Contract Source Code:

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.20;

import {IERC165} from "../../utils/introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC-721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon
     *   a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external;

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC-721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or
     *   {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon
     *   a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC-721
     * or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
     * understand this adds an external call which potentially creates a reentrancy vulnerability.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the address zero.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool approved) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (utils/introspection/IERC165.sol)

pragma solidity ^0.8.20;

/**
 * @dev Interface of the ERC-165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[ERC].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[ERC section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

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

import "@openzeppelin/contracts/token/ERC721/IERC721.sol";

/**
 * @title TieredNFTBurn
 * @dev A contract that allows users to "burn" NFTs by sending them to the null address.
 *      Users are rewarded with tiers based on the number of NFTs they burn.
 *      Tier 1: Burn 25 or more NFTs
 *      Tier 2: Burn 15-24 NFTs
 *      Tier 3: Burn 5-14 NFTs
 * @author jojoracky Rizz @github chimmykk 
 */
contract TieredNFTBurn {
    IERC721 public nftToken;
    address public constant burnAddress = address(0);

    // Mapping to track total NFTs burned by each address
    mapping(address => uint256) public burnCount;
    // Mapping to track assigned tier for each address
    mapping(address => uint8) public tier;

    // Tier thresholds for each reward level
    uint256 public constant TIER_1_THRESHOLD = 25;
    uint256 public constant TIER_2_THRESHOLD = 15;
    uint256 public constant TIER_3_THRESHOLD = 5;

    // Events for tracking burns and tier assignments
    event Burn(address indexed user, uint256 tokenId);
    event TierAssigned(address indexed user, uint8 tier);

    /**
     * @dev Initializes the contract with the NFT contract address.
     * @param _nftTokenAddress The address of the NFT contract.
     */
    constructor(address _nftTokenAddress) {
        nftToken = IERC721(_nftTokenAddress);
    }

    /**
     * @dev Allows a user to burn multiple NFTs by transferring them to the null address.
     *      Also updates the user's burn count and assigns a tier based on the total NFTs burned.
     * @param tokenIds An array of token IDs to be burned.
     *
     * Requirements:
     * - `msg.sender` must own each token ID in `tokenIds`.
     */
    function burn(uint256[] calldata tokenIds) external {
        uint256 amount = tokenIds.length;
        require(amount > 0, "Must burn at least one token");

        for (uint256 i = 0; i < amount; i++) {
            uint256 tokenId = tokenIds[i];
            // Verify ownership of the token before transferring to burn address
            require(nftToken.ownerOf(tokenId) == msg.sender, "Not the owner of this token");

            // Transfer the NFT to the burn address (null address) to "burn" it
            nftToken.transferFrom(msg.sender, burnAddress, tokenId);
            emit Burn(msg.sender, tokenId);
        }

        // Update the user's burn count
        burnCount[msg.sender] += amount;

        // Calculate the user's new tier based on the cumulative burn count
        uint8 newTier = 0;
        if (burnCount[msg.sender] >= TIER_1_THRESHOLD) {
            newTier = 1;
        } else if (burnCount[msg.sender] >= TIER_2_THRESHOLD) {
            newTier = 2;
        } else if (burnCount[msg.sender] >= TIER_3_THRESHOLD) {
            newTier = 3;
        }

        // Update and emit new tier if it's different from the current tier
        if (newTier > 0 && newTier != tier[msg.sender]) {
            tier[msg.sender] = newTier;
            emit TierAssigned(msg.sender, newTier);
        }
    }

    /**
     * @dev Returns the tier level of a given user.
     * @param user The address of the user to query.
     * @return The tier level of the user.
     */
    function getUserTier(address user) external view returns (uint8) {
        return tier[user];
    }

    /**
     * @dev Returns the total number of NFTs burned by a given user.
     * @param user The address of the user to query.
     * @return The total burn count of the user.
     */
    function getUserBurnCount(address user) external view returns (uint256) {
        return burnCount[user];
    }
}