refactor: error handling improvements (#9)

* issue on load.go

* fixed tests

* added client offline

* client_online.go

* added error handling on utils.go and unified both files

* added plugins.go

* added config, converter and libraries

* linted and fixed issues

* fixed some issues

client_offline.go

@@ -3,6 +3,7 @@ package rosetta
 import (
 	"context"
 	"encoding/hex"
+	"fmt"
 
 	"github.com/coinbase/rosetta-sdk-go/types"
 
@@ -48,17 +49,17 @@ func (c *Client) ConstructionPayload(_ context.Context, request *types.Construct
 
 	tx, err := c.converter.ToSDK().UnsignedTx(request.Operations)
 	if err != nil {
-		return nil, crgerrs.WrapError(crgerrs.ErrInvalidOperation, err.Error())
+		return nil, crgerrs.WrapError(crgerrs.ErrOffline, fmt.Sprintf("getting unsigned tx %s", err.Error()))
 	}
 
 	metadata := new(ConstructionMetadata)
 	if err = metadata.FromMetadata(request.Metadata); err != nil {
-		return nil, err
+		return nil, crgerrs.WrapError(crgerrs.ErrOffline, fmt.Sprintf("getting metadata from request %s", err.Error()))
 	}
 
 	txBytes, payloads, err := c.converter.ToRosetta().SigningComponents(tx, metadata, request.PublicKeys)
 	if err != nil {
-		return nil, err
+		return nil, crgerrs.WrapError(crgerrs.ErrOffline, fmt.Sprintf("getting signed components %s", err.Error()))
 	}
 
 	return &types.ConstructionPayloadsResponse{
@@ -75,13 +76,13 @@ func (c *Client) PreprocessOperationsToOptions(_ context.Context, req *types.Con
 	// now we need to parse the operations to cosmos sdk messages
 	tx, err := c.converter.ToSDK().UnsignedTx(req.Operations)
 	if err != nil {
-		return nil, err
+		return nil, crgerrs.WrapError(crgerrs.ErrOffline, fmt.Sprintf("converting unsigned tx %s", err.Error()))
 	}
 
 	// get the signers
 	signers, err := tx.GetSigners()
 	if err != nil {
-		return nil, err
+		return nil, crgerrs.WrapError(crgerrs.ErrOffline, fmt.Sprintf("getting signers from unsigned tx %s", err.Error()))
 	}
 
 	signersStr := make([]string, len(signers))
@@ -98,15 +99,15 @@ func (c *Client) PreprocessOperationsToOptions(_ context.Context, req *types.Con
 	meta := new(ConstructionPreprocessMetadata)
 	err = meta.FromMetadata(req.Metadata)
 	if err != nil {
-		return nil, err
+		return nil, crgerrs.WrapError(crgerrs.ErrOffline, fmt.Sprintf("parsing metadata %s", err.Error()))
 	}
 
 	if meta.GasPrice == "" {
-		return nil, crgerrs.WrapError(crgerrs.ErrBadArgument, "no gas prices")
+		return nil, crgerrs.WrapError(crgerrs.ErrOffline, "no gas price")
 	}
 
 	if meta.GasLimit == 0 {
-		return nil, crgerrs.WrapError(crgerrs.ErrBadArgument, "no gas limit")
+		return nil, crgerrs.WrapError(crgerrs.ErrOffline, "no gas limit")
 	}
 
 	// prepare the options to return
@@ -119,7 +120,7 @@ func (c *Client) PreprocessOperationsToOptions(_ context.Context, req *types.Con
 
 	metaOptions, err := options.ToMetadata()
 	if err != nil {
-		return nil, err
+		return nil, crgerrs.WrapError(crgerrs.ErrOffline, fmt.Sprintf("parsing metadata %s", err.Error()))
 	}
 	return &types.ConstructionPreprocessResponse{
 		Options:            metaOptions,
@@ -130,7 +131,7 @@ func (c *Client) PreprocessOperationsToOptions(_ context.Context, req *types.Con
 func (c *Client) AccountIdentifierFromPublicKey(pubKey *types.PublicKey) (*types.AccountIdentifier, error) {
 	pk, err := c.converter.ToSDK().PubKey(pubKey)
 	if err != nil {
-		return nil, err
+		return nil, crgerrs.WrapError(crgerrs.ErrConverter, fmt.Sprintf("converting pub key to sdk %s", err.Error()))
 	}
 
 	return &types.AccountIdentifier{