/**
 *Submitted for verification at Etherscan.io on 2020-07-04
*/

pragma solidity ^0.5.16;

interface IERC165 {
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

pragma solidity ^0.5.16;

contract IERC721 is IERC165 {
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    function balanceOf(address owner) public view returns (uint256 balance);
    function ownerOf(uint256 tokenId) public view returns (address owner);
    function approve(address to, uint256 tokenId) public;
    function getApproved(uint256 tokenId) public view returns (address operator);
    function setApprovalForAll(address operator, bool _approved) public;
    function isApprovedForAll(address owner, address operator) public view returns (bool);
    function transferFrom(address from, address to, uint256 tokenId) public;
    function safeTransferFrom(address from, address to, uint256 tokenId) public;
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory data) public;
}

pragma solidity ^0.5.16;

contract IERC721Receiver {
    function onERC721Received(address operator, address from, uint256 tokenId, bytes memory data)
    public returns (bytes4);
}

pragma solidity ^0.5.16;

library SafeMath {
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        require(c / a == b);
        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0);
        uint256 c = a / b;
        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;
        return c;
    }

    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);
        return c;
    }

    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }
}

pragma solidity ^0.5.16;

library Address {
    function isContract(address account) internal view returns (bool) {
        uint256 size;
        assembly { size := extcodesize(account) }
        return size > 0;
    }
}

pragma solidity ^0.5.16;

contract ERC165 is IERC165 {
    bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;
    mapping(bytes4 => bool) private _supportedInterfaces;

    constructor () internal {
        _registerInterface(_INTERFACE_ID_ERC165);
    }

    function supportsInterface(bytes4 interfaceId) external view returns (bool) {
        return _supportedInterfaces[interfaceId];
    }

    function _registerInterface(bytes4 interfaceId) internal {
        require(interfaceId != 0xffffffff);
        _supportedInterfaces[interfaceId] = true;
    }
}

pragma solidity ^0.5.16;

contract ERC721 is ERC165, IERC721 {
    using SafeMath for uint256;
    using Address for address;

    bytes4 private constant _ERC721_RECEIVED = 0x150b7a02;
    mapping (uint256 => address) private _tokenOwner;
    mapping (uint256 => address) private _tokenApprovals;
    mapping (address => uint256) private _ownedTokensCount;
    mapping (address => mapping (address => bool)) private _operatorApprovals;
    bytes4 private constant _INTERFACE_ID_ERC721 = 0x80ac58cd;

    constructor () public {
        _registerInterface(_INTERFACE_ID_ERC721);
    }

    function balanceOf(address owner) public view returns (uint256) {
        require(owner != address(0));
        return _ownedTokensCount[owner];
    }

    function ownerOf(uint256 tokenId) public view returns (address) {
        address owner = _tokenOwner[tokenId];
        require(owner != address(0));
        return owner;
    }

    function approve(address to, uint256 tokenId) public {
        address owner = ownerOf(tokenId);
        require(to != owner);
        require(msg.sender == owner || isApprovedForAll(owner, msg.sender));

        _tokenApprovals[tokenId] = to;
        emit Approval(owner, to, tokenId);
    }

    function getApproved(uint256 tokenId) public view returns (address) {
        require(_exists(tokenId));
        return _tokenApprovals[tokenId];
    }

    function setApprovalForAll(address to, bool approved) public {
        require(to != msg.sender);
        _operatorApprovals[msg.sender][to] = approved;
        emit ApprovalForAll(msg.sender, to, approved);
    }

    function isApprovedForAll(address owner, address operator) public view returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    function transferFrom(address from, address to, uint256 tokenId) public {
        require(_isApprovedOrOwner(msg.sender, tokenId));
        _transferFrom(from, to, tokenId);
    }

    function safeTransferFrom(address from, address to, uint256 tokenId) public {
        safeTransferFrom(from, to, tokenId, "");
    }

    function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory _data) public {
        transferFrom(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, _data));
    }

    function _exists(uint256 tokenId) internal view returns (bool) {
        address owner = _tokenOwner[tokenId];
        return owner != address(0);
    }

    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view returns (bool) {
        address owner = ownerOf(tokenId);
        return (spender == owner || getApproved(tokenId) == spender || isApprovedForAll(owner, spender));
    }

    function _mint(address to, uint256 tokenId) internal {
        require(to != address(0));
        require(!_exists(tokenId));

        _tokenOwner[tokenId] = to;
        _ownedTokensCount[to] = _ownedTokensCount[to].add(1);

        emit Transfer(address(0), to, tokenId);
    }

    function _transferFrom(address from, address to, uint256 tokenId) internal {
        require(ownerOf(tokenId) == from);
        require(to != address(0));

