package peer

import (
	"log"
	"net/netip"
	"time"

	"vppn/peer/control"
	"vppn/peer/wginterface"
)

func (a *App) onTick() {
	wgPeers := a.devPeers()

	now := time.Now().UnixNano()

	for _, wgPeer := range wgPeers {
		p, ok := a.peersByKey[wgPeer.PublicKey]
		if !ok {
			log.Printf("Wireguard peer not known. Removing: %v", wgPeer.PublicKey)
			a.devRemove(&Peer{wgPeer: wgPeer})
			continue
		}

		p.wgPeer = wgPeer

		// Log endpoint changes.
		if ep := p.WGEndpoint(); ep != p.EndpointWG {
			log.Printf("Client %s %s endpoint: %s -> %s", p.Name, p.VPNIP, p.EndpointWG, ep)
			p.EndpointWG = ep
		}

		// Send pings to peers where we're the client.
		if p.Role == control.Client {
			a.sendPing(p, now)
		}

		switch p.State {
		case StateRelayed:
			// If we have an ep to probe, add it.
			if ep := p.PreferredEndpoint(); ep.IsValid() {
				p.ProbeStart = time.Now()
				a.devAddProbe(p, ep)
			}

		case StateProbing:
			if time.Since(p.LastHandshakeTime()) < 2*wginterface.ProbeKeepalive {
				// Promote probing peers to direct once alive (direct path confirmed
				// working).
				a.devPromote(p)
			} else if ep := p.PreferredEndpoint(); ep.IsValid() && ep != p.WGEndpoint() {
				// Update the probe address if it's changed.
				a.devAddProbe(p, ep)
			} else if time.Since(p.ProbeStart) > 8*wginterface.ProbeKeepalive {
				// Give up probing if we haven't been able to handshake.
				p.EndpointV4 = netip.AddrPort{}
				p.EndpointV6 = netip.AddrPort{}
				p.EndpointLAN = netip.AddrPort{}
				a.devAddPeer(p)
			}

		case StateDirect:
			if p.IsPublic || a.isPublic || p.Up() {
				break
			}

			// Stale non-public direct peer: demote to relayed and wait for new IP
			// information.
			p.EndpointV4 = netip.AddrPort{}
			p.EndpointV6 = netip.AddrPort{}
			p.EndpointLAN = netip.AddrPort{}
			a.devAddPeer(p)
		}
	}

	// Ensure we have a live relay (if we're not public).
	if !a.isPublic && (a.relay == nil || !a.relay.Up()) {
		a.switchActiveRelay()
	}
}