControlFromRegistry(Control control, RegistryKey regKey)
        {
            if ((control is RichTextBox) || (control is ListView) || (control is DataGridView))
            {
                int newHeight = (int)regKey.GetValue(control.Name, control.Height);
                if ((control is RichTextBox) && (newHeight < richTextBoxMinHeight)) newHeight = richTextBoxMinHeight;
                else if ((control is ListView) && (newHeight < listViewMinHeight)) newHeight = listViewMinHeight;
                else if ((control is DataGridView) && (newHeight < dataGridViewMinHeight)) newHeight = dataGridViewMinHeight;
                ResizeParent(control, Point.Subtract(new Point(control.Width, newHeight), control.Size));
            }
            foreach (Control child in control.Controls)
            {
                LoadControlFromRegistry(child, regKey);
            }
        }
    }

    public class MouseEventArgsEx : MouseEventArgs
    {
        bool handled;

        public MouseEventArgsEx(MouseButtons button, int clicks, int x, int y, int delta): base(button, clicks, x, y, delta)
        {
            handled = false;
        }

        public bool Handled { get { return handled; } set { handled = value; } }
    }


    public class ResizableListView : ListView
    {
        public event EventHandler<MouseEventArgsEx> MouseDownEx;
        public event EventHandler<MouseEventArgsEx> MouseUpEx;
        public event EventHandler<MouseEventArgsEx> MouseMoveEx;

        protected override void WndProc(ref Message m)
        {
            Boolean handled = false;
            m.Result = IntPtr.Zero;

            const int WM_MOUSEMOVE = 0x0200;
            const int WM_LBUTTONDOWN = 0x0201;
            const int WM_LBUTTONUP = 0x0202;
            if (m.Msg == WM_LBUTTONDOWN)
            {
                IntPtr xy = m.LParam;
                int x = unchecked((short)(long)xy);
                int y = unchecked((short)((long)xy >> 16));
                MouseEventArgsEx eventArgs = new MouseEventArgsEx(MouseButtons.Left, 1, x, y, 0);
                MouseDownEx(this, eventArgs);
                handled = eventArgs.Handled;
            } else
            if (m.Msg == WM_LBUTTONUP)
            {
                IntPtr xy = m.LParam;
                int x = unchecked((short)(long)xy);
                int y = unchecked((short)((long)xy >> 16));
                MouseEventArgsEx eventArgs = new MouseEventArgsEx(MouseButtons.Left, 1, x, y, 0);
                MouseUpEx(this, eventArgs);
                handled = eventArgs.Handled;
            }
            else
            if (m.Msg == WM_MOUSEMOVE)
            {
                IntPtr xy = m.LParam;
                int x = unchecked((short)(long)xy);
                int y = unchecked((short)((long)xy >> 16));
                MouseEventArgsEx eventArgs = new MouseEventArgsEx(MouseButtons.Left, 1, x, y, 0);
                MouseMoveEx(this, eventArgs);
                handled = eventArgs.Handled;
            }
            if (!handled) base.WndProc(ref m);
               // else DefWndProc(ref m);
        }
    }
}