Token Buyback System
1. System Overview
The token buyback system is a token buyback and destruction management platform implemented in Solidity, supporting buyback, destruction, and price management of multiple tokens. The system implements flexible buyback strategies and comprehensive price control mechanisms.
1.1 Main Features
- Multi-token Buyback: Support multiple token buybacks
- Dynamic Pricing: Support dynamic price adjustments
- Automatic Destruction: Automated destruction process
- Price Protection: Price fluctuation protection mechanism
- Complete Records: Comprehensive operation records
2. Contract Implementation
solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import "@openzeppelin/contracts/utils/math/SafeMath.sol";
/**
* @title TokenBuyback
* @dev Token buyback contract
*/
contract TokenBuyback is Ownable, ReentrancyGuard {
using SafeMath for uint256;
// Buyback strategy information
struct Strategy {
IERC20 token; // Buyback token
IERC20 paymentToken; // Payment token
uint256 price; // Buyback price
uint256 minAmount; // Minimum buyback amount
uint256 maxAmount; // Maximum buyback amount
uint256 totalBought; // Total bought amount
uint256 totalPaid; // Total paid amount
uint256 lastUpdateTime; // Last update time
bool isActive; // Whether active
bool autoDestroy; // Whether auto destroy
}
// Buyback record
struct BuybackRecord {
address seller; // Seller address
uint256 amount; // Buyback amount
uint256 payment; // Payment amount
uint256 price; // Transaction price
uint256 timestamp; // Buyback time
bool isDestroyed; // Whether destroyed
}
// State variables
mapping(uint256 => Strategy) public strategies; // Buyback strategies
mapping(uint256 => BuybackRecord[]) public buybackRecords; // Buyback records
uint256 public strategyCount; // Strategy count
bool public paused; // Pause status
// Events
event StrategyCreated(uint256 indexed strategyId, address token, address paymentToken);
event TokenBoughtBack(uint256 indexed strategyId, address indexed seller, uint256 amount, uint256 payment);
event TokenDestroyed(uint256 indexed strategyId, uint256 amount);
event PriceUpdated(uint256 indexed strategyId, uint256 oldPrice, uint256 newPrice);
event StrategyStatusChanged(uint256 indexed strategyId, bool isActive);
/**
* @dev Constructor
*/
constructor() {
// Initialize state
}
/**
* @dev Create buyback strategy
*/
function createStrategy(
IERC20 _token,
IERC20 _paymentToken,
uint256 _price,
uint256 _minAmount,
uint256 _maxAmount,
bool _autoDestroy
) external onlyOwner {
require(address(_token) != address(0), "Invalid token");
require(address(_paymentToken) != address(0), "Invalid payment token");
require(_maxAmount >= _minAmount, "Invalid amounts");
require(_price > 0, "Invalid price");
strategies[strategyCount] = Strategy({
token: _token,
paymentToken: _paymentToken,
price: _price,
minAmount: _minAmount,
maxAmount: _maxAmount,
totalBought: 0,
totalPaid: 0,
lastUpdateTime: block.timestamp,
isActive: true,
autoDestroy: _autoDestroy
});
emit StrategyCreated(strategyCount, address(_token), address(_paymentToken));
strategyCount = strategyCount.add(1);
}
/**
* @dev Buyback tokens
*/
function buybackTokens(uint256 strategyId, uint256 amount) external nonReentrant {
require(!paused, "System paused");
require(strategyId < strategyCount, "Invalid strategy ID");
Strategy storage strategy = strategies[strategyId];
require(strategy.isActive, "Strategy not active");
require(amount >= strategy.minAmount, "Amount too small");
require(amount <= strategy.maxAmount, "Amount too large");
// Calculate payment amount
uint256 payment = amount.mul(strategy.price).div(1e18);
require(
strategy.paymentToken.balanceOf(address(this)) >= payment,
"Insufficient payment token balance"
);
// Transfer buyback tokens
strategy.token.transferFrom(msg.sender, address(this), amount);
// Pay tokens
strategy.paymentToken.transfer(msg.sender, payment);
// Update state
strategy.totalBought = strategy.totalBought.add(amount);
strategy.totalPaid = strategy.totalPaid.add(payment);
strategy.lastUpdateTime = block.timestamp;
// Record buyback
buybackRecords[strategyId].push(BuybackRecord({
seller: msg.sender,
amount: amount,
payment: payment,
price: strategy.price,
timestamp: block.timestamp,
isDestroyed: false
}));
emit TokenBoughtBack(strategyId, msg.sender, amount, payment);
// Auto destroy
if (strategy.autoDestroy) {
_destroyTokens(strategyId);
}
}
/**
* @dev Destroy tokens
*/
function destroyTokens(uint256 strategyId) external onlyOwner {
_destroyTokens(strategyId);
}
/**
* @dev Internal destroy function
*/
