// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Diagnostics;
 
namespace System.Text.Json.Serialization.Converters
{
    internal sealed class StringConverter : JsonPrimitiveConverter<string?>
    {
        public override string? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        {
            return reader.GetString();
        }
 
        public override void Write(Utf8JsonWriter writer, string? value, JsonSerializerOptions options)
        {
            // For performance, lift up the writer implementation.
            if (value == null)
            {
                writer.WriteNullValue();
            }
            else
            {
                writer.WriteStringValue(value.AsSpan());
            }
        }
 
        internal override string ReadAsPropertyNameCore(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        {
            Debug.Assert(reader.TokenType == JsonTokenType.PropertyName);
            return reader.GetString()!;
        }
 
        internal override void WriteAsPropertyNameCore(Utf8JsonWriter writer, string value, JsonSerializerOptions options, bool isWritingExtensionDataProperty)
        {
            if (value is null)
            {
                ThrowHelper.ThrowArgumentNullException(nameof(value));
            }
 
            if (options.DictionaryKeyPolicy != null && !isWritingExtensionDataProperty)
            {
                value = options.DictionaryKeyPolicy.ConvertName(value);
 
                if (value == null)
                {
                    ThrowHelper.ThrowInvalidOperationException_NamingPolicyReturnNull(options.DictionaryKeyPolicy);
                }
            }
 
            writer.WritePropertyName(value);
        }
    }
}