using System;
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
using System.Windows.Forms.VisualStyles;
using Vanara.Extensions;
using static Vanara.PInvoke.UxTheme;

namespace Vanara.Windows.Forms
{
	/// <summary>
	/// A table layout panel that supports a glass overlay.
	/// </summary>
	[ToolboxItem(true), ToolboxBitmap(typeof(ThemedTableLayoutPanel), "ThemedTableLayoutPanel.bmp")]
	public class ThemedTableLayoutPanel : TableLayoutPanel
	{
		private const string defaultClass = "WINDOW";
		private const int defaultPart = 29;
		private const int defaultState = 0;

		private string styleClass;
		private int stylePart;
		private int styleState;
		private bool supportGlass;
		private VisualTheme theme;

		/// <summary>Initializes a new instance of the <see cref="ThemedTableLayoutPanel"/> class.</summary>
		public ThemedTableLayoutPanel()
		{
			SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.UserPaint | ControlStyles.OptimizedDoubleBuffer | ControlStyles.ResizeRedraw, true);
			SetTheme(defaultClass, defaultPart, defaultState);
			HandleCreated += (s, e) => BindFormEvents(true);
			HandleDestroyed += (s, e) => BindFormEvents(false);
		}

		/// <summary>Sets the theme using a defined <see cref="VisualStyleElement"/>.</summary>
		[Browsable(false), DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
		public VisualStyleRenderer Style
		{
			get => new VisualStyleRenderer(styleClass, stylePart, styleState);
			set => SetTheme(value?.Class, value?.Part ?? 0, value?.State ?? 0);
		}

		/// <summary>Gets or sets the style class.</summary>
		/// <value>The style class.</value>
		[DefaultValue(defaultClass), Category("Appearance")]
		public string StyleClass
		{
			get => styleClass;
			set { if (styleClass != value) { styleClass = value; ResetTheme(); } }
		}

		/// <summary>Gets or sets the style part.</summary>
		/// <value>The style part.</value>
		[DefaultValue(defaultPart), Category("Appearance")]
		public int StylePart
		{
			get => stylePart;
			set { if (stylePart != value) { stylePart = value; Invalidate(); } }
		}

		/// <summary>Gets or sets the style part.</summary>
		/// <value>The style part.</value>
		[DefaultValue(defaultState), Category("Appearance")]
		public int StyleState
		{
			get => styleState;
			set { if (styleState != value) { styleState = value; Invalidate(); } }
		}

		/// <summary>Gets or sets a value indicating whether this table supports glass (can be enclosed in the glass margin).</summary>
		/// <value><c>true</c> if supports glass; otherwise, <c>false</c>.</value>
		[DefaultValue(false), Category("Appearance")]
		public bool SupportGlass
		{
			get => supportGlass;
			set { if (supportGlass != value) { supportGlass = value; Invalidate(); } }
		}

		/// <summary>Gets or sets a style part value that is used when focus is lost.</summary>
		/// <value>The non-focused style part value. A value of -1 will set the state to the same value as <see cref="StyleState"/>.</value>
		[DefaultValue(-1), Category("Appearance")]
		public int UnfocusedStyleState { get; set; } = -1;

		private bool ThemingSupported => Application.RenderWithVisualStyles || DesktopWindowManager.CompositionEnabled;

		/// <summary>Sets the theme using theme class information.</summary>
		/// <param name="className">Name of the theme class.</param>
		/// <param name="part">The theme part.</param>
		/// <param name="state">The theme state.</param>
		public void SetTheme(string className, int part, int state)
		{
			styleClass = className;
			stylePart = part;
			styleState = state;
			ResetTheme();
		}

		/// <summary>Sets the theme using <see cref="VisualStyleElement"/> information.</summary>
		/// <param name="visualStyle">The visual style.</param>
		public void SetTheme(VisualStyleElement visualStyle) => SetTheme(visualStyle?.ClassName, visualStyle?.Part ?? 0, visualStyle?.State ?? 0);

		/// <summary>Raises the <see cref="Control.Paint"/> event.</summary>
		/// <param name="e">A <see cref="PaintEventArgs"/> that contains the event data.</param>
		protected override void OnPaint(PaintEventArgs e)
		{
			if (Visible)
			{
				if (!this.IsDesignMode() && SupportGlass && ThemingSupported)
					try { e.Graphics.Clear(Color.Black); } catch { }
				else
				{
					var state = UnfocusedStyleState == -1 || FindForm().Focused ? styleState : UnfocusedStyleState;
					if (theme != null && ThemingSupported)
					{
						if (theme.IsBackgroundPartiallyTransparent(stylePart, state))
							theme.DrawParentBackground(this, e.Graphics, ClientRectangle);
						theme.DrawBackground(e.Graphics, stylePart, state, ClientRectangle, e.ClipRectangle);
						if (!string.IsNullOrEmpty(Text))
							theme.DrawText(e.Graphics, stylePart, state, ClientRectangle, Text, this.BuildTextFormatFlags(false), !Enabled);
					}
					else
					{
						try { e.Graphics.Clear(BackColor); } catch { }
						if (!string.IsNullOrEmpty(Text))
							TextRenderer.DrawText(e.Graphics, Text, Font, ClientRectangle, ForeColor, this.BuildTextFormatFlags(false));
					}
				}
			}
			base.OnPaint(e);
		}

		/// <summary>
		/// Fires the event indicating that the panel has been resized. Inheriting controls should use this in favor of actually listening to
		/// the event, but should still call base.onResize to ensure that the event is fired for external listeners.
		/// </summary>
		/// <param name="eventargs">An <see cref="EventArgs"/> that contains the event data.</param>
		protected override void OnResize(EventArgs eventargs)
		{
			base.OnResize(eventargs);
			Refresh();
		}

		private void BindFormEvents(bool attach)
		{
			var pForm = FindForm();
			if (pForm != null)
			{
				if (attach)
				{
					pForm.Activated += ParentStateChanged;
					pForm.Deactivate += ParentStateChanged;
				}
				else
				{
					pForm.Activated -= ParentStateChanged;
					pForm.Deactivate -= ParentStateChanged;
				}
			}
		}

		private void ParentStateChanged(object sender, EventArgs e) => Refresh();

		private void ResetTheme()
		{
			if (styleClass != null && ThemingSupported)
			{
				try
				{
					theme = new VisualTheme(Parent, styleClass, SupportGlass ? OpenThemeDataOptions.OTD_NONCLIENT : OpenThemeDataOptions.None);
				}
				catch
				{
					theme = null;
				}
			}
			else
				theme = null;
			Refresh();
		}
	}
}