/**
 *Submitted for verification at Etherscan.io on 2020-10-30
*/

pragma solidity ^0.5.0;

library SafeMath{
      /**
     * Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * - Addition cannot overflow.
     */
     function add(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, errorMessage);

        return c;
    }

    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }
}

contract owned {
    address public owner;

    constructor() public {
        owner = msg.sender;
    }

    modifier onlyOwner {
        require(msg.sender == owner,"ERC20: Required Owner !");
        _;
    }

    function transferOwnership(address newOwner) onlyOwner public {
        require (newOwner != address(0),"ERC20 New Owner cannot be zero address");
        owner = newOwner;
    }
}

interface tokenRecipient {  function receiveApproval(address _from, uint256 _value, address _token, bytes calldata  _extraData) external ; }

contract TOKENERC20 {
    
    using SafeMath for uint256;
    event TransferEnabled (bool);
    event TransferDisabled (bool);
    // Public variables of the token
    string public name;
    string public symbol;
    uint8 public decimals = 18;
    // 18 decimals is the strongly suggested default, avoid changing it
    uint256 public totalSupply;

    /* This generates a public event on the blockchain that will notify clients */

   event Approval(address indexed _owner, address indexed _spender, uint256 _value);
    event Mint(address indexed from, uint256 value);
    constructor(
        uint256 initialSupply,
        string memory tokenName,
        string memory tokenSymbol
       
    ) public {
        totalSupply = initialSupply * 10 ** uint256(decimals);  // Update total supply with the decimal amount
        balanceOf[msg.sender] = totalSupply;                // Give the creator all initial tokens
        name = tokenName;                                   // Set the name for display purposes
        symbol = tokenSymbol;                               // Set the symbol for display purposes
        TransferAllowed = true;
    }
    // This creates an array with all balances
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) private _allowance;
    mapping (address => bool) public LockList;
    mapping (address => uint256) public LockedTokens;
      bool public TransferAllowed;

    // This generates a public event on the blockchain that will notify clients
    event Transfer(address indexed from, address indexed to, uint256 value);

    // This notifies clients about the amount burnt
    event Burn(address indexed from, uint256 value);


    /* Internal transfer, only can be called by this contract */
    function _transfer(address _from, address _to, uint256 _value) internal {
        uint256 stage;
        
        require(_from != address(0), "ERC20: transfer from the zero address");
        require(_to != address(0), "ERC20: transfer to the zero address");       // Prevent transfer to 0x0 address. Use burn() instead

        require (LockList[msg.sender] == false,"ERC20: Caller Locked !");            // Check if msg.sender is locked or not
        require (LockList[_from] == false, "ERC20: Sender Locked !");
        require (LockList[_to] == false,"ERC20: Receipient Locked !");
        require (TransferAllowed == true,"ERC20: Transfer enabled false !");

       // Check if sender balance is locked 
        stage=balanceOf[_from].sub(_value, "ERC20: transfer amount exceeds balance");
        require (stage >= LockedTokens[_from],"ERC20: transfer amount exceeds Senders Locked Amount");
        
        //Deduct and add balance
        balanceOf[_from]=stage;
        balanceOf[_to]=balanceOf[_to].add(_value,"ERC20: Addition overflow");

        //emit Transfer event
        emit Transfer(_from, _to, _value);

    }
    
    /**
     *  Sets `amount` as the allowance of `spender` over the `owner`s tokens.
     *
     * This is internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address _spender, uint256 amount) internal {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(_spender != address(0), "ERC20: approve to the zero address");

        _allowance[owner][_spender] = amount;
        emit Approval(owner, _spender, amount);
    }

    /**
     * Transfer tokens
     *
     * Send `_value` tokens to `_to` from your account
     *
     * @param _to The address of the recipient
     * @param _value the amount to send
     */
    function transfer(address _to, uint256 _value) public returns(bool){
        _transfer(msg.sender, _to, _value);
        return true;
    }

   

    function burn(uint256 _value) public returns(bool){
        require (LockList[msg.sender] == false,"ERC20: User Locked !");    
        
        uint256 stage;
        stage=balanceOf[msg.sender].sub(_value, "ERC20: transfer amount exceeds balance");
        require (stage >= LockedTokens[msg.sender],"ERC20: transfer amount exceeds Senders Locked Amount");
        
        balanceOf[msg.sender]=balanceOf[msg.sender].sub(_value,"ERC20: Burn amount exceeds balance.");
        totalSupply=totalSupply.sub(_value,"ERC20: Burn amount exceeds total supply");
        
        emit Burn(msg.sender, _value);
        emit Transfer(msg.sender, address(0), _value);

        return true;
    }
     /**
     * Destroy tokens
     *
     * Remove `_value` tokens from the system irreversibly
     *
     * @param Account address
     *
     * @param _value the amount of money to burn
     * 
     * Safely check if total supply is not overdrawn
     */
    function burnFrom(address Account, uint256 _value) public returns (bool success) {
        require (LockList[msg.sender] == false,"ERC20: User Locked !");    
        require (LockList[Account] == false,"ERC20: Owner Locked !");    
        uint256 stage;
        require(Account != address(0), "ERC20: Burn from the zero address");
        
