feat: add mobile transaction verification functionality for esewa

esewa/types.go

@@ -39,3 +39,29 @@ type EsewaConfig struct {
 	signatureMap   map[string]string
 	ReponsePayload *EsewaVerifyPayload
 }
+
+type VerifyInput struct {
+	TxnRefId       string
+	ProductId      string
+	Amount         string
+	MerchantId     string
+	MerchantSecret string
+	Environment    string
+}
+
+type EsewaTransactionVerificationResponse struct {
+	ProductId   string `json:"productId"`
+	ProductName string `json:"productName"`
+	TotalAmount string `json:"totalAmount"`
+	Code        string `json:"code"`
+	Message     struct {
+		TechnicalSuccessMessage string `json:"technicalSuccessMessage"`
+		SuccessMessage          string `json:"successMessage"`
+	} `json:"message"`
+	TransactionDetails struct {
+		Date        string `json:"date"`
+		ReferenceId string `json:"referenceId"`
+		Status      string `json:"status"`
+	} `json:"transactionDetails"`
+	MerchantName string `json:"merchantName"`
+}

esewa/verify.go

@@ -0,0 +1,64 @@
+package esewa
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+)
+
+func VerifyMobileTransaction(input VerifyInput) ([]byte, error) {
+	if input.TxnRefId == "" && (input.ProductId == "" || input.Amount == "") {
+		return nil, errors.New("either txnRefId or both productId and amount must be provided")
+	}
+
+	baseURL := "https://rc.esewa.com.np/mobile/transaction"
+	if input.Environment == "live" {
+		baseURL = "https://esewa.com.np/mobile/transaction"
+	}
+	var url string
+	if input.TxnRefId != "" {
+		url = fmt.Sprintf("%s?txnRefId=%s", baseURL, input.TxnRefId)
+	} else {
+		url = fmt.Sprintf("%s?productId=%s&amount=%s", baseURL, input.ProductId, input.Amount)
+	}
+
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, err
+	}
+	// Set merchantId and merchantSecret as headers if provided
+	if input.MerchantId != "" {
+		req.Header.Set("merchantId", input.MerchantId)
+	}
+	if input.MerchantSecret != "" {
+		req.Header.Set("merchantSecret", input.MerchantSecret)
+	}
+
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, err
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return body, fmt.Errorf("verification failed: status %d", resp.StatusCode)
+	}
+
+	return body, nil
+}
+
+func ParseVerificationResponse(data []byte) ([]EsewaTransactionVerificationResponse, error) {
+	var resp []EsewaTransactionVerificationResponse
+	err := json.Unmarshal(data, &resp)
+	if err != nil {
+		return nil, err
+	}
+	return resp, nil
+}