// This code is based on http://objectlistview.sourceforge.net (GPLv3 tree/list controls 
// by phillip.piper@gmail.com). Phillip has explicitly granted permission for his design
// and code to be used in this library under the MIT license.

using System.Collections.Generic;

namespace Terminal.Gui {
	/// <summary>
	/// Event args for the <see cref="TreeView{T}.DrawLine"/> event
	/// </summary>
	/// <typeparam name="T"></typeparam>
	public class DrawTreeViewLineEventArgs<T> where T : class {

		/// <summary>
		/// The object at this line in the tree
		/// </summary>
		public T Model { get; init; }

		/// <summary>
		/// The <see cref="TreeView{T}"/> that is performing the
		/// rendering.
		/// </summary>
		public TreeView<T> Tree { get; init; }

		/// <summary>
		/// The line within tree view bounds that is being rendered
		/// </summary>
		public int Y { get; init; }

		/// <summary>
		/// Set to true to cancel drawing (e.g. if you have already manually
		/// drawn content).
		/// </summary>
		public bool Handled { get; set; }

		/// <summary>
		/// The rune and color of each symbol that will be rendered.  Note
		/// that only <see cref="ColorScheme.Normal"/> is respected.  You
		/// can modify these to change what is rendered.
		/// </summary>
		/// <remarks>
		/// Changing the length of this collection may result in corrupt rendering
		/// </remarks>
		public List<RuneCell> RuneCells { get; init; }

		/// <summary>
		/// The notional index in <see cref="RuneCells"/> which contains the first
		/// character of the <see cref="TreeView{T}.AspectGetter"/> text (i.e.
		/// after all branch lines and expansion/collapse sybmols).
		/// </summary>
		/// <remarks>
		/// May be negative or outside of bounds of <see cref="RuneCells"/> if the view
		/// has been scrolled horizontally.
		/// </remarks>

		public int IndexOfModelText { get; init; }

		/// <summary>
		/// If line contains a branch that can be expanded/collapsed then this is
		/// the index in <see cref="RuneCells"/> at which the symbol is (or null for
		/// leaf elements).
		/// </summary>
		public int? IndexOfExpandCollapseSymbol { get; init; }

	}
}