Staking Protocol Smart Contract

This contract implements a reward distribution mechanism where users can stake their Sui coins and earn FARM token rewards over a specified duration. The contract keeps track of user balances, rewards to be claimed, and manages a treasury for holding staking rewards and staked coins.

Overview

RewardState is a struct that tracks details about the reward and has the following fields:

• id (UID): Identifier for the reward state object.
• duration (u64): Duration of rewards to be paid out in seconds. This is set by the contract owner.
• finishAt (u64): Timestamp indicating when the rewards will finish.
• updatedAt (u64): The minimum of the last updated time and reward finish time.
• rewardRate (u64): The reward to be paid out per second, determined by the duration and amount of rewards.

UserState is a struct that keeps track of users' rewards and has the following parameters associated with it:

• id (UID): Identifier for the user state object.
• rewardPerTokenStored (u64): Sum of (reward rate * dt * 1^(token_decimal) / total staked supply), where dt is the time difference between the current time and the last updated time.
• userRewardPerTokenPaid (VecMap<address, u64>): Mapping that keeps track of user's rewardPerTokenStored.
• balanceOf (VecMap<address, u64>): Mapping that keeps track of user's staked amount.
• rewards (VecMap<address, u64>): Mapping that keeps track of user's rewards to be claimed.

Treasury is a struct that holds user funds and staking rewards and has the following fields:

• id (UID): Identifier for the treasury object.
• rewardsTreasury (Balance<FARM>): Staking rewards held in the treasury.
• stakedCoinsTreasury (Balance<SUI>): Staked SUI coins held in the treasury.

Access to Admin functions setRewardDuration() and setRewardAmount() are granted via the AdminCap capability which is owned by the owner of the contract.

The contract includes the following functions:

stake

This function allows users to stake their tokens.

public entry fun stake (payment: Coin<SUI>, userState: &mut UserState, rewardState: &mut RewardState, treasury: &mut Treasury, clock: &Clock, ctx: &mut TxContext)

If the function succeeds, it will deposit the user's coins into the treasury and emit a Staked event containing the user's address and the amount staked.

withdraw

This function allows users to withdraw their staked tokens.

public entry fun withdraw(userState: &mut UserState, rewardState: &mut RewardState, treasury: &mut Treasury, amount: u64, clock: &Clock, ctx: &mut TxContext)

If the function succeeds, it will withdraw the user's coins from the treasury, return them to the user and emit a Withdrawn event containing the user's address and the amount withdrawn.

getRewards

This function allows users to collect their rewards.

public entry fun getReward(userState: &mut UserState, rewardState: &mut RewardState, treasury: &mut Treasury, clock: &Clock, ctx: &mut TxContext)

If the function succeeds, it will transfer the user's rewards from the treasury and emit a RewardPaid event containing the user's address and the reward paid.

setRewardDuration

This function allows the contract owner to set the reward duration.

public entry fun setRewardDuration(_: &AdminCap, rewardState: &mut RewardState, duration: u64, clock: &Clock)

If the function succeeds, it will set the duration for the staking rewards and emit a RewardDurationUpdated event containing the updated reward duration.

setRewardAmount

This function allows the contract owner to add rewards to the treasury.

public entry fun setRewardAmount(_: &AdminCap, reward: Coin<FARM>, userState: &mut UserState, rewardState: &mut RewardState, treasury: &mut Treasury, clock: &Clock)

If the function succeeds, it will add rewards to the treasury and emit a RewardAdded event containing the reward amount.

The contract also contains helper functions updateReward(), earned(), and rewardPerToken() which are used for computing the staking rewards.

Contract Compilation & Testing

To compile the contract, execute the following command in the root directory of the project:

sui move build

This will generate the compiled bytecode of the contract. To test the contract, there are test cases located in ./tests. You can run the tests by executing the following command in the root directory of the project:

sui move test

Deployment

To deploy the smart contract, please follow these steps:

1. Set your Sui client to the desired network (mainnet/testnet/devnet).

2. Navigate to the root directory of the smart contract.

3. Ensure that you have sufficient gas balance for the deployment.

4. Type the following command, replacing <gas-value> with the desired amount of gas

   sui client --publish --gas-budget <gas-value>

Usage

The contract is designed to be used in conjunction with a user interface, such as a web application. When a user performs an action, the user interface should call the corresponding function on the smart contract.