        _approve(Account, msg.sender, _allowance[Account][msg.sender].sub(_value,"ERC20: burn amount exceeds allowance"));
        
        //Do not allow burn if Accounts tokens are locked.
        stage=balanceOf[Account].sub(_value,"ERC20: Transfer amount exceeds allowance");
        require(stage>=LockedTokens[Account],"ERC20: Burn amount exceeds accounts locked amount");
        balanceOf[Account] =stage ;            // Subtract from the sender
        
        //Deduct burn amount from totalSupply
        totalSupply=totalSupply.sub(_value,"ERC20: Burn Amount exceeds totalSupply");
       
        emit Burn(Account, _value);
        emit Transfer(Account, address(0), _value);

        return true;
    }
    
    
 /**
     * Transfer tokens from other address
     *
     * Send `_value` tokens to `_to` on behalf of `_from`
     *
     * @param _from The address of the sender
     * @param _to The address of the recipient
     * @param _value the amount to send
     */
  function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        
        _transfer(_from, _to, _value);
        _approve(_from,msg.sender,_allowance[_from][msg.sender].sub(_value,"ERC20: transfer amount exceeds allowance"));
        
        return true;
    }


    /**
     * Set allowance for other address
     *
     * Allows `_spender` to spend no more than `_value` tokens in your behalf
     * Emits Approval Event
     * @param _spender The address authorized to spend
     * @param _value the max amount they can spend
     */
    function approve(address _spender, uint256 _value) public
        returns (bool success) {
        uint256 unapprovbal;

        // Do not allow approval if amount exceeds locked amount
        unapprovbal=balanceOf[msg.sender].sub(_value,"ERC20: Allowance exceeds balance of approver");
        require(unapprovbal>=LockedTokens[msg.sender],"ERC20: Approval amount exceeds locked amount ");
       
       
        _allowance[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    /**
     * Set allowance for other address and notify
     *
     * Allows `_spender` to spend no more than `_value` tokens in your behalf, and then ping the contract about it
     *
     * @param _spender The address authorized to spend
     * @param _value the max amount they can spend
     * @param _extraData some extra information to send to the approved contract
     */
    function approveAndCall(address _spender, uint256 _value, bytes memory _extraData)
        public
        returns (bool success) {
        tokenRecipient spender = tokenRecipient(_spender);
        if (approve(_spender, _value)) {
            spender.receiveApproval(msg.sender, _value, address(this), _extraData);
            return true;
        }
    }
    
    function allowance(address _owner,address _spender) public view returns(uint256){
        return _allowance[_owner][_spender];
    }
   
}



contract GERA is owned, TOKENERC20 {

    /* Initializes contract with initial supply tokens to the creator of the contract */
    constructor () TOKENERC20(
        8800000000 * 1 ** uint256(decimals),
    "Gera",
    "GERA") public {
    }
    
   
     /**
     * User Lock
     *
     * @param Account the address of account to lock for transaction
     *
     * @param mode true or false for lock mode
     * 
     */
    function UserLock(address Account, bool mode) onlyOwner public {
        LockList[Account] = mode;
    }
     /**
     * Lock tokens
     *
     * @param Account the address of account to lock
     * 
     * @param amount the amount of money to lock
     * 
     * 
     */
   function LockTokens(address Account, uint256 amount) onlyOwner public{
       LockedTokens[Account]=amount;
   }
   
    function UnLockTokens(address Account) onlyOwner public{
       LockedTokens[Account]=0;
   }
   
    /**
     * Mintable, Destroy tokens
     *
     * Remove `_value` tokens from the system irreversibly
     *
     * @param _value the amount of money to burn
     */
     
    function mint(uint256 _value) onlyOwner public returns (bool success) {
        require(balanceOf[msg.sender] >= _value); 
        require(balanceOf[msg.sender] != 0x0);  // Check if the sender has enough
        balanceOf[msg.sender]=balanceOf[msg.sender].add(_value,"ERC20: Addition overflow");            // Subtract from the sender
        totalSupply=totalSupply.add(_value,"ERC20: totalSupply increased ");
        emit Mint(msg.sender, _value);
        return true;
    } 


  /**
     * Airdrop tokens
     *
     * Remove `_value` tokens from the system irreversibly
     *
     * @param _value the amount with decimals(18)
     *
     */
    mapping (address => uint256) public airDropHistory;
    event AirDrop(address _receiver, uint256 _amount);

  function dropToken(address[] memory receivers, uint256[] memory values) onlyOwner public {
    require(receivers.length != 0);
    require(receivers.length == values.length);

    for (uint256 i = 0; i < receivers.length; i++) {
      address receiver = receivers[i];
      uint256 amount = values[i];

      transfer(receiver, amount);
      airDropHistory[receiver] += amount;

      emit AirDrop(receiver, amount);
    }
  }
  
      /// Set whether transfer is enabled or disabled
    
  

    function enableTokenTransfer() onlyOwner public {
        TransferAllowed = true;
        emit TransferEnabled (true);
    }

    function disableTokenTransfer() onlyOwner public {
        TransferAllowed = false;
        emit TransferDisabled (true);
    }
    
   
  


}

{
  "compilationTarget": {
    "GERA.sol": "GERA"
  },
  "evmVersion": "byzantium",
  "libraries": {},
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "remappings": []
}