Add local navigation API

internal/store/counts.go

@@ -0,0 +1,50 @@
+package store
+
+import "database/sql"
+
+// SessionDatasetCounts holds row counts for session-scoped datasets.
+type SessionDatasetCounts struct {
+	Drivers      int
+	Results      int
+	StartingGrid int
+	Stints       int
+	PitStops     int
+	Positions    int
+	RaceControl  int
+	Weather      int
+	Laps         int
+}
+
+// CountSessionDatasets returns row counts for ingested session datasets.
+func (s *Store) CountSessionDatasets(sessionKey int) (SessionDatasetCounts, error) {
+	var c SessionDatasetCounts
+	err := s.db.QueryRow(`
+		SELECT
+			(SELECT COUNT(*) FROM session_drivers WHERE session_key = ?),
+			(SELECT COUNT(*) FROM session_results WHERE session_key = ?),
+			(SELECT COUNT(*) FROM starting_grid WHERE session_key = ?),
+			(SELECT COUNT(*) FROM stints WHERE session_key = ?),
+			(SELECT COUNT(*) FROM pit_stops WHERE session_key = ?),
+			(SELECT COUNT(*) FROM positions WHERE session_key = ?),
+			(SELECT COUNT(*) FROM race_control WHERE session_key = ?),
+			(SELECT COUNT(*) FROM weather WHERE session_key = ?),
+			(SELECT COUNT(*) FROM laps WHERE session_key = ?)
+	`,
+		sessionKey, sessionKey, sessionKey, sessionKey, sessionKey,
+		sessionKey, sessionKey, sessionKey, sessionKey,
+	).Scan(
+		&c.Drivers,
+		&c.Results,
+		&c.StartingGrid,
+		&c.Stints,
+		&c.PitStops,
+		&c.Positions,
+		&c.RaceControl,
+		&c.Weather,
+		&c.Laps,
+	)
+	if err == sql.ErrNoRows {
+		return SessionDatasetCounts{}, nil
+	}
+	return c, err
+}