VikingVault - Erc20 SingleStaking with rewards distribution.

Table of contents

• VikingVault - Erc20 SingleStaking with rewards distribution.
  • Table of contents
  • Introduction
  • How To
    • Step-by-step tutorial
      • 1. Step One
      • 2. Step two
  • Smart-Contracts
  • VikingVault Code
    • Constructor
    • Enum Status description
    • Structs
    • Custom errors
    • Methods
      • Public methods
      • Restricted methods
      • Private methods

---

Introduction

VikingVault.sol is a smart contract written in Solidity language.

Context:

We wanted to develop and deploy a smart contract that would allow us to incentivize and reward our community, for being long-term token HODLERS, contributing to our community, and supporting our project.

We decided that Staking would be the safest and best solution to reach our goal, to distribute rewards among those who wants to stake their tokens with us long-term.

TicketVault is a custom developed smart-contract for single ERC20 staking and rewards distribution.

With this documentation, we will give you an in-depth description of the features in this smart contract.

How To

• Installation guide
• Step-by-Step tutorial

Step-by-step tutorial

To be able to follow this step-by-step tutorial, please be sure to follow the installation guide, and that you run the unit tests and they passed without errors before continuing with the following steps.

1. Step One

• Deploy VikingVault staking contract.

• Before we can deploy the VikingVault contract, there are a couple of variables that are optional to change inside the contract constructor. These variables are located at line 110, 112, and 113.

  1. stakingPeriod is the total number of weeks for this staking vault.
     • The default stakingPeriod value is set to 13 weeks (~3 months).
  2. withdrawPenaltyPeriod is the number of weeks where rewards are being accumulated.
     • Within this WithdrawPenaltyPeriod, if a stakeholder wants to withdraw their position and exit the staking pool, they will not get their accumulated rewards.
     • The default WithdrawPenaltyPeriod value is set to 2 weeks (~1/2 month).
  3. withdrawFee is the percentage value of the withdrawal fee.

     • Example fee values:

     • 0.1% fee, use value 10.

     • 5% fee, use value 500.

     • 10% fee, use value 1000.

     • Default withdrawFee value is set to 700 (7%).

• With these variables set in the contract code, we can now deploy the TicketVault to the network of your choice.

  • Open 1_deploy_contracts.js, at line 8, change CONTRACT_ADDRESS with the ERC20 contract address you want to use.

  • In your terminal, go to folder ../smart_contracts, and enter the code below to deploy the TicketVault smart-contract.

