From f620e39c71e2f200e99145aaa3370df307d060a6 Mon Sep 17 00:00:00 2001
From: Martin Hloska <martin.hloska@gmail.com>
Date: Wed, 9 Jun 2021 18:07:25 +0200
Subject: [PATCH 1/8] feat(multi-payment): add fallback price for each accepted
 currencies to use if pool does not exist

---
 pallets/transaction-multi-payment/Cargo.toml  |  2 +
 pallets/transaction-multi-payment/src/lib.rs  | 48 ++++++++++++-------
 pallets/transaction-multi-payment/src/mock.rs |  7 ++-
 .../transaction-multi-payment/src/tests.rs    | 26 +++++-----
 4 files changed, 50 insertions(+), 33 deletions(-)

diff --git a/pallets/transaction-multi-payment/Cargo.toml b/pallets/transaction-multi-payment/Cargo.toml
index 855fca888..910d2086e 100644
--- a/pallets/transaction-multi-payment/Cargo.toml
+++ b/pallets/transaction-multi-payment/Cargo.toml
@@ -62,4 +62,6 @@ std = [
   'sp-runtime/std',
   'orml-tokens/std',
   'orml-traits/std',
+  'pallet-balances/std',
+  'pallet-asset-registry/std',
 ]
diff --git a/pallets/transaction-multi-payment/src/lib.rs b/pallets/transaction-multi-payment/src/lib.rs
index 92728d012..00fae53c4 100644
--- a/pallets/transaction-multi-payment/src/lib.rs
+++ b/pallets/transaction-multi-payment/src/lib.rs
@@ -52,8 +52,6 @@ use primitives::asset::AssetPair;
 use primitives::traits::{CurrencySwap, AMM};
 use primitives::{Amount, AssetId, Balance, CORE_ASSET_ID};
 
-use orml_utilities::OrderedSet;
-
 type NegativeImbalanceOf<C, T> = <C as Currency<<T as frame_system::Config>::AccountId>>::NegativeImbalance;
 // Re-export pallet items so that they can be accessed from the crate namespace.
 pub use pallet::*;
@@ -63,6 +61,7 @@ pub mod pallet {
 	use super::*;
 	use frame_support::pallet_prelude::*;
 	use frame_system::pallet_prelude::OriginFor;
+	use primitives::Price;
 
 	#[pallet::pallet]
 	pub struct Pallet<T>(_);
@@ -146,12 +145,12 @@ pub mod pallet {
 	/// Account currency map
 	#[pallet::storage]
 	#[pallet::getter(fn get_currency)]
-	pub type AccountCurrencyMap<T: Config> = StorageMap<_, Blake2_128Concat, T::AccountId, Option<AssetId>, ValueQuery>;
+	pub type AccountCurrencyMap<T: Config> = StorageMap<_, Blake2_128Concat, T::AccountId, AssetId, OptionQuery>;
 
 	/// Curated list of currencies which fees can be paid with
 	#[pallet::storage]
 	#[pallet::getter(fn currencies)]
-	pub type AcceptedCurrencies<T: Config> = StorageValue<_, OrderedSet<AssetId>, ValueQuery>;
+	pub type AcceptedCurrencies<T: Config> = StorageMap<_, Twox64Concat, AssetId, Price, OptionQuery>;
 
 	#[pallet::storage]
 	#[pallet::getter(fn authorities)]
@@ -159,7 +158,7 @@ pub mod pallet {
 
 	#[pallet::genesis_config]
 	pub struct GenesisConfig<T: Config> {
-		pub currencies: OrderedSet<AssetId>,
+		pub currencies: Vec<(AssetId, Price)>,
 		pub authorities: Vec<T::AccountId>,
 	}
 
@@ -167,8 +166,8 @@ pub mod pallet {
 	impl<T: Config> Default for GenesisConfig<T> {
 		fn default() -> Self {
 			GenesisConfig {
-				currencies: OrderedSet::new(),
 				authorities: vec![],
+				currencies: vec![],
 			}
 		}
 	}
@@ -177,7 +176,11 @@ pub mod pallet {
 	impl<T: Config> GenesisBuild<T> for GenesisConfig<T> {
 		fn build(&self) {
 			Authorities::<T>::put(self.authorities.clone());
-			AcceptedCurrencies::<T>::put(self.currencies.clone());
+
+			for (asset, price) in &self.currencies {
+				AcceptedCurrencies::<T>::insert(asset, price);
+			}
+			//AcceptedCurrencies::<T>::put(self.currencies.clone());
 		}
 	}
 	#[pallet::call]
@@ -197,12 +200,12 @@ pub mod pallet {
 		pub fn set_currency(origin: OriginFor<T>, currency: AssetId) -> DispatchResultWithPostInfo {
 			let who = ensure_signed(origin)?;
 
-			if currency == CORE_ASSET_ID || Self::currencies().contains(&currency) {
+			if currency == CORE_ASSET_ID || AcceptedCurrencies::<T>::contains_key(&currency) {
 				if T::MultiCurrency::free_balance(currency, &who) == Balance::zero() {
 					return Err(Error::<T>::ZeroBalance.into());
 				}
 
-				<AccountCurrencyMap<T>>::insert(who.clone(), Some(currency));
+				<AccountCurrencyMap<T>>::insert(who.clone(), currency);
 
 				if T::WithdrawFeeForSetCurrency::get() == Pays::Yes {
 					Self::withdraw_set_fee(&who, currency)?;
@@ -224,7 +227,7 @@ pub mod pallet {
 		///
 		/// Emits `CurrencyAdded` event when successful.
 		#[pallet::weight((<T as Config>::WeightInfo::add_currency(), DispatchClass::Normal, Pays::No))]
-		pub fn add_currency(origin: OriginFor<T>, currency: AssetId) -> DispatchResultWithPostInfo {
+		pub fn add_currency(origin: OriginFor<T>, currency: AssetId, price: Price) -> DispatchResultWithPostInfo {
 			let who = ensure_signed(origin)?;
 
 			ensure!(currency != CORE_ASSET_ID, Error::<T>::CoreAssetNotAllowed);
@@ -232,11 +235,15 @@ pub mod pallet {
 			// Only selected accounts can perform this action
 			ensure!(Self::authorities().contains(&who), Error::<T>::NotAllowed);
 
