#if (!UNITY_WEBGL || UNITY_EDITOR) && !BESTHTTP_DISABLE_ALTERNATE_SSL

using System;
using System.Collections.Generic;

using Best.HTTP.Shared.Extensions;
using Best.HTTP.Shared.PlatformSupport.Memory;
using Best.HTTP.Shared.PlatformSupport.Text;

namespace Best.HTTP.Hosts.Connections.HTTP2
{
    // https://httpwg.org/specs/rfc7540.html#iana-frames
    public enum HTTP2FrameTypes : byte
    {
        DATA = 0x00,
        HEADERS = 0x01,
        PRIORITY = 0x02,
        RST_STREAM = 0x03,
        SETTINGS = 0x04,
        PUSH_PROMISE = 0x05,
        PING = 0x06,
        GOAWAY = 0x07,
        WINDOW_UPDATE = 0x08,
        CONTINUATION = 0x09,

        // https://tools.ietf.org/html/rfc7838#section-4
        ALT_SVC = 0x0A
    }

    [Flags]
    public enum HTTP2DataFlags : byte
    {
        None = 0x00,
        END_STREAM = 0x01,
        PADDED = 0x08,
    }

    [Flags]
    public enum HTTP2HeadersFlags : byte
    {
        None = 0x00,
        END_STREAM = 0x01,
        END_HEADERS = 0x04,
        PADDED = 0x08,
        PRIORITY = 0x20,
    }

    [Flags]
    public enum HTTP2SettingsFlags : byte
    {
        None = 0x00,
        ACK = 0x01,
    }

    [Flags]
    public enum HTTP2PushPromiseFlags : byte
    {
        None = 0x00,
        END_HEADERS = 0x04,
        PADDED = 0x08,
    }

    [Flags]
    public enum HTTP2PingFlags : byte
    {
        None = 0x00,
        ACK = 0x01,
    }

    [Flags]
    public enum HTTP2ContinuationFlags : byte
    {
        None = 0x00,
        END_HEADERS = 0x04,
    }

    public struct HTTP2FrameHeaderAndPayload
    {
        public HTTP2FrameTypes Type;
        public byte Flags;
        public UInt32 StreamId;

        //public byte[] Payload;
        public BufferSegment Payload;

        //public UInt32 PayloadOffset;
        //public UInt32 PayloadLength;

        public bool DontUseMemPool;

        public override string ToString()
        {
            return $"[HTTP2FrameHeaderAndPayload Type: {Type}, Flags: {Flags.ToBinaryStr()}, StreamId: {StreamId}, DontUseMemPool: {DontUseMemPool}, Payload: {Payload}]";
        }

        public string PayloadAsHex() => this.Payload.ToString();
    }

    public struct HTTP2SettingsFrame
    {
        public readonly HTTP2FrameHeaderAndPayload Header;
        public HTTP2SettingsFlags Flags { get { return (HTTP2SettingsFlags)this.Header.Flags; } }
        public List<KeyValuePair<HTTP2Settings, UInt32>> Settings;

        public HTTP2SettingsFrame(HTTP2FrameHeaderAndPayload header)
        {
            this.Header = header;
            this.Settings = null;
        }

        public override string ToString()
        {
            string settings = null;
            if (this.Settings != null)
            {
                System.Text.StringBuilder sb = StringBuilderPool.Get(this.Settings.Count + 2);

                sb.Append("[");
                foreach (var kvp in this.Settings)
                    sb.AppendFormat("[{0}: {1}]", kvp.Key, kvp.Value);
                sb.Append("]");

                settings = StringBuilderPool.ReleaseAndGrab(sb);
            }

            return string.Format("[HTTP2SettingsFrame Header: {0}, Flags: {1}, Settings: {2}]", this.Header.ToString(), this.Flags, settings ?? "Empty");
        }
    }

    public struct HTTP2DataFrame
    {
        public readonly HTTP2FrameHeaderAndPayload Header;
        public HTTP2DataFlags Flags { get { return (HTTP2DataFlags)this.Header.Flags; } }

        public byte? PadLength;

        public BufferSegment Data;

        public HTTP2DataFrame(HTTP2FrameHeaderAndPayload header)
        {
            this.Header = header;
            this.PadLength = null;
            this.Data = BufferSegment.Empty;
        }

