feat: its scale coins and flow limits (#64)

Co-authored-by: Milap Sheth <[email protected]>

.gitignore

@@ -68,5 +68,7 @@ target/
 # MSVC Windows builds of rustc generate these, which store debugging information
 *.pdb
 
+# dist
+dist
 # move_compile
 move_compile/

move/its/sources/coin_info.move

@@ -6,33 +6,38 @@ module its::coin_info {
     use std::ascii;
     use std::string::String;
 
-    use sui::coin::{Self, CoinMetadata};
+    use sui::coin::CoinMetadata;
+
+    use its::utils;
 
     public struct CoinInfo<phantom T> has store {
         name: String,
         symbol: ascii::String,
         decimals: u8,
+        remote_decimals: u8,
         metadata: Option<CoinMetadata<T>>,
     }
 
     /// Create a new coin info from the given name, symbol and decimals.
     public fun from_info<T>(
-        name: String, symbol: ascii::String, decimals: u8
+        name: String, symbol: ascii::String, decimals: u8, remote_decimals: u8,
     ): CoinInfo<T> {
         CoinInfo {
             name,
             symbol,
             decimals,
+            remote_decimals,
             metadata: option::none(),
         }
     }
 
     /// Create a new coin info from the given `CoinMetadata` object.
-    public fun from_metadata<T>(metadata: CoinMetadata<T>): CoinInfo<T> {
+    public fun from_metadata<T>(metadata: CoinMetadata<T>, remote_decimals: u8): CoinInfo<T> {
         CoinInfo {
-            name: coin::get_name(&metadata),
-            symbol: coin::get_symbol(&metadata),
-            decimals: coin::get_decimals(&metadata),
+            name: metadata.get_name(),
+            symbol: metadata.get_symbol(),
+            decimals: metadata.get_decimals(),
+            remote_decimals,
             metadata: option::some(metadata),
         }
     }
@@ -51,17 +56,25 @@ module its::coin_info {
         self.decimals
     }
 
+    public fun remote_decimals<T>(self: &CoinInfo<T>): u8 {
+        self.remote_decimals
+    }
+
+    public fun scaling<T>(self: &CoinInfo<T>): u256 {
+        utils::pow(10, self.remote_decimals - self.decimals)
+    }
+
     public fun metadata<T>(self: &CoinInfo<T>): &Option<CoinMetadata<T>> {
         &self.metadata
     }
 
     #[test_only]
     public fun drop<T>(coin_info: CoinInfo<T>) {
-        let CoinInfo {name: _, symbol: _, decimals: _, metadata } = coin_info;
-        if (option::is_some(&metadata)) {
+        let CoinInfo {name: _, symbol: _, decimals: _, remote_decimals: _, metadata } = coin_info;
+        if (metadata.is_some()) {
             abort 0
         } else {
-            option::destroy_none(metadata)
+            metadata.destroy_none()
         }
     }
 }

move/its/sources/coin_management.move

@@ -4,6 +4,9 @@ module its::coin_management {
 
     use sui::coin::{Self, TreasuryCap, Coin};
     use sui::balance::{Self, Balance};
+    use sui::clock::Clock;
+
+    use its::flow_limit::{Self, FlowLimit};
 
     /// Trying to add a distributor to a `CoinManagement` that does not
     /// have a `TreasuryCap`.
@@ -14,6 +17,10 @@ module its::coin_management {
         treasury_cap: Option<TreasuryCap<T>>,
         balance: Option<Balance<T>>,
         distributor: Option<address>,
+        operator: Option<address>,
+        flow_limit: FlowLimit,
+        scaling: u256,
+        dust: u256,
     }
 
     /// Create a new `CoinManagement` with a `TreasuryCap`.
@@ -23,6 +30,10 @@ module its::coin_management {
             treasury_cap: option::some(treasury_cap),
             balance: option::none(),
             distributor: option::none(),
+            operator: option::none(),
+            flow_limit: flow_limit::new(),
+            scaling: 0, // placeholder, this gets edited when a coin is registered.
+            dust: 0,
         }
     }
 
@@ -33,6 +44,10 @@ module its::coin_management {
             treasury_cap: option::none(),
             balance: option::some(balance::zero()),
             distributor: option::none(),
+            operator: option::none(),
+            flow_limit: flow_limit::new(),
+            scaling: 0, // placeholder, this gets edited when a coin is registered.
+            dust: 0,
         }
     }
 
@@ -43,34 +58,61 @@ module its::coin_management {
         self.distributor.fill(distributor);
     }
 
