using System.Drawing.Drawing2D;

namespace iptools;

public class RoundButton : Button
{
 public int CornerRadius { get; set; } = 12;

 public Color HoverBackColor { get; set; } = Color.Empty;

 public Color PressedBackColor { get; set; } = Color.Empty;

 private bool _isHovered;
 private bool _isPressed;

 public RoundButton()
 {
 FlatStyle = FlatStyle.Flat;
 FlatAppearance.BorderSize = 0;
 Cursor = Cursors.Hand;
 Resize += (_, _) => UpdateRegion();
 }

 protected override void OnMouseEnter(EventArgs e)
 {
 _isHovered = true;
 Invalidate();
 base.OnMouseEnter(e);
 }

 protected override void OnMouseLeave(EventArgs e)
 {
 _isHovered = false;
 _isPressed = false;
 Invalidate();
 base.OnMouseLeave(e);
 }

 protected override void OnMouseDown(MouseEventArgs mevent)
 {
 _isPressed = true;
 Invalidate();
 base.OnMouseDown(mevent);
 }

 protected override void OnMouseUp(MouseEventArgs mevent)
 {
 _isPressed = false;
 Invalidate();
 base.OnMouseUp(mevent);
 }

 protected override void OnPaint(PaintEventArgs pevent)
 {
 pevent.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
 pevent.Graphics.Clear(Parent?.BackColor ?? SystemColors.Control);

 var rect = ClientRectangle;
 rect.Width -= 1;
 rect.Height -= 1;

 using var path = CreateRoundPath(rect, CornerRadius);
 using var brush = new SolidBrush(GetCurrentBackColor());

 pevent.Graphics.FillPath(brush, path);
 TextRenderer.DrawText(
 pevent.Graphics,
 Text,
 Font,
 rect,
 ForeColor,
 TextFormatFlags.HorizontalCenter | TextFormatFlags.VerticalCenter | TextFormatFlags.EndEllipsis);
 }

 private Color GetCurrentBackColor()
 {
 if (_isPressed && PressedBackColor != Color.Empty)
 {
 return PressedBackColor;
 }

 if (_isHovered && HoverBackColor != Color.Empty)
 {
 return HoverBackColor;
 }

 return BackColor;
 }

 private void UpdateRegion()
 {
 if (Width <= 0 || Height <= 0)
 {
 return;
 }

 using var path = CreateRoundPath(new Rectangle(0, 0, Width, Height), CornerRadius);
 Region = new Region(path);
 }

 private static GraphicsPath CreateRoundPath(Rectangle rect, int radius)
 {
 var diameter = Math.Max(1, radius * 2);
 var path = new GraphicsPath();
 path.StartFigure();
 path.AddArc(rect.X, rect.Y, diameter, diameter, 180, 90);
 path.AddArc(rect.Right - diameter, rect.Y, diameter, diameter, 270, 90);
 path.AddArc(rect.Right - diameter, rect.Bottom - diameter, diameter, diameter, 0, 90);
 path.AddArc(rect.X, rect.Bottom - diameter, diameter, diameter, 90, 90);
 path.CloseFigure();
 return path;
 }
}