// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using Microsoft.CodeAnalysis.Editor.Implementation.Adornments;
using Microsoft.VisualStudio.Text.Classification;
using Microsoft.VisualStudio.Text.Editor;
using Microsoft.VisualStudio.Text.Formatting;
 
namespace Microsoft.CodeAnalysis.Editor.Implementation.LineSeparators
{
    /// <summary>
    /// Tag that specifies line separator.
    /// </summary>
    internal class LineSeparatorTag : GraphicsTag
    {
        public LineSeparatorTag(IEditorFormatMap editorFormatMap)
            : base(editorFormatMap)
        {
        }
 
        protected override Color? GetColor(
            IWpfTextView view, IEditorFormatMap editorFormatMap)
        {
            var brush = view.VisualElement.TryFindResource("outlining.verticalrule.foreground") as SolidColorBrush;
            return brush?.Color;
        }
 
        /// <summary>
        /// Creates a very long line at the bottom of bounds.
        /// </summary>
        public override GraphicsResult GetGraphics(IWpfTextView view, Geometry bounds, TextFormattingRunProperties? format)
        {
            var border = new Border()
            {
                BorderBrush = GetBrush(view),
                BorderThickness = new Thickness(0, 0, 0, bottom: 1),
                Height = 1,
                Width = view.ViewportWidth
            };
 
            view.ViewportWidthChanged += ViewportWidthChangedHandler;
 
            // Subtract rect.Height to ensure that the line separator is drawn
            // at the bottom of the line, rather than immediately below.
            // This makes the line separator line up with the outlining bracket.
            Canvas.SetTop(border, bounds.Bounds.Bottom - border.Height);
 
            return new GraphicsResult(border,
                () => view.ViewportWidthChanged -= ViewportWidthChangedHandler);
 
            void ViewportWidthChangedHandler(object s, EventArgs e)
            {
                border.Width = view.ViewportWidth;
            }
        }
    }
}