-			if AcceptedCurrencies::<T>::mutate(|x| x.insert(currency)) {
+			AcceptedCurrencies::<T>::try_mutate_exists(currency, |maybe_price| -> DispatchResultWithPostInfo {
+				if maybe_price.is_some() {
+					return Err(Error::<T>::AlreadyAccepted.into());
+				}
+
+				*maybe_price = Some(price);
 				Self::deposit_event(Event::CurrencyAdded(who, currency));
-				return Ok(().into());
-			}
-			Err(Error::<T>::AlreadyAccepted.into())
+				Ok(().into())
+			})
 		}
 
 		/// Remove currency from the list of supported currencies
@@ -254,12 +261,17 @@ pub mod pallet {
 			// Only selected accounts can perform this action
 			ensure!(Self::authorities().contains(&who), Error::<T>::NotAllowed);
 
-			if AcceptedCurrencies::<T>::mutate(|x| x.remove(&currency)) {
+			AcceptedCurrencies::<T>::try_mutate(currency, |x| -> DispatchResultWithPostInfo {
+				if x.is_none() {
+					return Err(Error::<T>::UnsupportedCurrency.into());
+				}
+
+				*x = None;
+
 				Self::deposit_event(Event::CurrencyRemoved(who, currency));
-				return Ok(().into());
-			}
 
-			Err(Error::<T>::UnsupportedCurrency.into())
+				Ok(().into())
+			})
 		}
 
 		/// Add an account as member to list of authorities who can manage list of accepted currencies
diff --git a/pallets/transaction-multi-payment/src/mock.rs b/pallets/transaction-multi-payment/src/mock.rs
index c538cbc9a..1c5d13994 100644
--- a/pallets/transaction-multi-payment/src/mock.rs
+++ b/pallets/transaction-multi-payment/src/mock.rs
@@ -31,7 +31,7 @@ use sp_runtime::{
 use frame_support::weights::IdentityFee;
 use frame_support::weights::Weight;
 use orml_currencies::BasicCurrencyAdapter;
-use primitives::{Amount, AssetId, Balance};
+use primitives::{Amount, AssetId, Balance, Price};
 
 use pallet_xyk::AssetPairAccountIdFor;
 use std::cell::RefCell;
@@ -291,7 +291,10 @@ impl ExtBuilder {
 		.unwrap();
 
 		crate::GenesisConfig::<Test> {
-			currencies: OrderedSet::from(vec![SUPPORTED_CURRENCY_NO_BALANCE, SUPPORTED_CURRENCY_WITH_BALANCE]),
+			currencies: vec![
+				(SUPPORTED_CURRENCY_NO_BALANCE, Price::from(1)),
+				(SUPPORTED_CURRENCY_WITH_BALANCE, Price::from_float(0.2)),
+			],
 			authorities: vec![self.payment_authority],
 		}
 		.assimilate_storage(&mut t)
diff --git a/pallets/transaction-multi-payment/src/tests.rs b/pallets/transaction-multi-payment/src/tests.rs
index 550870648..48a953f46 100644
--- a/pallets/transaction-multi-payment/src/tests.rs
+++ b/pallets/transaction-multi-payment/src/tests.rs
@@ -22,7 +22,6 @@ use sp_runtime::traits::SignedExtension;
 
 use frame_support::weights::DispatchInfo;
 use orml_traits::MultiCurrency;
-use orml_utilities::OrderedSet;
 use pallet_balances::Call as BalancesCall;
 use primitives::Price;
 
@@ -216,29 +215,29 @@ fn fee_payment_non_native_insufficient_balance() {
 #[test]
 fn add_new_accepted_currency() {
 	ExtBuilder::default().base_weight(5).build().execute_with(|| {
-		assert_eq!(PaymentPallet::currencies(), OrderedSet::from(vec![2000, 3000]));
-
-		assert_ok!(PaymentPallet::add_currency(Origin::signed(BOB), 100));
-		assert_eq!(PaymentPallet::currencies(), OrderedSet::from(vec![2000, 3000, 100]));
+		assert_ok!(PaymentPallet::add_currency(
+			Origin::signed(BOB),
+			100,
+			Price::from_float(1.1)
+		));
+		assert_eq!(PaymentPallet::currencies(100), Some(Price::from_float(1.1)));
 		assert_noop!(
-			PaymentPallet::add_currency(Origin::signed(ALICE), 1000),
+			PaymentPallet::add_currency(Origin::signed(ALICE), 1000, Price::from_float(1.2)),
 			Error::<Test>::NotAllowed
 		);
 		assert_noop!(
-			PaymentPallet::add_currency(Origin::signed(BOB), 100),
+			PaymentPallet::add_currency(Origin::signed(BOB), 100, Price::from(10)),
 			Error::<Test>::AlreadyAccepted
 		);
-		assert_eq!(PaymentPallet::currencies(), OrderedSet::from(vec![2000, 3000, 100]));
+		assert_eq!(PaymentPallet::currencies(100), Some(Price::from_float(1.1)));
 	});
 }
 
 #[test]
 fn removed_accepted_currency() {
 	ExtBuilder::default().base_weight(5).build().execute_with(|| {
-		assert_eq!(PaymentPallet::currencies(), OrderedSet::from(vec![2000, 3000]));
-
-		assert_ok!(PaymentPallet::add_currency(Origin::signed(BOB), 100));
-		assert_eq!(PaymentPallet::currencies(), OrderedSet::from(vec![2000, 3000, 100]));
+		assert_ok!(PaymentPallet::add_currency(Origin::signed(BOB), 100, Price::from(3)));
+		assert_eq!(PaymentPallet::currencies(100), Some(Price::from(3)));
 
 		assert_noop!(
 			PaymentPallet::remove_currency(Origin::signed(ALICE), 100),
@@ -252,11 +251,12 @@ fn removed_accepted_currency() {
 
 		assert_ok!(PaymentPallet::remove_currency(Origin::signed(BOB), 100));
 
