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internal/domains/api/services/processors/qcxg/car_plate.go

@@ -0,0 +1,43 @@
+package qcxg
+
+import (
+	_ "embed"
+	"encoding/json"
+	"strings"
+	"unicode/utf8"
+)
+
+//go:embed data/car_plate.json
+var carPlateJSON []byte
+
+var carPlateCityMap map[string]string
+
+func init() {
+	carPlateCityMap = make(map[string]string)
+	_ = json.Unmarshal(carPlateJSON, &carPlateCityMap)
+}
+
+// lookupCityByPlateNo 根据车牌号前缀（省简称+字母）查城市，未匹配返回 "-"
+func lookupCityByPlateNo(plateNo string) string {
+	prefix := extractPlatePrefix(plateNo)
+	if prefix == "" {
+		return "-"
+	}
+	if city, ok := carPlateCityMap[prefix]; ok && city != "" {
+		return city
+	}
+	return "-"
+}
+
+// extractPlatePrefix 取车牌前两个字符作为字典键，如 "鲁A12345" -> "鲁A"
+func extractPlatePrefix(plateNo string) string {
+	plateNo = strings.TrimSpace(plateNo)
+	if plateNo == "" {
+		return ""
+	}
+	if utf8.RuneCountInString(plateNo) < 2 {
+		return ""
+	}
+	runes := []rune(plateNo)
+	return string(runes[:2])
+}