using System;

using System.Collections.Generic;

using System.Text;

using System.Drawing;

using Aga.Controls.Tree.NodeControls;

namespace Aga.Controls.Tree

{

	public class AutoRowHeightLayout: IRowLayout

	{

		private DrawContext _measureContext;

		private TreeViewAdv _treeView;

		private List<Rectangle> _rowCache;

		public AutoRowHeightLayout(TreeViewAdv treeView, int rowHeight)

		{

			_rowCache = new List<Rectangle>();

			_treeView = treeView;

			PreferredRowHeight = rowHeight;

			_measureContext = new DrawContext();

			_measureContext.Graphics = Graphics.FromImage(new Bitmap(1, 1));

		}

		private int _rowHeight;

		public int PreferredRowHeight

		{

			get { return _rowHeight; }

			set { _rowHeight = value; }

		}

		public int PageRowCount

		{

			get 

			{

				if (_treeView.RowCount == 0)

					return 0;

				else

				{

					int pageHeight = _treeView.DisplayRectangle.Height - _treeView.ColumnHeaderHeight;

					int y = 0;

					for (int i = _treeView.RowCount - 1; i >= 0; i--)

					{

						y += GetRowHeight(i);

						if (y > pageHeight)

							return Math.Max(0, _treeView.RowCount - 1 - i);

					}

					return _treeView.RowCount;

				}

			}

		}

		public int CurrentPageSize

		{

			get

			{

				if (_treeView.RowCount == 0)

					return 0;

				else

				{

					int pageHeight = _treeView.DisplayRectangle.Height - _treeView.ColumnHeaderHeight;

					int y = 0;

					for (int i = _treeView.FirstVisibleRow; i < _treeView.RowCount; i++)

					{

						y += GetRowHeight(i);

						if (y > pageHeight)

							return Math.Max(0, i - _treeView.FirstVisibleRow);

					}

					return Math.Max(0, _treeView.RowCount - _treeView.FirstVisibleRow);

				}

			}

		}

		public Rectangle GetRowBounds(int rowNo)

		{

			if (rowNo >= _rowCache.Count)

			{

				int count = _rowCache.Count;

				int y = count > 0 ? _rowCache[count - 1].Bottom : 0;

				for (int i = count; i <= rowNo; i++)

				{

					int height = GetRowHeight(i);

					_rowCache.Add(new Rectangle(0, y, 0, height));

					y += height;

				}

				if (rowNo < _rowCache.Count - 1)

					return Rectangle.Empty;

			}

			if (rowNo >= 0 && rowNo < _rowCache.Count)

				return _rowCache[rowNo];

			else

				return Rectangle.Empty;

		}

		private int GetRowHeight(int rowNo)

		{

			if (rowNo < _treeView.RowMap.Count)

			{

				TreeNodeAdv node = _treeView.RowMap[rowNo];

				if (node.Height == null)

				{

					int res = 0;

					_measureContext.Font = _treeView.Font;

					foreach (NodeControl nc in _treeView.NodeControls)

					{

						int h = nc.GetActualSize(node, _measureContext).Height;

						if (h > res)

							res = h;

					}

					node.Height = res;

				}

				return node.Height.Value;

			}

			else

				return 0;

		}

		public int GetRowAt(Point point)

		{

			int py = point.Y - _treeView.ColumnHeaderHeight;

			int y = 0;

			for (int i = _treeView.FirstVisibleRow; i < _treeView.RowCount; i++)

			{

				int h = GetRowHeight(i);

				if (py >= y && py < y + h)

					return i;

				else

					y += h;

			}

			return -1;

		}

		public int GetFirstRow(int lastPageRow)

		{

			int pageHeight = _treeView.DisplayRectangle.Height - _treeView.ColumnHeaderHeight;

			int y = 0;

			for (int i = lastPageRow; i >= 0; i--)

			{

				y += GetRowHeight(i);

				if (y > pageHeight)

					return Math.Max(0, i + 1);

			}

			return 0;

		}

		public void ClearCache()

		{

			_rowCache.Clear();

		}

	}

}