Dex swap fees

zenlink-protocol/src/fee/mock.rs

@@ -71,6 +71,7 @@ parameter_types! {
 
 	pub const BlockHashCount: u64 = 250;
 	pub const ZenlinkPalletId: PalletId = PalletId(*b"/zenlink");
+	pub const NativeSwapFeesPotId: PalletId = PalletId(*b"/swpfees");
 	pub const MaxReserves: u32 = 50;
 	pub const MaxLocks:u32 = 50;
 }
@@ -145,6 +146,7 @@ impl Config for Test {
 	type RuntimeEvent = RuntimeEvent;
 	type MultiAssetsHandler = ZenlinkMultiAssets<Zenlink, Balances, LocalAssetAdaptor<Tokens>>;
 	type PalletId = ZenlinkPalletId;
+	type NativeSwapFeesPotId = NativeSwapFeesPotId;
 	type AssetId = AssetId;
 	type LpGenerate = PairLpGenerate<Self>;
 	type SelfParaId = ();

zenlink-protocol/src/foreign/mock.rs

@@ -35,6 +35,7 @@ parameter_types! {
 
 	pub const BlockHashCount: u64 = 250;
 	pub const ZenlinkPalletId: PalletId = PalletId(*b"/zenlink");
+	pub const NativeSwapFeesPotId: PalletId = PalletId(*b"/swpfees");
 	pub const MaxReserves: u32 = 50;
 }
 
@@ -81,6 +82,7 @@ impl Config for Test {
 	type RuntimeEvent = RuntimeEvent;
 	type MultiAssetsHandler = ZenlinkMultiAssets<Zenlink, Balances>;
 	type PalletId = ZenlinkPalletId;
+	type NativeSwapFeesPotId = NativeSwapFeesPotId;
 	type AssetId = AssetId;
 	type LpGenerate = PairLpGenerate<Self>;
 	type SelfParaId = ();

zenlink-protocol/src/lib.rs

@@ -96,6 +96,9 @@ pub mod pallet {
 		/// This parachain id.
 		type SelfParaId: Get<u32>;
 
+		/// Account Identifier from which the internal Pot is generated.
+		type NativeSwapFeesPotId: Get<PalletId>;
+
 		/// Weight information for extrinsics in this pallet.
 		type WeightInfo: WeightInfo;
 	}
@@ -193,6 +196,10 @@ pub mod pallet {
 		ValueQuery,
 	>;
 
+	#[pallet::storage]
+	#[pallet::getter(fn get_native_swap_fee_factor)]
+	pub type NativeSwapFeeFactor<T: Config> = StorageValue<_, u128, ValueQuery>;
+
 	#[pallet::genesis_config]
 	/// Refer: https://github.com/Uniswap/uniswap-v2-core/blob/master/contracts/UniswapV2Pair.sol#L88
 	pub struct GenesisConfig<T: Config> {
@@ -984,5 +991,19 @@ pub mod pallet {
 
 			Ok(())
 		}
+
+		#[pallet::call_index(18)]
+		#[pallet::weight(100_000_000)]
+		#[frame_support::transactional]
+		pub fn set_native_swap_fee_factor(
+			origin: OriginFor<T>,
+			native_swap_fees_factor: u128,
+		) -> DispatchResult {
+			ensure_root(origin)?;
+
+			NativeSwapFeeFactor::<T>::put(native_swap_fees_factor);
+
+			Ok(())
+		}
 	}
 }

zenlink-protocol/src/primitives.rs

@@ -42,12 +42,17 @@ pub struct AssetId {
 
 pub trait AssetInfo {
 	fn is_support(&self) -> bool;
+	fn is_native(&self, self_chain_id: u32) -> bool;
 }
 
 impl AssetInfo for AssetId {
 	fn is_support(&self) -> bool {
 		matches!(self.asset_type, NATIVE | LIQUIDITY | LOCAL | RESERVED)
 	}
+
+	fn is_native(&self, self_chain_id: u32) -> bool {
+		self.chain_id == self_chain_id && self.asset_type == NATIVE && self.asset_index == 0
+	}
 }
 