+		assert_eq!(PaymentPallet::currencies(100), None);
+
 		assert_noop!(
 			PaymentPallet::remove_currency(Origin::signed(BOB), 100),
 			Error::<Test>::UnsupportedCurrency
 		);
-		assert_eq!(PaymentPallet::currencies(), OrderedSet::from(vec![2000, 3000]));
 	});
 }
 

From ba6330b625e6bb1beaa4af0b1f8a8a64467ff3eb Mon Sep 17 00:00:00 2001
From: Martin Hloska <martin.hloska@gmail.com>
Date: Thu, 10 Jun 2021 10:21:59 +0200
Subject: [PATCH 2/8] add fallback account

---
 pallets/transaction-multi-payment/src/lib.rs  | 17 ++++++++++++++++-
 pallets/transaction-multi-payment/src/mock.rs |  2 ++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/pallets/transaction-multi-payment/src/lib.rs b/pallets/transaction-multi-payment/src/lib.rs
index 00fae53c4..e76595e66 100644
--- a/pallets/transaction-multi-payment/src/lib.rs
+++ b/pallets/transaction-multi-payment/src/lib.rs
@@ -140,6 +140,9 @@ pub mod pallet {
 
 		/// Account is not a member of authorities.
 		NotAMember,
+
+		/// Fallback price cannot be zero.
+		ZeroPrice,
 	}
 
 	/// Account currency map
@@ -156,10 +159,16 @@ pub mod pallet {
 	#[pallet::getter(fn authorities)]
 	pub type Authorities<T: Config> = StorageValue<_, Vec<T::AccountId>, ValueQuery>;
 
+	/// Account to use when pool does not exist.
+	#[pallet::storage]
+	#[pallet::getter(fn fallback_acccount)]
+	pub type FallbackAccount<T: Config> = StorageValue<_, T::AccountId, ValueQuery>;
+
 	#[pallet::genesis_config]
 	pub struct GenesisConfig<T: Config> {
 		pub currencies: Vec<(AssetId, Price)>,
 		pub authorities: Vec<T::AccountId>,
+		pub fallback_account: T::AccountId,
 	}
 
 	#[cfg(feature = "std")]
@@ -168,6 +177,7 @@ pub mod pallet {
 			GenesisConfig {
 				authorities: vec![],
 				currencies: vec![],
+				fallback_account: Default::default(),
 			}
 		}
 	}
@@ -175,12 +185,17 @@ pub mod pallet {
 	#[pallet::genesis_build]
 	impl<T: Config> GenesisBuild<T> for GenesisConfig<T> {
 		fn build(&self) {
+			if self.fallback_account == Default::default() {
+				panic!("Fallback account is not set");
+			}
+
+			FallbackAccount::<T>::put(self.fallback_account.clone());
+
 			Authorities::<T>::put(self.authorities.clone());
 
 			for (asset, price) in &self.currencies {
 				AcceptedCurrencies::<T>::insert(asset, price);
 			}
-			//AcceptedCurrencies::<T>::put(self.currencies.clone());
 		}
 	}
 	#[pallet::call]
diff --git a/pallets/transaction-multi-payment/src/mock.rs b/pallets/transaction-multi-payment/src/mock.rs
index 1c5d13994..1c5865d18 100644
--- a/pallets/transaction-multi-payment/src/mock.rs
+++ b/pallets/transaction-multi-payment/src/mock.rs
@@ -45,6 +45,7 @@ pub const INITIAL_BALANCE: Balance = 1000_000_000_000_000u128;
 
 pub const ALICE: AccountId = 1;
 pub const BOB: AccountId = 2;
+pub const FALLBACK_ACCOUNT: AccountId = 300;
 
 pub const HDX: AssetId = 0;
 pub const SUPPORTED_CURRENCY_NO_BALANCE: AssetId = 2000;
@@ -296,6 +297,7 @@ impl ExtBuilder {
 				(SUPPORTED_CURRENCY_WITH_BALANCE, Price::from_float(0.2)),
 			],
 			authorities: vec![self.payment_authority],
+			fallback_account: FALLBACK_ACCOUNT,
 		}
 		.assimilate_storage(&mut t)
 		.unwrap();

From f03868c101cb0f17aa9a59153d95f3ee8723ab9a Mon Sep 17 00:00:00 2001
From: Martin Hloska <martin.hloska@gmail.com>
Date: Thu, 10 Jun 2021 11:06:51 +0200
Subject: [PATCH 3/8] feat(multi-payment): use fixed price if pool does not
 exist

---
 pallets/transaction-multi-payment/src/lib.rs  | 67 +++++++++++++++----
 pallets/transaction-multi-payment/src/mock.rs |  2 +-
 .../transaction-multi-payment/src/tests.rs    | 65 ++++++++++++++++++
 .../transaction-multi-payment/src/traits.rs   | 11 +++
 primitives/src/traits.rs                      |  5 --
 5 files changed, 132 insertions(+), 18 deletions(-)
 create mode 100644 pallets/transaction-multi-payment/src/traits.rs

diff --git a/pallets/transaction-multi-payment/src/lib.rs b/pallets/transaction-multi-payment/src/lib.rs
index e76595e66..64251bb6b 100644
--- a/pallets/transaction-multi-payment/src/lib.rs
+++ b/pallets/transaction-multi-payment/src/lib.rs
@@ -27,6 +27,7 @@ mod mock;
 
 #[cfg(test)]
 mod tests;
+mod traits;
 
 use frame_support::{
 	dispatch::DispatchResult,
@@ -46,10 +47,11 @@ use sp_std::prelude::*;
 use pallet_transaction_payment::OnChargeTransaction;
 use sp_std::marker::PhantomData;
 
+use frame_support::sp_runtime::FixedPointNumber;
 use frame_support::weights::{Pays, Weight};
 use orml_traits::{MultiCurrency, MultiCurrencyExtended};
 use primitives::asset::AssetPair;
-use primitives::traits::{CurrencySwap, AMM};
+use primitives::traits::AMM;
 use primitives::{Amount, AssetId, Balance, CORE_ASSET_ID};
 
 type NegativeImbalanceOf<C, T> = <C as Currency<<T as frame_system::Config>::AccountId>>::NegativeImbalance;
@@ -143,6 +145,12 @@ pub mod pallet {
 