function _destroyTokens(uint256 strategyId) internal {
require(strategyId < strategyCount, "Invalid strategy ID");
Strategy storage strategy = strategies[strategyId];
uint256 balance = strategy.token.balanceOf(address(this));
require(balance > 0, "No tokens to destroy");
// Destroy tokens (transfer to zero address)
strategy.token.transfer(address(0), balance);
// Update records
BuybackRecord[] storage records = buybackRecords[strategyId];
for (uint256 i = 0; i < records.length; i++) {
if (!records[i].isDestroyed) {
records[i].isDestroyed = true;
}
}
emit TokenDestroyed(strategyId, balance);
}
/**
* @dev Update buyback price
*/
function updatePrice(uint256 strategyId, uint256 newPrice) external onlyOwner {
require(strategyId < strategyCount, "Invalid strategy ID");
require(newPrice > 0, "Invalid price");
Strategy storage strategy = strategies[strategyId];
uint256 oldPrice = strategy.price;
strategy.price = newPrice;
emit PriceUpdated(strategyId, oldPrice, newPrice);
}
/**
* @dev Set strategy status
*/
function setStrategyStatus(uint256 strategyId, bool isActive) external onlyOwner {
require(strategyId < strategyCount, "Invalid strategy ID");
strategies[strategyId].isActive = isActive;
emit StrategyStatusChanged(strategyId, isActive);
}
/**
* @dev Update strategy parameters
*/
function updateStrategy(
uint256 strategyId,
uint256 minAmount,
uint256 maxAmount,
bool autoDestroy
) external onlyOwner {
require(strategyId < strategyCount, "Invalid strategy ID");
require(maxAmount >= minAmount, "Invalid amounts");
Strategy storage strategy = strategies[strategyId];
strategy.minAmount = minAmount;
strategy.maxAmount = maxAmount;
strategy.autoDestroy = autoDestroy;
}
/**
* @dev Pause/resume system
*/
function setPaused(bool _paused) external onlyOwner {
paused = _paused;
}
/**
* @dev Get strategy information
*/
function getStrategyInfo(uint256 strategyId) external view returns (
address token,
address paymentToken,
uint256 price,
uint256 minAmount,
uint256 maxAmount,
uint256 totalBought,
uint256 totalPaid,
uint256 lastUpdateTime,
bool isActive,
bool autoDestroy
) {
Strategy storage strategy = strategies[strategyId];
return (
address(strategy.token),
address(strategy.paymentToken),
strategy.price,
strategy.minAmount,
strategy.maxAmount,
strategy.totalBought,
strategy.totalPaid,
strategy.lastUpdateTime,
strategy.isActive,
strategy.autoDestroy
);
}
}System Architecture
1. Core Components
- Buyback Contract: Manages token buybacks
- Strategy System: Controls buyback strategies
- Price Module: Manages buyback prices
- Destruction Module: Handles token destruction
2. Process Flow
- Admin creates buyback strategy
- Users sell tokens
- System executes buyback
- Optional auto-destruction
- Record keeping
Security Measures
1. Access Control
- Owner permissions
- Strategy management
- Price controls
- Emergency pause
2. Transaction Security
- Input validation
- Reentrancy protection
- Balance checks
- Status tracking
Best Practices
1. Implementation Guidelines
- Validate all inputs
- Implement proper access control
- Handle edge cases
- Maintain comprehensive logs
2. Operation Guidelines
- Regular security audits
- Strategy management
- Emergency response plan
- Regular price reviews
FAQ
1. Basic Concepts
Q: What is a token buyback? A: A token buyback is a mechanism where a project buys back its tokens from the market, often used to maintain token value and reduce circulating supply.
Q: How does buyback pricing work? A: Buyback pricing involves:
- Price setting
- Market monitoring
- Dynamic adjustments
- Value protection
2. Security
Q: How to ensure buyback security? A: Security measures include:
- Access control
- Price limits
- Amount restrictions
- Emergency mechanisms
- Regular audits
Q: How to handle buyback attacks? A: Protection measures include:
- Amount validation
- Price protection
- Rate limiting
- Transaction monitoring
- Quick response plan
3. Operations
Q: How to manage buybacks effectively? A: Management strategies include:
- Strategy planning
- Price monitoring
- Volume control
- Market analysis
- Risk management
Q: How to handle price fluctuations? A: Price management includes:
- Dynamic pricing
- Market monitoring
- Price limits
- Adjustment periods
- Risk controls
4. Maintenance
Q: How to maintain the buyback system? A: Maintenance includes:
- Regular updates
- Performance monitoring
- Security checks
- Strategy reviews
- Market analysis
Q: How to monitor buyback progress? A: Monitoring includes:
- Transaction tracking
- Volume analysis
- Price monitoring
- Market impact
- Success metrics