feat(state): add missing BeforeDelete/BeforeUpdate for threads, members, channels and roles (#1647)

events.go

@@ -60,6 +60,7 @@ type ChannelUpdate struct {
 // ChannelDelete is the data for a ChannelDelete event.
 type ChannelDelete struct {
 	*Channel
+	BeforeDelete *Channel `json:"-"`
 }
 
 // ChannelPinsUpdate stores data for a ChannelPinsUpdate event.
@@ -84,6 +85,7 @@ type ThreadUpdate struct {
 // ThreadDelete is the data for a ThreadDelete event.
 type ThreadDelete struct {
 	*Channel
+	BeforeDelete *Channel `json:"-"`
 }
 
 // ThreadListSync is the data for a ThreadListSync event.
@@ -158,6 +160,7 @@ type GuildMemberUpdate struct {
 // GuildMemberRemove is the data for a GuildMemberRemove event.
 type GuildMemberRemove struct {
 	*Member
+	BeforeDelete *Member `json:"-"`
 }
 
 // GuildRoleCreate is the data for a GuildRoleCreate event.
@@ -168,12 +171,14 @@ type GuildRoleCreate struct {
 // GuildRoleUpdate is the data for a GuildRoleUpdate event.
 type GuildRoleUpdate struct {
 	*GuildRole
+	BeforeUpdate *Role `json:"-"`
 }
 
 // A GuildRoleDelete is the data for a GuildRoleDelete event.
 type GuildRoleDelete struct {
-	RoleID  string `json:"role_id"`
-	GuildID string `json:"guild_id"`
+	RoleID       string `json:"role_id"`
+	GuildID      string `json:"guild_id"`
+	BeforeDelete *Role  `json:"-"`
 }
 
 // A GuildEmojisUpdate is the data for a guild emoji update event.

state.go

@@ -1014,6 +1014,12 @@ func (s *State) OnInterface(se *Session, i interface{}) (err error) {
 
 		// Removes member from the cache if tracking is enabled.
 		if s.TrackMembers {
+			old, err := s.Member(t.Member.GuildID, t.Member.User.ID)
+			if err == nil {
+				oldCopy := *old
+				t.BeforeDelete = &oldCopy
+			}
+
 			err = s.MemberRemove(t.Member)
 		}
 	case *GuildMembersChunk:
@@ -1035,10 +1041,22 @@ func (s *State) OnInterface(se *Session, i interface{}) (err error) {
 		}
 	case *GuildRoleUpdate:
 		if s.TrackRoles {
+			old, err := s.Role(t.GuildID, t.Role.ID)
+			if err == nil {
+				oldCopy := *old
+				t.BeforeUpdate = &oldCopy
+			}
+
 			err = s.RoleAdd(t.GuildID, t.Role)
 		}
 	case *GuildRoleDelete:
 		if s.TrackRoles {
+			old, err := s.Role(t.GuildID, t.RoleID)
+			if err == nil {
+				oldCopy := *old
+				t.BeforeDelete = &oldCopy
+			}
+
 			err = s.RoleRemove(t.GuildID, t.RoleID)
 		}
 	case *GuildEmojisUpdate:
@@ -1078,6 +1096,11 @@ func (s *State) OnInterface(se *Session, i interface{}) (err error) {
 		}
 	case *ChannelDelete:
 		if s.TrackChannels {
+			old, err := s.Channel(t.ID)
+			if err == nil {
+				oldCopy := *old
+				t.BeforeDelete = &oldCopy
+			}
 			err = s.ChannelRemove(t.Channel)
 		}
 	case *ThreadCreate:
@@ -1095,6 +1118,11 @@ func (s *State) OnInterface(se *Session, i interface{}) (err error) {
 		}
 	case *ThreadDelete:
 		if s.TrackThreads {
+			old, err := s.Channel(t.ID)
+			if err == nil {
+				oldCopy := *old
+				t.BeforeDelete = &oldCopy
+			}
 			err = s.ChannelRemove(t.Channel)
 		}
 	case *ThreadMemberUpdate: