Entrypoints

This section outlines the core entrypoints for the Invariant smart contract, providing developers with essential methods to interact with the protocol. These entrypoints cover various aspects of the contract, including protocol fee management, fee tier administration, pool creation and management, position handling, and swap functionality.

Constructor

#[ink(constructor)]
pub fn new(protocol_fee: Percentage) -> Self;

This constructor method initializes the contract with the specified protocol fee. The administrator role is assigned to the caller.

Input parameters

Name	Type	Description
protocol_fee	Percentage	The percentage for the protocol fee.

Protocol fee

Get protocol fee

#[ink(message)]
pub fn get_protocol_fee(&self) -> Percentage;

This method retrieves the current protocol fee percentage.

Output parameters

Type	Description
Percentage	The current protocol fee.

Withdraw protocol fee

#[ink(message)]
pub fn withdraw_protocol_fee(&mut self, pool_key: PoolKey) -> Result<(), InvariantError>;

This operation enables the withdrawal of protocol fees associated with a specific pool, based on the provided pool key. The withdrawn funds are sent to the fee receiver wallet. Please note that this action can only be performed by fee receiver.

Input parameters

Name	Type	Description
pool_key	PoolKey	The pool key that corresponds to the withdrawal of fees from the associated pool.

Errors

Code	Description
NotFeeReceiver	Reverts the call when the caller is unauthorized receiver.

External Contracts

• PSP22

Change protocol fee

#[ink(message)]
pub fn change_protocol_fee(&mut self, protocol_fee: Percentage) -> Result<(), InvariantError>;

This function allows for the adjustment of the current protocol fee percentage. Note that this operation is restricted to administrators.

Input parameters

Name	Type	Description
protocol_fee	Percentage	The new protocol fee percentage.

Errors

Code	Description
NotAdmin	Reverts the call when the caller is an unauthorized user.

Change fee receiver

#[ink(message)]
pub fn change_fee_receiver(
    &mut self,
    pool_key: PoolKey,
    fee_receiver: AccountId,
) -> Result<(), InvariantError>;

This function allows for the modification of the fee receiver of a pool. Please note that this action is exclusively available to administrators.

Input parameters

Name	Type	Description
pool_key	PoolKey	The pool key of the pool where the change is to be made.
fee_receiver	AccountId	The new fee receiver's address of the pool.

Errors

Code	Description
NotAdmin	Reverts the call when the caller is unauthorized user.

Fee tier

Add fee tier

#[ink(message)]
pub fn add_fee_tier(&mut self, fee_tier: FeeTier) -> Result<(), InvariantError>;

This function enables the addition of a new fee tier, which users can subsequently utilize when creating pools. Please note that this action is restricted to administrators.

Input parameters

Name	Type	Description
fee_tier	FeeTier	The fee tier to be added.

Errors

Code	Description
NotAdmin	Fails if an unauthorized user attempts to create a fee tier.
InvalidTickSpacing	Fails if the tick spacing is invalid.
FeeTierAlreadyExist	Fails if the fee tier already exists.
InvalidFee	Fails if fee is invalid.

Fee Tier exist

#[ink(message)]
pub fn fee_tier_exist(&self, key: FeeTier) -> bool;

This function is used to verify the existence of a specified fee tier.

Input parameters

Name	Type	Description
key	FeeTier	The key associated with the fee tier to be checked for existence.

Output parameters

Type	Description
bool	boolean indicating if the fee tier is added.

Get fee tiers

#[ink(message)]
pub fn get_fee_tiers(&self) -> Vec<FeeTier>;

Retrieves all available fee tiers.

Output parameters

Type	Description
Vec<FeeTier>	Vector containing all fee tiers.

Remove fee tier

#[ink(message)]
pub fn remove_fee_tier(&mut self, key: FeeTier) -> Result<(), InvariantError>;

This function removes a fee tier based on the provided fee tier key. After removal, the fee tier will no longer be available for use in pool creation. It is important to note that existing pools with that fee tier will remain unaffected. This action is exclusively available to administrators.

Input parameters

Name	Type	Description
key	FeeTier	The key associated with the fee tier to be removed.

Errors

Code	Description
NotAdmin	Fails if an unauthorized user attempts to create a fee tier.
FeeTierNotFound	Fails if fee tier does not exist.

Pools

Create pool

#[ink(message)]
pub fn create_pool(
    &mut self,
    token_0: AccountId,
    token_1: AccountId,
    fee_tier: FeeTier,
    init_sqrt_price: SqrtPrice
    init_tick: i32,
) -> Result<(), InvariantError>;

This function creates a pool based on a pair of tokens and the specified fee tier. The order of the tokens is irrelevant, and only one pool can exist with a specific combination of two tokens and a fee tier.

Input parameters

Name	Type	Description
token_0	AccountId	Address of the first PSP22 token in the pair.
token_1	AccountId	Address of the second PSP22 token in the pair.
fee_tier	FeeTier	The fee tier to be applied.
init_sqrt_price	SqrtPrice	The square root of the price for the initial pool related to init_tick
init_tick	i32	The initial tick value for the pool.

Errors

Code	Description
FeeTierNotFound	Fails if the specified fee tier cannot be found.
TokensAreSame	Fails if the user attempts to create a pool for the same tokens.
PoolAlreadyExist	Fails if Pool with same tokens and fee tier already exist.
InvalidInitTick	Fails if the init tick is not divisible by the tick spacing.
InvalidInitSqrtPrice	Fails if the init sqrt price is not related to the init tick.

Get pool

#[ink(message)]
pub fn get_pool(
    &self,
    token_0: AccountId,
    token_1: AccountId,
    fee_tier: FeeTier,
) -> Result<Pool, InvariantError>;

This function retrieves a pool based on two tokens and the specified fee tier. It returns an error if the pool does not exist.

Input parameters

Name	Type	Description
token_0	AccountId	Address of the first token in the pair.
token_1	AccountId	Address of the second token in the pair.
fee_tier	FeeTier	The fee tier of the pool you want to retrieve.

Output parameters

Type	Description
Pool	A struct containing pool data.

Errors

Code	Description
PoolNotFound	Fails if there is no pool associated with created key.
TokensAreSame	Fails if the user attempts to create a pool for the same tokens.

Get pools

#[ink(message)]
pub fn get_pools(
    &self,
) -> Vec<PoolKey>;

This function retrieves a listed pool keys.

Output parameters

Type	Description
Vec<PoolKey>	Vector with pool keys that indicates all pools listed.

Position

Create position

#[ink(message)]
pub fn create_position(
    &mut self,
    pool_key: PoolKey,
    lower_tick: i32,
    upper_tick: i32,
    liquidity_delta: Liquidity,
    slippage_limit_lower: SqrtPrice,
    slippage_limit_upper: SqrtPrice,
) -> Result<Position, InvariantError>;

This function creates a position based on the provided parameters. The amount of tokens specified in liquidity delta will be deducted from the user's token balances. Position creation will fail if the user does not have enough tokens or has not approved enough tokens.

Input parameters

Name	Type	Description
pool_key	PoolKey	The pool key for which you want to create a position.
lower_tick	i32	The lower tick of your position.
upper_tick	i32	The upper tick of your position.
liquidity_delta	Liquidity	The liquidity you want to provide.
slippage_limit_lower	SqrtPrice	The lower square root of price fluctuation you are willing to accept.
slippage_limit_upper	SqrtPrice	The upper square root of price fluctuation you are willing to accept.

Output parameters

Type	Description
Position	The position that was created.

Errors

Code	Description
ZeroLiquidity	Fails if the user attempts to open a position with zero liquidity.
InvalidTickIndexOrTickSpacing	Fails if the user attempts to create a position with invalid tick indexes or tick spacing.
PriceLimitReached	Fails if the price has reached the slippage limit.
TransferError	Fails if the allowance is insufficient or the user balance transfer fails.
PoolNotFound	Fails if pool does not exist.

External Contracts

• PSP22

Transfer position

#[ink(message)]
pub fn transfer_position(
    &mut self,
    index: u32,
    receiver: AccountId,
) -> Result<(), InvariantError>;

This function changes ownership of an existing position based on the position index in the user's position list. You can only change ownership of positions that you own; otherwise, it will return an error.

Input parameters

Name	Type	Description
index	u32	Index of the position in the user's position list.
receiver	AccountId	Address of the user who will receive the position.

Remove position

#[ink(message)]
pub fn remove_position(
    &mut self,
    index: u32,
) -> Result<(TokenAmount, TokenAmount), InvariantError>;

This function removes a position from the user's position list and transfers the tokens used to create the position to the user's address.

Input parameters

Name	Type	Description
index	u32	Index of the position in the user's position list.

Output parameters

Type	Description
TokenAmount	Amount of token X sent to the user's wallet address.
TokenAmount	Amount of token Y sent to the user's wallet address.

Errors

Code	Description
PositionNotFound	Fails if Position cannot be found.

External Contracts

• PSP22

Claim fee

#[ink(message)]
pub fn claim_fee(
    &mut self,
    index: u32,
) -> Result<(TokenAmount, TokenAmount), InvariantError>;

This function allows the user to claim fees from an existing position. Tokens will be sent to the user's address.

Input parameters

Name	Type	Description
index	u32	Index of the position in the user's position list.

