package transport

import(
	"encoding/binary"
	"fmt"
	"net"
	"ripple/types"
)

const (
	accountType = 0
	counterpartType = 2
)

func getAddr(addrStr string, port int) (*net.UDPAddr, error) {
	dest := fmt.Sprintf("%s:%d", addrStr, port)
	return net.ResolveUDPAddr("udp", dest)
}

func parseTxFrom(tx []byte) types.UserIdentifier {
	raw := tx[33:97]
	return types.NewUserIdentifierFromBytes(raw)
}

func buildTx(txType byte, toUsername string, fromID types.UserIdentifier, counter uint32, instr types.Instruction) []byte {
	buf := make([]byte, 102+len(instr.Arguments))
	buf[0] = txType
	copy(buf[1:33], []byte(toUsername))
	copy(buf[33:65], []byte(fromID.Username))
	copy(buf[65:97], []byte(fromID.ServerAddress))
	binary.BigEndian.PutUint32(buf[97:101], counter)
	buf[101] = instr.Command
	copy(buf[102:], instr.Arguments)
	return buf
}