Fees in community currency

Cargo.toml

@@ -1,6 +1,7 @@
 [workspace]
 members = [
     'balances',
+    'balances-tx-payment',
     'bazaar',
     'bazaar/rpc',
     'bazaar/rpc/runtime-api',

balances-tx-payment/Cargo.toml

@@ -0,0 +1,38 @@
+[package]
+name = "encointer-balances-tx-payment"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+pallet-encointer-balances = { path = "../balances", default-features = false }
+pallet-encointer-communities = { path = "../communities", default-features = false }
+encointer-primitives = { path = "../primitives", default-features = false }
+
+# substrate dependencies
+frame-support = { version = "4.0.0-dev", git = "https://github.com/paritytech/substrate.git", default-features = false, branch = "master" }
+frame-system = { version = "4.0.0-dev", git = "https://github.com/paritytech/substrate.git", default-features = false, branch = "master" }
+pallet-asset-tx-payment = { version = "4.0.0-dev", git = "https://github.com/paritytech/substrate.git", default-features = false, branch = "master" }
+pallet-transaction-payment = { version = "4.0.0-dev", git = "https://github.com/paritytech/substrate.git", default-features = false, branch = "master" }
+sp-runtime = { version = "6.0.0", git = "https://github.com/paritytech/substrate.git", default-features = false, branch = "master" }
+
+[dev-dependencies]
+codec = { package = "parity-scale-codec", version = "3.0.0", default-features = false, features = ["derive"] }
+rstest = "0.12.0"
+scale-info = { version = "2.0.1", default-features = false }
+sp-io = { version = "6.0.0", git = "https://github.com/paritytech/substrate.git", branch = "master" }
+test-utils = { path = "../test-utils" }
+
+[features]
+default = ["std"]
+std = [
+    "pallet-encointer-balances/std",
+    "pallet-encointer-communities/std",
+    "encointer-primitives/std",
+
+    # substrate deps
+    "frame-support/std",
+    "frame-system/std",
+    "pallet-asset-tx-payment/std",
+    "pallet-transaction-payment/std",
+    "sp-runtime/std",
+]

balances-tx-payment/src/balance_conversion.rs

@@ -0,0 +1,76 @@
+// Copyright (c) 2019 Alain Brenzikofer
+// This file is part of Encointer
+//
+// Encointer is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Encointer is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Encointer.  If not, see <http://www.gnu.org/licenses/>.
+
+use crate::{AssetBalanceOf, AssetIdOf, BalanceOf};
+use core::marker::PhantomData;
+use encointer_primitives::{balances::EncointerBalanceConverter, communities::CommunityIdentifier};
+use frame_support::traits::tokens::BalanceConversion;
+use pallet_encointer_balances::Pallet as BalancesPallet;
+use pallet_encointer_communities::{Config as CommunitiesConfig, Pallet as CommunitiesPallet};
+use sp_runtime::traits::Convert;
+
+/// 1 micro KSM with 12 decimals
+pub const ONE_MICRO_KSM: u128 = 1_000_000;
+
+/// 1 KSM with 12 decimals
+pub const ONE_KSM: u128 = 1_000_000 * ONE_MICRO_KSM;
+
+/// 1 Kilo-KSM with 12 decimals
+pub const ONE_KILO_KSM: u128 = 1_000 * ONE_KSM;
+
+/// Transforms the native token to the community currency
+///
+/// Assumptions:
+/// * Native token has 12 decimals
+/// * fee_conversion_factor is in Units 1 / [pKSM]
+///
+/// Applies the formula: Community Currency = KSM * FeeConversionFactor * Reward
+pub fn apply_fee_conversion_factor(
+	balance: u128,
+	reward: u128,
+	fee_conversion_factor: u128,
+) -> u128 {
+	return balance
+		.saturating_mul(reward)
+		.saturating_mul(fee_conversion_factor as u128)
+		.checked_div(ONE_KILO_KSM) // <- unit discrepancy: balance [pKSM] vs. fee_conversion_factor [KKSM]
+		.expect("Divisor != 0; qed")
+}
+
+pub struct BalanceToCommunityBalance<T>(PhantomData<T>);
+
+impl<T> BalanceConversion<BalanceOf<T>, AssetIdOf<T>, AssetBalanceOf<T>>
+	for BalanceToCommunityBalance<T>
+where
+	T: CommunitiesConfig + pallet_asset_tx_payment::Config,
+	CommunityIdentifier: From<AssetIdOf<T>>,
+	AssetBalanceOf<T>: From<u128>,
+	u128: From<BalanceOf<T>>,
+{
+	type Error = frame_system::Error<T>;
+
+	fn to_asset_balance(
+		balance: BalanceOf<T>,
+		asset_id: AssetIdOf<T>,
+	) -> Result<AssetBalanceOf<T>, Self::Error> {
+		let fee_conversion_factor = BalancesPallet::<T>::fee_conversion_factor();
+		let reward = EncointerBalanceConverter::convert(CommunitiesPallet::<T>::nominal_income(
+			CommunityIdentifier::from(asset_id),
+		));
+
+		Ok(apply_fee_conversion_factor(balance.into(), reward, fee_conversion_factor).into())
+	}
+}

