add metric endpoint to public API (#72, #80)

internal/app/api/v1/backend/metrics_service.go

@@ -0,0 +1,131 @@
+package backend
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/h44z/wg-portal/internal/config"
+	"github.com/h44z/wg-portal/internal/domain"
+)
+
+type MetricsServiceDatabaseRepo interface {
+	GetPeersStats(ctx context.Context, ids ...domain.PeerIdentifier) ([]domain.PeerStatus, error)
+	GetInterfaceStats(ctx context.Context, id domain.InterfaceIdentifier) (
+		*domain.InterfaceStatus,
+		error,
+	)
+	GetUserPeers(ctx context.Context, id domain.UserIdentifier) ([]domain.Peer, error)
+}
+
+type MetricsServiceUserManagerRepo interface {
+	GetUser(ctx context.Context, id domain.UserIdentifier) (*domain.User, error)
+}
+
+type MetricsServicePeerManagerRepo interface {
+	GetPeer(ctx context.Context, id domain.PeerIdentifier) (*domain.Peer, error)
+}
+
+type MetricsService struct {
+	cfg *config.Config
+
+	db    MetricsServiceDatabaseRepo
+	users MetricsServiceUserManagerRepo
+	peers MetricsServicePeerManagerRepo
+}
+
+func NewMetricsService(
+	cfg *config.Config,
+	db MetricsServiceDatabaseRepo,
+	users MetricsServiceUserManagerRepo,
+	peers MetricsServicePeerManagerRepo,
+) *MetricsService {
+	return &MetricsService{
+		cfg:   cfg,
+		db:    db,
+		users: users,
+		peers: peers,
+	}
+}
+
+func (m MetricsService) GetForInterface(ctx context.Context, id domain.InterfaceIdentifier) (
+	*domain.InterfaceStatus,
+	error,
+) {
+	if !m.cfg.Statistics.CollectInterfaceData {
+		return nil, fmt.Errorf("interface statistics collection is disabled")
+	}
+
+	// validate admin rights
+	if err := domain.ValidateAdminAccessRights(ctx); err != nil {
+		return nil, err
+	}
+
+	interfaceStats, err := m.db.GetInterfaceStats(ctx, id)
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch stats for interface %s: %w", id, err)
+	}
+
+	return interfaceStats, nil
+}
+
+func (m MetricsService) GetForUser(ctx context.Context, id domain.UserIdentifier) (
+	*domain.User,
+	[]domain.PeerStatus,
+	error,
+) {
+	if !m.cfg.Statistics.CollectPeerData {
+		return nil, nil, fmt.Errorf("statistics collection is disabled")
+	}
+
+	if err := domain.ValidateUserAccessRights(ctx, id); err != nil {
+		return nil, nil, err
+	}
+
+	user, err := m.users.GetUser(ctx, id)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	peers, err := m.db.GetUserPeers(ctx, user.Identifier)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to fetch peers for user %s: %w", user.Identifier, err)
+	}
+
+	peerIds := make([]domain.PeerIdentifier, len(peers))
+	for i, peer := range peers {
+		peerIds[i] = peer.Identifier
+	}
+
+	peerStats, err := m.db.GetPeersStats(ctx, peerIds...)
+	if err != nil {
+		return nil, nil, fmt.Errorf("failed to fetch peer stats for user %s: %w", user.Identifier, err)
+	}
+
+	return user, peerStats, nil
+}
+
+func (m MetricsService) GetForPeer(ctx context.Context, id domain.PeerIdentifier) (*domain.PeerStatus, error) {
+	if !m.cfg.Statistics.CollectPeerData {
+		return nil, fmt.Errorf("peer statistics collection is disabled")
+	}
+
+	peer, err := m.peers.GetPeer(ctx, id)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := domain.ValidateUserAccessRights(ctx, peer.UserIdentifier); err != nil {
+		return nil, err
+	}
+
+	peerStats, err := m.db.GetPeersStats(ctx, peer.Identifier)
+	if err != nil {
+		return nil, fmt.Errorf("failed to fetch stats for peer %s: %w", peer.Identifier, err)
+	}
+
+	if len(peerStats) == 0 {
+		return nil, fmt.Errorf("no stats found for peer %s: %w", peer.Identifier, domain.ErrNotFound)
+	}
+
+	return &peerStats[0], nil
+}