 		/// Fallback price cannot be zero.
 		ZeroPrice,
+
+		/// Fallback price was not found.
+		FallbackPriceNotFound,
+
+		/// Math overflow
+		Overflow,
 	}
 
 	/// Account currency map
@@ -161,7 +169,7 @@ pub mod pallet {
 
 	/// Account to use when pool does not exist.
 	#[pallet::storage]
-	#[pallet::getter(fn fallback_acccount)]
+	#[pallet::getter(fn fallback_account)]
 	pub type FallbackAccount<T: Config> = StorageValue<_, T::AccountId, ValueQuery>;
 
 	#[pallet::genesis_config]
@@ -330,6 +338,10 @@ pub mod pallet {
 }
 
 impl<T: Config> Pallet<T> {
+	fn account_currency(who: &T::AccountId) -> AssetId {
+		Pallet::<T>::get_currency(who).unwrap_or(CORE_ASSET_ID)
+	}
+
 	/// Execute a trade to buy HDX and sell selected currency.
 	pub fn swap_currency(who: &T::AccountId, fee: Balance) -> DispatchResult {
 		// Let's determine currency in which user would like to pay the fee
@@ -378,9 +390,34 @@ impl<T: Config> Pallet<T> {
 	}
 }
 
+use crate::traits::PaymentSwapResult;
+use frame_support::dispatch::DispatchError;
+use traits::CurrencySwap;
+
 impl<T: Config> CurrencySwap<<T as frame_system::Config>::AccountId, Balance> for Pallet<T> {
-	fn swap_currency(who: &T::AccountId, fee: u128) -> DispatchResult {
-		Self::swap_currency(who, fee)
+	fn swap(who: &T::AccountId, fee: u128) -> Result<PaymentSwapResult, DispatchError> {
+		match Self::account_currency(who) {
+			CORE_ASSET_ID => Ok(PaymentSwapResult::NATIVE),
+			currency => {
+				if T::AMMPool::exists(AssetPair {
+					asset_in: currency,
+					asset_out: CORE_ASSET_ID,
+				}) {
+					Self::swap_currency(who, fee)?;
+					Ok(PaymentSwapResult::SWAPPED)
+				} else {
+					// If pool does not exists, let's use the currency fixed price
+
+					let price = Self::currencies(currency).ok_or(Error::<T>::FallbackPriceNotFound)?;
+
+					let amount = price.checked_mul_int(fee).ok_or(Error::<T>::Overflow)?;
+
+					T::MultiCurrency::transfer(currency, who, &Self::fallback_account(), amount)?;
+
+					Ok(PaymentSwapResult::TRANSFERRED)
+				}
+			}
+		}
 	}
 }
 
@@ -423,14 +460,20 @@ where
 			WithdrawReasons::TRANSACTION_PAYMENT | WithdrawReasons::TIP
 		};
 
-		if SW::swap_currency(&who, fee.into()).is_err() {
-			return Err(InvalidTransaction::Payment.into());
-		}
-
-		match C::withdraw(who, fee, withdraw_reason, ExistenceRequirement::KeepAlive) {
-			Ok(imbalance) => Ok(Some(imbalance)),
-			Err(_) => Err(InvalidTransaction::Payment.into()),
-		}
+		return if let Some(detail) = SW::swap(&who, fee.into()).ok() {
+			match detail {
+				PaymentSwapResult::TRANSFERRED => Ok(None),
+				PaymentSwapResult::ERROR => Err(InvalidTransaction::Payment.into()),
+				PaymentSwapResult::NATIVE | PaymentSwapResult::SWAPPED => {
+					match C::withdraw(who, fee, withdraw_reason, ExistenceRequirement::KeepAlive) {
+						Ok(imbalance) => Ok(Some(imbalance)),
+						Err(_) => Err(InvalidTransaction::Payment.into()),
+					}
+				}
+			}
+		} else {
+			Err(InvalidTransaction::Payment.into())
+		};
 	}
 
