//
// TableLayout.cs
//
// 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.
//
// Copyright (c) 2006 Jonathan Pobst
//
// Authors:
//	Jonathan Pobst (monkey@jpobst.com)
//


#undef TABLE_DEBUG

using System;
using System.Drawing;

namespace System.Windows.Forms.Layout
{
	internal class TableLayout : LayoutEngine
	{
		private static Control dummy_control = new Control ("Dummy");	// Used as a placeholder for row/col spans

		public TableLayout () : base ()
		{
		}
		
		public override void InitLayout (object child, BoundsSpecified specified)
		{
			base.InitLayout (child, specified);
		}

		// There are 3 steps to doing a table layout:
		// 1) Figure out which row/column each control goes into
		// 2) Figure out the sizes of each row/column
		// 3) Size and position each control
		public override bool Layout (object container, LayoutEventArgs args)
		{
			TableLayoutPanel panel = container as TableLayoutPanel;
			TableLayoutSettings settings = panel.LayoutSettings;
			
#if TABLE_DEBUG
			Console.WriteLine ("Beginning layout on panel: {0}, control count: {1}, col/row count: {2}x{3}", panel.Name, panel.Controls.Count, settings.ColumnCount, settings.RowCount);
#endif

			// STEP 1:
			// - Figure out which row/column each control goes into
			// - Store data in the TableLayoutPanel.actual_positions
			panel.actual_positions = CalculateControlPositions (panel, Math.Max (settings.ColumnCount, 1), Math.Max (settings.RowCount, 1));

			// STEP 2:
			// - Figure out the sizes of each row/column
			// - Store data in the TableLayoutPanel.widths/heights
			CalculateColumnRowSizes (panel, panel.actual_positions.GetLength (0), panel.actual_positions.GetLength (1));
			
			// STEP 3:
			// - Size and position each control
			LayoutControls(panel);

#if TABLE_DEBUG
			Console.WriteLine ("-- CalculatedPositions:");
			OutputControlGrid (panel.actual_positions, panel);

			Console.WriteLine ("Finished layout on panel: {0}", panel.Name);
			Console.WriteLine ();
#endif

			return false;
		}

		internal Control[,] CalculateControlPositions (TableLayoutPanel panel, int columns, int rows)
		{
			Control[,] grid = new Control[columns, rows];

			TableLayoutSettings settings = panel.LayoutSettings;

			// First place all controls that have an explicit col/row
			foreach (Control c in panel.Controls) {
				int col = settings.GetColumn (c);
				int row = settings.GetRow (c);
				if (col >= 0 && row >= 0) {
					if (col >= columns)
						 return CalculateControlPositions (panel, col + 1, rows);
					if (row >= rows)
						 return CalculateControlPositions (panel, columns, row + 1);

					if (grid[col, row] == null) {
						int col_span = Math.Min (settings.GetColumnSpan (c), columns);
						int row_span = Math.Min (settings.GetRowSpan (c), rows);

						if (col + col_span > columns) {
							if (row + 1 < rows) {
								grid[col, row] = dummy_control;
								row++;
								col = 0;
							}
							else if (settings.GrowStyle == TableLayoutPanelGrowStyle.AddColumns)
								return CalculateControlPositions (panel, columns + 1, rows);
							else
								throw new ArgumentException ();
						}

						if (row + row_span > rows) {
							if (settings.GrowStyle == TableLayoutPanelGrowStyle.AddRows)
								return CalculateControlPositions (panel, columns, rows + 1);
							else
								throw new ArgumentException ();
						}

						grid[col, row] = c;

						// Fill in the rest of this control's row/column extent with dummy
						// controls, so that other controls don't get put there.
						for (int i = 0; i < col_span; i++)
							for (int j = 0; j < row_span; j++)
								if (i != 0 || j != 0)
									grid[col + i, row + j] = dummy_control;
					}
				}
			}

			int x_pointer = 0;
			int y_pointer = 0;

