package node

import (
	"net"
	"net/netip"
	"net/url"
	"sync/atomic"
	"time"
)

const (
	bufferSize            = 1536
	if_mtu                = 1200
	if_queue_len          = 2048
	controlCipherOverhead = 16
	dataCipherOverhead    = 16
	signOverhead          = 64
)

var (
	multicastIP   = netip.AddrFrom4([4]byte{224, 0, 0, 157})
	multicastAddr = net.UDPAddrFromAddrPort(netip.AddrPortFrom(multicastIP, 4560))
)

type peerRoute struct {
	IP            byte
	Up            bool // True if data can be sent on the route.
	Relay         bool // True if the peer is a relay.
	Direct        bool // True if this is a direct connection.
	PubSignKey    []byte
	ControlCipher *controlCipher
	DataCipher    *dataCipher
	RemoteAddr    netip.AddrPort // Remote address if directly connected.
}

var (
	hubURL *url.URL
	apiKey string

	// Configuration for this peer.
	netName     string
	localIP     byte
	localPub    bool
	localAddr   netip.AddrPort
	privKey     []byte
	privSignKey []byte

	// Shared interface for writing.
	_iface *ifWriter

	// Shared connection for writing.
	_conn *connWriter

	// Counters for sending to each peer.
	sendCounters [256]uint64 = func() (out [256]uint64) {
		for i := range out {
			out[i] = uint64(time.Now().Unix()<<30 + 1)
		}
		return
	}()

	// Duplicate checkers for incoming packets.
	dupChecks [256]*dupCheck = func() (out [256]*dupCheck) {
		for i := range out {
			out[i] = newDupCheck(0)
		}
		return
	}()

	// Messages for the supervisor.
	messages = make(chan any, 512)

	// Global routing table.
	routingTable [256]*atomic.Pointer[peerRoute] = func() (out [256]*atomic.Pointer[peerRoute]) {
		for i := range out {
			out[i] = &atomic.Pointer[peerRoute]{}
			out[i].Store(&peerRoute{})
		}
		return
	}()

	// Managed by the relayManager.
	relayIP = &atomic.Pointer[byte]{}

	publicAddrs = newPubAddrStore()
)