Output parameters

Type	Description
TokenAmount	Amount of token X sent to the user's wallet address.
TokenAmount	Amount of token Y sent to the user's wallet address.

Errors

Code	Description
PositionNotFound	Fails if Position cannot be found.

External Contracts

• PSP22

Get position

#[ink(message)]
pub fn get_position(&mut self, owner_id: AccountId, index: u32) -> Result<Position, InvariantError>;

This function returns an result that contains error if the position cannot be found or a position if it actually exists.

Input parameters

Name	Type	Description
owner_id	AccountId	An AccountId identifying the user who owns the position.
index	u32	Index of the position in the user's position list.

Output parameters

Type	Description
Result<Position, Invariant Error>	An Error or a position struct with data if it exists.

Errors

Code	Description
PositionNotFound	Fails if Position cannot be found.

Get all positions

#[ink(message)]
pub fn get_all_positions(&mut self, owner_id: AccountId) -> Vec<Position>;

This function returns a list of positions owned by the caller. The list will be empty if you do not have any positions.

Input parameters

Name	Type	Description
owner_id	AccountId	An AccountId identifying the user who own the positions.

Output parameters

Type	Description
Vec<Position>	A list containing the user's positions.

Swap

Swap

#[ink(message)]
pub fn swap(
    &mut self,
    pool_key: PoolKey,
    x_to_y: bool,
    amount: TokenAmount,
    by_amount_in: bool,
    sqrt_price_limit: SqrtPrice,
) -> Result<CalculateSwapResult, InvariantError>;

This function executes a swap based on the provided parameters. It transfers tokens from the user's address to the contract's address and vice versa. The swap will fail if the user does not have enough tokens, has not approved enough tokens, or if there is insufficient liquidity.

Input parameters

Name	Type	Description
pool_key	PoolKey	Pool key of the pool on which you wish to perform the swap.
x_to_y	bool	Specifies the direction of the swap.
amount	TokenAmount	Amount of tokens you want to receive or give.
by_amount_in	bool	Indicates whether the entered amount represents the tokens you wish to receive or give.
sqrt_price_limit	SqrtPrice	If the swap achieves this square root of the price, it will be canceled.

Output parameters

Type	Description
CalculateSwapResult	A struct containing the amount in and amount out with starting and target square root of price, taken fee, pool and vector of crossed ticks.

Errors

Code	Description
AmountIsZero	Fails if the user attempts to perform a swap with zero amounts.
PriceLimitReached	Fails if the price has reached the specified price limit (or price associated with specified square root of price).
NoGainSwap	Fails if the user would receive zero tokens.
TransferError	Fails if the allowance is insufficient or the user balance transfer fails.
PoolNotFound	Fails if pool does not exist.

External Contracts

• PSP22

Swap route

#[ink(message)]
pub fn swap_route(
    &mut self,
    amount_in: TokenAmount,
    expected_amount_out: TokenAmount,
    slippage: Percentage,
    swaps: Vec<SwapHop>,
) -> Result<(), InvariantError>;

This function facilitates atomic swaps between the user's address and the contract's address, executing multiple swaps based on the provided parameters. Tokens are transferred bidirectionally, from the user to the contract and vice versa, all within a single transaction. The swap is designed to be atomic, ensuring that it either completes entirely or reverts entirely. The success of the swap depends on factors such as the user having sufficient tokens, having approved the necessary token amounts, and the presence of adequate liquidity. Any failure in meeting these conditions will result in the swap transaction being reverted.

Input parameters

Name	Type	Description
amount_in	TokenAmount	Amount of tokens you want to swap
expected_amount_out	TokenAmount	Expected amount to receive as output calculated off-chain
slippage	Percentage	Percentage difference influencing price change, emphasizing precision in the number of tokens received compared to the expected quantity
swaps	Vec<SwapHop>	Vector of pool keys and booleans identifying swap pool and direction

Errors

Code	Description
AmountIsZero	Fails if the user attempts to perform a swap with zero amounts.
PriceLimitReached	Fails if the price has reached the specified price limit (or price associated with specified square root of price).
NoGainSwap	Fails if the user would receive zero tokens.
TransferError	Fails if the allowance is insufficient or the user balance transfer fails.
PoolNotFound	Fails if pool does not exist.

External Contracts

• PSP22

Quote

#[ink(message)]
pub fn quote(
    &self,
    pool_key: PoolKey,
    x_to_y: bool,
    amount: TokenAmount,
    by_amount_in: bool,
    sqrt_price_limit: SqrtPrice,
) -> Result<QuoteResult, InvariantError>;

This function performs a simulation of a swap based on the provided parameters and returns the simulation results. It does not involve any actual token transfers.

