Make client an interface for mocks

Author: galt-tr

client.go

@@ -24,6 +24,9 @@ import (
 	"github.com/multiformats/go-multiaddr"
 )
 
+// Compile-time check to ensure Client implements P2PClient interface
+var _ P2PClient = (*Client)(nil)
+
 // Client represents a P2P messaging client.
 type Client struct {
 	config      Config
@@ -43,7 +46,7 @@ type Client struct {
 
 // NewClient creates and initializes a new P2P client.
 // It automatically starts the client and begins peer discovery.
-func NewClient(config Config) (*Client, error) {
+func NewClient(config Config) (P2PClient, error) {
 	if config.Name == "" {
 		return nil, fmt.Errorf("config.Name is required")
 	}

types.go

@@ -1,12 +1,32 @@
 package p2p
 
 import (
+	"context"
 	"sync"
 	"time"
 
 	"github.com/libp2p/go-libp2p/core/peer"
 )
 
+// P2PClient defines the interface for a P2P messaging client.
+type P2PClient interface {
+	// Subscribe subscribes to a topic and returns a channel that will receive messages.
+	// The returned channel will be closed when the client is closed.
+	Subscribe(topic string) <-chan Message
+
+	// Publish publishes a message to the specified topic.
+	Publish(ctx context.Context, topic string, data []byte) error
+
+	// GetPeers returns information about all known peers on subscribed topics.
+	GetPeers() []PeerInfo
+
+	// GetID returns this peer's ID as a string.
+	GetID() string
+
+	// Close shuts down the client and releases all resources.
+	Close() error
+}
+
 // Message represents a received message from a peer.
 type Message struct {
 	Topic     string    // The topic this message was received on