balances-tx-payment/src/lib.rs

@@ -0,0 +1,55 @@
+// Copyright (c) 2019 Alain Brenzikofer
+// This file is part of Encointer
+//
+// Encointer is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Encointer is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Encointer.  If not, see <http://www.gnu.org/licenses/>.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+use frame_support::traits::fungibles;
+use pallet_asset_tx_payment::HandleCredit;
+use pallet_transaction_payment::OnChargeTransaction;
+
+pub mod balance_conversion;
+#[cfg(test)]
+mod mock;
+#[cfg(test)]
+mod tests;
+
+pub use balance_conversion::*;
+
+pub type OnChargeTransactionOf<T> = <T as pallet_transaction_payment::Config>::OnChargeTransaction;
+
+pub type BalanceOf<T> = <OnChargeTransactionOf<T> as OnChargeTransaction<T>>::Balance;
+
+pub type FungiblesOf<T> = <T as pallet_asset_tx_payment::Config>::Fungibles;
+
+pub type AccountIdOf<T> = <T as frame_system::Config>::AccountId;
+
+pub type AssetBalanceOf<T> = <FungiblesOf<T> as fungibles::Inspect<AccountIdOf<T>>>::Balance;
+
+pub type AssetIdOf<T> = <FungiblesOf<T> as fungibles::Inspect<AccountIdOf<T>>>::AssetId;
+
+pub struct BurnCredit;
+impl<T> HandleCredit<<T as frame_system::Config>::AccountId, pallet_encointer_balances::Pallet<T>>
+	for BurnCredit
+where
+	T: frame_system::Config + pallet_encointer_balances::Config,
+{
+	fn handle_credit(
+		_credit: fungibles::CreditOf<AccountIdOf<T>, pallet_encointer_balances::Pallet<T>>,
+	) {
+		// just doing nothing with the credit, will use the default implementation
+		// of fungibles an decrease total issuance.
+	}
+}

