Use Loan pallet as NAV source for investor pool

pallets/tinlake-investor-pool/src/lib.rs

@@ -15,7 +15,7 @@ mod tests;
 mod benchmarking;
 
 use codec::HasCompact;
-use common_traits::PoolReserve;
+use common_traits::{PoolNAV, PoolReserve};
 use core::{convert::TryFrom, ops::AddAssign};
 use frame_support::{dispatch::DispatchResult, pallet_prelude::*, traits::UnixTime};
 use frame_system::pallet_prelude::*;
@@ -67,8 +67,6 @@ pub struct PoolDetails<AccountId, CurrencyId, EpochId, Balance> {
 	pub max_reserve: Balance,
 	pub available_reserve: Balance,
 	pub total_reserve: Balance,
-
-	pub fake_nav: Balance,
 }
 
 /// Per-tranche and per-user order details.
@@ -172,6 +170,9 @@ pub mod pallet {
 			CurrencyId = Self::CurrencyId,
 		>;
 
+		type LoanAmount: Into<Self::Balance>;
+		type NAV: PoolNAV<Self::PoolId, Self::LoanAmount>;
+
 		/// A conversion from a tranche ID to a CurrencyId
 		type TrancheToken: TrancheToken<Self>;
 		type Time: UnixTime;
@@ -259,6 +260,8 @@ pub mod pallet {
 		InsufficientReserve,
 		/// Subordination Ratio validation failed
 		SubordinationRatioViolated,
+		/// The NAV was not available
+		NoNAV,
 		/// Generic error for invalid input data provided
 		InvalidData,
 	}
@@ -322,7 +325,6 @@ pub mod pallet {
 					max_reserve,
 					available_reserve: Zero::zero(),
 					total_reserve: Zero::zero(),
-					fake_nav: Zero::zero(),
 				},
 			);
 			Self::deposit_event(Event::PoolCreated(pool_id, owner));
@@ -438,9 +440,7 @@ pub mod pallet {
 				pool.last_epoch_closed = current_epoch_end;
 				pool.available_reserve = Zero::zero();
 				let epoch_reserve = pool.total_reserve;
-
-				// TODO: get NAV
-				let nav = pool.fake_nav;
+				let nav = T::NAV::nav(pool_id).ok_or(Error::<T>::NoNAV)?.0.into();
 
 				if pool
 					.tranches
@@ -561,64 +561,6 @@ pub mod pallet {
 				Ok(())
 			})
 		}
-
-		// Reserve Operations
-
-		#[pallet::weight(100)]
-		pub fn test_payback(
-			origin: OriginFor<T>,
-			pool_id: T::PoolId,
-			amount: T::Balance,
-		) -> DispatchResult {
-			// Internal/pvt call from Coordinator, so no need to check origin on final implementation
-			let who = ensure_signed(origin)?;
-			Self::do_payback(who, pool_id, amount)
-		}
-
-		#[pallet::weight(100)]
-		pub fn test_borrow(
-			origin: OriginFor<T>,
-			pool_id: T::PoolId,
-			amount: T::Balance,
-		) -> DispatchResult {
-			// Internal/pvt call from Coordinator, so no need to check origin on final implementation
-			let who = ensure_signed(origin)?;
-			Self::do_borrow(who, pool_id, amount)
-		}
-
-		#[pallet::weight(100)]
-		pub fn test_nav_up(
-			origin: OriginFor<T>,
-			pool_id: T::PoolId,
-			amount: T::Balance,
-		) -> DispatchResult {
-			let _ = ensure_signed(origin)?;
-			Pool::<T>::try_mutate(pool_id, |pool| {
-				let pool = pool.as_mut().ok_or(Error::<T>::NoSuchPool)?;
-				pool.fake_nav = pool
-					.fake_nav
-					.checked_add(&amount)
-					.ok_or(Error::<T>::Overflow)?;
-				Ok(())
-			})
-		}
-
-		#[pallet::weight(100)]
-		pub fn test_nav_down(
-			origin: OriginFor<T>,
-			pool_id: T::PoolId,
-			amount: T::Balance,
-		) -> DispatchResult {
-			let _ = ensure_signed(origin)?;
-			Pool::<T>::try_mutate(pool_id, |pool| {
-				let pool = pool.as_mut().ok_or(Error::<T>::NoSuchPool)?;
-				pool.fake_nav = pool
-					.fake_nav
-					.checked_sub(&amount)
-					.ok_or(Error::<T>::Overflow)?;
-				Ok(())
-			})
-		}
 	}
 
 	impl<T: Config> Pallet<T> {
@@ -921,7 +863,7 @@ pub mod pallet {
 				.ok_or(Error::<T>::Overflow)?;
 
