XTZ return the mean network fees

LedgerHQ · Aug 18, 2020 · 5e1aa1c · 5e1aa1c
1 parent 4b2e5c7
commit 5e1aa1c
Showing 1 changed file with 29 additions and 10 deletions.
diff --git a/core/src/wallet/tezos/explorers/ExternalTezosLikeBlockchainExplorer.cpp b/core/src/wallet/tezos/explorers/ExternalTezosLikeBlockchainExplorer.cpp
@@ -69,11 +69,23 @@ namespace ledger {
         Future<std::shared_ptr<BigInt>>
         ExternalTezosLikeBlockchainExplorer::getFees() {
             const bool parseNumbersAsString = true;
-            auto feesField =
+            const auto feesField =
               getConfiguration()->getString(api::Configuration::BLOCKCHAIN_EXPLORER_API_ENDPOINT)
                 .value_or(api::TezosConfigurationDefaults::TEZOS_DEFAULT_API_ENDPOINT) == api::TezosConfigurationDefaults::TZSTATS_API_ENDPOINT ?
                   "fee" :
                   "fees";
+            // The best value is probably
+            // divider_tx = (n_ops - n_ops_failed - n_ops_contract -
+            //     n_seed_nonce_revelation - n_double_baking_evidence -
+            //     n_double_endorsement_evidence - n_endorsement - n_reveal)
+            // so we are counting all
+            // n_delegation + n_origination + n_activation + n_tx
+            // But the deviation of fees in all those transactions is too high so the mean fees value would not be
+            // accurate anyway.
+            //
+            // Therefore, we only return totalFees/n_tx and leave the caller make some adjustments on the value
+            // afterwards
+            const auto txCountField = "n_tx";
 
             return _http->GET("block/head")
                     .json(parseNumbersAsString).mapPtr<BigInt>(getContext(), [=](const HttpRequest::JsonResult &result) {
@@ -83,17 +95,24 @@ namespace ledger {
                         if (!json.IsObject() || !json.HasMember(feesField) ||
                             !json[feesField].IsString()) {
                             throw make_exception(api::ErrorCode::HTTP_ERROR,
-                                                 "Failed to get fees from network, no (or malformed) field \"result\" in response");
+                                                 fmt::format("Failed to get fees from network, no (or malformed) field \"{}\" in response", feesField));
                         }
-                        std::string fees = json[feesField].GetString();
-                        // Sometimes network is sending 0 for fees
-                        if (fees == "0") {
-                            fees = api::TezosConfigurationDefaults::TEZOS_DEFAULT_FEES;
-                        } else if (fees.find('.') != std::string::npos) {
-                            fees = api::BigInt::fromDecimalString(fees, 6, ".")->toString(10);
+
+                        // Return 0 if the block had no transaction at all
+                        if (!json.HasMember(txCountField) || !json[txCountField].IsString()) {
+                            return std::make_shared<BigInt>(0);
+                        }
+
+                        const auto totalTx = api::BigInt::fromIntegerString(json[txCountField].GetString(), 10);
+                        const auto totalFees = api::BigInt::fromDecimalString(json[feesField].GetString(), 6, ".");
+                        std::string fees = api::TezosConfigurationDefaults::TEZOS_DEFAULT_FEES;
+                        if (fees != "0" && totalTx->intValue() != 0) {
+                            fees = totalFees->divide(totalTx)->toString(10);
                         }
-                        // Since nodes are giving some awkward values, we set a threshold to avoid having really fees
-                        // Factor for threshold is inspired from other XTZ wallets
+                        // Since nodes are giving some awkward values, we set a threshold to avoid
+                        // having really fees Factor for threshold is inspired from other XTZ
+                        // wallets
+                        return std::make_shared<BigInt>(std::min(std::stoi(fees), std::stoi(api::TezosConfigurationDefaults::TEZOS_DEFAULT_MAX_FEES)));
                         return std::make_shared<BigInt>(std::min(std::stoi(fees), std::stoi(api::TezosConfigurationDefaults::TEZOS_DEFAULT_MAX_FEES)));
                     });
         }