/*
The MIT License

Copyright (c) 2009-2010. Carlos Guzmán Álvarez. http://chronoswpf.codeplex.com/

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;
using System.Windows;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using Chronos.Presentation.Windows.Controls;

namespace Chronos.Presentation.Windows
{
    /// <summary>
    /// Addorner for the rubber band selection
    /// </summary>
    public class RubberbandAdorner : Adorner
    {
        #region · Fields ·

        private Point?  startPoint;
        private Point?  endPoint;
        private Pen     rubberbandPen;
        private Desktop desktop;
        private Brush   backgroundBrush;

        #endregion        

        #region · Constructors ·

        /// <summary>
        /// Initializes a new instance of the <see cref="RubberbandAdorner"/> class.
        /// </summary>
        /// <param name="canvas">The canvas.</param>
        /// <param name="dragStartPoint">The drag start point.</param>
        public RubberbandAdorner(Desktop canvas, Point? dragStartPoint)
            : base(canvas)
        {
            ColorConverter cconverter = new ColorConverter();

            this.desktop                    = canvas;
            this.startPoint                 = dragStartPoint;
            this.rubberbandPen              = new Pen(new SolidColorBrush((Color)cconverter.ConvertFrom("#FF7AA3D4")), 1);
            this.rubberbandPen.DashStyle    = new DashStyle();
            this.backgroundBrush            = new SolidColorBrush((Color)cconverter.ConvertFrom("#FFC5D5E9"));
            this.backgroundBrush.Opacity    = 0.40;
        }

        #endregion

        #region · Protected Methods ·

        /// <summary>
        /// Invoked when an unhandled <see cref="E:System.Windows.Input.Mouse.MouseMove"/> attached event reaches an element in its route that is derived from this class. Implement this method to add class handling for this event.
        /// </summary>
        /// <param name="e">The <see cref="T:System.Windows.Input.MouseEventArgs"/> that contains the event data.</param>
        protected override void OnMouseMove(System.Windows.Input.MouseEventArgs e)
        {
            if (e.LeftButton == MouseButtonState.Pressed)
            {
                if (!this.IsMouseCaptured)
                {
                    this.CaptureMouse();
                }

                endPoint = e.GetPosition(this);

                this.UpdateSelection();
                this.InvalidateVisual();
            }
            else
            {
                if (this.IsMouseCaptured)
                {
                    this.ReleaseMouseCapture();
                }
            }

            e.Handled = true;
        }

        /// <summary>
        /// Invoked when an unhandled <see cref="E:System.Windows.Input.Mouse.MouseUp"/> routed event 
        /// reaches an element in its route that is derived from this class. 
        /// Implement this method to add class handling for this event.
        /// </summary>
        /// <param name="e">The <see cref="T:System.Windows.Input.MouseButtonEventArgs"/> that contains the event data. 
        /// The event data reports that the mouse button was released.</param>
        protected override void OnMouseUp(System.Windows.Input.MouseButtonEventArgs e)
        {
            // release mouse capture
            if (this.IsMouseCaptured)
            {
                this.ReleaseMouseCapture();
            }

            // remove this adorner from adorner layer
            AdornerLayer adornerLayer = AdornerLayer.GetAdornerLayer(this.desktop);
            if (adornerLayer != null)
            {
                adornerLayer.Remove(this);
            }

            e.Handled = true;
        }

        /// <summary>
        /// When overridden in a derived class, participates in rendering operations that are directed by the layout system. The rendering instructions for this element are not used directly when this method is invoked, and are instead preserved for later asynchronous use by layout and drawing.
        /// </summary>
        /// <param name="drawingContext">The drawing instructions for a specific element. This context is provided to the layout system.</param>
        protected override void OnRender(DrawingContext drawingContext)
        {
            base.OnRender(drawingContext);

            // without a background the OnMouseMove event would not be fired!
            // Alternative: implement a Canvas as a child of this adorner, like
            // the ConnectionAdorner does.
            drawingContext.DrawRectangle(Brushes.Transparent, null, new Rect(RenderSize));
            
            if (this.startPoint.HasValue && this.endPoint.HasValue)
            {
                drawingContext.DrawRectangle(this.backgroundBrush, rubberbandPen, new Rect(this.startPoint.Value, this.endPoint.Value));
            }
        }

        #endregion

        #region · Private Methods ·

        private void UpdateSelection()
        {
            desktop.SelectionService.ClearSelection();

            Rect rubberBand = new Rect(startPoint.Value, endPoint.Value);

            foreach (UIElement item in desktop.Children)
            {
                Rect itemRect   = VisualTreeHelper.GetDescendantBounds(item);
                Rect itemBounds = item.TransformToAncestor(desktop).TransformBounds(itemRect);

                if (rubberBand.Contains(itemBounds))
                {
                    if (item is ISelectable)
                    {
                        ISelectable di = item as ISelectable;

                        if (di.ParentId == Guid.Empty)
                        {
                            desktop.SelectionService.AddToSelection(di);
                        }
                    }
                }
            }
        }

        #endregion
    }
}