From b428c0236e74b043e4141db7a228837c349d4573 Mon Sep 17 00:00:00 2001
From: gazebo <gazeboxu@gmail.com>
Date: Fri, 13 Dec 2019 18:39:54 +0800
Subject: [PATCH] =?UTF-8?q?GenFakeUPC=E8=80=83=E8=99=91=E6=A0=A1=E9=AA=8C?=
 =?UTF-8?q?=E8=A7=84=E5=88=99?=
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---
 business/jxutils/jxutils.go      | 23 ++++++++++++++++++++++-
 business/jxutils/jxutils_test.go | 12 +++++++++---
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/business/jxutils/jxutils.go b/business/jxutils/jxutils.go
index e6662dd29..65f23bdc7 100644
--- a/business/jxutils/jxutils.go
+++ b/business/jxutils/jxutils.go
@@ -409,8 +409,29 @@ func SplitSkuName(skuName string) (prefix, name, comment, specUnit, unit string,
 	return prefix, name, comment, specUnit, unit, specQuality
 }
 
+// https://my.oschina.net/hyller/blog/700414
+func CalUpcCheckSum(upc12 int64) (checkSum int) {
+	var sum [2]int
+	for i := 0; i < 12; i++ {
+		base := int64(math.Pow10(i))
+		sum[i%2] += int((upc12 / base) % 10)
+	}
+	sum[0] *= 3
+	return (10 - (sum[0]+sum[1])%10)
+}
+
+func IsUpcValid(upc string) bool {
+	if len(upc) != 13 {
+		return false
+	}
+	upcInt := utils.Str2Int64WithDefault(upc, 0)
+	checkSum := CalUpcCheckSum(upcInt / 10)
+	return int(utils.Str2Int64(upc[12:])) == checkSum
+}
+
 func GenFakeUPC(skuID int) string {
-	return fmt.Sprintf("%013d", int64(skuID)+6666000000000)
+	id := int64(skuID) + 666600000000
+	return fmt.Sprintf("%012d%d", id, CalUpcCheckSum(id))
 }
 
 func MakeValidationMapFromSlice(validValues []string, flag int) map[string]int {
diff --git a/business/jxutils/jxutils_test.go b/business/jxutils/jxutils_test.go
index f1bab58e6..d6ecd5e26 100644
--- a/business/jxutils/jxutils_test.go
+++ b/business/jxutils/jxutils_test.go
@@ -288,11 +288,11 @@ func TestGetOneEmailFromStr(t *testing.T) {
 func TestGenFakeUPC(t *testing.T) {
 	for _, v := range [][]string{
 		[]string{
-			"6666000000123",
-			"123",
+			"6666000298034",
+			"29803",
 		},
 		[]string{
-			"6666007654321",
+			"6666076543212",
 			"7654321",
 		},
 	} {
@@ -300,4 +300,10 @@ func TestGenFakeUPC(t *testing.T) {
 			t.Errorf("%s failed, result:%s, expect:%s", v[1], str, v[0])
 		}
 	}
+	if !IsUpcValid("6666076543212") {
+		t.Fatal("wrong1")
+	}
+	if IsUpcValid("6666076543210") {
+		t.Fatal("wrong2")
+	}
 }