fix: bonded pallet runtime call rounding is different from module (#848)

## fixes https://github.com/KILTprotocol/ticket/issues/3755

Author: rflechtner

pallets/pallet-bonded-coins/src/lib.rs

@@ -1355,7 +1355,7 @@ pub mod pallet {
 		/// # Errors
 		/// - `ArithmeticError`: If there is an error during the conversion to
 		///   fixed point.
-		fn calculate_normalized_passive_issuance(
+		pub fn calculate_normalized_passive_issuance(
 			bonded_currencies: &[FungiblesAssetIdOf<T>],
 			denomination: u8,
 			currency_idx: usize,

pallets/pallet-bonded-coins/src/types.rs

@@ -180,7 +180,7 @@ pub struct PoolManagingTeam<AccountId> {
 }
 
 /// Enum, to specify the rounding direction.
-#[derive(PartialEq, Clone, Copy, Eq)]
+#[derive(PartialEq, Clone, Copy, Eq, Encode, Decode, TypeInfo, MaxEncodedLen)]
 pub enum Round {
 	/// Round up.
 	Up,

runtime-api/bonded-coins/src/lib.rs

@@ -18,6 +18,7 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 
+use pallet_bonded_coins::Round;
 use parity_scale_codec::{alloc::string::String, Codec, Decode, Encode};
 use scale_info::TypeInfo;
 use sp_std::vec::Vec;
@@ -71,6 +72,7 @@ sp_api::decl_runtime_apis! {
 				currency_idx: u8,
 				low: Balance,
 				high: Balance,
+				rounding: Round
 			) -> Result<Balance, Error>;
 
 			/// Query all pool IDs where the given account is the manager.

runtimes/peregrine/src/runtime_apis.rs

@@ -63,9 +63,9 @@ use crate::{
 	kilt::{DipProofError, DipProofRequest, DotName, NativeAndForeignAssets, UniqueLinkingDeployment},
 	parachain::ConsensusHook,
 	xcm::UniversalLocation,
-	AssetSwitchPool1, Aura, Block, BondedFungibles, DotNames, Executive, InherentDataExt, ParachainStaking,
-	ParachainSystem, Runtime, RuntimeCall, RuntimeGenesisConfig, SessionKeys, TransactionPayment, UniqueLinking,
-	VERSION,
+	AssetSwitchPool1, Aura, Block, BondedCurrencies, BondedFungibles, DotNames, Executive, InherentDataExt,
+	ParachainStaking, ParachainSystem, Runtime, RuntimeCall, RuntimeGenesisConfig, SessionKeys, TransactionPayment,
+	UniqueLinking, VERSION,
 };
 
 // This is necessary since by default `RUNTIME_API_VERSIONS` generated by
@@ -506,37 +506,34 @@ impl_runtime_apis! {
 
 			let currency_supply = BondedFungibles::total_issuance(currency_id.to_owned());
 
-			let (low, high, _) = match operation {
+			let (low, high, rounding) = match operation {
 				Operation::Mint(amount) => (currency_supply, currency_supply.saturating_add(amount), Round::Up),
 				Operation::Burn(amount) => (currency_supply.saturating_sub(amount), currency_supply, Round::Down),
 			};
 
-			Self::quote_for_low_and_high_bounds(pool_id, currency_idx, low, high)
+			Self::quote_for_low_and_high_bounds(pool_id, currency_idx, low, high, rounding)
 		}
 
 		fn quote_for_low_and_high_bounds(
 			pool_id: AccountId,
 			currency_idx: u8,
 			low: Balance,
 			high: Balance,
+			rounding: Round,
 		) -> Result<Balance, BondedCurrencyError> {
 			let pool = Pools::<Runtime>::get(pool_id).ok_or(BondedCurrencyError::PoolNotFound)?;
 			let PoolDetailsOf::<Runtime> { curve, bonded_currencies, denomination, collateral, .. } = pool;
-			let currency_id = bonded_currencies.get(currency_idx.saturated_into::<usize>()).ok_or(BondedCurrencyError::CurrencyNotFound)?;
-
 			let collateral_denomination = NativeAndForeignAssets::decimals(collateral);
 
-			let normalized_low = balance_to_fixed(low, denomination, Round::Down).map_err(|_| BondedCurrencyError::BalanceConversion)?;
-			let normalized_high = balance_to_fixed(high, denomination, Round::Up).map_err(|_| BondedCurrencyError::BalanceConversion)?;
+			let normalized_low = balance_to_fixed(low, denomination, rounding).map_err(|_| BondedCurrencyError::BalanceConversion)?;
+			let normalized_high = balance_to_fixed(high, denomination, rounding).map_err(|_| BondedCurrencyError::BalanceConversion)?;
+
 
-			let passive_supply = bonded_currencies
-				.iter()
-				.filter_map(|id| (id != currency_id).then_some(BondedFungibles::total_issuance(id.to_owned())))
-				.map(|supply| balance_to_fixed(supply, denomination, Round::Up).map_err(|_| BondedCurrencyError::BalanceConversion))
-				.collect::<Result<Vec<FixedPoint>, BondedCurrencyError>>()?;
+			let (_, passive_supply) = BondedCurrencies::calculate_normalized_passive_issuance(&bonded_currencies, denomination, currency_idx.into(), rounding)
+				.map_err(|_| BondedCurrencyError::BalanceConversion)?;
 
 			let normalized_collateral = curve.calculate_costs(normalized_low, normalized_high, passive_supply).map_err(|_| BondedCurrencyError::CalculationError)?;
-			fixed_to_balance(normalized_collateral, collateral_denomination, Round::Up).map_err(|_| BondedCurrencyError::BalanceConversion)
+			fixed_to_balance(normalized_collateral, collateral_denomination, rounding).map_err(|_| BondedCurrencyError::BalanceConversion)
 		}
 
 		fn query_pools_by_manager(account: AccountId) -> Vec<PoolDetails<AccountId, Balance, BondedAssetId, AssetId>> {