//-----------------------------------------------------------------------
// <copyright file="CenterLayout.cs" company="bedug.com">
//     Copyright © 2012 Nils Hammar. All rights reserved.
// </copyright>
//-----------------------------------------------------------------------
/*
 * Software to access vehicle information via the OBD-II connector.
 * 
 * Copyright © 2012 Nils Hammar
 * 
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 * 
 * Alternative licensing is possible, see the licensing document.
 * 
 * The above text may not be removed or modified.
 */

namespace Gauges.TelltalePanel
{
    using System;
    using System.Collections.Generic;
    using System.Drawing;
    using System.Linq;
    using System.Text;
    using System.Windows.Forms;

    /// <summary>
    /// Layout engine that works best for equally sized object which shall be displayed around the center of a panel.
    /// </summary>
    public class CenterLayout : System.Windows.Forms.Layout.LayoutEngine
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="TelltaleDetails" /> class.
        /// </summary>
        /// <param name="container">Container to layout in.</param>
        /// <param name="layoutEventArgs">Layout event arguments.</param>
        /// <returns>Whether or not the container's 
        /// parent should perform layout as a result of this 
        /// layout.</returns>
        public override bool Layout(
            object container,
            LayoutEventArgs layoutEventArgs)
        {
            Control parent = container as Control;

            // Use DisplayRectangle so that parent.Padding is honored.
            Rectangle parentDisplayRectangle = parent.DisplayRectangle;
            int displayWidth = parentDisplayRectangle.Width;
            int center = parent.Width / 2;

            int maxItemWidth = 0;
            int maxItemHeight = 0;

            foreach (Control c in parent.Controls)
            {
                int h = c.Height + c.Margin.Top + c.Margin.Bottom;
                int w = c.Width + c.Margin.Left + c.Margin.Right;

                if (h > maxItemHeight)
                {
                    maxItemHeight = h;
                }

                if (w > maxItemWidth)
                {
                    maxItemWidth = w;
                }
            }

            if (center < maxItemWidth)
            {
                center = 0;
            }

            int leftPos = center - maxItemWidth;
            int rightPos = center;
            int nextY = 0;
            bool incYleft = false;
            bool incYright = false;
            bool visible = true;

            int n = 1;
            foreach (Control c in parent.Controls)
            {
                c.Visible = visible;

                // Only apply layout to visible controls.
                if (!c.Visible)
                {
                    continue;
                }

                // Determine location.
                Point location;
                if ((n % 2) == 0)
                {
                    location = new Point(leftPos, nextY);

                    leftPos -= maxItemWidth;
                    if (leftPos < 0)
                    {
                        incYleft = true;
                    }
                }
                else
                {
                    location = new Point(rightPos, nextY);

                    rightPos += maxItemWidth;
                    if (rightPos > displayWidth)
                    {
                        incYright = true;
                    }
                }

                // Respect the margin of the control:
                // shift over the left and the top.
                location.Offset(c.Margin.Left, c.Margin.Top);

                // Set the location of the control.
                c.Location = location;

                if (incYleft || incYright || center < maxItemWidth)
                {
                    nextY += maxItemHeight;
                    leftPos = center - maxItemWidth;
                    rightPos = center;

                    incYleft = false;
                    incYright = false;

                    if ((nextY + maxItemHeight) > parentDisplayRectangle.Height)
                    {
                        visible = false;
                    }
                }

                if (center < maxItemWidth)
                {
                    n += 2;
                }
                else
                {
                    n++;
                }
            }

            // Optional: Return whether or not the container's 
            // parent should perform layout as a result of this 
            // layout. Some layout engines return the value of 
            // the container's AutoSize property.
            return false;
        }
    }
}