        public override string ToString()
        {
            return string.Format("[HTTP2DataFrame Header: {0}, Flags: {1}, PadLength: {2}, Data: {3}]",
                this.Header.ToString(),
                this.Flags,
                this.PadLength == null ? ":Empty" : this.PadLength.Value.ToString(),
                this.Data.ToString());
        }
    }

    public struct HTTP2HeadersFrame
    {
        public readonly HTTP2FrameHeaderAndPayload Header;
        public HTTP2HeadersFlags Flags { get { return (HTTP2HeadersFlags)this.Header.Flags; } }

        public byte? PadLength;
        public byte? IsExclusive;
        public UInt32? StreamDependency;
        public byte? Weight;

        public BufferSegment HeaderBlockFragment;

        public HTTP2HeadersFrame(HTTP2FrameHeaderAndPayload header)
        {
            this.Header = header;
            this.PadLength = null;
            this.IsExclusive = null;
            this.StreamDependency = null;
            this.Weight = null;
            this.HeaderBlockFragment = BufferSegment.Empty;
        }

        public override string ToString()
        {
            return string.Format("[HTTP2HeadersFrame Header: {0}, Flags: {1}, PadLength: {2}, IsExclusive: {3}, StreamDependency: {4}, Weight: {5}, HeaderBlockFragmentLength: {6}]",
                this.Header.ToString(),
                this.Flags,
                this.PadLength == null ? ":Empty" : this.PadLength.Value.ToString(),
                this.IsExclusive == null ? "Empty" : this.IsExclusive.Value.ToString(),
                this.StreamDependency == null ? "Empty" : this.StreamDependency.Value.ToString(),
                this.Weight == null ? "Empty" : this.Weight.Value.ToString(),
                this.HeaderBlockFragment.ToString());
        }
    }

    public struct HTTP2PriorityFrame
    {
        public readonly HTTP2FrameHeaderAndPayload Header;

        public byte IsExclusive;
        public UInt32 StreamDependency;
        public byte Weight;

        public HTTP2PriorityFrame(HTTP2FrameHeaderAndPayload header)
        {
            this.Header = header;
            this.IsExclusive = 0;
            this.StreamDependency = 0;
            this.Weight = 0;
        }

        public override string ToString()
        {
            return string.Format("[HTTP2PriorityFrame Header: {0}, IsExclusive: {1}, StreamDependency: {2}, Weight: {3}]",
                this.Header.ToString(), this.IsExclusive, this.StreamDependency, this.Weight);
        }
    }

    public struct HTTP2RSTStreamFrame
    {
        public readonly HTTP2FrameHeaderAndPayload Header;

        public UInt32 ErrorCode;
        public HTTP2ErrorCodes Error { get { return (HTTP2ErrorCodes)this.ErrorCode; } }

        public HTTP2RSTStreamFrame(HTTP2FrameHeaderAndPayload header)
        {
            this.Header = header;
            this.ErrorCode = 0;
        }

        public override string ToString()
        {
            return string.Format("[HTTP2RST_StreamFrame Header: {0}, Error: {1}({2})]", this.Header.ToString(), this.Error, this.ErrorCode);
        }
    }

    public struct HTTP2PushPromiseFrame
    {
        public readonly HTTP2FrameHeaderAndPayload Header;
        public HTTP2PushPromiseFlags Flags { get { return (HTTP2PushPromiseFlags)this.Header.Flags; } }

        public byte? PadLength;
        public byte ReservedBit;
        public UInt32 PromisedStreamId;

        public BufferSegment HeaderBlockFragment;
        //public UInt32 HeaderBlockFragmentIdx;
        //public byte[] HeaderBlockFragment;
        //public UInt32 HeaderBlockFragmentLength;

        public HTTP2PushPromiseFrame(HTTP2FrameHeaderAndPayload header)
        {
            this.Header = header;
            this.PadLength = null;
            this.ReservedBit = 0;
            this.PromisedStreamId = 0;
            //this.HeaderBlockFragmentIdx = 0;
            //this.HeaderBlockFragment = null;
            //this.HeaderBlockFragmentLength = 0;
            this.HeaderBlockFragment = BufferSegment.Empty;
        }

        public override string ToString()
        {
            return string.Format("[HTTP2Push_PromiseFrame Header: {0}, Flags: {1}, PadLength: {2}, ReservedBit: {3}, PromisedStreamId: {4}, HeaderBlockFragmentLength: {5}]",
                this.Header.ToString(),
                this.Flags,
                this.PadLength == null ? "Empty" : this.PadLength.Value.ToString(),
                this.ReservedBit,
                this.PromisedStreamId,
                this.HeaderBlockFragment);
        }
    }

    public struct HTTP2PingFrame
    {
        public readonly HTTP2FrameHeaderAndPayload Header;
        public HTTP2PingFlags Flags { get { return (HTTP2PingFlags)this.Header.Flags; } }

