Loans: Add Runtime API

libs/traits/Cargo.toml

@@ -16,6 +16,7 @@ codec = { package = "parity-scale-codec", version = "3.0.0", features = ["derive
 frame-support = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-v0.9.38" }
 impl-trait-for-tuples = "0.2.1"
 scale-info = { version = "2.3.0", default-features = false, features = ["derive"] }
+serde = { version = "1.0", optional = true }
 sp-arithmetic = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-v0.9.38" }
 sp-runtime = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-v0.9.38" }
 sp-std = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-v0.9.38" }
@@ -43,6 +44,7 @@ std = [
   "sp-std/std",
   "cfg-primitives/std",
   "scale-info/std",
+  "serde/std",
 ]
 try-runtime = [
   "frame-support/try-runtime",

libs/traits/src/interest.rs

@@ -11,13 +11,15 @@ use sp_runtime::{
 };
 
 #[derive(Encode, Decode, Clone, PartialEq, Eq, TypeInfo, RuntimeDebug, MaxEncodedLen)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub enum CompoundingSchedule {
 	/// Interest compounds every second
 	Secondly,
 }
 
 /// Interest rate method with compounding schedule information
 #[derive(Encode, Decode, Clone, PartialEq, Eq, TypeInfo, RuntimeDebug, MaxEncodedLen)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub enum InterestRate<Rate> {
 	/// Interest accrues at a fixed rate
 	Fixed {

pallets/loans/Cargo.toml

@@ -13,6 +13,7 @@ targets = ["x86_64-unknown-linux-gnu"]
 [dependencies]
 codec = { package = "parity-scale-codec", default-features = false, version = "3.0.0", features = ["derive"] }
 scale-info = { version = "2.3.0", default-features = false, features = ["derive"] }
+serde = { version = "1.0", optional = true }
 
 frame-support = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-v0.9.38" }
 frame-system = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-v0.9.38" }
@@ -63,6 +64,7 @@ std = [
   "sp-io/std",
   "strum/std",
   "orml-traits/std",
+  "serde/std",
 ]
 runtime-benchmarks = [
   "frame-benchmarking",

pallets/loans/docs/types.md

@@ -5,28 +5,14 @@ set namespaceSeparator ::
 hide methods
 
 enum Maturity {
-    Fixed: Moment
+    Fixed::date: Moment
+    Fixed::extension: Moment
 }
 
-enum CalendarEvent {
-    End
-}
-
-enum ReferenceDate{
-    CalendarDate: CalendarEvent,
-    OriginationDate
-}
-
-ReferenceDate *--> CalendarEvent
-
 enum InterestPayments {
     None
-    Monthly: ReferenceDate
-    SemiAnnually: ReferenceDate
 }
 
-InterestPayments *-----> ReferenceDate
-
 enum PayDownSchedule {
     None
 }
@@ -38,8 +24,8 @@ class RepaymentSchedule {
 }
 
 RepaymentSchedule *--> Maturity
-RepaymentSchedule *--> PayDownSchedule
-RepaymentSchedule *--> InterestPayments
+RepaymentSchedule *---> PayDownSchedule
+RepaymentSchedule *----> InterestPayments
 
 enum BorrowRestrictions {
     NoWrittenOff
@@ -59,24 +45,27 @@ class LoanRestrictions {
 LoanRestrictions *--> BorrowRestrictions
 LoanRestrictions *--> RepayRestrictions
 
-enum CompoundingCadence {
-    Secondly: ReferenceDate
-}
-
-CompoundingCadence *-r-> ReferenceDate
-
-enum InterestRate {
-    Fixed: Rate, CompoundingCadence
-}
-
-InterestRate *--> CompoundingCadence
-
 class RepaidAmount {
     principal: Balance
     interest: Balance
     unscheduled: Balance
 }
 