        _clearApproval(tokenId);

        _ownedTokensCount[from] = _ownedTokensCount[from].sub(1);
        _ownedTokensCount[to] = _ownedTokensCount[to].add(1);
        _tokenOwner[tokenId] = to;

        emit Transfer(from, to, tokenId);
    }

    function _checkOnERC721Received(address from, address to, uint256 tokenId, bytes memory _data)
        internal returns (bool)
    {
        if (!to.isContract()) {
            return true;
        }

        bytes4 retval = IERC721Receiver(to).onERC721Received(msg.sender, from, tokenId, _data);
        return (retval == _ERC721_RECEIVED);
    }

    function _clearApproval(uint256 tokenId) private {
        if (_tokenApprovals[tokenId] != address(0)) {
            _tokenApprovals[tokenId] = address(0);
        }
    }

    function uint2str(uint i) internal pure returns (string memory){
        if (i == 0) return "0";
        uint j = i;
        uint length;
        while (j != 0){
            length++;
            j /= 10;
        }
        bytes memory bstr = new bytes(length);
        uint k = length - 1;
        while (i != 0){
            bstr[k--] = byte(uint8(48 + i % 10));
            i /= 10;
        }
        return string(bstr);
    }

    function strConcat(string memory _a, string memory _b, string memory _c) internal pure returns (string memory) {
        bytes memory _ba = bytes(_a);
        bytes memory _bb = bytes(_b);
        bytes memory _bc = bytes(_c);
        string memory abc = new string(_ba.length + _bb.length + _bc.length);
        bytes memory babc = bytes(abc);
        uint k = 0;
        for (uint i = 0; i < _ba.length; i++) babc[k++] = _ba[i];
        for (uint j = 0; j < _bb.length; j++) babc[k++] = _bb[j];
        for (uint j = 0; j < _bc.length; j++) babc[k++] = _bc[j];
        return string(babc);
    }

}

pragma solidity ^0.5.16;

contract IERC721Enumerable is IERC721 {
    function totalSupply() public view returns (uint256);
    function tokenOfOwnerByIndex(address owner, uint256 index) public view returns (uint256 tokenId);
    function tokenByIndex(uint256 index) public view returns (uint256);
}

pragma solidity ^0.5.16;

contract ERC721Enumerable is ERC165, ERC721, IERC721Enumerable {

    mapping(address => uint256[]) private _ownedTokens;
    mapping(uint256 => uint256) private _ownedTokensIndex;
    uint256[] private _allTokens;
    mapping(uint256 => uint256) private _allTokensIndex;
    bytes4 private constant _INTERFACE_ID_ERC721_ENUMERABLE = 0x780e9d63;

    constructor () public {
        _registerInterface(_INTERFACE_ID_ERC721_ENUMERABLE);
    }

    function tokenOfOwnerByIndex(address owner, uint256 index) public view returns (uint256) {
        require(index < balanceOf(owner));
        return _ownedTokens[owner][index];
    }

    function totalSupply() public view returns (uint256) {
        return _allTokens.length;
    }

    function tokenByIndex(uint256 index) public view returns (uint256) {
        require(index < totalSupply());
        return _allTokens[index];
    }

    function _transferFrom(address from, address to, uint256 tokenId) internal {
        super._transferFrom(from, to, tokenId);
        _removeTokenFromOwnerEnumeration(from, tokenId);
        _addTokenToOwnerEnumeration(to, tokenId);
    }

    function _mint(address to, uint256 tokenId) internal {
        super._mint(to, tokenId);
        _addTokenToOwnerEnumeration(to, tokenId);
        _addTokenToAllTokensEnumeration(tokenId);
    }

    function _tokensOfOwner(address owner) internal view returns (uint256[] storage) {
        return _ownedTokens[owner];
    }

    function _addTokenToOwnerEnumeration(address to, uint256 tokenId) private {
        _ownedTokensIndex[tokenId] = _ownedTokens[to].length;
        _ownedTokens[to].push(tokenId);
    }

    function _addTokenToAllTokensEnumeration(uint256 tokenId) private {
        _allTokensIndex[tokenId] = _allTokens.length;
        _allTokens.push(tokenId);
    }

    function _removeTokenFromOwnerEnumeration(address from, uint256 tokenId) private {
        uint256 lastTokenIndex = _ownedTokens[from].length.sub(1);
        uint256 tokenIndex = _ownedTokensIndex[tokenId];

        if (tokenIndex != lastTokenIndex) {
            uint256 lastTokenId = _ownedTokens[from][lastTokenIndex];
            _ownedTokens[from][tokenIndex] = lastTokenId;
            _ownedTokensIndex[lastTokenId] = tokenIndex;
        }