			// Fill in gaps with controls that do not have an explicit col/row
			foreach (Control c in panel.Controls) {
				int col = settings.GetColumn (c);
				int row = settings.GetRow (c);

				if ((col >= 0 && col < columns) && (row >= 0 && row < rows) && (grid[col, row] == c || grid[col, row] == dummy_control))
					continue;

				for (int y = y_pointer; y < rows; y++) {
					y_pointer = y;
					x_pointer = 0;

					for (int x = x_pointer; x < columns; x++) {
						x_pointer = x;

						if (grid[x, y] == null) {
							int col_span = Math.Min (settings.GetColumnSpan (c), columns);
							int row_span = Math.Min (settings.GetRowSpan (c), rows);

							if (x + col_span > columns) {
								if (y + 1 < rows)
									break;
								else if (settings.GrowStyle == TableLayoutPanelGrowStyle.AddColumns)
									return CalculateControlPositions (panel, columns + 1, rows);
								else
									throw new ArgumentException ();
							}

							if (y + row_span > rows) {
								if (x + 1 < columns)
									break;
								else if (settings.GrowStyle == TableLayoutPanelGrowStyle.AddRows)
									return CalculateControlPositions (panel, columns, rows + 1);
								else
									throw new ArgumentException ();
							}

							grid[x, y] = c;

							// Fill in the rest of this control's row/column extent with dummy
							// controls, so that other controls don't get put there.
							for (int i = 0; i < col_span; i++)
								for (int j = 0; j < row_span; j++)
									if (i != 0 || j != 0)
										grid[x + i, y + j] = dummy_control;

							// I know someone will kill me for using a goto, but 
							// sometimes they really are the easiest way...
							goto Found;
						} else {
							// MS adds the controls only to the first row if 
							// GrowStyle is AddColumns and RowCount is 0,
							// so interrupt the search for a free horizontal cell 
							// beyond the first one in the given vertical
							if (settings.GrowStyle == TableLayoutPanelGrowStyle.AddColumns && 
							    settings.RowCount == 0)
								break;
						}
					}
				}

				// MS adds rows instead of columns even when GrowStyle is AddColumns, 
				// but RowCount is 0.
				TableLayoutPanelGrowStyle adjustedGrowStyle = settings.GrowStyle;
				if (settings.GrowStyle == TableLayoutPanelGrowStyle.AddColumns) {
					if (settings.RowCount == 0)
						adjustedGrowStyle = TableLayoutPanelGrowStyle.AddRows;
				}

				switch (adjustedGrowStyle) {
					case TableLayoutPanelGrowStyle.AddColumns:
						return CalculateControlPositions (panel, columns + 1, rows);
					case TableLayoutPanelGrowStyle.AddRows:
					default:
						return CalculateControlPositions (panel, columns, rows + 1);
					case TableLayoutPanelGrowStyle.FixedSize:
						throw new ArgumentException ();
				}

			Found: ;
			}

			return grid;
		}

		private void CalculateColumnRowSizes (TableLayoutPanel panel, int columns, int rows)
		{
			TableLayoutSettings settings = panel.LayoutSettings;

			panel.column_widths = new int[panel.actual_positions.GetLength (0)];
			panel.row_heights = new int[panel.actual_positions.GetLength (1)];

			int border_width = TableLayoutPanel.GetCellBorderWidth (panel.CellBorderStyle);
				
			Rectangle parentDisplayRectangle = panel.DisplayRectangle;

			TableLayoutColumnStyleCollection col_styles = new TableLayoutColumnStyleCollection (panel);
			
			foreach (ColumnStyle cs in settings.ColumnStyles)
				col_styles.Add( new ColumnStyle(cs.SizeType, cs.Width));

			TableLayoutRowStyleCollection row_styles = new TableLayoutRowStyleCollection (panel);

			foreach (RowStyle rs in settings.RowStyles)
				row_styles.Add (new RowStyle (rs.SizeType, rs.Height));
		
			// If we have more columns than columnstyles, temporarily add enough columnstyles
			if (columns > col_styles.Count)
			{
				for (int i = col_styles.Count; i < columns; i++)
					col_styles.Add(new ColumnStyle());			
			}