 	/// Hand the fee and the tip over to the `[OnUnbalanced]` implementation.
diff --git a/pallets/transaction-multi-payment/src/mock.rs b/pallets/transaction-multi-payment/src/mock.rs
index 1c5865d18..47e7b741d 100644
--- a/pallets/transaction-multi-payment/src/mock.rs
+++ b/pallets/transaction-multi-payment/src/mock.rs
@@ -294,7 +294,7 @@ impl ExtBuilder {
 		crate::GenesisConfig::<Test> {
 			currencies: vec![
 				(SUPPORTED_CURRENCY_NO_BALANCE, Price::from(1)),
-				(SUPPORTED_CURRENCY_WITH_BALANCE, Price::from_float(0.2)),
+				(SUPPORTED_CURRENCY_WITH_BALANCE, Price::from_float(1.5)),
 			],
 			authorities: vec![self.payment_authority],
 			fallback_account: FALLBACK_ACCOUNT,
diff --git a/pallets/transaction-multi-payment/src/tests.rs b/pallets/transaction-multi-payment/src/tests.rs
index 48a953f46..0c731d747 100644
--- a/pallets/transaction-multi-payment/src/tests.rs
+++ b/pallets/transaction-multi-payment/src/tests.rs
@@ -298,3 +298,68 @@ fn add_member() {
 		);
 	});
 }
+
+#[test]
+fn fee_payment_in_non_native_currency_with_no_pool() {
+	const CHARLIE: AccountId = 5;
+
+	ExtBuilder::default()
+		.base_weight(5)
+		.account_native_balance(CHARLIE, 0)
+		.account_tokens(CHARLIE, SUPPORTED_CURRENCY_WITH_BALANCE, 1000)
+		.build()
+		.execute_with(|| {
+			// Make sure Charlie ain't got a penny!
+			assert_eq!(Balances::free_balance(CHARLIE), 0);
+
+			assert_ok!(PaymentPallet::set_currency(
+				Origin::signed(CHARLIE),
+				SUPPORTED_CURRENCY_WITH_BALANCE
+			));
+
+			let len = 10;
+			let info = DispatchInfo {
+				weight: 5,
+				..Default::default()
+			};
+
+			assert!(ChargeTransactionPayment::<Test>::from(0)
+				.pre_dispatch(&CHARLIE, CALL, &info, len)
+				.is_ok());
+
+			//Native balance check - Charlie should be still broke!
+			assert_eq!(Balances::free_balance(CHARLIE), 0);
+
+			// token check should be less by the fee amount and -1 as fee in amm swap
+			assert_eq!(Tokens::free_balance(SUPPORTED_CURRENCY_WITH_BALANCE, &CHARLIE), 970);
+		});
+}
+
+#[test]
+fn fee_payment_non_native_insufficient_balance_with_no_pool() {
+	const CHARLIE: AccountId = 5;
+
+	ExtBuilder::default()
+		.base_weight(5)
+		.account_native_balance(CHARLIE, 0)
+		.account_tokens(CHARLIE, SUPPORTED_CURRENCY_WITH_BALANCE, 10)
+		.build()
+		.execute_with(|| {
+			assert_ok!(PaymentPallet::set_currency(
+				Origin::signed(CHARLIE),
+				SUPPORTED_CURRENCY_WITH_BALANCE
+			));
+
+			let len = 10;
+			let info = DispatchInfo {
+				weight: 5,
+				..Default::default()
+			};
+
+			assert!(ChargeTransactionPayment::<Test>::from(0)
+				.pre_dispatch(&CHARLIE, CALL, &info, len)
+				.is_err());
+
+			assert_eq!(Tokens::free_balance(SUPPORTED_CURRENCY_WITH_BALANCE, &CHARLIE), 10);
+		});
+}
diff --git a/pallets/transaction-multi-payment/src/traits.rs b/pallets/transaction-multi-payment/src/traits.rs
new file mode 100644
index 000000000..6366f9e34
--- /dev/null
+++ b/pallets/transaction-multi-payment/src/traits.rs
@@ -0,0 +1,11 @@
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum PaymentSwapResult {
+	NATIVE,
+	ERROR,
+	SWAPPED,
+	TRANSFERRED,
+}
+
+pub trait CurrencySwap<AccountId, Balance> {
+	fn swap(who: &AccountId, fee: Balance) -> Result<PaymentSwapResult, frame_support::sp_runtime::DispatchError>;
+}
diff --git a/primitives/src/traits.rs b/primitives/src/traits.rs
index 269adeee4..8b43abf72 100644
--- a/primitives/src/traits.rs
+++ b/primitives/src/traits.rs
@@ -18,7 +18,6 @@
 #![allow(clippy::upper_case_acronyms)]
 
 use frame_support::dispatch;
-use frame_support::dispatch::DispatchResult;
 use sp_std::vec::Vec;
 
 /// Hold information to perform amm transfer
@@ -107,7 +106,3 @@ pub trait Resolver<AccountId, Intention, E> {
 	/// Intention ```intention``` must be validated prior to call this function.
 	fn resolve_matched_intentions(pair_account: &AccountId, intention: &Intention, matched: &[Intention]);
 }
-
-pub trait CurrencySwap<AccountId, Balance> {
-	fn swap_currency(who: &AccountId, fee: Balance) -> DispatchResult;
-}

From 1449395d8a35ae77bf4f7223680bd0cce17292ec Mon Sep 17 00:00:00 2001
From: Martin Hloska <martin.hloska@gmail.com>
Date: Thu, 10 Jun 2021 11:19:34 +0200
Subject: [PATCH 4/8] fix benchmarks and update runtime and chainspec

---
 node/src/chain_spec.rs                        | 18 ++++++++++++++----
 .../benchmarking/src/lib.rs                   | 19 +++++++++++--------
 .../benchmarking/src/mock.rs                  |  3 ++-
 runtime/src/lib.rs                            |  2 +-
 4 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/node/src/chain_spec.rs b/node/src/chain_spec.rs
index ef4d5c088..9151625ae 100644
--- a/node/src/chain_spec.rs
+++ b/node/src/chain_spec.rs
@@ -5,9 +5,9 @@ use hydra_dx_runtime::opaque::SessionKeys;
 use hydra_dx_runtime::pallet_claims::EthereumAddress;
 use hydra_dx_runtime::{
 	AccountId, AssetRegistryConfig, AuthorityDiscoveryConfig, BabeConfig, BalancesConfig, ClaimsConfig, CouncilConfig,
-	ElectionsConfig, FaucetConfig, GenesisConfig, GenesisHistoryConfig, GrandpaConfig, ImOnlineConfig, Perbill,
-	SessionConfig, Signature, StakerStatus, StakingConfig, SudoConfig, SystemConfig, TechnicalCommitteeConfig,
-	TokensConfig, CORE_ASSET_ID, WASM_BINARY,
+	ElectionsConfig, FaucetConfig, GenesisConfig, GenesisHistoryConfig, GrandpaConfig, ImOnlineConfig,
+	MultiTransactionPaymentConfig, Perbill, SessionConfig, Signature, StakerStatus, StakingConfig, SudoConfig,
+	SystemConfig, TechnicalCommitteeConfig, TokensConfig, CORE_ASSET_ID, WASM_BINARY,
 };
 use pallet_staking::Forcing;
 use sc_service::ChainType;
@@ -317,7 +317,7 @@ fn testnet_genesis(
 		pallet_grandpa: Default::default(),
 		pallet_sudo: SudoConfig {
 			// Assign network admin rights.
-			key: root_key,
+			key: root_key.clone(),
 		},
 		pallet_asset_registry: AssetRegistryConfig {
 			core_asset_id: CORE_ASSET_ID,
@@ -335,6 +335,11 @@ fn testnet_genesis(
 			],
 			next_asset_id: 11,
 		},
+		pallet_transaction_multi_payment: MultiTransactionPaymentConfig {
+			currencies: vec![],
+			authorities: vec![],
+			fallback_account: root_key,
+		},
 		orml_tokens: TokensConfig {
 			endowed_accounts: endowed_accounts
 				.iter()
@@ -470,6 +475,11 @@ fn lerna_genesis(
 			asset_ids: vec![],
 			next_asset_id: 1,
 		},
+		pallet_transaction_multi_payment: MultiTransactionPaymentConfig {
+			currencies: vec![],
+			authorities: vec![],
+			fallback_account: hex!["6d6f646c70792f74727372790000000000000000000000000000000000000000"].into(),
+		},
 		orml_tokens: TokensConfig {
 			endowed_accounts: endowed_accounts.iter().flat_map(|_x| vec![]).collect(),
 		},
diff --git a/pallets/transaction-multi-payment/benchmarking/src/lib.rs b/pallets/transaction-multi-payment/benchmarking/src/lib.rs
index c5b4dec1f..d626c1de1 100644
--- a/pallets/transaction-multi-payment/benchmarking/src/lib.rs
+++ b/pallets/transaction-multi-payment/benchmarking/src/lib.rs
@@ -20,11 +20,11 @@
 mod mock;
 
