feat:增加获取各个国家国旗方法

country.go

@@ -10,6 +10,7 @@ package consts
 import (
 	_ "embed"
 	"encoding/json"
+	"fmt"
 )
 
 type Country struct {
@@ -55,6 +56,31 @@ func (country Country) GetLanguage() string {
 	return country.Language
 }
 
+// GetNationalFlag 获取国家国旗链接
+func (country Country) GetNationalFlag(width uint, height uint) string {
+	supportSizeList := []string{
+		"16x12", "20x15", "24x18", "28x21",
+		"32x24", "36x27", "40x30", "48x36",
+		"56x42", "60x45", "64x48", "72x54",
+		"80x60", "84x63", "96x72", "108x81",
+		"112x84", "120x90", "128x96", "144x108",
+		"160x120", "192x144", "224x168", "256x192",
+	}
+	size := fmt.Sprintf("%vx%v", width, height)
+	isSupportSize := false
+	for _, itemSize := range supportSizeList {
+		if itemSize == size {
+			isSupportSize = true
+			break
+		}
+	}
+	if !isSupportSize {
+		// 不支持
+		return ""
+	}
+	return fmt.Sprintf("https://flagcdn.com/%vx%v/%v.png", width, height, country.ShortLower)
+}
+
 //go:embed country.json
 var countryJSON []byte