+node traits {
+    package interest {
+        enum CompoundingSchedule {
+            Secondly
+        }
+
+        enum InterestRate {
+            Fixed::rate_per_year: Rate
+            Fixed::compounding: CompoundingSchedule
+        }
+
+        InterestRate *--> CompoundingSchedule
+    }
+}
+
 package portfolio {
     class PortfolioValuation {
         value: Balance

pallets/loans/src/entities/interest.rs

@@ -9,6 +9,7 @@ use crate::pallet::Config;
 
 #[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebugNoBound, TypeInfo, MaxEncodedLen)]
 #[scale_info(skip_type_params(T))]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub struct ActiveInterestRate<T: Config> {
 	/// The current interest rate value (per year).
 	/// It the rate it has been penalized,

pallets/loans/src/entities/loans.rs

@@ -138,6 +138,8 @@ impl<T: Config> ClosedLoan<T> {
 /// Data containing an active loan.
 #[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebugNoBound, TypeInfo, MaxEncodedLen)]
 #[scale_info(skip_type_params(T))]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "std", serde(bound = ""))]
 pub struct ActiveLoan<T: Config> {
 	/// Specify the repayments schedule of the loan
 	schedule: RepaymentSchedule,
@@ -489,3 +491,47 @@ impl<T: Config> ActiveLoan<T> {
 		self.schedule.maturity = crate::types::Maturity::fixed(duration);
 	}
 }
+
+/// Data containing an active loan with extra computed.
+#[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebugNoBound, TypeInfo, MaxEncodedLen)]
+#[scale_info(skip_type_params(T))]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "std", serde(bound = ""))]
+pub struct ActiveLoanInfo<T: Config> {
+	/// Related active loan
+	active_loan: ActiveLoan<T>,
+
+	/// Interest accrued for this loan
+	interest_accrued: T::Balance,
+
+	/// Present value of the loan
+	present_value: T::Balance,
+}
+
+impl<T: Config> TryFrom<ActiveLoan<T>> for ActiveLoanInfo<T> {
+	type Error = DispatchError;
+
+	fn try_from(active_loan: ActiveLoan<T>) -> Result<Self, Self::Error> {
+		let (interest_accrued, present_value) = match &active_loan.pricing {
+			ActivePricing::Internal(inner) => {
+				let principal = active_loan
+					.total_borrowed
+					.ensure_sub(active_loan.total_repaid.principal)?;
+
+				let maturity_date = active_loan.schedule.maturity.date();
+
+				(
+					inner.current_interest(principal)?,
+					inner.present_value(active_loan.origination_date, maturity_date)?,
+				)
+			}
+			ActivePricing::External(inner) => (inner.current_interest()?, inner.present_value()?),
+		};
+
+		Ok(Self {
+			active_loan,
+			interest_accrued,
+			present_value,
+		})
+	}
+}

pallets/loans/src/entities/pricing.rs

@@ -14,6 +14,8 @@ pub mod internal;
 /// Loan pricing method
 #[derive(Encode, Decode, Clone, PartialEq, Eq, TypeInfo, RuntimeDebugNoBound, MaxEncodedLen)]
 #[scale_info(skip_type_params(T))]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "std", serde(bound = ""))]
 pub enum Pricing<T: Config> {
 	/// Calculated internally
 	Internal(internal::InternalPricing<T>),
@@ -25,6 +27,8 @@ pub enum Pricing<T: Config> {
 /// Pricing attributes for active loans
 #[derive(Encode, Decode, Clone, PartialEq, Eq, TypeInfo, RuntimeDebugNoBound, MaxEncodedLen)]
 #[scale_info(skip_type_params(T))]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "std", serde(bound = ""))]
 pub enum ActivePricing<T: Config> {
 	/// External attributes
 	Internal(internal::InternalActivePricing<T>),

