Squashed commit of the following:

commit 5b11756af6
Author: netscrawler <mariarthyjamesoo@gmail.com>
Date:   Thu Jul 4 00:44:15 2024 +0300

    v0.1

commit c99f477e35
Author: netscrawler <mariarthyjamesoo@gmail.com>
Date:   Sun Jun 30 20:44:53 2024 +0300

    v0.0.6

internal/grpc/cnvrt/server.go

@@ -0,0 +1,59 @@
+package cnvrt
+
+import (
+	"context"
+	cnvrtv1 "github.com/netscrawler/protoss/gen/go/changeAPI"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+type Converter interface {
+	Convert(ctx context.Context,
+		amount uint32,
+		targetCurrency string,
+	) (convertedAmount uint32, rate float32, err error)
+}
+
+type serverAPI struct {
+	cnvrtv1.UnimplementedConverterServer
+	convert Converter
+}
+
+func Register(gRPC *grpc.Server, convert Converter) {
+	cnvrtv1.RegisterConverterServer(gRPC, &serverAPI{convert: convert})
+}
+
+func (s *serverAPI) Convert(
+	ctx context.Context,
+	req *cnvrtv1.ConvertRequest) (
+	*cnvrtv1.ConvertResponse, error) {
+	if !isValidCurrency(req.GetTargetCurrency()) {
+		return nil, status.Error(codes.InvalidArgument, "Invalid target currency")
+	}
+
+	convertedAmount, rate, err := s.convert.Convert(ctx, req.GetAmount(), req.GetTargetCurrency())
+	if err != nil {
+		//todo error handler
+		return nil, status.Error(codes.Internal, "Internal error")
+	}
+	return &cnvrtv1.ConvertResponse{
+		BaseAmount:        req.GetAmount(),
+		ConvertedAmount:   convertedAmount,
+		ConvertedCurrency: req.GetTargetCurrency(),
+		Rate:              rate,
+	}, nil
+}
+
+func isValidCurrency(currency string) bool {
+
+	currencies := map[string]bool{
+		"AUD": true, "GBP": true, "BYR": true, "DKK": true, "USD": true, "EUR": true,
+		"ISK": true, "KZT": true, "CAD": true, "NOK": true, "XDR": true, "SGD": true,
+		"TRL": true, "UAH": true, "SEK": true, "CHF": true, "JPY": true,
+	}
+	if currencies[currency] {
+		return true
+	}
+	return false
+}