// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
namespace Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2;
 
/// <summary>
/// Represents an HTTP/2 frame. The expected use pattern is that it will be instantiated once
/// and then, each time a frame is received or sent, it is reset with a PrepareX method.
/// This type is not responsible for binary serialization or deserialization.
/// </summary>
/// <remarks>
/// From https://tools.ietf.org/html/rfc7540#section-4.1:
///    +-----------------------------------------------+
///    |                 Length (24)                   |
///    +---------------+---------------+---------------+
///    |   Type (8)    |   Flags (8)   |
///    +-+-------------+---------------+-------------------------------+
///    |R|                 Stream Identifier (31)                      |
///    +=+=============================================================+
///    |                   Frame Payload (0...)                      ...
///    +---------------------------------------------------------------+
/// </remarks>
internal partial class Http2Frame
{
    public int PayloadLength { get; set; }
 
    public Http2FrameType Type { get; set; }
 
    public byte Flags { get; set; }
 
    public int StreamId { get; set; }
 
    internal object ShowFlags()
    {
        switch (Type)
        {
            case Http2FrameType.CONTINUATION:
                return ContinuationFlags;
            case Http2FrameType.DATA:
                return DataFlags;
            case Http2FrameType.HEADERS:
                return HeadersFlags;
            case Http2FrameType.SETTINGS:
                return SettingsFlags;
            case Http2FrameType.PING:
                return PingFlags;
 
            // Not Implemented
            case Http2FrameType.PUSH_PROMISE:
 
            // No flags defined
            case Http2FrameType.PRIORITY:
            case Http2FrameType.RST_STREAM:
            case Http2FrameType.GOAWAY:
            case Http2FrameType.WINDOW_UPDATE:
            default:
                return $"0x{Flags:x}";
        }
    }
 
    public override string ToString()
    {
        return $"{Type} Stream: {StreamId} Length: {PayloadLength} Flags: {ShowFlags()}";
    }
}