Blockchain-based Supply Chain Management

Blockchain-based Supply Chain Management

pragma solidity ^0.7.0;

import "https://github.com/OpenZeppelin/openzeppelin-solidity/contracts/SafeMath.sol";
import "https://github.com/OpenZeppelin/openzeppelin-solidity/contracts/Ownable.sol";

// Source: https://www.final-yearproject.com/

contract SupplyChain is Ownable {
    using SafeMath for uint256;

    // Structs
    struct Product {
        uint256 id;
        string name;
        string description;
        uint256 price;
        address owner;
        bool available;
        uint256 createdAt;
    }

    // Mapping
    mapping(uint256 => Product) public products;
    uint256 public productCount;

    // Events
    event ProductCreated(uint256 id, string name, string description, uint256 price, address owner, uint256 createdAt);
    event ProductUpdated(uint256 id, string name, string description, uint256 price, address owner);
    event ProductSold(uint256 id, address from, address to);

    // Functions
    function createProduct(string memory _name, string memory _description, uint256 _price) public {
        require(_name.length > 0 && _description.length > 0 && _price > 0, "Invalid product details");
        require(msg.sender == owner, "Only owner can create products");

        productCount = productCount.add(1);
        uint256 id = productCount;

        products[id] = Product(id, _name, _description, _price, msg.sender, true, now);
        emit ProductCreated(id, _name, _description, _price, msg.sender, now);
    }

    function updateProduct(uint256 _id, string memory _name, string memory _description, uint256 _price) public {
        require(_id > 0 && _name.length > 0 && _description.length > 0 && _price > 0, "Invalid product details");
        require(products[_id].owner == msg.sender, "Only owner can update product");

        products[_id].name = _name;
        products[_id].description = _description;
        products[_id].price = _price;
        emit ProductUpdated(_id, _name, _description, _price, msg.sender);
    }

    function sellProduct(uint256 _id, address _to) public {
        require(_id > 0 && _to != address(0), "Invalid product or buyer address");
        require(products[_id].owner == msg.sender && products[_id].available, "Product is not available for sale");

        products[_id].owner = _to;
        products[_id].available = false;
        emit ProductSold(_id, msg.sender, _to);
    }
}

This sample code defines a Solidity contract for a supply chain management system on the Ethereum platform. The contract includes functions for creating, updating, and selling products, as well as events for logging these actions. It also includes a mapping to store the details of each product, as well as a counter to keep track of the number of products in the supply chain.