package transport

import (
	"encoding/binary"
	"net"
	"ripple/crypto"
	"ripple/types"
	"ripple/udpr"
)

type UserTransport struct {
	d *Data
	c *udpr.UDPRConn
	w *userSenderWorker
}

func NewUserTransport(c *udpr.UDPRConn, d *Data) *UserTransport {
	t := &UserTransport{d: d, c: c}
	t.w = newUserSenderWorker(t)
	return t
}

func (t *UserTransport) Receive(data []byte, addr *net.UDPAddr) (types.UserRequest, error) {
	if len(data) < 6+32 {
		return types.UserRequest{}, errInvalidUserRequest
	}
	if !crypto.VerifySignature(data, t.d.Storage.User.SecretKey) {
		return types.UserRequest{}, errInvalidUserRequest
	}
	counter := binary.BigEndian.Uint32(data[1:5])
	if counter <= t.d.Storage.User.Counter {
		return types.UserRequest{}, errInvalidUserRequest
	}
	if err := t.d.setUserCounter(counter); err != nil {
		return types.UserRequest{}, err
	}
	cmd := data[5]
	args := data[6 : len(data)-32]
	return types.UserRequest{
		Remote: types.ClientRemote{Addr: addr, Counter: counter},
		Instruction: types.Instruction{Command: cmd, Arguments: args},
	}, nil
}

func (t *UserTransport) send(req types.UserRequest) {
	buf := make([]byte, 5+len(req.Instruction.Arguments))
	binary.BigEndian.PutUint32(buf[0:4], req.Remote.Counter)
	buf[4] = req.Instruction.Command
	copy(buf[5:], req.Instruction.Arguments)
	signed := crypto.SignData(buf, t.d.Storage.User.SecretKey)
	_ = t.c.WriteToUDPR(signed, req.Remote.Addr)
}

func (t *UserTransport) Send(req types.UserRequest) {
	t.w.enqueue(req)
}