Payment API minimal implementation.

bot.go

@@ -99,6 +99,8 @@ type Update struct {
 	Query             *Query    `json:"inline_query,omitempty"`
 
 	ChosenInlineResult *ChosenInlineResult `json:"chosen_inline_result,omitempty"`
+
+	PreCheckoutQuery *PreCheckoutQuery `json:"pre_checkout_query,omitempty"`
 }
 
 // ChosenInlineResult represents a result of an inline query that was chosen
@@ -113,6 +115,14 @@ type ChosenInlineResult struct {
 	Location *Location `json:"location,omitempty"`
 }
 
+type PreCheckoutQuery struct {
+	ID       string `json:"id"`
+	Sender   *User  `json:"from"`
+	Currency string `json:"currency"`
+	Total    int    `json:"total_amount"`
+	Payload  string `json:"invoice_payload"`
+}
+
 // Handle lets you set the handler for some command name or
 // one of the supported endpoints.
 //
@@ -379,6 +389,24 @@ func (b *Bot) incomingUpdate(upd *Update) {
 		}
 		return
 	}
+
+	if upd.PreCheckoutQuery != nil {
+		if handler, ok := b.handlers[OnCheckout]; ok {
+			if handler, ok := handler.(func(*PreCheckoutQuery)); ok {
+				// i'm not 100% sure that any of the values
+				// won't be cached, so I pass them all in:
+				go func(b *Bot, handler func(*PreCheckoutQuery),
+					r *PreCheckoutQuery) {
+					defer b.deferDebug()
+					handler(r)
+				}(b, handler, upd.PreCheckoutQuery)
+
+			} else {
+				panic("telebot: checkout handler is bad")
+			}
+		}
+		return
+	}
 }
 
 func (b *Bot) handle(end string, m *Message) bool {
@@ -747,6 +775,27 @@ func (b *Bot) Notify(recipient Recipient, action ChatAction) error {
 	return extractOkResponse(respJSON)
 }
 
+// Accept finalizes the deal.
+func (b *Bot) Accept(query *PreCheckoutQuery, errorMessage ...string) error {
+	params := map[string]string{
+		"pre_checkout_query_id": query.ID,
+	}
+
+	if len(errorMessage) == 0 {
+		params["ok"] = "True"
+	} else {
+		params["ok"] = "False"
+		params["error_message"] = errorMessage[0]
+	}
+
+	respJSON, err := b.Raw("answerPreCheckoutQuery", params)
+	if err != nil {
+		return err
+	}
+
+	return extractOkResponse(respJSON)
+}
+
 // Answer sends a response for a given inline query. A query can only
 // be responded to once, subsequent attempts to respond to the same query
 // will result in an error.

payments.go

@@ -1,21 +1,59 @@
 package telebot
 
-import "encoding/json"
+import (
+	"encoding/json"
+	"math"
+)
+
+type Invoice struct {
+	// Product name, 1-32 characters.
+	Title string `json:"title"`
+
+	// Product description, 1-255 characters.
+	Description string `json:"description"`
+
+	// Custom payload, required, 1-128 bytes.
+	Payload string `json:"payload"`
+
+	// Unique deep-linking parameter that can be used to
+	// generate this invoice when used as a start parameter.
+	Start string `json:"start_parameter"`
+
+	// Provider token to use.
+	Token string `json:"provider_token"`
+
+	Currency string `json:"currency"`
+
+	Prices []Price `json:"prices"`
+}
+
+type Price struct {
+	Label  string `json:"label"`
+	Amount int    `json:"amount"`
+}
 
 type Currency struct {
-	Code         string `json:"code"`
-	Title        string `json:"title"`
-	Symbol       string `json:"symbol"`
-	Native       string `json:"native"`
-	ThousandsSep string `json:"thousands_sep"`
-	DecimalSep   string `json:"decimal_sep"`
-	SymbolLeft   bool   `json:"symbol_left"`
-	SpaceBetween bool   `json:"space_between"`
-	Exp          int    `json:"exp"`
+	Code         string      `json:"code"`
+	Title        string      `json:"title"`
+	Symbol       string      `json:"symbol"`
+	Native       string      `json:"native"`
+	ThousandsSep string      `json:"thousands_sep"`
+	DecimalSep   string      `json:"decimal_sep"`
+	SymbolLeft   bool        `json:"symbol_left"`
+	SpaceBetween bool        `json:"space_between"`
+	Exp          int         `json:"exp"`
 	MinAmount    interface{} `json:"min_amount"`
 	MaxAmount    interface{} `json:"max_amount"`
 }
 
+func (c Currency) FromTotal(total int) float64 {
+	return float64(total) / math.Pow(10, float64(c.Exp))
+}
+
+func (c Currency) ToTotal(total float64) int {
+	return int(total) * int(math.Pow(10, float64(c.Exp)))
+}
+
 var SupportedCurrencies = map[string]Currency{}
 
 func init() {

sendable.go

@@ -1,6 +1,7 @@
 package telebot
 
 import (
+	"encoding/json"
 	"fmt"
 	"strconv"
 )
@@ -239,3 +240,27 @@ func (v *Venue) Send(b *Bot, to Recipient, opt *SendOptions) (*Message, error) {
 
 	return extractMsgResponse(respJSON)
 }
+
+// Send delivers media through bot b to recipient.
+func (i *Invoice) Send(b *Bot, to Recipient, opt *SendOptions) (*Message, error) {
+	prices, _ := json.Marshal(i.Prices)
+
+	params := map[string]string{
+		"chat_id":         to.Recipient(),
+		"title":           i.Title,
+		"description":     i.Description,
+		"start_parameter": i.Start,
+		"payload":         i.Payload,
+		"provider_token":  i.Token,
+		"currency":        i.Currency,
+		"prices":          string(prices),
+	}
+	embedSendOptions(params, opt)
+
+	respJSON, err := b.Raw("sendInvoice", params)
+	if err != nil {
+		return nil, err
+	}
+
+	return extractMsgResponse(respJSON)
+}

telebot.go

@@ -83,6 +83,11 @@ const (
 	//
 	// Handler: func(*ChosenInlineResult)
 	OnChosenInlineResult = "\achosen_inline_result"
+
+	// Will fire on PreCheckoutQuery.
+	//
+	// Handler: func(*PreCheckoutQuery)
+	OnCheckout = "\apre_checkout_query"
 )
 
 // ChatAction is a client-side status indicating bot activity.