 use sp_std::prelude::*;
+use sp_std::vec;
 
 use frame_benchmarking::{account, benchmarks};
 use frame_system::RawOrigin;
 use orml_traits::{MultiCurrency, MultiCurrencyExtended};
-use orml_utilities::OrderedSet;
 use pallet_transaction_multi_payment::Pallet as MultiPaymentModule;
 use primitives::{Amount, AssetId, Balance, Price};
 
@@ -69,7 +69,7 @@ benchmarks! {
 		let maker = funded_account::<T>("maker", 1);
 		initialize_pool::<T>(maker.clone(), ASSET_ID, 1000, Price::from(1))?;
 		MultiPaymentModule::<T>::add_new_member(&maker);
-		MultiPaymentModule::<T>::add_currency(RawOrigin::Signed(maker).into(), ASSET_ID)?;
+		MultiPaymentModule::<T>::add_currency(RawOrigin::Signed(maker).into(), ASSET_ID, Price::from(10))?;
 
 		let caller = funded_account::<T>("caller", 2);
 		MultiPaymentModule::<T>::set_currency(RawOrigin::Signed(caller.clone()).into(), ASSET_ID)?;
@@ -83,7 +83,7 @@ benchmarks! {
 	set_currency {
 		let maker = funded_account::<T>("maker", 1);
 		MultiPaymentModule::<T>::add_new_member(&maker);
-		MultiPaymentModule::<T>::add_currency(RawOrigin::Signed(maker).into(), ASSET_ID)?;
+		MultiPaymentModule::<T>::add_currency(RawOrigin::Signed(maker).into(), ASSET_ID, Price::from(10))?;
 
 		let caller = funded_account::<T>("caller", 123);
 
@@ -97,21 +97,24 @@ benchmarks! {
 	add_currency {
 		let caller = funded_account::<T>("maker", 1);
 		MultiPaymentModule::<T>::add_new_member(&caller);
-	}: { MultiPaymentModule::<T>::add_currency(RawOrigin::Signed(caller.clone()).into(), 10)? }
+
+		let price = Price::from(10);
+
+	}: { MultiPaymentModule::<T>::add_currency(RawOrigin::Signed(caller.clone()).into(), 10, price)? }
 	verify {
-		assert_eq!(MultiPaymentModule::<T>::currencies(), OrderedSet::from(vec![10]));
+		assert_eq!(MultiPaymentModule::<T>::currencies(10), Some(price));
 	}
 
 	remove_currency {
 		let caller = funded_account::<T>("maker", 1);
 		MultiPaymentModule::<T>::add_new_member(&caller);
-		MultiPaymentModule::<T>::add_currency(RawOrigin::Signed(caller.clone()).into(), 10)?;
+		MultiPaymentModule::<T>::add_currency(RawOrigin::Signed(caller.clone()).into(), 10, Price::from(2))?;
 
-		assert_eq!(MultiPaymentModule::<T>::currencies(), OrderedSet::from(vec![10]));
+		assert_eq!(MultiPaymentModule::<T>::currencies(10), Some(Price::from(2)));
 
 	}: { MultiPaymentModule::<T>::remove_currency(RawOrigin::Signed(caller.clone()).into(), 10)? }
 	verify {
-		assert_eq!(MultiPaymentModule::<T>::currencies(), OrderedSet::<AssetId>::new())
+		assert_eq!(MultiPaymentModule::<T>::currencies(10), None)
 	}
 
 	add_member{
diff --git a/pallets/transaction-multi-payment/benchmarking/src/mock.rs b/pallets/transaction-multi-payment/benchmarking/src/mock.rs
index 00abda8b1..74bb3efaa 100644
--- a/pallets/transaction-multi-payment/benchmarking/src/mock.rs
+++ b/pallets/transaction-multi-payment/benchmarking/src/mock.rs
@@ -249,8 +249,9 @@ impl ExtBuilder {
 		.unwrap();
 
 		pallet_transaction_multi_payment::GenesisConfig::<Test> {
-			currencies: OrderedSet::from(vec![]),
+			currencies: vec![],
 			authorities: vec![],
+			fallback_account: 1000,
 		}
 		.assimilate_storage(&mut t)
 		.unwrap();
diff --git a/runtime/src/lib.rs b/runtime/src/lib.rs
index e8498bcd0..fc643e03e 100644
--- a/runtime/src/lib.rs
+++ b/runtime/src/lib.rs
@@ -1009,7 +1009,7 @@ construct_runtime!(
 		Claims: pallet_claims::{Pallet, Call, Storage, Event<T>, Config<T>},
 		Exchange: pallet_exchange::{Pallet, Call, Storage, Event<T>},
 		Faucet: pallet_faucet::{Pallet, Call, Storage, Config, Event<T>},
-		MultiTransactionPayment: pallet_transaction_multi_payment::{Pallet, Call, Storage, Event<T>},
+		MultiTransactionPayment: pallet_transaction_multi_payment::{Pallet, Call, Config<T>, Storage, Event<T>},
 		GenesisHistory: pallet_genesis_history::{Pallet, Storage, Config},
 	}
 );

From 93dfa6e30073c07a9e087160c0d18acdbcd60014 Mon Sep 17 00:00:00 2001
From: Martin Hloska <martin.hloska@gmail.com>
Date: Thu, 10 Jun 2021 11:23:45 +0200
Subject: [PATCH 5/8] bump versions

