feat: use six-digit numeric member invite codes

server/internal/logic/sys/app_member_invite.go

@@ -0,0 +1,31 @@
+package sys
+
+import (
+	"context"
+	"crypto/rand"
+	"fmt"
+	"math/big"
+
+	"hotgo/internal/dao"
+
+	"github.com/gogf/gf/v2/database/gdb"
+	"github.com/gogf/gf/v2/errors/gerror"
+)
+
+func newAppMemberInviteCode(ctx context.Context, members *gdb.Model) (string, error) {
+	for attempt := 0; attempt < 20; attempt++ {
+		number, err := rand.Int(rand.Reader, big.NewInt(1000000))
+		if err != nil {
+			return "", gerror.Wrap(err, "生成邀请码失败")
+		}
+		code := fmt.Sprintf("%06d", number.Int64())
+		count, err := members.Unscoped().Where(dao.AppMember.Columns().InviteCode, code).Count()
+		if err != nil {
+			return "", gerror.Wrap(err, "检查邀请码失败")
+		}
+		if count == 0 {
+			return code, nil
+		}
+	}
+	return "", gerror.New("邀请码暂时无法生成，请稍后重试")
+}