balances-tx-payment/src/mock.rs

@@ -0,0 +1,70 @@
+// Copyright (c) 2019 Alain Brenzikofer
+// This file is part of Encointer
+//
+// Encointer is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Encointer is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Encointer.  If not, see <http://www.gnu.org/licenses/>.
+
+//! Mock runtime for the encointer_communities module
+
+use frame_support::pallet_prelude::GenesisBuild;
+
+use encointer_primitives::scheduler::CeremonyPhaseType;
+use test_utils::*;
+
+type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<TestRuntime>;
+type Block = frame_system::mocking::MockBlock<TestRuntime>;
+
+frame_support::construct_runtime!(
+	pub enum TestRuntime where
+		Block = Block,
+		NodeBlock = Block,
+		UncheckedExtrinsic = UncheckedExtrinsic,
+	{
+		System: frame_system::{Pallet, Call, Config, Storage, Event<T>},
+		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
+		EncointerScheduler: encointer_scheduler::{Pallet, Call, Storage, Config<T>, Event},
+		EncointerCommunities: pallet_encointer_communities::{Pallet, Call, Storage, Event<T>},
+		EncointerBalances: pallet_encointer_balances::{Pallet, Call, Storage, Event<T>},
+	}
+);
+
+// boilerplate
+impl_frame_system!(TestRuntime);
+impl_timestamp!(TestRuntime);
+impl_encointer_scheduler!(TestRuntime);
+impl_encointer_balances!(TestRuntime);
+impl_encointer_communities!(TestRuntime);
+
+// genesis values
+#[allow(unused)]
+pub fn new_test_ext() -> sp_io::TestExternalities {
+	let mut t = frame_system::GenesisConfig::default().build_storage::<TestRuntime>().unwrap();
+
+	encointer_scheduler::GenesisConfig::<TestRuntime> {
+		current_phase: CeremonyPhaseType::REGISTERING,
+		current_ceremony_index: 1,
+		phase_durations: vec![
+			(CeremonyPhaseType::REGISTERING, ONE_DAY),
+			(CeremonyPhaseType::ASSIGNING, ONE_DAY),
+			(CeremonyPhaseType::ATTESTING, ONE_DAY),
+		],
+	}
+	.assimilate_storage(&mut t)
+	.unwrap();
+
+	let conf =
+		pallet_encointer_communities::GenesisConfig { min_solar_trip_time_s: 1, max_speed_mps: 83 };
+	GenesisBuild::<TestRuntime>::assimilate_storage(&conf, &mut t).unwrap();
+
+	t.into()
+}

balances-tx-payment/src/tests.rs

@@ -0,0 +1,23 @@
+use crate::{apply_fee_conversion_factor, ONE_MICRO_KSM};
+use rstest::*;
+
+/// one unit of community currency is a fixpoint with 64 fractional bits
+const ONE_CC: u128 = 1 << 64;
+
+#[rstest(ksm_balance, ceremony_reward, conversion_factor, expected_community_balance,
+case(5 * ONE_MICRO_KSM, 20 * ONE_CC, 100_000, ONE_CC / 100),
+case(10 * ONE_MICRO_KSM, 20 * ONE_CC, 100_000, ONE_CC / 50),
+case(5 * ONE_MICRO_KSM, 10 * ONE_CC, 100_000, ONE_CC / 200),
+case(5_000 * ONE_MICRO_KSM, 20 * ONE_CC, 100_000, ONE_CC * 10),
+case(5 * ONE_MICRO_KSM, 20_000_000 * ONE_CC, 100_000, ONE_CC * 10_000),
+case(5 * ONE_MICRO_KSM, 20_000_000 * ONE_CC, 50_000, ONE_CC * 5_000),
+)]
+fn balance_to_community_balance_works(
+	ksm_balance: u128,
+	ceremony_reward: u128,
+	conversion_factor: u128,
+	expected_community_balance: u128,
+) {
+	let balance = apply_fee_conversion_factor(ksm_balance, ceremony_reward, conversion_factor);
+	assert_eq!(balance, expected_community_balance);
+}

balances/Cargo.toml

@@ -19,6 +19,8 @@ frame-support = { version = "4.0.0-dev", default-features = false,git = "https:/
 frame-system = { version = "4.0.0-dev", default-features = false,git = "https://github.com/paritytech/substrate.git", branch = "master" }
 sp-std = { version = "4.0.0-dev", default-features = false,git = "https://github.com/paritytech/substrate.git", branch = "master" }
 sp-runtime = { version = "6.0.0", default-features = false,git = "https://github.com/paritytech/substrate.git", branch = "master" }
+pallet-transaction-payment = { version = "4.0.0-dev" , default-features = false, git = "https://github.com/paritytech/substrate.git", branch = "master" }
+pallet-asset-tx-payment  = { version = "4.0.0-dev" , default-features = false, git = "https://github.com/paritytech/substrate.git", branch = "master" }
 
 [dev-dependencies]
 approx = "0.5.1"