// 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.Collections.Generic;
using System.Threading;
using Microsoft.CodeAnalysis.Diagnostics;
using Microsoft.CodeAnalysis.Text;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.Formatting
{
    internal abstract partial class AbstractTriviaDataFactory
    {
        protected class FormattedWhitespace : TriviaData
        {
            private readonly string _newString;
 
            public FormattedWhitespace(SyntaxFormattingOptions options, int lineBreaks, int indentation, string language)
                : base(options, language)
            {
                this.LineBreaks = Math.Max(0, lineBreaks);
                this.Spaces = Math.Max(0, indentation);
 
                _newString = CreateString(Options.NewLine);
            }
 
            private string CreateString(string newLine)
            {
                if (this.SecondTokenIsFirstTokenOnLine)
                {
                    var builder = StringBuilderPool.Allocate();
                    for (var i = 0; i < LineBreaks; i++)
                    {
                        builder.Append(newLine);
                    }
 
                    builder.AppendIndentationString(Spaces, Options.UseTabs, Options.TabSize);
                    return StringBuilderPool.ReturnAndFree(builder);
                }
 
                // space case. always use space
                return new string(' ', Spaces);
            }
 
            public override bool TreatAsElastic => false;
 
            public override bool IsWhitespaceOnlyTrivia => true;
 
            public override bool ContainsChanges => true;
 
            public override IEnumerable<TextChange> GetTextChanges(TextSpan textSpan)
                => SpecializedCollections.SingletonEnumerable<TextChange>(new TextChange(textSpan, _newString));
 
            public override TriviaData WithSpace(int space, FormattingContext context, ChainedFormattingRules formattingRules)
                => throw new NotImplementedException();
 
            public override TriviaData WithLine(int line, int indentation, FormattingContext context, ChainedFormattingRules formattingRules, CancellationToken cancellationToken)
                => throw new NotImplementedException();
 
            public override TriviaData WithIndentation(int indentation, FormattingContext context, ChainedFormattingRules formattingRules, CancellationToken cancellationToken)
                => throw new NotImplementedException();
 
            public override void Format(
                FormattingContext context, ChainedFormattingRules formattingRules, Action<int, TokenStream, TriviaData> formattingResultApplier, CancellationToken cancellationToken, int tokenPairIndex = TokenPairIndexNotNeeded)
            {
                throw new NotImplementedException();
            }
        }
    }
}