package frame

import (
	coder "git.hpds.cc/Component/mq_coder"
)

// HandshakeAckFrame is used to ack handshake, It is always that the first frame
// is HandshakeAckFrame after client acquire a new stream.
// HandshakeAckFrame is a coder encoded bytes.
type HandshakeAckFrame struct {
	streamId string
}

// NewHandshakeAckFrame returns a HandshakeAckFrame.
func NewHandshakeAckFrame(streamId string) *HandshakeAckFrame {
	return &HandshakeAckFrame{streamId}
}

// Type gets the type of the HandshakeAckFrame.
func (f *HandshakeAckFrame) Type() Type {
	return TagOfHandshakeAckFrame
}

// StreamId returns the id of stream be acked.
func (f *HandshakeAckFrame) StreamId() string {
	return f.streamId
}

// Encode encodes HandshakeAckFrame to coder encoded bytes.
func (f *HandshakeAckFrame) Encode() []byte {
	ack := coder.NewNodePacketEncoder(byte(f.Type()))
	// streamId
	streamIDBlock := coder.NewPrimitivePacketEncoder(byte(TagOfHandshakeAckStreamId))
	streamIDBlock.SetStringValue(f.streamId)

	ack.AddPrimitivePacket(streamIDBlock)

	return ack.Encode()
}

// DecodeToHandshakeAckFrame decodes coder encoded bytes to HandshakeAckFrame
func DecodeToHandshakeAckFrame(buf []byte) (*HandshakeAckFrame, error) {
	node := coder.NodePacket{}
	_, err := coder.DecodeToNodePacket(buf, &node)
	if err != nil {
		return nil, err
	}

	ack := &HandshakeAckFrame{}
	// streamID
	if streamIDBlock, ok := node.PrimitivePackets[byte(TagOfHandshakeAckStreamId)]; ok {
		streamId, err := streamIDBlock.ToUTF8String()
		if err != nil {
			return nil, err
		}
		ack.streamId = streamId
	}
	return ack, nil
}