provider: replace flag emojis with country codes in removeEmojisFromTags

adapter/provider/adapter.go

@@ -289,11 +289,21 @@ func uniquifyTags(opts []option.Outbound) {
 
 func removeEmojisFromTags(opts []option.Outbound) {
 	for i, opt := range opts {
-		cleaned := emojiRegex.ReplaceAllString(opt.Tag, "")
+		cleaned := flagRegex.ReplaceAllStringFunc(opt.Tag, flagToCountryCode)
+		cleaned = emojiRegex.ReplaceAllString(cleaned, "")
 		cleaned = multiSpaceRegex.ReplaceAllString(cleaned, " ")
 		opts[i].Tag = strings.TrimSpace(cleaned)
 	}
 }
 
+func flagToCountryCode(flag string) string {
+	runes := []rune(flag)
+	if len(runes) == 2 {
+		return string(rune(runes[0]-0x1F1E6+'A')) + string(rune(runes[1]-0x1F1E6+'A')) + " "
+	}
+	return ""
+}
+
+var flagRegex = regexp.MustCompile(`[\x{1F1E6}-\x{1F1FF}]{2}`)
 var emojiRegex = regexp.MustCompile(`[\x{1F1E0}-\x{1F1FF}\x{1F300}-\x{1F9FF}\x{2600}-\x{27BF}\x{FE00}-\x{FE0F}\x{200D}]+`)
 var multiSpaceRegex = regexp.MustCompile(`\s{2,}`)

adapter/provider/adapter_test.go

@@ -0,0 +1,45 @@
+package provider
+
+import (
+	"testing"
+
+	"github.com/sagernet/sing-box/option"
+)
+
+func TestFlagToCountryCodeAllFlags(t *testing.T) {
+	for first := 'A'; first <= 'Z'; first++ {
+		for second := 'A'; second <= 'Z'; second++ {
+			flag := string(rune(0x1F1E6+(first-'A'))) + string(rune(0x1F1E6+(second-'A')))
+			expected := string(first) + string(second)
+			result := flagToCountryCode(flag)
+			// flagToCountryCode appends a space
+			if result != expected+" " {
+				t.Errorf("flagToCountryCode(%q) = %q, want %q", expected, result, expected+" ")
+			}
+		}
+	}
+}
+
+func TestRemoveEmojisFromTags(t *testing.T) {
+	tests := []struct {
+		input    string
+		expected string
+	}{
+		{"🇺🇸 United States", "US United States"},
+		{"🇷🇺 Россия", "RU Россия"},
+		{"🇩🇪 Germany 🚀", "DE Germany"},
+		{"🇫🇷🇬🇧 France-UK", "FR GB France-UK"},
+		{"No emojis here", "No emojis here"},
+		{"🌍 World", "World"},
+		{"🇯🇵 Tokyo ⚡ Fast", "JP Tokyo Fast"},
+		{"Germany 🇩🇪", "Germany DE"},
+		{"Server 🇺🇸 Node", "Server US Node"},
+	}
+	for _, tt := range tests {
+		opts := []option.Outbound{{Tag: tt.input}}
+		removeEmojisFromTags(opts)
+		if opts[0].Tag != tt.expected {
+			t.Errorf("removeEmojisFromTags(%q) = %q, want %q", tt.input, opts[0].Tag, tt.expected)
+		}
+	}
+}