+    /// Adds the distributor address to the `CoinManagement`.
+    /// Only works for a `CoinManagement` with a `TreasuryCap`.
+    public fun add_operator<T>(self: &mut CoinManagement<T>, operator: address) {
+        self.operator.fill(operator);
+    }
+
     // === Protected Methods ===
 
-    /// Takes the given amount of Coins from user.
-    public(package) fun take_coin<T>(self: &mut CoinManagement<T>, to_take: Coin<T>) {
+    /// Takes the given amount of Coins from user. Returns the amount that the ITS is supposed to give on other chains.
+    public(package) fun take_coin<T>(self: &mut CoinManagement<T>, to_take: Coin<T>, clock: &Clock): u256 {
+        self.flow_limit.add_flow_out(to_take.value(), clock);
+        let amount = (to_take.value() as u256) * self.scaling;
         if (has_capability(self)) {
-            self.treasury_cap
-                .borrow_mut()
-                .burn(to_take);
+            self.burn(to_take);
         } else {
             self.balance
                 .borrow_mut()
                 .join(to_take.into_balance());
-        }
+        };
+        amount
     }
 
-    /// Withdraws or mints the given amount of coins.
+    /// Withdraws or mints the given amount of coins. Any leftover amount from previous transfers is added to the coin here.
     public(package) fun give_coin<T>(
-        self: &mut CoinManagement<T>, amount: u64, ctx: &mut TxContext
+        self: &mut CoinManagement<T>, mut amount: u256, clock: &Clock, ctx: &mut TxContext
     ): Coin<T> {
+        amount  = amount + self.dust;
+        self.dust = amount % self.scaling;
+        let sui_amount = ( amount / self.scaling as u64);
+        self.flow_limit.add_flow_out(sui_amount, clock);
         if (has_capability(self)) {
-            self.treasury_cap
-                .borrow_mut()
-                .mint(amount, ctx)
+            self.mint(sui_amount, ctx)
         } else {
-            coin::take(self.balance.borrow_mut(), amount, ctx)
+            coin::take(self.balance.borrow_mut(), sui_amount, ctx)
         }
     }
 
+    // helper function to mint as a distributor.
+    public(package) fun mint<T>(self: &mut CoinManagement<T>, amount: u64, ctx: &mut TxContext): Coin<T> {
+        self.treasury_cap
+            .borrow_mut()
+            .mint(amount, ctx)
+    }
+
+    // helper function to burn as a distributor.
+    public(package) fun burn<T>(self: &mut CoinManagement<T>, coin: Coin<T>) {
+        self.treasury_cap
+            .borrow_mut()
+            .burn(coin);
+    }
+
+    public(package) fun set_scaling<T>(self: &mut CoinManagement<T>, scaling: u256) {
+        self.scaling = scaling;
+    }
+
     // === Views ===
 
     /// Checks if the given address is a `distributor`.
@@ -108,17 +150,19 @@ module its::coin_management {
 
         let mut coin = cap.mint(amount1, ctx);
         let mut management1 = new_locked<COIN_MANAGEMENT>();
-        management1.take_coin(coin);
+        let clock = sui::clock::create_for_testing(ctx);
+        management1.take_coin(coin, &clock);
 
         assert!(management1.balance.borrow().value() == amount1, 0);
 
         coin = cap.mint(amount2, ctx);
         let mut management2 = new_with_cap<COIN_MANAGEMENT>(cap);
-        management2.take_coin(coin);
+        management2.take_coin(coin, &clock);
 
         sui::test_utils::destroy(metadata);
         sui::test_utils::destroy(management1);
         sui::test_utils::destroy(management2);
+        sui::test_utils::destroy(clock);
     }
 
     #[test]
@@ -130,22 +174,26 @@ module its::coin_management {
 
         let mut coin = cap.mint(amount1, ctx);
         let mut management1 = new_locked<COIN_MANAGEMENT>();
-        management1.take_coin(coin);
-        coin = management1.give_coin(amount1, ctx);
+        management1.scaling = 1;
+        let clock = sui::clock::create_for_testing(ctx);
+        management1.take_coin(coin, &clock);
+        coin = management1.give_coin((amount1 as u256), &clock, ctx);
 
         assert!(management1.balance.borrow().value() == 0, 0);
         assert!(coin.value() == amount1, 0);
 
         sui::test_utils::destroy(coin);
 
         let mut management2 = new_with_cap<COIN_MANAGEMENT>(cap);
-        coin = management2.give_coin(amount2, ctx);
+        management2.scaling = 1;
+        coin = management2.give_coin((amount2 as u256), &clock, ctx);
 
         assert!(coin.value() == amount2, 1);
 
         sui::test_utils::destroy(coin);
         sui::test_utils::destroy(metadata);
         sui::test_utils::destroy(management1);
         sui::test_utils::destroy(management2);
+        sui::test_utils::destroy(clock);
     }
 }

move/its/sources/discovery.move

@@ -93,7 +93,8 @@ module its::discovery {
 
             let arguments = vector[
                 arg,
-                vector[2]
+                vector[2],
+                vector[0, 6],
             ];
 
