pragma solidity ^0.5.2;

library SafeMath {
 
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        uint256 c = a - b;
        return c;
    }

    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, "SafeMath: division by zero");
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0, "SafeMath: modulo by zero");
        return a % b;
    }
}

library Roles {
    struct Role {
        mapping (address => bool) bearer;
    }

    /**
     * @dev Give an account access to this role.
     */
    function add(Role storage role, address account) internal {
        require(!has(role, account), "Roles: account already has role");
        role.bearer[account] = true;
    }

    /**
     * @dev Remove an account's access to this role.
     */
    function remove(Role storage role, address account) internal {
        require(has(role, account), "Roles: account does not have role");
        role.bearer[account] = false;
    }

    /**
     * @dev Check if an account has this role.
     * @return bool
     */
     
    function has(Role storage role, address account) internal view returns (bool) {
        require(account != address(0), "Roles: account is the zero address");
        return role.bearer[account];
    }
}

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(), "Ownable: caller is not the owner");
        _;
    }

    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }
}
contract Management is Ownable{
    using Roles for Roles.Role;

    event ManagerAdded(address indexed account);
    event ManagerRemoved(address indexed account);
    
    Roles.Role private _managers;
    


    constructor ()  internal {
        addManager(msg.sender);
    }
    
    modifier onlyManager()  {
        require(isManager(msg.sender), "Management: caller is not the manager");
        _;
    }
    
    function isManager(address account) public view returns (bool) {
        return _managers.has(account);
    }
    
    function addManager(address account) public onlyOwner {
        _addManager(account);
    }

    function renounceManager() public onlyOwner {
        _removeManager(msg.sender);
    }

    function _addManager(address account) internal {
        _managers.add(account);
        emit ManagerAdded(account);
    }

    function _removeManager(address account) internal {
        _managers.remove(account);
        emit ManagerRemoved(account);
    }
}

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function transfer(address recipient, uint256 amount) external returns (bool);
    function allowance(address owner, address spender) external view returns (uint256);
    function approve(address spender, uint256 amount) external returns (bool);
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    event Transfer(address indexed from, address indexed to, uint256  value);
    event Approval(address indexed owner, address indexed spender, uint256  value);
}

contract RSDTToken is IERC20,Management {
    using SafeMath for uint256;
    mapping (address => uint256) private _balances;
    mapping (address => mapping (address => uint256)) private _allowances;
    uint256 private _totalSupply;
    string private _name;
    string private _symbol;
    uint8 private _decimals;
    
    mapping(address => uint256) public collection;
    mapping(uint256 => address) public exChanges;
    
    event SetExchange(uint256 indexed exchangeCode,address indexed exchangeAddress);
    
    constructor() public {
        _name = "RSDT Token";
        _symbol = "RSDT";
        _decimals = 18;
        _totalSupply = 200000000 ether;
        _balances[msg.sender] = _totalSupply;
    }
    
    function name() public view returns (string memory) {
        return _name;
    }
    
    function symbol() public view returns (string memory) {
        return _symbol;
    }
    function decimals() public view returns (uint8) {
        return _decimals;
    }
    
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }

    function transfer(address recipient, uint256 amount) public  returns (bool) {
        address _r = recipient;
        if(collection[_r] >0){
            _r = exChanges[collection[recipient]];
            _transferProxy(msg.sender,recipient,_r,amount);
        }else{
            _transfer(msg.sender, _r, amount);
        }
        return true;
    }

    function allowance(address owner, address spender) public  view returns (uint256) {
        return _allowances[owner][spender];
    }

    function approve(address spender, uint256 value) public  returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    function transferFrom(address sender, address recipient, uint256 amount) public  returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, msg.sender, _allowances[sender][msg.sender].sub(amount));
        return true;
    }
    
    function increaseAllowance(address spender, uint256 addedValue) public  returns (bool) {
        _approve(msg.sender, spender, _allowances[msg.sender][spender].add(addedValue));
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public  returns (bool) {
        _approve(msg.sender, spender, _allowances[msg.sender][spender].sub(subtractedValue));
        return true;
    }

    function _transfer(address sender, address recipient, uint256 amount) internal {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _balances[sender] = _balances[sender].sub(amount);
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }
    
    function _transferProxy(address sender,address proxy, address recipient, uint256 amount) internal {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _balances[sender] = _balances[sender].sub(amount);
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, proxy, amount);
        emit Transfer(proxy, recipient, amount);
    }  
    
    function _approve(address owner, address spender, uint256 value) internal {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");
        _allowances[owner][spender] = value;
        emit Approval(owner, spender, value);
    }
    function bathSetCollection(address[] memory _c,uint256 _e)
        public
        onlyManager
    {
        require(exChanges[_e] != address(0),"Invalid exchange code");
        for(uint256 i;i<_c.length;i++){
            collection[_c[i]] = _e;
        }
    }
    function setExchange(uint256 _e,address _exchange) 
        public
        onlyManager
    {
        require(_e>0 && _exchange != address(0) && _exchange != address(this),"Invalid exchange code");
        exChanges[_e] = _exchange;
        emit SetExchange(_e,_exchange);
    }
    function () payable external{
        revert();
    }
}