#region
//Copyright (c) 2008 Jason Kemp
//
//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.
#endregion
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
using System.Windows.Documents;
using System.Windows.Media;

namespace Soundmind.Windows
{
   public static class CueBannerService
   {
      //there is absolutely no way to write this statement out
      //to look pretty
      public static readonly DependencyProperty CueBannerProperty = DependencyProperty.RegisterAttached(
         "CueBanner", typeof (object), typeof (CueBannerService), 
         new FrameworkPropertyMetadata("", CueBannerPropertyChanged));

      public static object GetCueBanner(Control control)
      {
         return control.GetValue(CueBannerProperty);
      }

      public static void SetCueBanner(Control control, object value)
      {
         control.SetValue(CueBannerProperty, value);
      }

      private static void CueBannerPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
      {
         Control control = (Control)d;
         control.Loaded += control_Loaded;
         if (d is ComboBox || d is TextBox)
         {
            control.GotFocus += control_GotFocus;
            control.LostFocus += control_Loaded;
         }
         if (d is ItemsControl && !(d is ComboBox))
         {
            ItemsControl i = (ItemsControl) d;
            //for Items property
            i.ItemContainerGenerator.ItemsChanged += ItemsChanged;
            itemsControls.Add(i.ItemContainerGenerator, i);
            //for ItemsSource property
            DependencyPropertyDescriptor prop =
               DependencyPropertyDescriptor.FromProperty(ItemsControl.ItemsSourceProperty, i.GetType());
            prop.AddValueChanged(i, ItemsSourceChanged);
         }
      }
    
      private static readonly Dictionary<object, ItemsControl> itemsControls = new Dictionary<object, ItemsControl>();
      private static void ItemsSourceChanged(object sender, EventArgs e)
      {
         ItemsControl c = (ItemsControl)sender;
         if (c.ItemsSource != null)
            RemoveCueBanner(c);
         else
            ShowCueBanner(c);
      }

      private static void ItemsChanged(object sender, ItemsChangedEventArgs e)
      {
         ItemsControl control;
         if (itemsControls.TryGetValue(sender, out control))
         {
            if (e.ItemCount > 0)
               RemoveCueBanner(control);
            else
               ShowCueBanner(control);
         }
      }

      private static void control_GotFocus(object sender, RoutedEventArgs e)
      {
         Control c = (Control)sender;
         if (ShouldShowCueBanner(c))
         {
            RemoveCueBanner(c);
         }
      }

      private static void control_Loaded(object sender, RoutedEventArgs e)
      {
         Control control = (Control)sender;
         if (ShouldShowCueBanner(control))
         {
            ShowCueBanner(control);
         }
      }

      private static void RemoveCueBanner(UIElement control)
      {
         AdornerLayer layer = AdornerLayer.GetAdornerLayer(control);

         Adorner[] adorners = layer.GetAdorners(control);
         if (adorners == null) return;
         foreach (Adorner adorner in adorners)
         {
            if (adorner is CueBannerAdorner)
            {
               adorner.Visibility = Visibility.Hidden;
               layer.Remove(adorner);
            }
         }
      }

      private static void ShowCueBanner(Control control)
      {
         AdornerLayer layer = AdornerLayer.GetAdornerLayer(control);
         layer.Add(new CueBannerAdorner(control, GetCueBanner(control)));
      }

      private static bool ShouldShowCueBanner(Control c)
      {
         DependencyProperty dp = GetDependencyProperty(c);
         if (dp == null) return true;
         return c.GetValue(dp).Equals("");
      }

      private static DependencyProperty GetDependencyProperty (Control control)
      {
         if (control is ComboBox)
            return ComboBox.TextProperty;
         if (control is TextBoxBase)
            return TextBox.TextProperty;
         return null;
      }
   }

   internal class CueBannerAdorner : Adorner
   {
      private readonly ContentPresenter contentPresenter;

      public CueBannerAdorner(UIElement adornedElement, object cueBanner) : 
         base(adornedElement)
      {
         this.IsHitTestVisible = false;

         contentPresenter = new ContentPresenter();
         contentPresenter.Content = cueBanner;
         contentPresenter.Opacity = 0.7;
         contentPresenter.Margin =
            new Thickness(Control.Margin.Left + Control.Padding.Left, 
                          Control.Margin.Top + Control.Padding.Top, 0, 0);
      }

      private Control Control
      {
         get { return (Control) this.AdornedElement; }
      }

      protected override Visual GetVisualChild(int index)
      {
         return contentPresenter;
      }

      protected override int VisualChildrenCount
      {
         get { return 1; }
      }

      protected override Size MeasureOverride(Size constraint)
      {
         contentPresenter.Measure(Control.RenderSize);
         return Control.RenderSize;
      }

      protected override Size ArrangeOverride(Size finalSize)
      {
         contentPresenter.Arrange(new Rect(finalSize));
         return finalSize;
      }
   }
}