// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

using System.Collections.Generic;
using System.Diagnostics;

using UyghurEditPP.Document;

namespace UyghurEditPP.Rendering
{
	/// <summary>
	/// A node in the text view's height tree.
	/// </summary>
	sealed class HeightTreeNode
	{
		internal readonly DocumentLine documentLine;
		internal HeightTreeLineNode lineNode;

		internal HeightTreeNode left, right, parent;
		internal bool color;

		internal HeightTreeNode()
		{
		}

		internal HeightTreeNode(DocumentLine documentLine, double height)
		{
			this.documentLine = documentLine;
			this.totalCount = 1;
			this.lineNode = new HeightTreeLineNode(height);
			this.totalHeight = height;
		}

		internal HeightTreeNode LeftMost {
			get {
				HeightTreeNode node = this;
				while (node.left != null)
					node = node.left;
				return node;
			}
		}

		internal HeightTreeNode RightMost {
			get {
				HeightTreeNode node = this;
				while (node.right != null)
					node = node.right;
				return node;
			}
		}

		/// <summary>
		/// Gets the inorder successor of the node.
		/// </summary>
		internal HeightTreeNode Successor {
			get {
				if (right != null) {
					return right.LeftMost;
				} else {
					HeightTreeNode node = this;
					HeightTreeNode oldNode;
					do {
						oldNode = node;
						node = node.parent;
						// go up until we are coming out of a left subtree
					} while (node != null && node.right == oldNode);
					return node;
				}
			}
		}

		/// <summary>
		/// The number of lines in this node and its child nodes.
		/// Invariant:
		///   totalCount = 1 + left.totalCount + right.totalCount
		/// </summary>
		internal int totalCount;

		/// <summary>
		/// The total height of this node and its child nodes, excluding directly collapsed nodes.
		/// Invariant:
		///   totalHeight = left.IsDirectlyCollapsed ? 0 : left.totalHeight
		///               + lineNode.IsDirectlyCollapsed ? 0 : lineNode.Height
		///               + right.IsDirectlyCollapsed ? 0 : right.totalHeight
		/// </summary>
		internal double totalHeight;

		/// <summary>
		/// List of the sections that hold this node collapsed.
		/// Invariant 1:
		///   For each document line in the range described by a CollapsedSection, exactly one ancestor
		///   contains that CollapsedSection.
		/// Invariant 2:
		///   A CollapsedSection is contained either in left+middle or middle+right or just middle.
		/// Invariant 3:
		///   Start and end of a CollapsedSection always contain the collapsedSection in their
		///   documentLine (middle node).
		/// </summary>
		internal List<CollapsedLineSection> collapsedSections;

		internal bool IsDirectlyCollapsed {
			get {
				return collapsedSections != null;
			}
		}

		internal void AddDirectlyCollapsed(CollapsedLineSection section)
		{
			if (collapsedSections == null) {
				collapsedSections = new List<CollapsedLineSection>();
				totalHeight = 0;
			}
			Debug.Assert(!collapsedSections.Contains(section));
			collapsedSections.Add(section);
		}


		internal void RemoveDirectlyCollapsed(CollapsedLineSection section)
		{
			Debug.Assert(collapsedSections.Contains(section));
			collapsedSections.Remove(section);
			if (collapsedSections.Count == 0) {
				collapsedSections = null;
				totalHeight = lineNode.TotalHeight;
				if (left != null)
					totalHeight += left.totalHeight;
				if (right != null)
					totalHeight += right.totalHeight;
			}
		}

#if DEBUG
		public override string ToString()
		{
			return "[HeightTreeNode "
				+ documentLine.LineNumber + " CS=" + GetCollapsedSections(collapsedSections)
				+ " Line.CS=" + GetCollapsedSections(lineNode.collapsedSections)
				+ " Line.Height=" + lineNode.height
				+ " TotalHeight=" + totalHeight
				+ "]";
		}

		static string GetCollapsedSections(List<CollapsedLineSection> list)
		{
			if (list == null)
				return "{}";
			return "{" +
				string.Join(",",
							list.ConvertAll(cs => cs.ID).ToArray())
				+ "}";
		}
#endif
	}
}
