// 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 Microsoft.CodeAnalysis.Shared.Extensions;
using Microsoft.CodeAnalysis.Text;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.Formatting
{
    internal abstract partial class TreeData
    {
        private class StructuredTrivia : TreeData
        {
            private readonly int _initialColumn;
            private readonly SyntaxTrivia _trivia;
            private readonly TreeData _treeData;
 
            public StructuredTrivia(SyntaxTrivia trivia, int initialColumn)
                : base(trivia.GetStructure()!)
            {
                Contract.ThrowIfFalse(trivia.HasStructure);
 
                _trivia = trivia;
 
                var root = trivia.GetStructure()!;
                var text = GetText();
 
                _initialColumn = initialColumn;
                _treeData = (text == null) ? new Node(root) : new NodeAndText(root, text);
            }
 
            public override string GetTextBetween(SyntaxToken token1, SyntaxToken token2)
                => _treeData.GetTextBetween(token1, token2);
 
            public override int GetOriginalColumn(int tabSize, SyntaxToken token)
            {
                if (_treeData is NodeAndText)
                {
                    return _treeData.GetOriginalColumn(tabSize, token);
                }
 
                var text = _trivia.ToFullString()[..(token.SpanStart - _trivia.FullSpan.Start)];
 
                return text.GetTextColumn(tabSize, _initialColumn);
            }
 
            private SourceText? GetText()
            {
                var root = _trivia.GetStructure()!;
                if (root.SyntaxTree != null && root.SyntaxTree.GetText() != null)
                {
                    return root.SyntaxTree.GetText();
                }
 
                var parent = _trivia.Token.Parent;
                if (parent != null && parent.SyntaxTree != null && parent.SyntaxTree.GetText() != null)
                {
                    return parent.SyntaxTree.GetText();
                }
 
                return null;
            }
        }
    }
}