feat: user asset balance (#176)

Co-authored-by: Crossle Song <[email protected]>

asset.go

@@ -140,6 +140,25 @@ func AssetBalanceWithSafeUser(ctx context.Context, kernelAssetId string, su *Saf
 	return total, nil
 }
 
+
+func UserAssetBalance(ctx context.Context, userID, assetID, accessToken string) (common.Integer, error) {
+	if id, _ := uuid.FromString(assetID); assetID == id.String() {
+		assetID = crypto.Sha256Hash([]byte(assetID)).String()
+	}
+
+	membersHash := HashMembers([]string{userID})
+	outputs, err := ListUnspentOutputsByToken(ctx, membersHash, 1, assetID, accessToken)
+	if err != nil {
+		return common.Zero, err
+	}
+	var total common.Integer
+	for _, o := range outputs {
+		amt := common.NewIntegerFromString(o.Amount)
+		total = total.Add(amt)
+	}
+	return total, nil
+}
+
 func ReadAssetFee(ctx context.Context, assetId, destination string, su *SafeUser) ([]*AssetFee, error) {
 	params := url.Values{}
 	params.Set("destination", destination)

output.go

@@ -81,6 +81,41 @@ func ListOutputs(ctx context.Context, membersHash string, threshold byte, assetI
 	return resp.Data, nil
 }
 
+func ListUnspentOutputsByToken(ctx context.Context, membersHash string, threshold byte, kernelAssetId string, accessToken string) ([]*Output, error) {
+	return ListOutputsByToken(ctx, membersHash, threshold, kernelAssetId, "unspent", 0, 500, accessToken)
+}
+
+func ListOutputsByToken(ctx context.Context, membersHash string, threshold byte, assetId, state string, offset uint64, limit int, accessToken string) ([]*Output, error) {
+	v := url.Values{}
+	v.Set("members", membersHash)
+	v.Set("threshold", fmt.Sprint(threshold))
+	v.Set("limit", strconv.Itoa(limit))
+	if offset > 0 {
+		v.Set("offset", fmt.Sprint(offset))
+	}
+	if assetId != "" {
+		v.Set("asset", assetId)
+	}
+	if state != "" {
+		v.Set("state", state)
+	}
+	method, path := "GET", fmt.Sprintf("/safe/outputs?"+v.Encode())
+	body, err := Request(ctx, method, path, []byte{}, accessToken)
+
+  var resp struct {
+		Data  []*Output `json:"data"`
+		Error Error     `json:"error"`
+	}
+	err = json.Unmarshal(body, &resp)
+	if err != nil {
+		return nil, BadDataError(ctx)
+	}
+	if resp.Error.Code > 0 {
+		return nil, resp.Error
+	}
+	return resp.Data, nil
+}
+
 func GetOutput(ctx context.Context, id string, u *SafeUser) (*Output, error) {
 	method, path := "GET", fmt.Sprintf("/safe/outputs/%s", id)
 	token, err := SignAuthenticationToken(method, path, "", u)