			// Same for rows..
			if (rows > row_styles.Count) 
			{
				for (int i = row_styles.Count; i < rows; i++)
					row_styles.Add (new RowStyle ());
			}

			while (row_styles.Count > rows)
				row_styles.RemoveAt (row_styles.Count - 1);
			while (col_styles.Count > columns)
				col_styles.RemoveAt (col_styles.Count - 1);
				
			// Find the largest column-span/row-span values.
			int max_colspan = 0, max_rowspan = 0;
			foreach (Control c in panel.Controls) {
				max_colspan = Math.Max (max_colspan, settings.GetColumnSpan (c));
				max_rowspan = Math.Max (max_rowspan, settings.GetRowSpan (c));
			}

			// Figure up all the column widths
			int total_width = parentDisplayRectangle.Width - (border_width * (columns + 1));
			int index = 0;

			// First assign all the Absolute sized columns..
			foreach (ColumnStyle cs in col_styles) {
				if (cs.SizeType == SizeType.Absolute) {
					panel.column_widths[index] = (int)cs.Width;
					total_width -= (int)cs.Width;
				}

				index++;
			}

			// Next, assign all the AutoSize columns to the width of their widest
			// control.  If the table-layout is auto-sized, then make sure that
			// no column with Percent styling clips its contents.
			// (per http://msdn.microsoft.com/en-us/library/ms171690.aspx)
			for (int colspan = 0; colspan < max_colspan; ++colspan)
			{
				for (index = colspan; index < col_styles.Count - colspan; ++index)
				{
					ColumnStyle cs = col_styles[index];
					if (cs.SizeType == SizeType.AutoSize
					|| (panel.AutoSize && cs.SizeType == SizeType.Percent))
					{
						int max_width = panel.column_widths[index];

						// Find the widest control in the column
						for (int i = 0; i < rows; i ++)
						{
							Control c = panel.actual_positions[index - colspan, i];

							if (c != null && c != dummy_control && c.VisibleInternal)
							{
								// Skip any controls not being sized in this pass.
								if (settings.GetColumnSpan (c) != colspan + 1)
									continue;

								// Calculate the maximum control width.
								if (c.AutoSize)
									max_width = Math.Max (max_width, c.PreferredSize.Width + c.Margin.Horizontal);
								else
									max_width = Math.Max (max_width, c.ExplicitBounds.Width + c.Margin.Horizontal);
								max_width = Math.Max (max_width, c.Width + c.Margin.Left + c.Margin.Right);
							}
						}

						// Subtract the width of prior columns, if any.
						for (int i = Math.Max (index - colspan, 0); i < index; ++i)
							max_width -= panel.column_widths[i];

						// If necessary, increase this column's width.
						if (max_width > panel.column_widths[index])
						{
							max_width -= panel.column_widths[index];
							panel.column_widths[index] += max_width;
							total_width -= max_width;
						}
					}
				}
			}
			
			index = 0;
			float total_percent = 0;
			
			// Finally, assign the remaining space to Percent columns, if any.
			if (total_width > 0)
			{
				int percent_width = total_width; 
				
				// Find the total percent (not always 100%)
				foreach (ColumnStyle cs in col_styles) 
				{
					if (cs.SizeType == SizeType.Percent)
						total_percent += cs.Width;
				}

				// Divvy up the space..
				foreach (ColumnStyle cs in col_styles) 
				{
					if (cs.SizeType == SizeType.Percent) 
					{
						int width_change = (int)(((cs.Width / total_percent) * percent_width)
							- panel.column_widths[index]);
						if (width_change > 0)
						{
							panel.column_widths[index] += width_change;
							total_width -= width_change;
						}
					}

					index++;
				}
			}

			if (total_width > 0)
			{
				// Find the last column that isn't an Absolute SizeType, and give it
				// all this free space.  (Absolute sized columns need to retain their
				// absolute width if at all possible!)
				int col = col_styles.Count - 1;
				for (; col >= 0; --col)
				{
					if (col_styles[col].SizeType != SizeType.Absolute)
						break;
				}
				if (col < 0)
					col = col_styles.Count - 1;
				panel.column_widths[col] += total_width;
			}

			// Figure up all the row heights
			int total_height = parentDisplayRectangle.Height - (border_width * (rows + 1));
			index = 0;