pallets/loans/src/entities/pricing/external.rs

@@ -47,6 +47,7 @@ impl<T: Config> ExternalAmount<T> {
 
 /// Define the max borrow amount of a loan
 #[derive(Encode, Decode, Clone, PartialEq, Eq, TypeInfo, RuntimeDebug, MaxEncodedLen)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub enum MaxBorrowAmount<Quantity> {
 	/// You can borrow until the pool reserve
 	NoLimit,
@@ -58,6 +59,8 @@ pub enum MaxBorrowAmount<Quantity> {
 /// External pricing method
 #[derive(Encode, Decode, Clone, PartialEq, Eq, TypeInfo, RuntimeDebugNoBound, MaxEncodedLen)]
 #[scale_info(skip_type_params(T))]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "std", serde(bound = ""))]
 pub struct ExternalPricing<T: Config> {
 	/// Id of an external price
 	pub price_id: T::PriceId,
@@ -85,6 +88,8 @@ impl<T: Config> ExternalPricing<T> {
 /// External pricing method with extra attributes for active loans
 #[derive(Encode, Decode, Clone, PartialEq, Eq, TypeInfo, RuntimeDebugNoBound, MaxEncodedLen)]
 #[scale_info(skip_type_params(T))]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "std", serde(bound = ""))]
 pub struct ExternalActivePricing<T: Config> {
 	/// Basic external pricing info
 	info: ExternalPricing<T>,

pallets/loans/src/entities/pricing/internal.rs

@@ -23,6 +23,7 @@ use crate::{
 
 /// Diferents methods of how to compute the amount can be borrowed
 #[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug, TypeInfo, MaxEncodedLen)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub enum MaxBorrowAmount<Rate> {
 	/// Max borrow amount computation using the total borrowed
 	UpToTotalBorrowed { advance_rate: Rate },
@@ -34,6 +35,8 @@ pub enum MaxBorrowAmount<Rate> {
 /// Internal pricing method
 #[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebugNoBound, TypeInfo, MaxEncodedLen)]
 #[scale_info(skip_type_params(T))]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "std", serde(bound = ""))]
 pub struct InternalPricing<T: Config> {
 	/// Value of the collateral used for this loan
 	pub collateral_value: T::Balance,
@@ -59,6 +62,8 @@ impl<T: Config> InternalPricing<T> {
 /// Internal pricing method with extra attributes for active loans
 #[derive(Encode, Decode, Clone, PartialEq, Eq, TypeInfo, RuntimeDebugNoBound, MaxEncodedLen)]
 #[scale_info(skip_type_params(T))]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
+#[cfg_attr(feature = "std", serde(bound = ""))]
 pub struct InternalActivePricing<T: Config> {
 	/// Basic internal pricing info
 	info: InternalPricing<T>,

pallets/loans/src/lib.rs

@@ -84,7 +84,7 @@ pub mod pallet {
 	};
 	use codec::HasCompact;
 	use entities::{
-		loans::{self, ActiveLoan, LoanInfo},
+		loans::{self, ActiveLoan, ActiveLoanInfo, LoanInfo},
 		pricing::{PricingAmount, RepaidPricingAmount},
 	};
 	use frame_support::{
@@ -120,7 +120,7 @@ pub mod pallet {
 		<T as Config>::PriceId,
 		<T as Config>::PoolId,
 	>>::Collection;
-
+	pub type PortfolioInfoOf<T> = Vec<(<T as Config>::LoanId, ActiveLoanInfo<T>)>;
 	pub type AssetOf<T> = (<T as Config>::CollectionId, <T as Config>::ItemId);
 	pub type PriceOf<T> = (<T as Config>::Balance, Moment);
 	pub type PriceResultOf<T> = Result<PriceOf<T>, DispatchError>;
@@ -190,7 +190,7 @@ pub mod pallet {
 			+ MaxEncodedLen;
 
 		/// Defines the balance type used for math computations
-		type Balance: tokens::Balance + FixedPointOperand;
+		type Balance: tokens::Balance + FixedPointOperand + MaybeSerializeDeserialize;
 
