// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Text;

namespace Microsoft.AspNetCore.Rewrite.PatternSegments;

internal sealed class ToLowerSegment : PatternSegment
{
    private readonly Pattern _pattern;

    public ToLowerSegment(Pattern pattern)
    {
        _pattern = pattern;
    }

    public override string? Evaluate(RewriteContext context, BackReferenceCollection? ruleBackReferences, BackReferenceCollection? conditionBackReferences)
    {
        // PERF as we share the string builder across the context, we need to make a new one here to evaluate
        // lowercase segments.
        var tempBuilder = context.Builder;
        context.Builder = new StringBuilder(64);
        var pattern = _pattern.Evaluate(context, ruleBackReferences, conditionBackReferences);
        context.Builder = tempBuilder;
        return pattern.ToLowerInvariant();
    }
}