 impl AssetId {

zenlink-protocol/src/swap/mock.rs

@@ -71,6 +71,7 @@ parameter_types! {
 
 	pub const BlockHashCount: u64 = 250;
 	pub const ZenlinkPalletId: PalletId = PalletId(*b"/zenlink");
+	pub const NativeSwapFeesPotId: PalletId = PalletId(*b"/swpfees");
 	pub const MaxReserves: u32 = 50;
 	pub const MaxLocks:u32 = 50;
 }
@@ -145,6 +146,7 @@ impl Config for Test {
 	type RuntimeEvent = RuntimeEvent;
 	type MultiAssetsHandler = ZenlinkMultiAssets<Zenlink, Balances, LocalAssetAdaptor<Tokens>>;
 	type PalletId = ZenlinkPalletId;
+	type NativeSwapFeesPotId = NativeSwapFeesPotId;
 	type AssetId = AssetId;
 	type LpGenerate = PairLpGenerate<Self>;
 	type SelfParaId = ();

zenlink-protocol/src/swap/mod.rs

@@ -214,12 +214,36 @@ impl<T: Config> Pallet<T> {
 		path: &[T::AssetId],
 		recipient: &T::AccountId,
 	) -> DispatchResult {
-		let amounts = Self::get_amount_out_by_path(amount_in, path)?;
+		let mut amount_in_less_native_swap_fee = amount_in;
+		if path[0].is_native(T::SelfParaId::get()) {
+			let native_swap_fee_factor = Self::get_native_swap_fee_factor();
+			if native_swap_fee_factor != 0u128 {
+				// charge a configurable % going to a pallet account for later distribution
+				let native_swap_fee =
+					amount_in.checked_div(native_swap_fee_factor).unwrap_or_default();
+				amount_in_less_native_swap_fee = amount_in.saturating_sub(native_swap_fee);
+				let native_swap_fees_account =
+					T::NativeSwapFeesPotId::get().into_account_truncating();
+				T::MultiAssetsHandler::transfer(
+					path[0],
+					who,
+					&native_swap_fees_account,
+					native_swap_fee,
+				)?;
+			}
+		}
+
+		let amounts = Self::get_amount_out_by_path(amount_in_less_native_swap_fee, path)?;
 		ensure!(amounts[amounts.len() - 1] >= amount_out_min, Error::<T>::InsufficientTargetAmount);
 
 		let pair_account = Self::pair_account_id(path[0], path[1]);
 
-		T::MultiAssetsHandler::transfer(path[0], who, &pair_account, amount_in)?;
+		T::MultiAssetsHandler::transfer(
+			path[0],
+			who,
+			&pair_account,
+			amount_in_less_native_swap_fee,
+		)?;
 		Self::swap(&amounts, path, recipient)?;
 
 		Self::deposit_event(Event::AssetSwap(

zenlink-swap-router/src/mock.rs

@@ -26,8 +26,7 @@ use crate as router;
 use crate::{Config, Pallet};
 use orml_traits::{parameter_type_with_key, MultiCurrency};
 use zenlink_protocol::{
-	AssetBalance, AssetId, AssetIdConverter, LocalAssetHandler, PairLpGenerate, ZenlinkMultiAssets,
-	LOCAL,
+	AssetBalance, AssetId, LocalAssetHandler, PairLpGenerate, ZenlinkMultiAssets, LOCAL,
 };
 use zenlink_stable_amm::traits::{StablePoolLpCurrencyIdGenerate, ValidateCurrency};
 
@@ -40,6 +39,7 @@ parameter_types! {
 	pub const BlockHashCount: u64 = 250;
 	pub const StableAmmPalletId: PalletId = PalletId(*b"/zlkSAmm");
 	pub const ZenlinkPalletId: PalletId = PalletId(*b"/zenlink");
+	pub const NativeSwapFeesPotId: PalletId = PalletId(*b"/swpfees");
 	pub const MaxReserves: u32 = 50;
 	pub const MaxLocks:u32 = 50;
 	pub const MinimumPeriod: Moment = SLOT_DURATION / 2;
@@ -210,13 +210,10 @@ impl zenlink_protocol::Config for Test {
 	type RuntimeEvent = RuntimeEvent;
 	type MultiAssetsHandler = ZenlinkMultiAssets<Zenlink, Balances, LocalAssetAdaptor<Tokens>>;
 	type PalletId = ZenlinkPalletId;
+	type NativeSwapFeesPotId = NativeSwapFeesPotId;
 	type AssetId = AssetId;
-	type LpGenerate = PairLpGenerate<Self>;
-	type TargetChains = ();
 	type SelfParaId = SelfParaId;
-	type XcmExecutor = ();
-	type AccountIdConverter = ();
-	type AssetIdConverter = AssetIdConverter;
+	type LpGenerate = PairLpGenerate<Self>;
 	type WeightInfo = ();
 }