ac12644

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import '@openzeppelin/contracts/access/Ownable.sol';
import '@openzeppelin/contracts/utils/math/SafeMath.sol';

contract Fundraiser is Ownable {
  using SafeMath for uint256;
 
}

ac12644

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
...

function addFarmer(address account) public onlyFarmer {
        _addFarmer(account);
    }

    function renounceFarmer() public {
        _removeFarmer(_msgSender());

ac12644

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
...

    // Define a function 'fetchItemBufferOne' that fetches the data
    function fetchItemBufferOne(uint256 _productCode)
        public
        view
        returns (
            uint256 itemstockUnit,

ac12644

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
...

    // 12th step in supply chain process
    function sellItemByRetailer(uint256 _productCode, uint256 _price)
        public
        onlyRetailer // check _msgSender() belongs to RetailerRole
        receivedByRetailer(_productCode)
        verifyCaller(items[_productCode].ownerID) // check _msgSender() is ownerID

ac12644

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
...
    // 9th step in supply chain process
    function purchaseItemByRetailer(uint256 _productCode)
        public
        payable
        onlyRetailer // check _msgSender() belongs to RetailerRole
        forSaleByDistributor(_productCode)
        paidEnough(items[_productCode].productPrice)

ac12644

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
...

  // 6th step in supply chain process
    function processedItemByDistributor(uint256 _productCode, uint256 slices)
        public
        onlyDistributor // check _msgSender() belongs to DistributorRole
        receivedByDistributor(_productCode)
        verifyCaller(items[_productCode].ownerID) // check _msgSender() is owner

ac12644

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
...

  // 4th step in supply chain process
    function shippedItemByFarmer(uint256 _productCode)
        public
        payable
        onlyFarmer // check _msgSender() belongs to FarmerRole
        purchasedByDistributor(_productCode)

ac12644

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
...

//2nd step of suppply chain process
function sellItemByFarmer(uint256 _productCode, uint256 _price)
        public
        onlyFarmer // check _msgSender() belongs to farmerRole
        producedByFarmer(_productCode) // check items state has been produced
        verifyCaller(items[_productCode].ownerID) // check _msgSender() is owner

ac12644

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

... 

// 1st step in supply chain process 
function produceItemByFarmer(
        uint256 _productCode,
        string memory _originFarmName,

ac12644

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

...

//Item State Modifiers
    modifier producedByFarmer(uint256 _productCode) {
        require(items[_productCode].itemState == State.ProduceByFarmer);
        _;
    }