feat: support new username system (#1387)

* Add support for new username system in User.String and User.AvatarURL
* Move default avatar index logic from EndpointDefaultUserAvatar into User.DefaultAvatarIndex

---------

Co-authored-by: Fedor Lapshin <fe.lap.prog@gmail.com>

endpoints.go

@@ -49,9 +49,8 @@ var (
 	EndpointUser               = func(uID string) string { return EndpointUsers + uID }
 	EndpointUserAvatar         = func(uID, aID string) string { return EndpointCDNAvatars + uID + "/" + aID + ".png" }
 	EndpointUserAvatarAnimated = func(uID, aID string) string { return EndpointCDNAvatars + uID + "/" + aID + ".gif" }
-	EndpointDefaultUserAvatar  = func(uDiscriminator string) string {
-		uDiscriminatorInt, _ := strconv.Atoi(uDiscriminator)
-		return EndpointCDN + "embed/avatars/" + strconv.Itoa(uDiscriminatorInt%5) + ".png"
+	EndpointDefaultUserAvatar  = func(idx int) string {
+		return EndpointCDN + "embed/avatars/" + strconv.Itoa(idx) + ".png"
 	}
 	EndpointUserBanner = func(uID, cID string) string {
 		return EndpointCDNBanners + uID + "/" + cID + ".png"

user.go

@@ -1,5 +1,9 @@
 package discordgo
 
+import (
+	"strconv"
+)
+
 // UserFlags is the flags of "user" (see UserFlags* consts)
 // https://discord.com/developers/docs/resources/user#user-object-user-flags
 type UserFlags int
@@ -44,6 +48,10 @@ type User struct {
 	// The discriminator of the user (4 numbers after name).
 	Discriminator string `json:"discriminator"`
 
+	// The user's display name, if it is set.
+	// For bots, this is the application name.
+	GlobalName string `json:"global_name"`
+
 	// The token of the user. This is only present for
 	// the user represented by the current session.
 	Token string `json:"token"`
@@ -81,7 +89,14 @@ type User struct {
 }
 
 // String returns a unique identifier of the form username#discriminator
+// or just username, if the discriminator is set to "0".
 func (u *User) String() string {
+	// If the user has been migrated from the legacy username system, their discriminator is "0".
+	// See https://support-dev.discord.com/hc/en-us/articles/13667755828631
+	if u.Discriminator == "0" {
+		return u.Username
+	}
+
 	return u.Username + "#" + u.Discriminator
 }
 
@@ -91,17 +106,35 @@ func (u *User) Mention() string {
 }
 
 // AvatarURL returns a URL to the user's avatar.
-//    size:    The size of the user's avatar as a power of two
-//             if size is an empty string, no size parameter will
-//             be added to the URL.
+//
+//	size:    The size of the user's avatar as a power of two
+//	         if size is an empty string, no size parameter will
+//	         be added to the URL.
 func (u *User) AvatarURL(size string) string {
-	return avatarURL(u.Avatar, EndpointDefaultUserAvatar(u.Discriminator),
-		EndpointUserAvatar(u.ID, u.Avatar), EndpointUserAvatarAnimated(u.ID, u.Avatar), size)
+	return avatarURL(
+		u.Avatar,
+		EndpointDefaultUserAvatar(u.DefaultAvatarIndex()),
+		EndpointUserAvatar(u.ID, u.Avatar),
+		EndpointUserAvatarAnimated(u.ID, u.Avatar),
+		size,
+	)
 }
 
 // BannerURL returns the URL of the users's banner image.
-//    size:    The size of the desired banner image as a power of two
-//             Image size can be any power of two between 16 and 4096.
+//
+//	size:    The size of the desired banner image as a power of two
+//	         Image size can be any power of two between 16 and 4096.
 func (u *User) BannerURL(size string) string {
 	return bannerURL(u.Banner, EndpointUserBanner(u.ID, u.Banner), EndpointUserBannerAnimated(u.ID, u.Banner), size)
 }
+
+// DefaultAvatarIndex returns the index of the user's default avatar.
+func (u *User) DefaultAvatarIndex() int {
+	if u.Discriminator == "0" {
+		id, _ := strconv.ParseUint(u.ID, 10, 64)
+		return int((id >> 22) % 6)
+	}
+
+	id, _ := strconv.Atoi(u.Discriminator)
+	return id % 5
+}

user_test.go

@@ -2,15 +2,36 @@ package discordgo
 
 import "testing"
 
-func TestUser(t *testing.T) {
+func TestUser_String(t *testing.T) {
 	t.Parallel()
 
-	user := &User{
-		Username:      "bob",
-		Discriminator: "8192",
+	tests := []struct {
+		name string
+		u    *User
+		want string
+	}{
+		{
+			name: "User with a discriminator",
+			u: &User{
+				Username:      "bob",
+				Discriminator: "8192",
+			},
+			want: "bob#8192",
+		},
+		{
+			name: "User with discriminator set to 0",
+			u: &User{
+				Username:      "aldiwildan",
+				Discriminator: "0",
+			},
+			want: "aldiwildan",
+		},
 	}
-
-	if user.String() != "bob#8192" {
-		t.Errorf("user.String() == %v", user.String())
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := tc.u.String(); got != tc.want {
+				t.Errorf("User.String() = %v, want %v", got, tc.want)
+			}
+		})
 	}
 }