 		/// Fetching method for the time of the current block
 		type Time: UnixTime;
@@ -992,6 +992,26 @@ pub mod pallet {
 			Ok((loan, count))
 		}
 
+		pub fn get_active_loans_info(
+			pool_id: T::PoolId,
+		) -> Result<PortfolioInfoOf<T>, DispatchError> {
+			ActiveLoans::<T>::get(pool_id)
+				.into_iter()
+				.map(|(loan_id, loan)| Ok((loan_id, loan.try_into()?)))
+				.collect()
+		}
+
+		pub fn get_active_loan_info(
+			pool_id: T::PoolId,
+			loan_id: T::LoanId,
+		) -> Result<Option<ActiveLoanInfo<T>>, DispatchError> {
+			ActiveLoans::<T>::get(pool_id)
+				.into_iter()
+				.find(|(id, _)| *id == loan_id)
+				.map(|(_, loan)| loan.try_into())
+				.transpose()
+		}
+
 		/// Set the maturity date of the loan to this instant.
 		#[cfg(feature = "runtime-benchmarks")]
 		pub fn expire(pool_id: T::PoolId, loan_id: T::LoanId) -> DispatchResult {

pallets/loans/src/types/mod.rs

@@ -92,6 +92,7 @@ pub enum MutationError {
 
 /// Specify the expected repayments date
 #[derive(Encode, Decode, Clone, PartialEq, Eq, TypeInfo, RuntimeDebug, MaxEncodedLen)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub enum Maturity {
 	/// Fixed point in time, in secs
 	Fixed {
@@ -131,13 +132,15 @@ impl Maturity {
 
 /// Interest payment periods
 #[derive(Encode, Decode, Clone, PartialEq, Eq, TypeInfo, RuntimeDebug, MaxEncodedLen)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub enum InterestPayments {
 	/// All interest is expected to be paid at the maturity date
 	None,
 }
 
 /// Specify the paydown schedules of the loan
 #[derive(Encode, Decode, Clone, PartialEq, Eq, TypeInfo, RuntimeDebug, MaxEncodedLen)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub enum PayDownSchedule {
 	/// The entire borrowed amount is expected to be paid back at the maturity
 	/// date
@@ -146,6 +149,7 @@ pub enum PayDownSchedule {
 
 /// Specify the repayment schedule of the loan
 #[derive(Encode, Decode, Clone, PartialEq, Eq, TypeInfo, RuntimeDebug, MaxEncodedLen)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub struct RepaymentSchedule {
 	/// Expected repayments date for remaining debt
 	pub maturity: Maturity,
@@ -166,6 +170,7 @@ impl RepaymentSchedule {
 
 /// Specify how offer a loan can be borrowed
 #[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug, TypeInfo, MaxEncodedLen)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub enum BorrowRestrictions {
 	/// The loan can not be borrowed if it has been written off.
 	NotWrittenOff,
@@ -176,6 +181,7 @@ pub enum BorrowRestrictions {
 
 /// Specify how offer a loan can be repaid
 #[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug, TypeInfo, MaxEncodedLen)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub enum RepayRestrictions {
 	/// No restrictions
 	None,
@@ -186,6 +192,7 @@ pub enum RepayRestrictions {
 
 /// Define the loan restrictions
 #[derive(Encode, Decode, Clone, PartialEq, Eq, RuntimeDebug, TypeInfo, MaxEncodedLen)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub struct LoanRestrictions {
 	/// How offen can be borrowed
 	pub borrows: BorrowRestrictions,
@@ -222,6 +229,7 @@ pub enum Change<LoanId, Rate, MaxRules: Get<u32>> {
 }
 
 #[derive(Default, Encode, Decode, Clone, PartialEq, Eq, TypeInfo, RuntimeDebug, MaxEncodedLen)]
+#[cfg_attr(feature = "std", derive(serde::Serialize, serde::Deserialize))]
 pub struct RepaidAmount<Balance> {
 	pub principal: Balance,
 	pub interest: Balance,