        //public readonly byte[] OpaqueData;
        //public readonly byte OpaqueDataLength;
        public readonly BufferSegment OpaqueData;

        public HTTP2PingFrame(HTTP2FrameHeaderAndPayload header)
        {
            this.Header = header;
            this.OpaqueData = BufferPool.Get(8, true).AsBuffer(8);
        }

        public override string ToString()
        {
            return string.Format("[HTTP2PingFrame Header: {0}, Flags: {1}, OpaqueData: {2}]",
                this.Header.ToString(),
                this.Flags,
                this.OpaqueData);
        }
    }

    public struct HTTP2GoAwayFrame
    {
        public readonly HTTP2FrameHeaderAndPayload Header;
        public HTTP2ErrorCodes Error { get { return (HTTP2ErrorCodes)this.ErrorCode; } }

        public byte ReservedBit;
        public UInt32 LastStreamId;
        public UInt32 ErrorCode;

        public BufferSegment AdditionalDebugData;
        //public byte[] AdditionalDebugData;
        //public UInt32 AdditionalDebugDataLength;

        public HTTP2GoAwayFrame(HTTP2FrameHeaderAndPayload header)
        {
            this.Header = header;
            this.ReservedBit = 0;
            this.LastStreamId = 0;
            this.ErrorCode = 0;
            this.AdditionalDebugData = BufferSegment.Empty;
        }

        public override string ToString()
        {
            return string.Format("[HTTP2GoAwayFrame Header: {0}, ReservedBit: {1}, LastStreamId: {2}, Error: {3}({4}), AdditionalDebugData: {5}]",
                this.Header.ToString(),
                this.ReservedBit,
                this.LastStreamId,
                this.Error,
                this.ErrorCode,
                this.AdditionalDebugData.ToString());
        }
    }

    public struct HTTP2WindowUpdateFrame
    {
        public readonly HTTP2FrameHeaderAndPayload Header;

        public byte ReservedBit;
        public UInt32 WindowSizeIncrement;

        public HTTP2WindowUpdateFrame(HTTP2FrameHeaderAndPayload header)
        {
            this.Header = header;
            this.ReservedBit = 0;
            this.WindowSizeIncrement = 0;
        }

        public override string ToString()
        {
            return string.Format("[HTTP2WindowUpdateFrame Header: {0}, ReservedBit: {1}, WindowSizeIncrement: {2}]",
                this.Header.ToString(), this.ReservedBit, this.WindowSizeIncrement);
        }
    }

    public struct HTTP2ContinuationFrame
    {
        public readonly HTTP2FrameHeaderAndPayload Header;

        public HTTP2ContinuationFlags Flags { get { return (HTTP2ContinuationFlags)this.Header.Flags; } }

        public BufferSegment HeaderBlockFragment;
        
        public HTTP2ContinuationFrame(HTTP2FrameHeaderAndPayload header)
        {
            this.Header = header;
            this.HeaderBlockFragment = BufferSegment.Empty;
        }

        public override string ToString()
        {
            return string.Format("[HTTP2ContinuationFrame Header: {0}, Flags: {1}, HeaderBlockFragment: {2}]",
                this.Header.ToString(),
                this.Flags,
                this.HeaderBlockFragment);
        }
    }

    /// <summary>
    /// https://tools.ietf.org/html/rfc7838#section-4
    /// </summary>
    public struct HTTP2AltSVCFrame
    {
        public readonly HTTP2FrameHeaderAndPayload Header;

        public string Origin;
        public string AltSvcFieldValue;

        public HTTP2AltSVCFrame(HTTP2FrameHeaderAndPayload header)
        {
            this.Header = header;
            this.Origin = null;
            this.AltSvcFieldValue = null;
        }
    }
}

#endif