update

internal/qso/qso.go

@@ -807,6 +807,39 @@ func (r *Repo) Count(ctx context.Context) (int64, error) {
 	return n, err
 }
 
+// ExistingDedupeKeys returns a set of every QSO key currently in the DB,
+// used by the ADIF importer to skip records that would re-create the
+// same contact. The key is callsign|YYYY-MM-DDTHH:MM|band|mode — minute
+// precision so two loggers that wrote a few seconds apart still match.
+//
+// On a 25k-row table this returns ~25k strings (~2MB RAM) in one pass —
+// far cheaper than N exists-queries during the import loop.
+func (r *Repo) ExistingDedupeKeys(ctx context.Context) (map[string]struct{}, error) {
+	rows, err := r.db.QueryContext(ctx, `
+		SELECT callsign, strftime('%Y-%m-%dT%H:%M', qso_date), band, mode
+		FROM qso`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	out := make(map[string]struct{}, 1024)
+	for rows.Next() {
+		var call, when, band, mode string
+		if err := rows.Scan(&call, &when, &band, &mode); err != nil {
+			return nil, err
+		}
+		out[DedupeKey(call, when, band, mode)] = struct{}{}
+	}
+	return out, rows.Err()
+}
+
+// DedupeKey is the canonical dedupe identity for a QSO. Exposed so the
+// importer can compute the key from in-flight records and check against
+// the same map ExistingDedupeKeys returns.
+func DedupeKey(callsign, qsoDateMinute, band, mode string) string {
+	return strings.ToUpper(callsign) + "|" + qsoDateMinute + "|" + strings.ToLower(band) + "|" + strings.ToUpper(mode)
+}
+
 // scanner is what both *sql.Row and *sql.Rows satisfy for our needs.
 type scanner interface {
 	Scan(dest ...any) error