fix: handle fetching conversion rate for same token (#38)

* Expand average strategy to support case when base and foreign currency are equal

* add logs for errors

api/api.go

@@ -71,6 +71,7 @@ func (h *Handler) getRate(c *gin.Context) {
 
 	gp, err := h.consensus.FilterLocalGasPriceData(h.gasPriceStore, toDomain.Name)
 	if err != nil {
+		h.log.Errorf("get gasprice process failed: %v", err)
 		ginErrorReturn(c, http.StatusInternalServerError, newReturnErrorResp(&oracleErrors.InternalServerError, err))
 		return
 	}
@@ -81,13 +82,15 @@ func (h *Handler) getRate(c *gin.Context) {
 		toDomain.BaseCurrencySymbol,
 		fromDomain.BaseCurrencySymbol)
 	if err != nil {
+		h.log.Errorf("calculate ber process failed: %v", err)
 		ginErrorReturn(c, http.StatusInternalServerError, newReturnErrorResp(&oracleErrors.InternalServerError, err))
 		return
 	}
 	h.log.Debugf("base rate calculation: to: %s, from: %s\n", toDomain.BaseCurrencySymbol, fromDomain.BaseCurrencySymbol)
 
 	ter, err := h.calculateTokenRate(resource, ber, fromDomain, toDomain)
 	if err != nil {
+		h.log.Errorf("calculate ter process failed: %v", err)
 		ginErrorReturn(c, http.StatusInternalServerError, newReturnErrorResp(&oracleErrors.InternalServerError, err))
 		return
 	}
@@ -108,6 +111,7 @@ func (h *Handler) getRate(c *gin.Context) {
 	}
 	rate.Signature, err = signature.RateSignature(h.conf, rate, h.identity, fromDomain.ID, resource.ID)
 	if err != nil {
+		h.log.Errorf("signature process failed: %v", err)
 		ginErrorReturn(c, http.StatusInternalServerError, newReturnErrorResp(&oracleErrors.InternalServerError, err))
 		return
 	}

consensus/strategy/average.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"math"
 	"strconv"
+	"time"
 
 	"github.com/ChainSafe/sygma-fee-oracle/store"
 	"github.com/ChainSafe/sygma-fee-oracle/types"
@@ -61,6 +62,15 @@ func (a *Average) GasPrice(store *store.GasPriceStore, domainName string) (*type
 }
 
 func (a *Average) ConversionRate(store *store.ConversionRateStore, base, foreign string) (*types.ConversionRate, error) {
+	if base == foreign {
+		return &types.ConversionRate{
+			Base:    base,
+			Foreign: foreign,
+			Rate:    1,
+			Time:    time.Now().Unix(),
+		}, nil
+	}
+
 	re, err := store.GetConversionRatesByCurrencyPair(base, foreign)
 	if err != nil {
 		return nil, err