        _ownedTokens[from].length--;
    }

    function _removeTokenFromAllTokensEnumeration(uint256 tokenId) private {

        uint256 lastTokenIndex = _allTokens.length.sub(1);
        uint256 tokenIndex = _allTokensIndex[tokenId];
        uint256 lastTokenId = _allTokens[lastTokenIndex];

        _allTokens[tokenIndex] = lastTokenId;
        _allTokensIndex[lastTokenId] = tokenIndex;

        _allTokens.length--;
        _allTokensIndex[tokenId] = 0;
    }
}

pragma solidity ^0.5.16;

contract IERC721Metadata is IERC721 {
    function name() external view returns (string memory);
    function symbol() external view returns (string memory);
    function tokenURI(uint256 tokenId) external view returns (string memory);
}


pragma solidity ^0.5.16;

contract ERC721Metadata is ERC165, ERC721, IERC721Metadata {

    string private _name;
    string private _symbol;

    bytes4 private constant _INTERFACE_ID_ERC721_METADATA = 0x5b5e139f;

    constructor (string memory name, string memory symbol) public {
        _name = name;
        _symbol = symbol;
        _registerInterface(_INTERFACE_ID_ERC721_METADATA);
    }

    function name() external view returns (string memory) {
        return _name;
    }

    function symbol() external view returns (string memory) {
        return _symbol;
    }

    function tokenURI(uint256 tokenId) external view returns (string memory) {
        require(_exists(tokenId));
        string memory infoUrl;
        infoUrl = strConcat('https://ethereum.cn/token/', uint2str(tokenId),'.json');
        return infoUrl;
    }
}

pragma solidity ^0.5.16;

contract ERC721Full is ERC721, ERC721Enumerable, ERC721Metadata {
    constructor (string memory name, string memory symbol) public ERC721Metadata(name, symbol) {
    }
}

pragma solidity ^0.5.16;

library Roles {
    struct Role {
        mapping (address => bool) bearer;
    }

    function add(Role storage role, address account) internal {
        require(account != address(0));
        require(!has(role, account));

        role.bearer[account] = true;
    }

    function remove(Role storage role, address account) internal {
        require(account != address(0));
        require(has(role, account));

        role.bearer[account] = false;
    }

    function has(Role storage role, address account) internal view returns (bool) {
        require(account != address(0));
        return role.bearer[account];
    }
}

pragma solidity ^0.5.16;


contract MinterRole {
    using Roles for Roles.Role;
    event MinterAdded(address indexed account);
    event MinterRemoved(address indexed account);

    Roles.Role private _minters;

    constructor () internal {
        _addMinter(msg.sender);
    }

    modifier onlyMinter() {
        require(isMinter(msg.sender));
        _;
    }

    function isMinter(address account) public view returns (bool) {
        return _minters.has(account);
    }

    function addMinter(address account) public onlyMinter {
        _addMinter(account);
    }

    function renounceMinter() public {
        _removeMinter(msg.sender);
    }

    function _addMinter(address account) internal {
        _minters.add(account);
        emit MinterAdded(account);
    }

    function _removeMinter(address account) internal {
        _minters.remove(account);
        emit MinterRemoved(account);
    }
}

pragma solidity ^0.5.16;

contract ERC721Mintable is ERC721, MinterRole {

    function mint(address to, uint256 tokenId) public onlyMinter returns (bool) {
        _mint(to, tokenId);
        return true;
    }
}


pragma solidity ^0.5.16;

contract Ownable {
    address private _owner;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }

    function owner() public view returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(isOwner());
        _;
    }

    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0));
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}


pragma solidity ^0.5.16;

contract Commemorative_token is ERC721Full, ERC721Mintable, Ownable {
    using SafeMath for uint256;
    uint256 private tid = 1;

    constructor (string memory _name, string memory _symbol) public
        ERC721Mintable()
        ERC721Full(_name, _symbol){
    }

    function transfer(address _to, uint256 _tokenId) public {
        safeTransferFrom(msg.sender, _to, _tokenId);
    }

    function claim() public {
        _mint(msg.sender,tid);
        tid = tid.add(1);
    }
    
    function reset(uint256 _newtid) public onlyOwner{
        tid = _newtid;
    }
    
    function gettid() external view returns (uint256) {
        return tid;
    }
    
    function draw() public onlyOwner{
        msg.sender.transfer(address(this).balance);
    }
    
    function () external{
        claim();
    }

}