package transport

import (
	"encoding/binary"
	"net"

	"ripple/crypto"
	"ripple/types"
	"ripple/udpr"
)

type CounterpartTransport struct {
	d *Data
	c *udpr.UDPRConn
}

func NewCounterpartTransport(c *udpr.UDPRConn, d *Data) *CounterpartTransport {
	return &CounterpartTransport{d: d, c: c}
}

func (t *CounterpartTransport) Receive(tx []byte, addr *net.UDPAddr) (types.Instruction, error) {
	if len(tx) < 1+32+64+4+1+32 {
		return types.Instruction{}, errInvalidTransaction
	}
	if t.d.Memory.Counterpart.Identifier != parseTxFrom(tx) {
		return types.Instruction{}, errInvalidTransaction
	}
	if !crypto.VerifySignature(tx, t.d.Memory.Counterpart.SecretKey) {
		return types.Instruction{}, errInvalidTransaction
	}
	counter := binary.BigEndian.Uint32(tx[97:101])
	if counter <= t.d.Memory.Counterpart.CounterIn {
		return types.Instruction{}, errInvalidTransaction
	}
	t.d.Memory.Counterpart.CounterIn = counter
	cmd := tx[101]
	args := tx[102 : len(tx)-32]
	return types.Instruction{Command: cmd, Arguments: args}, nil
}

func (t *CounterpartTransport) Send(instr types.Instruction) {
	t.d.Memory.Counterpart.CounterOut++
	counter := t.d.Memory.Counterpart.CounterOut
	id := t.d.Memory.Counterpart.Identifier
	raw := buildTx(
		counterpartType,
		id.Username,
		t.d.Storage.User.UserIdentifier,
		counter,
		instr,
	)
	tx := crypto.SignData(raw, t.d.Memory.Counterpart.SecretKey)
	addr, err := getAddr(id.ServerAddress, t.d.Memory.Counterpart.Port)
	if err != nil {
		return
	}
	go t.c.WriteToUDPR(tx, addr)
}