// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
// 
// 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.Collections.Generic;
using System.Linq;
using AvaloniaEdit.Document;
using AvaloniaEdit.Utils;

namespace AvaloniaEdit.Editing
{
	/// <summary>
	/// <see cref="IReadOnlySectionProvider"/> that has no read-only sections; all text is editable.
	/// </summary>
	sealed class NoReadOnlySections : IReadOnlySectionProvider
	{
		public static readonly NoReadOnlySections Instance = new NoReadOnlySections();
		
		public bool CanInsert(int offset)
		{
			return true;
		}
		
		public IEnumerable<ISegment> GetDeletableSegments(ISegment segment)
		{
			if (segment == null)
				throw new ArgumentNullException(nameof(segment));
			// the segment is always deletable
			return ExtensionMethods.Sequence(segment);
		}
	}
	
	/// <summary>
	/// <see cref="IReadOnlySectionProvider"/> that completely disables editing.
	/// </summary>
	sealed class ReadOnlySectionDocument : IReadOnlySectionProvider
	{
		public static readonly ReadOnlySectionDocument Instance = new ReadOnlySectionDocument();
		
		public bool CanInsert(int offset)
		{
			return false;
		}
		
		public IEnumerable<ISegment> GetDeletableSegments(ISegment segment)
		{
			return Enumerable.Empty<ISegment>();
		}
	}
}