 
@@ -127,6 +128,7 @@ module its::discovery {
                     vector[
                         discovery_arg,
                         channel_id_arg,
+                        vector[0, 6],
                     ],
                     vector[],
                 )],
@@ -253,7 +255,8 @@ module its::discovery {
 
         let arguments = vector[
             arg,
-            vector[2]
+            vector[2],
+            vector[0, 6],
         ];
         assert!(call_info.arguments() == arguments, 6);
         assert!(call_info.type_arguments() == vector[type_arg.into_string()], 7);

move/its/sources/flow_limit.move

@@ -0,0 +1,52 @@
+module its::flow_limit {
+    use sui::clock::Clock;
+
+    const EPOCH_TIME: u64 = 6 * 60 * 60 * 1000;
+
+    const EFlowLimitExceeded: u64 = 0;
+
+    public struct FlowLimit has store, copy, drop {
+        flow_limit: u64,
+        flow_in: u64,
+        flow_out: u64,
+        current_epoch: u64,
+    }
+
+    public(package) fun new(): FlowLimit {
+        FlowLimit {
+            flow_limit: 0,
+            flow_in: 0,
+            flow_out: 0,
+            current_epoch: 0,
+        }
+    }
+
+    fun update_epoch(self: &mut FlowLimit, clock: &Clock) {
+        let epoch = clock.timestamp_ms() / EPOCH_TIME;
+        if(epoch > self.current_epoch) {
+            self.current_epoch = epoch;
+            self.flow_in = 0;
+            self.flow_out = 0;
+        }
+    }
+
+    public(package) fun add_flow_in(self: &mut FlowLimit, amount: u64, clock: &Clock) {
+        if (self.flow_limit == 0) return;
+
+        update_epoch(self, clock);
+        assert!(self.flow_in + amount < self.flow_limit + self.flow_out, EFlowLimitExceeded);
+        self.flow_in = self.flow_in + amount;
+    }
+
+    public(package) fun add_flow_out(self: &mut FlowLimit, amount: u64, clock: &Clock) {
+        if (self.flow_limit == 0) return;
+
+        update_epoch(self, clock);
+        assert!(self.flow_out + amount < self.flow_limit + self.flow_in, EFlowLimitExceeded);
+        self.flow_out = self.flow_out + amount;
+    }
+
+    public(package) fun set_flow_limit(self: &mut FlowLimit, flow_limit: u64) {
+        self.flow_limit = flow_limit;
+    }
+}

move/its/sources/its.move

@@ -96,6 +96,15 @@ module its::its {
         &self.registered_coins[token_id]
     }
 
+    public(package) fun get_coin_data_mut<T>(self: &mut ITS, token_id: TokenId): &mut CoinData<T> {
+        assert!(self.registered_coins.contains(token_id), EUnregisteredCoin);
+        &mut self.registered_coins[token_id]
+    }
+
+    public(package) fun get_coin_scaling<T>(self: &CoinData<T>): u256 {
+        self.coin_info.scaling()
+    }
+
     public fun get_coin_info<T>(self: &ITS, token_id: TokenId): &CoinInfo<T> {
         &get_coin_data<T>(self, token_id).coin_info
     }
@@ -112,6 +121,10 @@ module its::its {
         get_coin_info<T>(self, token_id).decimals()
     }
 
+    public fun token_remote_decimals<T>(self: &ITS, token_id: TokenId): u8 {
+        get_coin_info<T>(self, token_id).remote_decimals()
+    }
+
     public fun get_trusted_address(self: &ITS, chain_name: String): String {
         *self.address_tracker.get_trusted_address(chain_name)
     }
@@ -169,9 +182,10 @@ module its::its {
     public(package) fun add_registered_coin<T>(
         self: &mut ITS,
         token_id: TokenId,
-        coin_management: CoinManagement<T>,
+        mut coin_management: CoinManagement<T>,
         coin_info: CoinInfo<T>,
     ) {
+        coin_management.set_scaling(coin_info.scaling());
         self.registered_coins.add(token_id, CoinData<T> {
             coin_management,
             coin_info,