  npx hardhat run scripts/1_deploy_contracts.js --network NETWORKNAME 
  

  • Wait until you see the deployment confirmation and contract address from etherscan like below.

  ```text Deploying contracts with the account: 0x2fa005F3e5a5d35D431b7B8A1655d2CAc77f22AB

---

| Deployment Status :
| Contract owner : 0x2fa005F3e5a5d35D431b7B8A1655d2CAc77f22AB | Fee address : 0x2fa005F3e5a5d35D431b7B8A1655d2CAc77f22AB | | —————————————————————————— | Contract deployed : | TokenAddress : 0x938f689d828D6d105BAc52F9DE605d6C6CCa1CD1 | TicketVault : 0x6Fa408C20cEC935e4e0F3227Fbb4B12499Cb99F3 | StakePeriod : 7862400 Sec. ———————————————————————————- ```

• Now you can verify the contract on etherscan.

2. Step two

• Add Rewards.

*

Smart-Contracts

1. VikingVault.sol
2. Fees.sol

VikingVault Code

Description of the code in VikingVault.sol.

Constructor

• Parameter.

  • address TokenAddress.

    • ERC20 contract address used for staking and rewards.

Enum Status description

• Status Collecting.
  • Enum index value = 0.
  • During vault status Collecting, only the public methods below is allowed to be called:
    • deposit()
    • exitWhileCollecting()
• Status Staking.
  • Enum index value = 1.
  • During vault status Staking, only the public methods below is allowed to be called:
    • exitWhileStaking().
• Status Completed.
  • Enum index value = 2.
  • During vault status Completed, only the public methods below is allowed to be called:
    • withdraw().

Structs

• VaultInfo
  • status
    • The status of the vault.
  • stakingPeriod
    • The length of stalking period in seconds.
  • startTimestamp
    • Unix timestamp when the staking started.
  • stopTimestamp
    • Unix timestamp when the staking finished.
  • totalVaultShares
    • The total amount of tokens staked in the vault.
  • totalVaultRewards
    • The total amount of tokens to be used as rewards for staking.

• RewardInfo

  • lastRewardUpdateTimeStamp
    • Is set every time the pendingVaultRewards is calulated.
  • rewardRate
    • The rate of reward.
    • rewardRate = totalVaultRewards / stakingPeriod
  • pendingVaultRewards
    • The accoumulated rewards that is ready to be released.
  • claimedVaultRewards
    • The rewards amount claimed.
  • remainingVaultRewards
    • The rewards amount remaining in the vault.

Custom errors

Custom errors are thrown if a function call has failed and is reverted.

• NotAuthorized().
  • Is thrown by the modifier isStakeholder.
• NoZeroValues().
  • Is thrown by the modifier noZeroValues.
• MaxStaked().
  • Is thrown by the modifier limiter.
• NotCollecting().
  • Is thrown by the modifier isCollecting.
• NotStaking().
  • Is thrown by the modifier isStaking.
• NotCompleted().
  • Is thrown by the modifier isCompleted.
• AddRewardsFailed().
  • Is thrown by the restricted method addRewards(uint256 amount).
• DepositFailed().
  • Is thrown by the public method deposit(uint256 amount).
• RewardFailed().
  • Is thrown by the public method withdraw().
• WithdrawFailed().
  • Is thrown by the public method withdraw().

Methods

Public methods

Public state variables, and other non-state changing methods, consumes no gas when they are executed and run.

• Public state variables.

  • token().

    • Returns the staked erc20 address.

  • owner().

    • Returns the owner address of this smart contract.

  • feeAddress().

    • Returns the fee address that receives the withdrawal fees.

  • vault().

    • Returns values from the VaultInfo struct.

  • withdrawFee().

    • Returns fee percentage, 100 = 1%.

• View methods.

  • getAccountErc20Balance(address account)

    • Returns the total user amount of the preset ERC20 token, available in the user account.

    • The parameter account is the address to query.

  • getAccountVaultBalance(address account).

    • Returns the staked balance of the account.

    • Parameter account is the address to query.

  • getRewardInfo().

    • Returns values from RewardInfo.

      • lastRewardUpdateTimeStamp.

      • rewardRate.
      • pendingVaultRewards.
      • claimedVaultRewards.
      • remainingVaultRewards.

• State changing methods/ transactions.

  • deposit(uint256 amount).

    • Requires status Collecting.

    • Allows a user to deposit and stake in the vault.
      • Parameter amount is in Wei (1 eth/erc20 = 1000000000000000000 Wei).

    • Requires the user to have approved TicketVault to spend the erc20 to deposit.

    • Throws depositFailed() event if the transaction fails.
  • exitWhileCollecting().

    • Requires status Collecting.

    • Allows a stakeholder to withdraw their staked amount.

      • A withdrawFee is calculated from withdrawAmount, then paid to the fee address.

      • Remaining withdrawAmount is transferred to the stakeholders account.

  • exitWhileStaking().

    • Requires status Staking.

    • Allows a stakeholder to exit their staked position.

      • If during withdrawPenaltyPeriod, rewards are locked in vault.

      • A withdrawFee is calculated from withdrawAmount, then paid to the fee address.

      • Remaining withdrawAmount is sent to stakeholders account.

  • withdraw().

    • Requires status Completed.

    • Allows a stakeholder to withdraw their stake, and accumulated rewards, without any withdraw fee.

    • Emits the event Withdraw(address indexed User, uint256 amount, uint256 rewards) to the network.

Restricted methods

onlyOwner restricted (only the owner address can call these methods).

• setFeeAddress(address newFeeAddress).

  • Assigns a new account to receive the withdrawal fees.

    • The parameter newFeeAddress is the address to receive the withdrawal fees.
• addRewards(uint256 amount).

  • Deposits the amount of ERC20 tokens to be distributed among the stakeholders as a reward for staking.

    • Parameter amount is in Wei (1 eth/erc20 = 1000000000000000000 Wei).

    • The amount is added to the existing totalVaultRewards variable in the VaultInfo struct.

    • Throws a custom error AddRewardsFailed() if the transaction is reverted.

• startStaking().

  • Initiates the staking for the pre-set staking period.

    • The Vault Status is changed from Collecting to Staking.

    • Sets the vault startTimestamp to current block.timestamp.

    • Sets the vault stopTimestamp by adding the vault stakingPeriod value to the startTimestamp value.

    • Emits the event StakingStarted.

• stopStaking().

  • Completes the staking period of this vault.

    • Vault Status is changed from Staking to Completed.

    • remainingVaultRewards is added to pendingVaultRewards, then reset to 0.

    • Emits the event StakingCompleted().

Private methods

Private methods are only visible internal and can only be called by this contract.

• _deposit().

  • Deposit funds to TicketVault.

  • Is used by addRewards() and deposit() to pull funds from msg.sender, and into TicketVault.

• _withdraw().

  • Withdraw funds from the TicketVault.

  • Is used by

    • withdraw(),
    • exitWhileStaking(),

    • exitWhileCollecting()

      to withdraw the users stake from TicketVault.

• _calculateUserReward(_totalUserShares).

  • Calculates the pending user reward.

  • Called by exitWhileStaking(), and withdraw() to calculate the user reward.

  • Calculation:

    pendingUserReward = (pendingVaultRewards * ((_totalUserShares * 10000) / totalVaultShares)) / 10000;
    

• _calculatefee(_amount).

  • Calculates the fee amount to pay to fee address.

  • Called by exitWhileStaking(), and exitWhileCollecting() to calculate the fee amount.

  • Calculation:

    feeAmount = _amount * withdrawFee / 10000;
    withdrawAmount = _amount - feeAmount;