MCPM Contracts

This repository contains the staking contracts for the Meme Coin Prediction Market (MCPM).

Overview

The contracts are based on well-known and audited implementations by Swapsicle. Below are the main contracts included in this repository:

• IceCreamVan: A simplified version of MasterChefV2, with rewards distributed based on blocks.
• IceCreamVanV2: A simplified version of MasterChefV2, with rewards distributed based on seconds.

Audit Information

The initial version of the IceCreamVan contract has been audited by Vibranium Audits. You can find the audit report here or download the PDF directly.

MCPMFarm Contract

The MCPMFarm contract is a fork of the IceCreamVanV2 contract, tailored to meet the needs of the Meme Coin Prediction Market. It introduces several enhancements and features:

Key Features

• Vesting:

  • Allows external contracts (e.g., airdrop contracts) to deposit tokens for users with a lockup period.
  • Vested tokens earn rewards during the lockup period but cannot be withdrawn until the vesting period ends.
  • The vesting period must be at least MINIMUM_VESTING_SECONDS (1 year).

• Rewards Distribution:

  • Rewards are distributed based on seconds rather than blocks.
  • Includes logic to calculate overpaid rewards when distributions are delayed beyond the cycle duration.

• Cycle Management:

  • Supports configurable reward cycles (cycleDuration) and calculates rewards per second for each cycle.
  • Tracks overpaid rewards when distributions are late.

Functions

• vest: Deposits tokens for users with a lockup period, allowing them to earn rewards while holding their tokens.
• distributeRewards: Updates the rewardsPerSecond variable and distributes rewards to stakers. Handles overpaid rewards when distributions are delayed.
• getWithdrawableAmount: Calculates the amount of staked tokens that can be withdrawn, excluding vested tokens.
• sweepErc20: Allows the operator to withdraw non-staking and non-reward tokens sent to the contract by mistake.

Events

• Deposit: Emitted when a user deposits tokens.
• Withdraw: Emitted when a user withdraws tokens.
• EmergencyWithdraw: Emitted when a user withdraws tokens without claiming rewards.
• UpdateRewardsPerSecond: Emitted when the rewards per second are updated.
• RewardsDistribution: Emitted when rewards are distributed.

Error Handling

The contract uses custom errors for better gas efficiency and clarity:

• InvalidAmount
• InvalidCycleDuration
• InsufficientBalance
• SweepingContractTokensNotAllowed
• And others.

Example Usage

Below is a dummy function illustrating how rewards might be distributed from an external betting contract:

/// @notice Dummy distribute function for the external distributor, to distribute rewards.
function _distribute() private {
    uint256 rewardsAmount; // dummy variable, this should be a global variable (or similar) in the betting contract
    IMCPMFarm farm = IMCPMFarm(address(this));
    if (block.timestamp >= farm.nextRewardsDistribution()) { // nextRewardsDistribution is when the next rewards distribution should occur
        farm.distributeRewards(rewardsAmount);
        rewardsAmount = 0; // assuming there is a global rewardsAmount variable, reset it to 0 after distribution
    }
}