package wire

import (
	"io"
	
	"github.com/p9c/p9/pkg/chainhash"
)

// MsgGetCFCheckpt is a request for filter headers at evenly spaced intervals throughout the blockchain history. It
// allows to set the FilterType field to get headers in the chain of basic (0x00) or extended (0x01) headers.
type MsgGetCFCheckpt struct {
	FilterType FilterType
	StopHash   chainhash.Hash
}

// BtcDecode decodes r using the bitcoin protocol encoding into the receiver. This is part of the Message interface
// implementation.
func (msg *MsgGetCFCheckpt) BtcDecode(r io.Reader, pver uint32, _ MessageEncoding) (e error) {
	if e = readElement(r, &msg.FilterType); E.Chk(e) {
		return
	}
	return readElement(r, &msg.StopHash)
}

// BtcEncode encodes the receiver to w using the bitcoin protocol encoding. This
// is part of the Message interface implementation.
func (msg *MsgGetCFCheckpt) BtcEncode(w io.Writer, pver uint32, _ MessageEncoding) (e error) {
	if e = writeElement(w, msg.FilterType); E.Chk(e) {
		return
	}
	return writeElement(w, &msg.StopHash)
}

// Command returns the protocol command string for the message. This is part of
// the Message interface implementation.
func (msg *MsgGetCFCheckpt) Command() string {
	return CmdGetCFCheckpt
}

// MaxPayloadLength returns the maximum length the payload can be for the
// receiver. This is part of the Message interface implementation.
func (msg *MsgGetCFCheckpt) MaxPayloadLength(pver uint32) uint32 {
	// Filter type + uint32 + block hash
	return 1 + chainhash.HashSize
}

// NewMsgGetCFCheckpt returns a new bitcoin getcfcheckpt message that conforms
// to the Message interface using the passed parameters and defaults for the
// remaining fields.
func NewMsgGetCFCheckpt(filterType FilterType, stopHash *chainhash.Hash) *MsgGetCFCheckpt {
	return &MsgGetCFCheckpt{
		FilterType: filterType,
		StopHash:   *stopHash,
	}
}