From 462f289121a4e7ee8e14107dd3edc3657acd0c4d Mon Sep 17 00:00:00 2001
From: Hamcha <zikyky@gmail.com>
Date: Thu, 13 Dec 2018 11:51:11 +0100
Subject: [PATCH] Initial support for callback queries

---
 api.go      | 22 +++++++++++++++++-----
 command.go  |  9 +++++++++
 telegram.go | 26 ++++++++++++++++++++++++--
 3 files changed, 50 insertions(+), 7 deletions(-)

diff --git a/api.go b/api.go
index 8a570fe..bcefde5 100644
--- a/api.go
+++ b/api.go
@@ -135,9 +135,10 @@ type APILocation struct {
 
 // APIUpdate represents the "Update" JSON structure
 type APIUpdate struct {
-	UpdateID int64           `json:"update_id"`
-	Message  *APIMessage     `json:"message"`
-	Inline   *APIInlineQuery `json:"inline_query,omitempty"`
+	UpdateID int64             `json:"update_id"`
+	Message  *APIMessage       `json:"message"`
+	Inline   *APIInlineQuery   `json:"inline_query,omitempty"`
+	Callback *APICallbackQuery `json:"callback_query,omitempty"`
 }
 
 // APIFile represents the "File" JSON structure
@@ -185,8 +186,9 @@ type APIInlineKeyboardMarkup struct {
 
 // APIInlineKeyboardButton is an inline message button
 type APIInlineKeyboardButton struct {
-	Text string `json:"text"`
-	URL  string `json:"url,omitempty"`
+	Text         string `json:"text"`
+	URL          string `json:"url,omitempty"`
+	CallbackData string `json:"callback_data,omitempty"`
 }
 
 // APIInputMediaPhoto is a media photo element (already on telegram servers or via HTTP URL) for albums and other cached pictures
@@ -196,3 +198,13 @@ type APIInputMediaPhoto struct {
 	Caption   string `json:"caption,omitempty"`
 	ParseMode string `json:"parse_mode,omitempty"`
 }
+
+// APICallbackQuery is a callback query triggered by an inline button
+type APICallbackQuery struct {
+	ID       string      `json:"id"`
+	User     APIAudio    `json:"from"`
+	Message  *APIMessage `json:"message,omitempty"`
+	InlineID *string     `json:"inline_message_id,omitempty"`
+	ChatID   string      `json:"chat_instance"`
+	Data     *string     `json:"data,omitempty"`
+}
diff --git a/command.go b/command.go
index 8b80a94..b5f3fcd 100644
--- a/command.go
+++ b/command.go
@@ -79,6 +79,15 @@ type ClientChatActionData struct {
 	Action ChatAction
 }
 
+// ClientCallbackQueryData is the required data for a CmdAnswerCallback request
+type ClientCallbackQueryData struct {
+	QueryID   string
+	Text      string
+	ShowAlert bool
+	URL       string
+	CacheTime int64
+}
+
 // ClientAlbumData is the required data for a CmdSendAlbum request
 type ClientAlbumData struct {
 	ChatID  int64
diff --git a/telegram.go b/telegram.go
index f0c0ee0..896ea4f 100644
--- a/telegram.go
+++ b/telegram.go
@@ -158,10 +158,10 @@ func (t Telegram) SendAlbum(data ClientAlbumData) {
 		"media":   {string(jsonmedia)},
 	}
 	if data.Silent {
-		postdata["disable_notification"] = []string{"true"}
+		postdata.Set("disable_notification", "true")
 	}
 	if data.ReplyID != nil {
-		postdata["reply_to_message_id"] = []string{strconv.FormatInt(*(data.ReplyID), 10)}
+		postdata.Set("reply_to_message_id", strconv.FormatInt(*(data.ReplyID), 10))
 	}
 
 	_, err = http.PostForm(t.apiURL("sendMediaGroup"), postdata)
@@ -191,6 +191,28 @@ func (t Telegram) SendChatAction(data ClientChatActionData) {
 	checkerr("SendChatAction/http.PostForm", err)
 }
 
+// AnswerCallback stops the progress bar after a callback query is initiated
+func (t Telegram) AnswerCallback(data ClientCallbackQueryData) {
+	postdata := url.Values{
+		"callback_query_id": {data.QueryID},
+	}
+	if data.Text != "" {
+		postdata.Set("text", data.Text)
+	}
+	if data.URL != "" {
+		postdata.Set("url", data.URL)
+	}
+	if data.ShowAlert {
+		postdata.Set("show_alert", "true")
+	}
+	if data.CacheTime != 0 {
+		postdata.Set("cache_time", strconv.FormatInt(data.CacheTime, 10))
+	}
+
+	_, err := http.PostForm(t.apiURL("answerCallbackQuery"), postdata)
+	checkerr("AnswerCallback/http.PostForm", err)
+}
+
 // AnswerInlineQuery replies to an inline query
 func (t Telegram) AnswerInlineQuery(data InlineQueryResponse) error {
 	jsonresults, err := json.Marshal(data.Results)