Input parameters

Name	Type	Description
pool_key	PoolKey	Pool key of the pool on which you wish to perform the swap.
x_to_y	bool	Specifies the direction of the swap.
amount	TokenAmount	Amount of tokens you want to receive or give.
by_amount_in	bool	Indicates whether the entered amount represents the tokens you wish to receive or give.
sqrt_price_limit	SqrtPrice	If the swap achieves this square root of the price, it will be canceled.

Output parameters

Type	Description
QuoteResult	A struct containing amount of tokens received, amount of tokens given, square root of price after the simulated swap and list of ticks that has been crossed durning the simulation

Errors

Code	Description
AmountIsZero	Fails if the user attempts to perform a swap with zero amounts.
PriceLimitReached	Fails if the price has reached the specified price limit (or price associated with specified square root of price).
NoGainSwap	Fails if the user would receive zero tokens.
PoolNotFound	Fails if pool does not exist.

Quote route

#[ink(message)]
pub fn quote_route(
    &self,
    amount_in: TokenAmount,
    swaps: Vec<SwapHop>,
) -> Result<TokenAmount, InvariantError>;

This function performs a simulation of multiple swaps based on the provided parameters and returns the simulation results. It does not involve any actual token transfers.

Input parameters

Name	Type	Description
amount_in	TokenAmount	Amount of tokens you want to swap.
swaps	Vec<SwapHop>	A vector containing all parameters needed to identify separate swap steps.

Output parameters

Type	Description
TokenAmount	Amount of tokens received in the simulation.

Errors

Code	Description
AmountIsZero	Fails if the user attempts to perform a swap with zero amounts.
PriceLimitReached	Fails if the price has reached the specified price limit (or price associated with specified square root of price).
NoGainSwap	Fails if the user would receive zero tokens.
PoolNotFound	Fails if pool does not exist.

Tick

Get tick

#[ink(message)]
pub fn get_tick(
    &self,
    key: PoolKey,
    index: i32
) -> Result<Tick, InvariantError>;

Retrieves information about a tick at a specified index.

Input parameters

Name	Type	Description
key	PoolKey	A unique key that identifies the specified pool.
index	i32	The tick index in the tickmap.

Output parameters

Type	Description
Tick	A struct containing tick data.

Errors

Code	Description
TickNotFound	Fails if tick cannot be found.

Is tick initialized

#[ink(message)]
pub fn is_tick_initialized(
    &self,
    key: PoolKey,
    index: i32
) -> bool;

Retrieves information about a tick at a specified index.

Input parameters

Name	Type	Description
key	PoolKey	A unique key that identifies the specified pool.
index	i32	The tick index in the tickmap.

Output parameters

Type	Description
bool	boolean identifying if the tick is initialized in tickmap.

Get position ticks

#[ink(message)]
fn get_position_ticks(&self, owner: AccountId, offset: u32) -> Vec<PositionTick>;

Retrieves list of lower and upper ticks of user positions.

Input parameters

Name	Type	Description
owner	AccountId	An AccountId identifying the user who owns the position.
offset	u32	The offset from the current position index.

Output parameters

Type	Description
Vec	Vector containing ticks of user positions.

Get user positions amount

#[ink(message)]
fn get_user_position_amount(&self, owner: AccountId) -> u32;

Retrieves the amount of positions held by the user.

Input parameters

Name	Type	Description
owner	AccountId	An AccountId identifying the user who owns the position.

Output parameters

Type	Description
u32	Number of user positions.

Get liquidity ticks

#[ink(message)]
fn get_liquidity_ticks(&self, pool_key: PoolKey, offset: u16) -> Vec<LiquidityTick>;

Retrieves ticks of a specified pool.

Input parameters

Name	Type	Description
pool_key	PoolKey	A unique key that identifies the specified pool.
offset	u16	The offset from which ticks will be retrieved.

Output parameters

Type	Description
Vec	Vector containing ticks of specified pool.

Get liquidity ticks amount

#[ink(message)]
fn get_liquidity_ticks_amount(&self, pool_key: PoolKey) -> u32;

Retrieves the amount of liquidity ticks of a specified pool.

Input parameters

Name	Type	Description
pool_key	PoolKey	A unique key that identifies the specified pool.

Output parameters

Type	Description
u32	Number of ticks on a specified pool.

Tickmap

Get tickmap

#[ink(message)]
fn get_tickmap(&self, pool_key: PoolKey, center_tick: i32) -> Vec<(u16,u64)>;

Retrieves tickmap chunks for a specified pool.

Input parameters

Name	Type	Description
pool_key	PoolKey	A unique key that identifies the specified pool.
center_tick	i32	Center tick index.

Output parameters

Type	Description
Vec<(u16,u64)/>	Vector containing tickmap chunks index and value.