 			// Rebalance tranches based on the new tranche asset values and ratios
-			let nav = pool.fake_nav;
+			let nav = T::NAV::nav(pool_id).ok_or(Error::<T>::NoNAV)?.0.into();
 			let mut remaining_nav = nav;
 			let mut remaining_reserve = pool.total_reserve;
 			let last_tranche = pool.tranches.len() - 1;
@@ -1005,10 +947,6 @@ pub mod pallet {
 					.total_reserve
 					.checked_add(&amount)
 					.ok_or(Error::<T>::Overflow)?;
-				pool.fake_nav = pool
-					.fake_nav
-					.checked_sub(&amount)
-					.ok_or(Error::<T>::Overflow)?;
 				let mut remaining_amount = amount;
 				for tranche in &mut pool.tranches {
 					Self::update_tranche_debt(tranche).ok_or(Error::<T>::Overflow)?;
@@ -1051,10 +989,6 @@ pub mod pallet {
 					.available_reserve
 					.checked_sub(&amount)
 					.ok_or(Error::<T>::Overflow)?;
-				pool.fake_nav = pool
-					.fake_nav
-					.checked_add(&amount)
-					.ok_or(Error::<T>::Overflow)?;
 				let mut remaining_amount = amount;
 				for tranche in &mut pool.tranches {
 					Self::update_tranche_debt(tranche).ok_or(Error::<T>::Overflow)?;

pallets/tinlake-investor-pool/src/mock.rs

@@ -1,4 +1,4 @@
-use crate::{self as pallet_tinlake_investor_pool, Config};
+use crate::{self as pallet_tinlake_investor_pool, Config, DispatchResult};
 use frame_support::{
 	parameter_types,
 	traits::{GenesisBuild, Hooks},
@@ -17,6 +17,49 @@ primitives_tokens::impl_tranche_token!();
 type UncheckedExtrinsic = frame_system::mocking::MockUncheckedExtrinsic<Test>;
 type Block = frame_system::mocking::MockBlock<Test>;
 
+mod fake_nav {
+	use super::Balance;
+	use codec::HasCompact;
+	use frame_support::pallet_prelude::*;
+	pub use pallet::*;
+
+	#[frame_support::pallet]
+	pub mod pallet {
+		use super::*;
+
+		#[pallet::config]
+		pub trait Config: frame_system::Config {
+			type PoolId: Member + Parameter + Default + Copy + HasCompact + MaxEncodedLen;
+		}
+
+		#[pallet::pallet]
+		#[pallet::generate_store(pub(super) trait Store)]
+		pub struct Pallet<T>(_);
+
+		#[pallet::storage]
+		pub type Nav<T: Config> = StorageMap<_, Blake2_128Concat, T::PoolId, Balance>;
+
+		impl<T: Config> Pallet<T> {
+			pub fn value(pool_id: T::PoolId) -> Balance {
+				Nav::<T>::get(pool_id).unwrap_or(0)
+			}
+
+			pub fn update(pool_id: T::PoolId, balance: Balance) {
+				Nav::<T>::insert(pool_id, balance);
+			}
+		}
+	}
+
+	impl<T: Config> common_traits::PoolNAV<T::PoolId, Balance> for Pallet<T> {
+		fn nav(pool_id: T::PoolId) -> Option<(Balance, u64)> {
+			Some((Self::value(pool_id), 0))
+		}
+		fn update_nav(pool_id: T::PoolId) -> Result<Balance, DispatchError> {
+			Ok(Self::value(pool_id))
+		}
+	}
+}
+
 // Configure a mock runtime to test the pallet.
 frame_support::construct_runtime!(
 	pub enum Test where
@@ -28,6 +71,7 @@ frame_support::construct_runtime!(
 		Timestamp: pallet_timestamp::{Pallet, Call, Storage, Inherent},
 		Tokens: orml_tokens::{Pallet, Storage, Event<T>, Config<T>},
 		TinlakeInvestorPool: pallet_tinlake_investor_pool::{Pallet, Call, Storage, Event<T>},
+		FakeNav: fake_nav::{Pallet, Storage},
 	}
 );
 
@@ -101,10 +145,16 @@ impl Config for Test {
 	type EpochId = u32;
 	type CurrencyId = CurrencyId;
 	type Tokens = Tokens;
+	type LoanAmount = Balance;
+	type NAV = FakeNav;
 	type TrancheToken = TrancheToken<Test>;
 	type Time = Timestamp;
 }
 
