api: Implement autocomplete components

api/interaction.go

@@ -24,6 +24,7 @@ const (
 	DeferredMessageInteractionWithSource
 	DeferredMessageUpdate
 	UpdateMessage
+	AutocompleteResult
 )
 
 // InteractionResponseFlags implements flags for an
@@ -72,6 +73,11 @@ type InteractionResponseData struct {
 	// Files represents a list of files to upload. This will not be
 	// JSON-encoded and will only be available through WriteMultipart.
 	Files []sendpart.File `json:"-"`
+
+	// Choices are the results to display on autocomplete interaction events.
+	//
+	// During all other events, this should not be provided.
+	Choices *[]AutocompleteChoice `json:"choices"`
 }
 
 // NeedsMultipart returns true if the InteractionResponseData has files.
@@ -83,6 +89,13 @@ func (d InteractionResponseData) WriteMultipart(body *multipart.Writer) error {
 	return sendpart.Write(body, d, d.Files)
 }
 
+// AutocompleteChoice is the choice in ApplicationCommandAutocompleteResult in
+// the official documentation.
+type AutocompleteChoice struct {
+	Name  string `json:"name"`
+	Value string `json:"value"`
+}
+
 // RespondInteraction responds to an incoming interaction. It is also known as
 // an "interaction callback".
 func (c *Client) RespondInteraction(
@@ -129,7 +142,7 @@ func (c *Client) RespondInteraction(
 		}
 	}
 
-	var URL = EndpointInteractions + id.String() + "/" + token + "/callback"
+	URL := EndpointInteractions + id.String() + "/" + token + "/callback"
 	return sendpart.POST(c.Client, resp, nil, URL)
 }
 

discord/application.go

@@ -181,12 +181,15 @@ func (c Command) CreatedAt() time.Time {
 }
 
 type CommandOption struct {
-	Type        CommandOptionType     `json:"type"`
-	Name        string                `json:"name"`
-	Description string                `json:"description"`
-	Required    bool                  `json:"required"`
-	Choices     []CommandOptionChoice `json:"choices,omitempty"`
-	Options     []CommandOption       `json:"options,omitempty"`
+	Type        CommandOptionType `json:"type"`
+	Name        string            `json:"name"`
+	Description string            `json:"description"`
+	Required    bool              `json:"required"`
+
+	// Choices cannot be present if Autocomplete is true.
+	Choices      []CommandOptionChoice `json:"choices,omitempty"`
+	Autocomplete bool                  `json:"autocomplete"`
+	Options      []CommandOption       `json:"options,omitempty"`
 
 	// If this option is a channel type, the channels shown will be restricted to these types
 	ChannelTypes []ChannelType `json:"-"`

discord/interaction.go

@@ -45,6 +45,8 @@ func (i *Interaction) UnmarshalJSON(p []byte) error {
 		i.Data = &ComponentInteractionData{}
 	case CommandInteraction:
 		i.Data = &CommandInteractionData{}
+	case AutocompleteInteraction:
+		i.Data = &AutocompleteInteractionData{}
 	default:
 		i.Data = &UnknownInteractionData{typ: v.Type}
 	}
@@ -58,6 +60,7 @@ const (
 	PingInteraction InteractionType = iota + 1
 	CommandInteraction
 	ComponentInteraction
+	AutocompleteInteraction
 )
 
 // InteractionData holds the data of an interaction.
@@ -87,6 +90,27 @@ func (*CommandInteractionData) Type() InteractionType {
 	return CommandInteraction
 }
 
+type AutocompleteInteractionData struct {
+	ID CommandID `json:"id"`
+
+	// Name of command autocomplete is triggered for.
+	Name        string                      `json:"name"`
+	CommandType CommandType                 `json:"type"`
+	Version     string                      `json:"version"`
+	Options     []AutocompleteCommandOption `json:"options"`
+}
+
+type AutocompleteCommandOption struct {
+	Type    CommandOptionType `json:"type"`
+	Name    string            `json:"name"`
+	Value   string            `json:"value"`
+	Focused bool              `json:"focused"`
+}
+
+func (*AutocompleteInteractionData) Type() InteractionType {
+	return AutocompleteInteraction
+}
+
 type UnknownInteractionData struct {
 	json.Raw
 	typ InteractionType