			// First assign all the Absolute sized rows..
			foreach (RowStyle rs in row_styles) {
				if (rs.SizeType == SizeType.Absolute) {
					panel.row_heights[index] = (int)rs.Height;
					total_height -= (int)rs.Height;
				}

				index++;
			}

			index = 0;

			// Next, assign all the AutoSize rows to the height of their tallest
			// control.  If the table-layout is auto-sized, then make sure that
			// no row with Percent styling clips its contents.
			// (per http://msdn.microsoft.com/en-us/library/ms171690.aspx)
			for (int rowspan = 0; rowspan < max_rowspan; ++rowspan)
			{
				for (index = rowspan; index < row_styles.Count - rowspan; ++index)
				{
					RowStyle rs = row_styles[index];
					if (rs.SizeType == SizeType.AutoSize
					|| (panel.AutoSize && rs.SizeType == SizeType.Percent))
					{
						int max_height = panel.row_heights[index];

						// Find the tallest control in the row
						for (int i = 0; i < columns; i++) {
							Control c = panel.actual_positions[i, index - rowspan];

							if (c != null && c != dummy_control && c.VisibleInternal)
							{
								// Skip any controls not being sized in this pass.
								if (settings.GetRowSpan (c) != rowspan + 1)
									continue;

								// Calculate the maximum control height.
								if (c.AutoSize)
									max_height = Math.Max (max_height, c.PreferredSize.Height + c.Margin.Vertical);
								else
									max_height = Math.Max (max_height, c.ExplicitBounds.Height + c.Margin.Vertical);
								max_height = Math.Max (max_height, c.Height + c.Margin.Top + c.Margin.Bottom);
							}
						}

						// Subtract the height of prior rows, if any.
						for (int i = Math.Max (index - rowspan, 0); i < index; ++i)
							max_height -= panel.row_heights[i];

						// If necessary, increase this row's height.
						if (max_height > panel.row_heights[index])
						{
							max_height -= panel.row_heights[index];
							panel.row_heights[index] += max_height;
							total_height -= max_height;
						}
					}
				}
			}

			index = 0;
			total_percent = 0;

			// Finally, assign the remaining space to Percent rows, if any.
			if (total_height > 0) {
				int percent_height = total_height;
				
				// Find the total percent (not always 100%)
				foreach (RowStyle rs in row_styles) {
					if (rs.SizeType == SizeType.Percent)
						total_percent += rs.Height;
				}

				// Divvy up the space..
				foreach (RowStyle rs in row_styles) {
					if (rs.SizeType == SizeType.Percent) {
						int height_change = (int)(((rs.Height / total_percent) * percent_height)
							- panel.row_heights[index]);
						if (height_change > 0)
						{
							panel.row_heights[index] += height_change;
							total_height -= height_change;
						}
					}

					index++;
				}
			}

			if (total_height > 0)
			{
				// Find the last row that isn't an Absolute SizeType, and give it
				// all this free space.  (Absolute sized rows need to retain their
				// absolute height if at all possible!)
				int row = row_styles.Count - 1;
				for (; row >= 0; --row)
				{
					if (row_styles[row].SizeType != SizeType.Absolute)
						break;
				}
				if (row < 0)
					row = row_styles.Count - 1;
				panel.row_heights[row] += total_height;
			}
		}
		
		private void LayoutControls (TableLayoutPanel panel)
		{
			TableLayoutSettings settings = panel.LayoutSettings;
			
			int border_width = TableLayoutPanel.GetCellBorderWidth (panel.CellBorderStyle);

			int columns = panel.actual_positions.GetLength(0);
			int rows = panel.actual_positions.GetLength(1);

			Point current_pos = new Point (panel.DisplayRectangle.Left + border_width, panel.DisplayRectangle.Top + border_width);

			for (int y = 0; y < rows; y++)
			{
				for (int x = 0; x < columns; x++)
				{
					Control c = panel.actual_positions[x,y];
					
					if(c != null && c != dummy_control) {
						Size preferred;
						
						if (c.AutoSize)
							preferred = c.PreferredSize;
						else
							preferred = c.ExplicitBounds.Size;
						
						int new_x = 0;
						int new_y = 0;
						int new_width = 0;
						int new_height = 0;
						
						// Figure out the width of the control
						int column_width = panel.column_widths[x];
						
						for (int i = 1; i < Math.Min (settings.GetColumnSpan(c), panel.column_widths.Length); i++)
							column_width += panel.column_widths[x + i];

						if (c.Dock == DockStyle.Fill || c.Dock == DockStyle.Top || c.Dock == DockStyle.Bottom || ((c.Anchor & AnchorStyles.Left) == AnchorStyles.Left && (c.Anchor & AnchorStyles.Right) == AnchorStyles.Right))
							new_width = column_width - c.Margin.Left - c.Margin.Right;
						else
							new_width = Math.Min (preferred.Width, column_width - c.Margin.Left - c.Margin.Right);
							
						// Figure out the height of the control
						int column_height = panel.row_heights[y];

						for (int i = 1; i < Math.Min (settings.GetRowSpan (c), panel.row_heights.Length); i++)
							column_height += panel.row_heights[y + i];

						if (c.Dock == DockStyle.Fill || c.Dock == DockStyle.Left || c.Dock == DockStyle.Right || ((c.Anchor & AnchorStyles.Top) == AnchorStyles.Top && (c.Anchor & AnchorStyles.Bottom) == AnchorStyles.Bottom))
							new_height = column_height - c.Margin.Top - c.Margin.Bottom;
						else
							new_height = Math.Min (preferred.Height, column_height - c.Margin.Top - c.Margin.Bottom);

						// Figure out the left location of the control
						if (c.Dock == DockStyle.Left || c.Dock == DockStyle.Fill || (c.Anchor & AnchorStyles.Left) == AnchorStyles.Left)
							new_x = current_pos.X + c.Margin.Left;
						else if (c.Dock == DockStyle.Right || (c.Anchor & AnchorStyles.Right) == AnchorStyles.Right)
							new_x = (current_pos.X + column_width) - new_width - c.Margin.Right;
						else	// (center control)
							new_x = (current_pos.X + (column_width - c.Margin.Left - c.Margin.Right) / 2) + c.Margin.Left - (new_width / 2);

						// Figure out the top location of the control
						if (c.Dock == DockStyle.Top || c.Dock == DockStyle.Fill || (c.Anchor & AnchorStyles.Top) == AnchorStyles.Top)
							new_y = current_pos.Y + c.Margin.Top;
						else if (c.Dock == DockStyle.Bottom || (c.Anchor & AnchorStyles.Bottom) == AnchorStyles.Bottom)
							new_y = (current_pos.Y + column_height) - new_height - c.Margin.Bottom;
						else	// (center control)
							new_y = (current_pos.Y + (column_height - c.Margin.Top - c.Margin.Bottom) / 2) + c.Margin.Top - (new_height / 2);

						c.SetBoundsInternal (new_x, new_y, new_width, new_height, BoundsSpecified.None);
					}

					current_pos.Offset (panel.column_widths[x] + border_width, 0);
				}

				current_pos.Offset ((-1 * current_pos.X) + border_width + panel.DisplayRectangle.Left, panel.row_heights[y] + border_width);
			}
		}
	
#if TABLE_DEBUG
		private void OutputControlGrid (Control[,] grid, TableLayoutPanel panel)
		{
			Console.WriteLine ("     Size: {0}x{1}", grid.GetLength (0), grid.GetLength (1));

			Console.Write ("        ");

			foreach (int i in panel.column_widths)
				Console.Write (" {0}px  ", i.ToString ().PadLeft (3));

			Console.WriteLine ();
				
			for (int y = 0; y < grid.GetLength (1); y++) {
				Console.Write (" {0}px |", panel.row_heights[y].ToString ().PadLeft (3));
				
				for (int x = 0; x < grid.GetLength (0); x++) {
					if (grid[x, y] == null)
						Console.Write ("  ---  |");
					else if (string.IsNullOrEmpty (grid[x, y].Name))
						Console.Write ("  ???  |");
					else
						Console.Write (" {0} |", grid[x, y].Name.PadRight (5).Substring (0, 5));
				}
				
				Console.WriteLine ();
			}
		}
#endif
	}
}