---
 Cargo.lock                                   | 6 +++---
 pallets/transaction-multi-payment/Cargo.toml | 2 +-
 primitives/Cargo.toml                        | 2 +-
 runtime/Cargo.toml                           | 2 +-
 runtime/src/lib.rs                           | 4 ++--
 5 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 5a355af99..9a1374c67 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2425,7 +2425,7 @@ dependencies = [
 
 [[package]]
 name = "hydra-dx-runtime"
-version = "15.1.0"
+version = "16.0.0"
 dependencies = [
  "frame-benchmarking",
  "frame-executive",
@@ -4612,7 +4612,7 @@ dependencies = [
 
 [[package]]
 name = "pallet-transaction-multi-payment"
-version = "3.1.0"
+version = "4.0.0"
 dependencies = [
  "frame-support",
  "frame-system",
@@ -5247,7 +5247,7 @@ dependencies = [
 
 [[package]]
 name = "primitives"
-version = "4.1.0"
+version = "4.2.0"
 dependencies = [
  "frame-support",
  "frame-system",
diff --git a/pallets/transaction-multi-payment/Cargo.toml b/pallets/transaction-multi-payment/Cargo.toml
index 910d2086e..380a93a7b 100644
--- a/pallets/transaction-multi-payment/Cargo.toml
+++ b/pallets/transaction-multi-payment/Cargo.toml
@@ -6,7 +6,7 @@ homepage = 'https://github.com/galacticcouncil/hydra-dx'
 license = 'Apache 2.0'
 name = 'pallet-transaction-multi-payment'
 repository = 'https://github.com/galacticcouncil/hydra-dx'
-version = '3.1.0'
+version = '4.0.0'
 
 [package.metadata.docs.rs]
 targets = ['x86_64-unknown-linux-gnu']
diff --git a/primitives/Cargo.toml b/primitives/Cargo.toml
index e378ae201..5471f7b34 100644
--- a/primitives/Cargo.toml
+++ b/primitives/Cargo.toml
@@ -2,7 +2,7 @@
 authors = ['GalacticCouncil']
 edition = '2018'
 name = 'primitives'
-version = '4.1.0'
+version = '4.2.0'
 
 [build-dependencies]
 substrate-wasm-builder = {package = 'substrate-wasm-builder', version = '3.0.0'}
diff --git a/runtime/Cargo.toml b/runtime/Cargo.toml
index 9be3d7080..b946b748e 100644
--- a/runtime/Cargo.toml
+++ b/runtime/Cargo.toml
@@ -5,7 +5,7 @@ homepage = 'https://github.com/galacticcouncil/hydradx-node'
 license = 'Apache 2.0'
 name = 'hydra-dx-runtime'
 repository = 'https://github.com/galacticcouncil/hydradx-node'
-version = '15.1.0'
+version = '16.0.0'
 
 [package.metadata.docs.rs]
 targets = ['x86_64-unknown-linux-gnu']
diff --git a/runtime/src/lib.rs b/runtime/src/lib.rs
index fc643e03e..6e09e5e94 100644
--- a/runtime/src/lib.rs
+++ b/runtime/src/lib.rs
@@ -148,8 +148,8 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	spec_name: create_runtime_str!("hydra-dx"),
 	impl_name: create_runtime_str!("hydra-dx"),
 	authoring_version: 1,
-	spec_version: 15,
-	impl_version: 2,
+	spec_version: 16,
+	impl_version: 0,
 	apis: RUNTIME_API_VERSIONS,
 	transaction_version: 1,
 };

From 4eb805e059ad402e79c37b387d54e093f5dba7eb Mon Sep 17 00:00:00 2001
From: Martin Hloska <martin.hloska@gmail.com>
Date: Thu, 10 Jun 2021 11:32:36 +0200
Subject: [PATCH 6/8] update test

---
 pallets/transaction-multi-payment/src/tests.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pallets/transaction-multi-payment/src/tests.rs b/pallets/transaction-multi-payment/src/tests.rs
index 0c731d747..7b3f8864f 100644
--- a/pallets/transaction-multi-payment/src/tests.rs
+++ b/pallets/transaction-multi-payment/src/tests.rs
@@ -332,6 +332,7 @@ fn fee_payment_in_non_native_currency_with_no_pool() {
 
 			// token check should be less by the fee amount and -1 as fee in amm swap
 			assert_eq!(Tokens::free_balance(SUPPORTED_CURRENCY_WITH_BALANCE, &CHARLIE), 970);
+			assert_eq!(Tokens::free_balance(SUPPORTED_CURRENCY_WITH_BALANCE, &FALLBACK_ACCOUNT), 30);
 		});
 }
 

From 1fb22f6dcd5eb7560dae08675b9516c3b50676ec Mon Sep 17 00:00:00 2001
From: Martin Hloska <martin.hloska@gmail.com>
Date: Thu, 10 Jun 2021 12:07:40 +0200
Subject: [PATCH 7/8] happy clipyp - happy life

---
 pallets/transaction-multi-payment/src/lib.rs    | 16 ++++++++--------
 pallets/transaction-multi-payment/src/traits.rs |  8 ++++----
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/pallets/transaction-multi-payment/src/lib.rs b/pallets/transaction-multi-payment/src/lib.rs
index 64251bb6b..fd7e24b1e 100644
--- a/pallets/transaction-multi-payment/src/lib.rs
+++ b/pallets/transaction-multi-payment/src/lib.rs
@@ -397,14 +397,14 @@ use traits::CurrencySwap;
 impl<T: Config> CurrencySwap<<T as frame_system::Config>::AccountId, Balance> for Pallet<T> {
 	fn swap(who: &T::AccountId, fee: u128) -> Result<PaymentSwapResult, DispatchError> {
 		match Self::account_currency(who) {
-			CORE_ASSET_ID => Ok(PaymentSwapResult::NATIVE),
+			CORE_ASSET_ID => Ok(PaymentSwapResult::Native),
 			currency => {
 				if T::AMMPool::exists(AssetPair {
 					asset_in: currency,
 					asset_out: CORE_ASSET_ID,
 				}) {
 					Self::swap_currency(who, fee)?;
-					Ok(PaymentSwapResult::SWAPPED)
+					Ok(PaymentSwapResult::Swapped)
 				} else {
 					// If pool does not exists, let's use the currency fixed price
 
