feat: show when there is an active huddle

This introduces a webhook which listens to events from livekit and
updates our firestore stream particle. It keeps the client simple,
reacting to changes to firestore docs.

go/internal/livekit/client.go

@@ -1,29 +1,47 @@
 package livekit
 
 import (
+	"context"
 	"time"
 
 	"github.com/flowy-live/llink/internal/utils"
 	"github.com/livekit/protocol/auth"
+	"github.com/livekit/protocol/livekit"
+	lksdk "github.com/livekit/server-sdk-go/v2"
 )
 
 type Client interface {
-	// Name will show up in the participant data
+	// GetJoinToken generates a JWT for a participant to join a room.
+	// Name will show up in the participant data.
 	GetJoinToken(roomId string, humanId string, name string) (string, error)
 	ServerUrl() string
+	// ListParticipants returns the current participants in a room.
+	ListParticipants(ctx context.Context, roomName string) ([]*livekit.ParticipantInfo, error)
+	// KeyProvider returns the key provider for verifying webhook signatures.
+	KeyProvider() auth.KeyProvider
 }
 
 type clientImpl struct {
-	apiSecret string
-	apiKey    string
-	hostUrl   string
+	apiSecret   string
+	apiKey      string
+	hostUrl     string
+	roomService *lksdk.RoomServiceClient
+	keyProvider auth.KeyProvider
 }
 
 func NewClient() Client {
+	apiKey := utils.MustGetEnv("LIVEKIT_API_KEY")
+	apiSecret := utils.MustGetEnv("LIVEKIT_API_SECRET")
+	hostUrl := utils.MustGetEnv("LIVEKIT_URL")
+
+	roomService := lksdk.NewRoomServiceClient(hostUrl, apiKey, apiSecret)
+
 	return &clientImpl{
-		apiSecret: utils.MustGetEnv("LIVEKIT_API_SECRET"),
-		apiKey:    utils.MustGetEnv("LIVEKIT_API_KEY"),
-		hostUrl:   utils.MustGetEnv("LIVEKIT_URL"),
+		apiSecret:   apiSecret,
+		apiKey:      apiKey,
+		hostUrl:     hostUrl,
+		roomService: roomService,
+		keyProvider: auth.NewSimpleKeyProvider(apiKey, apiSecret),
 	}
 }
 
@@ -44,3 +62,17 @@ func (c *clientImpl) GetJoinToken(room, humanId, name string) (string, error) {
 
 	return at.ToJWT()
 }
+
+func (c *clientImpl) ListParticipants(ctx context.Context, roomName string) ([]*livekit.ParticipantInfo, error) {
+	resp, err := c.roomService.ListParticipants(ctx, &livekit.ListParticipantsRequest{
+		Room: roomName,
+	})
+	if err != nil {
+		return nil, err
+	}
+	return resp.Participants, nil
+}
+
+func (c *clientImpl) KeyProvider() auth.KeyProvider {
+	return c.keyProvider
+}