Enhance Stream Status

src/base.cairo

@@ -1,2 +1,3 @@
 pub mod errors;
+pub mod helpers;
 pub mod types;

src/base/errors.cairo

@@ -47,5 +47,8 @@ pub mod Errors {
 
     /// Thrown when wrong recipient or delegate
     pub const WRONG_RECIPIENT_OR_DELEGATE: felt252 = 'WRONG_RECIPIENT_OR_DELEGATE';
+
+    /// @notice Thrown when trying to withdraw an amount greater than the withdrawable amount.
+    pub const OVERDRAW: felt252 = 'Error: Overdraw';
 }
 

src/base/helpers.cairo

@@ -0,0 +1,25 @@
+pub mod Helpers {
+    use core::num::traits::Pow;
+
+    /// @dev Descales the provided `amount` from 18 decimals fixed-point number to token's decimals
+    /// number.
+    pub fn descale_amount(amount: u256, decimals: u8) -> u256 {
+        if decimals == 18 {
+            return amount;
+        }
+
+        let scale_factor = 10_u256.pow(18 - decimals.into());
+        return amount / scale_factor;
+    }
+
+    /// @dev Scales the provided `amount` from token's decimals number to 18 decimals fixed-point
+    /// number.
+    pub fn scale_amount(amount: u256, decimals: u8) -> u256 {
+        if decimals == 18 {
+            return amount;
+        }
+
+        let scale_factor = 10_u256.pow(18 - decimals.into());
+        return amount * scale_factor;
+    }
+}

src/base/types.cairo

@@ -16,7 +16,8 @@ pub struct Stream {
     pub balance: u256,
     pub status: StreamStatus,
     pub rate_per_second: UFixedPoint123x128,
-    pub last_update_time: u64,
+    pub snapshot_debt_scaled: u256,
+    pub snapshot_time: u64,
     pub transferable: bool,
 }
 
@@ -45,7 +46,7 @@ pub struct WeightedDistribution {
 }
 
 /// @notice Enum representing the possible states of a stream
-#[derive(Drop, Serde, starknet::Store, PartialEq)]
+#[derive(Drop, Serde, starknet::Store, PartialEq, Debug)]
 #[allow(starknet::store_no_default_variant)]
 pub enum StreamStatus {
     Active, // Stream is actively streaming tokens

src/interfaces/IPaymentStream.cairo

@@ -1,6 +1,6 @@
 use fp::UFixedPoint123x128;
 use starknet::ContractAddress;
-use crate::base::types::{ProtocolMetrics, Stream, StreamMetrics};
+use crate::base::types::{ProtocolMetrics, Stream, StreamMetrics, StreamStatus};
 
 /// @title IPaymentStream
 /// @notice Creates and manages payment streams with linear streaming functions.
@@ -192,10 +192,6 @@ pub trait IPaymentStream<TContractState> {
     /// @param transferable Boolean indicating if the stream can be transferred
     fn set_transferability(ref self: TContractState, stream_id: u256, transferable: bool);
 
-    /// @notice Checks if the stream is transferable
-    /// @param stream_id The ID of the stream to check
-    /// @return Boolean indicating if the stream is transferable
-    fn is_transferable(self: @TContractState, stream_id: u256) -> bool;
     /// @notice Gets the protocol fee of the token
     /// @param token The ContractAddress of the token
     /// @return u256 The fee of the token
@@ -310,6 +306,32 @@ pub trait IPaymentStream<TContractState> {
     /// @return Boolean indicating if the refund and pause operation was successful
     fn refund_and_pause(ref self: TContractState, stream_id: u256, amount: u256) -> bool;
 
+    /// @notice Returns the stream's status.
+    /// @dev Reverts if `stream_id` references a null stream.
+    /// Integrators should exercise caution when depending on the return value of this function as
+    /// streams can be paused and resumed at any moment.
+    /// @param stream_id The stream ID for the query.
+    fn status_of(self: @TContractState, stream_id: u256) -> StreamStatus;
+
+    /// @notice Returns the amount of debt accrued since the snapshot time until now, denoted as a
+    /// fixed-point number where 1e18 is 1 token.
+    /// @dev Reverts if `stream_id` references a null stream.
+    /// @param stream_id The stream ID for the query.
+    fn ongoing_debt_scaled_of(self: @TContractState, stream_id: u256) -> u256;
+
+    /// @notice Calculates the amount that the recipient can withdraw from the stream, denoted in
+    /// token decimals.
+    /// @dev Reverts if `stream_id` references a null stream.
+    /// @param stream_id The stream ID for the query.
+    /// @return withdrawableAmount The amount that the recipient can withdraw.
+    fn covered_debt_of(self: @TContractState, stream_id: u256) -> u128;
+
+    /// @notice Returns the amount of debt not covered by the stream balance, denoted in token's
+    /// decimals.
+    /// @dev Reverts if `stream_id` references a null stream.
+    /// @param stream_id The stream ID for the query.
+    fn uncovered_debt_of(self: @TContractState, stream_id: u256) -> u256;
+
     /// @notice Retrieves the sum of balances of all streams
     /// @param token The ERC-20 token to query
     /// @return The aggregated balance across all streams