// 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.
 
#nullable disable
 
using System;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Editor;
using Microsoft.VisualStudio.Text.Projection;
 
namespace Roslyn.Hosting.Diagnostics.VenusMargin;
 
internal sealed class VenusMargin : IWpfTextViewMargin
{
    public const string MarginName = "VenusMargin";
 
    private readonly IProjectionBuffer _projectionBuffer;
    private readonly ProjectionBufferViewModel _viewModel = new ProjectionBufferViewModel();
    private readonly ProjectionBufferMargin _control;
 
    private bool _isDisposed = false;
 
    public VenusMargin(IWpfTextView textView, ITextEditorFactoryService textEditorFactory)
    {
        _projectionBuffer = (IProjectionBuffer)textView.TextBuffer;
 
        _control = new ProjectionBufferMargin
        {
            DataContext = _viewModel,
            TextEditorFactory = textEditorFactory,
            TextView = textView,
        };
 
        _projectionBuffer.Changed += OnProjectionBufferChanged;
        _projectionBuffer.SourceSpansChanged += this.OnProjectionBufferSourceSpansChanged;
        _projectionBuffer.SourceBuffersChanged += OnProjectionBufferSourceBuffersChanged;
 
        foreach (var b in _projectionBuffer.SourceBuffers)
        {
            _viewModel.SourceBuffers.Add(b);
        }
    }
 
    private void OnProjectionBufferSourceBuffersChanged(object sender, ProjectionSourceBuffersChangedEventArgs e)
    {
        foreach (var b in e.RemovedBuffers)
        {
            _viewModel.SourceBuffers.Remove(b);
        }
 
        foreach (var b in e.AddedBuffers)
        {
            _viewModel.SourceBuffers.Add(b);
        }
 
        UpdateSourceSpans();
    }
 
    private void OnProjectionBufferSourceSpansChanged(object sender, ProjectionSourceSpansChangedEventArgs e)
    {
        UpdateSourceSpans();
    }
 
    private void OnProjectionBufferChanged(object sender, TextContentChangedEventArgs e)
    {
        UpdateSourceSpans();
    }
 
    private void UpdateSourceSpans()
    {
        _viewModel.SourceSpans.Clear();
        foreach (var ss in _projectionBuffer.CurrentSnapshot.GetSourceSpans())
        {
            _viewModel.SourceSpans.Add(ss);
        }
 
        _viewModel.SourceSpans.Add(new SnapshotSpan(_projectionBuffer.CurrentSnapshot, 0, 0));
    }
 
    private void ThrowIfDisposed()
    {
        if (_isDisposed)
        {
            throw new ObjectDisposedException(MarginName);
        }
    }
 
    public System.Windows.FrameworkElement VisualElement
    {
        get
        {
            ThrowIfDisposed();
            return _control;
        }
    }
 
    public double MarginSize
    {
        get
        {
            ThrowIfDisposed();
            return _control.ActualHeight;
        }
    }
 
    public bool Enabled
    {
        get
        {
            ThrowIfDisposed();
            return true;
        }
    }
 
    public ITextViewMargin GetTextViewMargin(string marginName)
    {
        return marginName == MarginName ? this : null;
    }
 
    public void Dispose()
    {
        if (!_isDisposed)
        {
            _isDisposed = true;
        }
    }
}