// 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.Net.Http.Headers
{
    internal sealed class MediaTypeHeaderParser : BaseHeaderParser
    {
        private readonly Func<MediaTypeHeaderValue> _mediaTypeCreator;

        internal static readonly MediaTypeHeaderParser SingleValueParser = new MediaTypeHeaderParser(false, CreateMediaType);
        internal static readonly MediaTypeHeaderParser SingleValueWithQualityParser = new MediaTypeHeaderParser(false, CreateMediaTypeWithQuality);
        internal static readonly MediaTypeHeaderParser MultipleValuesParser = new MediaTypeHeaderParser(true, CreateMediaTypeWithQuality);

        private MediaTypeHeaderParser(bool supportsMultipleValues, Func<MediaTypeHeaderValue> mediaTypeCreator)
            : base(supportsMultipleValues)
        {
            Debug.Assert(mediaTypeCreator != null);
            _mediaTypeCreator = mediaTypeCreator;
        }

        protected override int GetParsedValueLength(string? value, int startIndex, object? storeValue,
            out object? parsedValue)
        {
            int resultLength = MediaTypeHeaderValue.GetMediaTypeLength(value, startIndex, _mediaTypeCreator, out MediaTypeHeaderValue? temp);

            parsedValue = temp;
            return resultLength;
        }

        private static MediaTypeHeaderValue CreateMediaType() => new MediaTypeHeaderValue();

        private static MediaTypeWithQualityHeaderValue CreateMediaTypeWithQuality() => new MediaTypeWithQualityHeaderValue();
    }
}