+impl fake_nav::Config for Test {
+	type PoolId = u32;
+}
+
 pub const CURRENCY: Balance = 1_000_000_000_000_000_000;
 
 // Build genesis storage according to the mock runtime.
@@ -143,3 +193,21 @@ pub fn next_block_after(seconds: u64) {
 	Timestamp::on_initialize(System::block_number());
 	Timestamp::set(Origin::none(), Timestamp::now() + seconds).unwrap();
 }
+
+pub fn test_borrow(borrower: u64, pool_id: u32, amount: Balance) -> DispatchResult {
+	test_nav_up(pool_id, amount);
+	TinlakeInvestorPool::do_borrow(borrower, pool_id, amount)
+}
+
+pub fn test_payback(borrower: u64, pool_id: u32, amount: Balance) -> DispatchResult {
+	test_nav_down(pool_id, amount);
+	TinlakeInvestorPool::do_payback(borrower, pool_id, amount)
+}
+
+pub fn test_nav_up(pool_id: u32, amount: Balance) {
+	FakeNav::update(pool_id, FakeNav::value(pool_id) + amount);
+}
+
+pub fn test_nav_down(pool_id: u32, amount: Balance) {
+	FakeNav::update(pool_id, FakeNav::value(pool_id) - amount);
+}

pallets/tinlake-investor-pool/src/tests.rs

@@ -37,7 +37,6 @@ fn core_constraints_currency_available_cant_cover_redemptions() {
 			max_reserve: 40,
 			available_reserve: Zero::zero(),
 			total_reserve: 39,
-			fake_nav: 0,
 		};
 
 		let epoch = EpochExecutionInfo {
@@ -105,7 +104,6 @@ fn pool_constraints_pool_reserve_above_max_reserve() {
 			max_reserve: 5,
 			available_reserve: Zero::zero(),
 			total_reserve: 40,
-			fake_nav: 90,
 		};
 
 		let epoch = EpochExecutionInfo {
@@ -178,7 +176,6 @@ fn pool_constraints_tranche_violates_sub_ratio() {
 			max_reserve: 150,
 			available_reserve: Zero::zero(),
 			total_reserve: 50,
-			fake_nav: 0,
 		};
 
 		let epoch = EpochExecutionInfo {
@@ -251,7 +248,6 @@ fn pool_constraints_pass() {
 			max_reserve: 150,
 			available_reserve: Zero::zero(),
 			total_reserve: 50,
-			fake_nav: 145,
 		};
 
 		let epoch = EpochExecutionInfo {
@@ -280,7 +276,7 @@ fn epoch() {
 		let tin_investor = Origin::signed(0);
 		let drop_investor = Origin::signed(1);
 		let pool_owner = Origin::signed(2);
-		let borrower = Origin::signed(3);
+		let borrower = 3;
 		let pool_account = Origin::signed(PoolLocator { pool_id: 0 }.into_account());
 
 		// Initialize pool with initial investments
@@ -332,11 +328,7 @@ fn epoch() {
 
 		// Borrow some money
 		next_block();
-		assert_ok!(TinlakeInvestorPool::test_borrow(
-			borrower.clone(),
-			0,
-			500 * CURRENCY
-		));
+		assert_ok!(test_borrow(borrower.clone(), 0, 500 * CURRENCY));
 
 		let pool = TinlakeInvestorPool::pool(0).unwrap();
 		assert_eq!(pool.tranches[0].debt, 250 * CURRENCY);
@@ -348,16 +340,8 @@ fn epoch() {
 
 		// Repay (with made up interest) after a month.
 		next_block_after(60 * 60 * 24 * 30);
-		assert_ok!(TinlakeInvestorPool::test_nav_up(
-			borrower.clone(),
-			0,
-			10 * CURRENCY
-		));
-		assert_ok!(TinlakeInvestorPool::test_payback(
-			borrower.clone(),
-			0,
-			510 * CURRENCY
-		));
+		test_nav_up(0, 10 * CURRENCY);
+		assert_ok!(test_payback(borrower.clone(), 0, 510 * CURRENCY));
 
 		let pool = TinlakeInvestorPool::pool(0).unwrap();
 		assert_eq!(pool.tranches[0].debt, 0);

runtime/development/src/lib.rs

@@ -635,6 +635,8 @@ impl pallet_tinlake_investor_pool::Config for Runtime {
 	type EpochId = u32;
 	type CurrencyId = CurrencyId;
 	type Tokens = Tokens;
+	type LoanAmount = Amount;
+	type NAV = Loan;
 	type TrancheToken = TrancheToken<Runtime>;
 	type Time = Timestamp;
 }