Add createInvoice mutation

invoice.go

@@ -0,0 +1,86 @@
+package sn
+
+import (
+	"encoding/json"
+	"fmt"
+	"time"
+)
+
+type Invoice struct {
+	Id                int       `json:"id,string"`
+	Hash              string    `json:"hash"`
+	Hmac              string    `json:"hmac"`
+	Bolt11            string    `json:"bolt11"`
+	CreatedAt         time.Time `json:"createdAt"`
+	ExpiresAt         time.Time `json:"expiresAt"`
+	Cancelled         bool      `json:"cancelled"`
+	ConfirmedAt       time.Time `json:"confirmedAt"`
+	SatsReceived      int       `json:"satsReceived"`
+	SatsRequested     int       `json:"satsRequested"`
+	Comment           string    `json:"nostr"`
+	IsHeld            int       `json:"isHeld"`
+	ConfirmedPreimage string    `json:"confirmedPreimage"`
+}
+
+type CreateInvoiceArgs struct {
+	Amount      int
+	ExpireSecs  int
+	HodlInvoice bool
+}
+
+type CreateInvoiceResponse struct {
+	Errors []GqlError `json:"errors"`
+	Data   struct {
+		CreateInvoice Invoice `json:"createInvoice"`
+	} `json:"data"`
+}
+
+func (c *Client) CreateInvoice(args *CreateInvoiceArgs) (*Invoice, error) {
+	if args == nil {
+		args = &CreateInvoiceArgs{}
+	}
+
+	body := GqlBody{
+		// TODO: add createdAt
+		//   when I wrote this code, createdAt returned null but is non-nullable
+		//   so I had to remove it.
+		Query: `
+		mutation createInvoice($amount: Int!, $expireSecs: Int, $hodlInvoice: Boolean) {
+			createInvoice(amount: $amount, expireSecs: $expireSecs, hodlInvoice: $hodlInvoice) {
+				id
+				hash
+				hmac
+				bolt11
+				satsRequested
+				satsReceived
+				isHeld
+				comment
+				confirmedPreimage
+				expiresAt
+				confirmedAt
+			}
+		}`,
+		Variables: map[string]interface{}{
+			"amount": args.Amount,
+		},
+	}
+
+	resp, err := c.callApi(body)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	var respBody CreateInvoiceResponse
+	err = json.NewDecoder(resp.Body).Decode(&respBody)
+	if err != nil {
+		err = fmt.Errorf("error decoding items: %w", err)
+		return nil, err
+	}
+
+	err = c.checkForErrors(respBody.Errors)
+	if err != nil {
+		return nil, err
+	}
+	return &respBody.Data.CreateInvoice, nil
+}