@@ -414,7 +414,7 @@ impl<T: Config> CurrencySwap<<T as frame_system::Config>::AccountId, Balance> fo
 
 					T::MultiCurrency::transfer(currency, who, &Self::fallback_account(), amount)?;
 
-					Ok(PaymentSwapResult::TRANSFERRED)
+					Ok(PaymentSwapResult::Transferred)
 				}
 			}
 		}
@@ -460,11 +460,11 @@ where
 			WithdrawReasons::TRANSACTION_PAYMENT | WithdrawReasons::TIP
 		};
 
-		return if let Some(detail) = SW::swap(&who, fee.into()).ok() {
+		if let Ok(detail) = SW::swap(&who, fee.into()) {
 			match detail {
-				PaymentSwapResult::TRANSFERRED => Ok(None),
-				PaymentSwapResult::ERROR => Err(InvalidTransaction::Payment.into()),
-				PaymentSwapResult::NATIVE | PaymentSwapResult::SWAPPED => {
+				PaymentSwapResult::Transferred => Ok(None),
+				PaymentSwapResult::Error => Err(InvalidTransaction::Payment.into()),
+				PaymentSwapResult::Native | PaymentSwapResult::Swapped => {
 					match C::withdraw(who, fee, withdraw_reason, ExistenceRequirement::KeepAlive) {
 						Ok(imbalance) => Ok(Some(imbalance)),
 						Err(_) => Err(InvalidTransaction::Payment.into()),
@@ -473,7 +473,7 @@ where
 			}
 		} else {
 			Err(InvalidTransaction::Payment.into())
-		};
+		}
 	}
 
 	/// Hand the fee and the tip over to the `[OnUnbalanced]` implementation.
diff --git a/pallets/transaction-multi-payment/src/traits.rs b/pallets/transaction-multi-payment/src/traits.rs
index 6366f9e34..619d33d04 100644
--- a/pallets/transaction-multi-payment/src/traits.rs
+++ b/pallets/transaction-multi-payment/src/traits.rs
@@ -1,9 +1,9 @@
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum PaymentSwapResult {
-	NATIVE,
-	ERROR,
-	SWAPPED,
-	TRANSFERRED,
+	Native,
+	Error,
+	Swapped,
+	Transferred,
 }
 
 pub trait CurrencySwap<AccountId, Balance> {

From 1716720eae622e998d7666e8fbd6dcac3e393e52 Mon Sep 17 00:00:00 2001
From: Martin Hloska <martin.hloska@gmail.com>
Date: Thu, 10 Jun 2021 12:47:40 +0200
Subject: [PATCH 8/8] fix benchmarking compilation

---
 Cargo.lock                                                 | 2 +-
 pallets/transaction-multi-payment/Cargo.toml               | 7 ++++---
 pallets/transaction-multi-payment/benchmarking/Cargo.toml  | 2 +-
 pallets/transaction-multi-payment/benchmarking/src/mock.rs | 1 -
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 9a1374c67..a09bb941e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4444,7 +4444,7 @@ dependencies = [
 
 [[package]]
 name = "pallet-multi-payment-benchmarking"
-version = "3.1.0"
+version = "4.0.0"
 dependencies = [
  "frame-benchmarking",
  "frame-support",
diff --git a/pallets/transaction-multi-payment/Cargo.toml b/pallets/transaction-multi-payment/Cargo.toml
index 380a93a7b..3eda705f2 100644
--- a/pallets/transaction-multi-payment/Cargo.toml
+++ b/pallets/transaction-multi-payment/Cargo.toml
@@ -40,14 +40,15 @@ sp-api = {default-features = false, version = '3.0.0'}
 sp-core = {default-features = false, version = '3.0.0'}
 sp-runtime = {default-features = false, version = '3.0.0'}
 sp-std = {default-features = false, version = '3.0.0'}
-
 pallet-transaction-payment = {default-features = false, version = '3.0.0'}
 
-[dev-dependencies]
+# These 2 dependencies are for testing only. But need to be here for benchmarking pallet - could not figure out why yet
+pallet-asset-registry = {path = '../asset-registry', default-features = false}
 pallet-balances = {default-features = false, version = '3.0.0'}
+
+[dev-dependencies]
 orml-currencies = {default-features = false, version = "0.4.1-dev"}
 pallet-xyk = {path = '../xyk', default-features = false}
-pallet-asset-registry = {path = '../asset-registry', default-features = false}
 sp-io = {default-features = false, version = '3.0.0'}
 
 [features]
diff --git a/pallets/transaction-multi-payment/benchmarking/Cargo.toml b/pallets/transaction-multi-payment/benchmarking/Cargo.toml
index 3aed3df72..d14cf1a01 100644
--- a/pallets/transaction-multi-payment/benchmarking/Cargo.toml
+++ b/pallets/transaction-multi-payment/benchmarking/Cargo.toml
@@ -6,7 +6,7 @@ homepage = 'https://github.com/galacticcouncil/hydra-dx'
 license = 'Apache 2.0'
 name = 'pallet-multi-payment-benchmarking'
 repository = 'https://github.com/galacticcouncil/hydra-dx'
-version = '3.1.0'
+version = '4.0.0'
 
 [package.metadata.docs.rs]
 targets = ['x86_64-unknown-linux-gnu']
diff --git a/pallets/transaction-multi-payment/benchmarking/src/mock.rs b/pallets/transaction-multi-payment/benchmarking/src/mock.rs
index 74bb3efaa..8308f07fd 100644
--- a/pallets/transaction-multi-payment/benchmarking/src/mock.rs
+++ b/pallets/transaction-multi-payment/benchmarking/src/mock.rs
@@ -38,7 +38,6 @@ use pallet_xyk::AssetPairAccountIdFor;
 use std::cell::RefCell;
 
 use frame_benchmarking::frame_support::weights::Pays;
-use orml_utilities::OrderedSet;
 use primitives::fee;
 
 pub type AccountId = u64;