// peer.go — Peer agent management.
//
// # Capability-Based Peer Access
//
// Peers implement the namespace-bounded capability model for inter-agent
// communication. An agent can only message agents that exist in its peer
// list—the peer/ directory is dynamically generated from this list.
//
// The enforcement point is in fs/spec.go: the peer/ directory is built via
// virtfs.Each(a.Peers()), so only declared peers appear as writable files.
// If agent A tries to write to peer/B but B is not in A's peer list, the
// file simply doesn't exist.
//
// This is structural enforcement: the directory listing IS the capability
// set. An agent cannot reference a peer that isn't in its namespace.
//
// Links are bidirectional: adding a peer on one agent adds the reverse link.
// This ensures both sides explicitly consent to the communication channel.

package agent

import "slices"

// AddPeer adds a peer agent by name.
func (ag *Agent) AddPeer(name string) {
	ag.peerMu.Lock()
	if ag.peers == nil {
		ag.peers = make(map[string]struct{})
	}
	ag.peers[name] = struct{}{}
	ag.peerMu.Unlock()
}

// RemovePeer removes a peer agent by name.
func (ag *Agent) RemovePeer(name string) {
	ag.peerMu.Lock()
	delete(ag.peers, name)
	ag.peerMu.Unlock()
}

// Peers returns the sorted list of peer agent names.
func (ag *Agent) Peers() []string {
	ag.peerMu.RLock()
	defer ag.peerMu.RUnlock()
	out := make([]string, 0, len(ag.peers))
	for name := range ag.peers {
		out = append(out, name)
	}
	slices.Sort(out)
	return out
}