all: implement API for Merchant Inquiry

The MerchantInquiry API request payment to the Duitku system (via virtual
account numbers, QRIS, e-wallet, and so on).

Ref: https://docs.duitku.com/api/en/#request-transaction

1 files changed, 117 insertions, 0 deletions

diff --git a/merchant_inquiry.go b/merchant_inquiry.go
new file mode 100644
index 0000000..26b8d35
--- /dev/null
+++ b/merchant_inquiry.go
@@ -0,0 +1,117 @@
+// SPDX-FileCopyrightText: 2023 M. Shulhan <ms@kilabit.info>
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package duitku
+
+import (
+	"crypto/md5"
+	"encoding/hex"
+	"fmt"
+)
+
+// MerchantInquiry define request data for payment using merchant.
+type MerchantInquiry struct {
+	// [REQ] Transaction number from merchant.
+	// Every request for a new transaction must use a new ID.
+	MerchantOrderId string `json:"merchantOrderId"`
+
+	// [REQ] PaymentMethod type of payment.
+	//
+	// Ref: https://docs.duitku.com/api/en/#payment-method
+	PaymentMethod string `json:"paymentMethod"`
+
+	// [REQ] Description about product/service on sale.
+	//
+	// You can fill in ProductDetails with a description of the product or
+	// service that you provide.
+	// You can also insert your store or brand name for more details.
+	// Then in ItemDetails you can fill in product variants or product
+	// model details, and other details about the products/services listed
+	// in the transaction.
+	ProductDetails string `json:"productDetails"`
+
+	// [REQ] Customer's email.
+	Email string `json:"email"`
+
+	// [REQ] The name that would be shown at bank payment system.
+	CustomerVaName string `json:"customerVaName"`
+
+	// [OPT] Additional parameter to be used by merchant.
+	// If its set, the value must be URL encoded.
+	AdditionalParam string `json:"additionalParam,omitempty"`
+
+	// [OPT] Customer's username.
+	MerchantUserInfo string `json:"merchantUserInfo,omitempty"`
+
+	// [OPT] Customer's phone number.
+	PhoneNumber string `json:"phoneNumber,omitempty"`
+
+	// [OPT] Customer's details.
+	// [REQ] If PaymentMethod is Credit (DN/AT).
+	CustomerDetail *CustomerDetail `json:"customerDetail,omitempty"`
+
+	// [OPT] Details for payment method.
+	AccountLink *AccountLink `json:"accountLink,omitempty"`
+
+	// [OPT] Detail of product being payed.
+	// [REQ] If PaymentMethod is Credit (DN/AT).
+	//
+	// The total of all price in ItemDetails must exactly match the
+	// PaymentAmount.
+	ItemDetails []ItemDetail `json:"itemDetails,omitempty"`
+
+	// [REQ] Amount of transaction.
+	//
+	// Make sure the PaymentAmount is equal to the total Price in the
+	// ItemDetails.
+	PaymentAmount int64 `json:"paymentAmount"`
+}
+
+// merchantInquiry contains internal fields that will be set by client
+// during Sign.
+type merchantInquiry struct {
+	// [REQ] A link for callback transaction.
+	// Default to ClientOptions.MerchantCallbackUrl.
+	CallbackUrl string `json:"callbackUrl"`
+
+	// [REQ] MerchantCode is a project that use Duitku.
+	//
+	// You can get this code on every project you register on the
+	// [merchant portal].
+	// Default to ClientOptions.MerchantCode.
+	//
+	// [merchant portal]: https://passport.duitku.com/merchant/Project
+	MerchantCode string `json:"merchantCode"`
+
+	// [REQ] A link that is used for redirect after exit payment page,
+	// being paid or not.
+	// Default to ClientOptions.MerchantReturnUrl.
+	ReturnUrl string `json:"returnUrl"`
+
+	// [REQ] Transaction security identification code.
+	// Formula: MD5(merchantCode + merchantOrderId + paymentAmount + apiKey).
+	Signature string `json:"signature"`
+
+	MerchantInquiry
+
+	// [OPT] Transaction expiry period in minutes.
+	// If its empty, it will set to [default] based on PaymentMethod.
+	//
+	// [default]: https://docs.duitku.com/api/en/#expiry-period
+	ExpiryPeriod int `json:"expiryPeriod,omitempty"`
+}
+
+func (inq *merchantInquiry) sign(opts ClientOptions) {
+	var merchant = opts.Merchant(inq.PaymentMethod)
+
+	inq.CallbackUrl = merchant.CallbackUrl
+	inq.MerchantCode = merchant.Code
+	inq.ReturnUrl = merchant.ReturnUrl
+
+	var (
+		plain    = fmt.Sprintf(`%s%s%d%s`, inq.MerchantCode, inq.MerchantOrderId, inq.PaymentAmount, merchant.ApiKey)
+		plainmd5 = md5.Sum([]byte(plain))
+	)
+
+	inq.Signature = hex.EncodeToString(plainmd5[:])
+}