up

internal/dxcc/adif_numbers.go

@@ -58,6 +58,60 @@ func NameForDXCC(n int) string {
 	return strings.Title(name) //nolint:staticcheck // ASCII entity names
 }
 
+// ZoneByCallDistrict returns the CQ and ITU zone for a callsign in a country
+// that is split across zones by call district (USA, Australia…). cty.dat and
+// ClubLog's cty.xml only carry one zone per entity, so loggers apply this
+// district→zone convention to get e.g. W6 = CQ3/ITU6 instead of the entity
+// default CQ5/ITU8. ok=false means no district rule applies (use the entity
+// default). The district is the first digit of the callsign.
+func ZoneByCallDistrict(adif int, call string) (cqz, ituz int, ok bool) {
+	d := districtDigit(call)
+	if d < 0 {
+		return 0, 0, false
+	}
+	switch adif {
+	case 291: // United States — standard district defaults (state-level
+		// exceptions exist, but this matches what Log4OM/DXKeeper default to).
+		if z, o := usDistrictZones[d]; o {
+			return z[0], z[1], true
+		}
+	case 150: // Australia — VK6/VK8 (west/north) are CQ29/ITU58, rest CQ30/ITU59.
+		if d == 6 || d == 8 {
+			return 29, 58, true
+		}
+		return 30, 59, true
+	}
+	return 0, 0, false
+}
+
+// usDistrictZones maps a US call district digit to its {CQ, ITU} zone.
+var usDistrictZones = map[int][2]int{
+	0: {4, 7}, 1: {5, 8}, 2: {5, 8}, 3: {5, 8}, 4: {5, 8},
+	5: {4, 7}, 6: {3, 6}, 7: {3, 6}, 8: {5, 8}, 9: {4, 8},
+}
+
+// firstDigit returns the first 0-9 digit in a callsign, or -1 if none.
+func firstDigit(call string) int {
+	for i := 0; i < len(call); i++ {
+		if call[i] >= '0' && call[i] <= '9' {
+			return int(call[i] - '0')
+		}
+	}
+	return -1
+}
+
+// districtDigit returns the effective call-area digit: a trailing "/N" (single
+// digit) re-homes the call to area N (W6ABC/7 → area 7), otherwise the first
+// digit of the call.
+func districtDigit(call string) int {
+	if i := strings.LastIndex(call, "/"); i >= 0 && i == len(call)-2 {
+		if c := call[len(call)-1]; c >= '0' && c <= '9' {
+			return int(c - '0')
+		}
+	}
+	return firstDigit(call)
+}
+
 // EntityNumberName pairs a DXCC entity number with its display name.
 type EntityNumberName struct {
 	Num  int