From 474a473181cc718094f8651bb6e786cbf3bb1a45 Mon Sep 17 00:00:00 2001
From: H1JK <hell0jack@protonmail.com>
Date: Thu, 15 Feb 2024 20:05:39 +0800
Subject: [PATCH] Fix Meta-geoip convert

---
 convert/v2ray_ip.go | 92 +++++++++++++++++++++++++++++++++++----------
 1 file changed, 73 insertions(+), 19 deletions(-)

diff --git a/convert/v2ray_ip.go b/convert/v2ray_ip.go
index c1fd197..e15d587 100644
--- a/convert/v2ray_ip.go
+++ b/convert/v2ray_ip.go
@@ -1,8 +1,10 @@
 package convert
 
 import (
+	"fmt"
 	"io"
 	"net"
+	"net/netip"
 	"strings"
 
 	"github.com/metacubex/geo/encoding/v2raygeo"
@@ -11,6 +13,8 @@ import (
 	"github.com/maxmind/mmdbwriter/inserter"
 	"github.com/maxmind/mmdbwriter/mmdbtype"
 	"github.com/sagernet/sing/common"
+	"golang.org/x/exp/constraints"
+	"golang.org/x/exp/slices"
 )
 
 func V2RayIPToSing(geoipList []*v2raygeo.GeoIP, output io.Writer) error {
@@ -62,33 +66,83 @@ func V2RayIPToMetaV0(geoipList []*v2raygeo.GeoIP, output io.Writer) error {
 		return err
 	}
 
+	included := make([]netip.Prefix, 0, 4*len(geoipList))
+	codeMap := make(map[netip.Prefix][]string, 4*len(geoipList))
 	for _, geoipEntry := range geoipList {
+		code := strings.ToLower(geoipEntry.CountryCode)
 		for _, cidrEntry := range geoipEntry.Cidr {
-			ipAddress := net.IP(cidrEntry.Ip)
-			if ip4 := ipAddress.To4(); ip4 != nil {
-				ipAddress = ip4
+			addr, ok := netip.AddrFromSlice(cidrEntry.Ip)
+			if !ok {
+				return fmt.Errorf("bad IP address: %v", cidrEntry.Ip)
 			}
-			ipNet := net.IPNet{
-				IP:   ipAddress,
-				Mask: net.CIDRMask(int(cidrEntry.Prefix), len(ipAddress)*8),
+			addr = addr.Unmap()
+			prefix := netip.PrefixFrom(addr, int(cidrEntry.Prefix))
+			included = append(included, prefix)
+			codeMap[prefix] = append(codeMap[prefix], code)
+		}
+	}
+	included = common.Uniq(included)
+	slices.SortFunc(included, func(a, b netip.Prefix) int {
+		// sort in ascending order
+		return cmpCompare(a.Bits(), b.Bits())
+	})
+
+	for _, prefix := range included {
+		ipAddress := net.IP(prefix.Addr().AsSlice())
+		ipNet := net.IPNet{
+			IP:   ipAddress,
+			Mask: net.CIDRMask(prefix.Bits(), len(ipAddress)*8),
+		}
+		codes := codeMap[prefix]
+		_, record := writer.Get(ipAddress)
+		switch typedRecord := record.(type) {
+		case nil:
+			if len(codes) == 1 {
+				record = mmdbtype.String(codes[0])
+			} else {
+				record = mmdbtype.Slice(common.Map(codes, func(it string) mmdbtype.DataType {
+					return mmdbtype.String(it)
+				}))
 			}
-			_, record := writer.Get(ipAddress)
-			switch typedRecord := record.(type) {
-			case nil:
-				record = mmdbtype.String(strings.ToLower(geoipEntry.CountryCode))
-			case mmdbtype.String:
-				record = mmdbtype.Slice{record, mmdbtype.String(strings.ToLower(geoipEntry.CountryCode))}
-			case mmdbtype.Slice:
-				record = append(typedRecord, mmdbtype.String(strings.ToLower(geoipEntry.CountryCode)))
-			default:
-				panic("bad record type")
+		case mmdbtype.String:
+			recordSlice := make(mmdbtype.Slice, 0, 1+len(codes))
+			recordSlice = append(recordSlice, typedRecord)
+			for _, code := range codes {
+				recordSlice = append(recordSlice, mmdbtype.String(code))
 			}
-			err = writer.Insert(&ipNet, record)
-			if err != nil {
-				return err
+			recordSlice = common.Uniq(recordSlice)
+			if len(recordSlice) == 1 {
+				record = recordSlice[0]
+			} else {
+				record = recordSlice
 			}
+		case mmdbtype.Slice:
+			recordSlice := typedRecord
+			for _, code := range codes {
+				recordSlice = append(recordSlice, mmdbtype.String(code))
+			}
+			recordSlice = common.Uniq(recordSlice)
+			record = recordSlice
+		default:
+			panic("bad record type")
+		}
+		err = writer.Insert(&ipNet, record)
+		if err != nil {
+			return err
 		}
 	}
 
 	return common.Error(writer.WriteTo(output))
 }
+
+// cmpCompare is a copy of cmp.Compare from the Go 1.21 release.
+// T cannot be float types.
+func cmpCompare[T constraints.Ordered](x, y T) int {
+	if x < y {
+		return -1
+	}
+	if x > y {
+		return +1
+	}
+	return 0
+}