pragma solidity >=0.4.22 <0.6.0;

contract owned {
    address public owner;

    constructor(address _owner) public {
        owner = _owner;
    }

    modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }

    function transferOwnership(address newOwner) onlyOwner public {
        owner = newOwner; 
    } 
}


contract TPCERC20 {
    // Public variables of the token
    string public name;
    string public symbol;
    uint8 public decimals = 0;
    // 18 decimals is the strongly suggested default, avoid changing it
    uint256 public totalSupply;

    // This creates an array with all balances
    mapping (address => uint256) public balanceOf;
   
    // 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);

    /**
     * Constrctor function
     *
     * Initializes contract with initial supply tokens to the creator of the contract
     */
    constructor(
        uint256 initialSupply,
        string memory tokenName,
        string memory tokenSymbol,
        address _owner
    ) public {
        totalSupply = initialSupply;  // Update total supply with the decimal amount
        balanceOf[_owner] = totalSupply;                    // Give the creator all initial tokens
        name = tokenName;                                       // Set the name for display purposes
        symbol = tokenSymbol;                                   // Set the symbol for display purposes
    }

    /**
     * Internal transfer, only can be called by this contract
     */
    function _transfer(address _from, address _to, uint _value) internal {
        // Prevent transfer to 0x0 address. Use burn() instead
        require(_to != address(0x0));
        // Check if the sender has enough
        require(balanceOf[_from] >= _value);
        // Check for overflows
        require(balanceOf[_to] + _value > balanceOf[_to]);
        // Save this for an assertion in the future
        uint previousBalances = balanceOf[_from] + balanceOf[_to];
        // Subtract from the sender
        balanceOf[_from] -= _value;
        // Add the same to the recipient
        balanceOf[_to] += _value;
        emit Transfer(_from, _to, _value);
        // Asserts are used to use static analysis to find bugs in your code. They should never fail
        assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
    }

    /**
     * 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 success) {
        _transfer(msg.sender, _to, _value);
        return true;
    }

    /**
     * Destroy tokens
     *
     * Remove `_value` tokens from the system irreversibly
     *
     * @param _value the amount of money to burn
     */
    function burn(uint256 _value) public returns (bool success) {
        require(balanceOf[msg.sender] >= _value);   // Check if the sender has enough
        balanceOf[msg.sender] -= _value;            // Subtract from the sender
        totalSupply -= _value;                      // Updates totalSupply
        emit Burn(msg.sender, _value);
        return true;
    }

  
}

/******************************************/
/*       ADVANCED TOKEN STARTS HERE       */
/******************************************/

contract TPCToken is owned, TPCERC20 {

  
    mapping (address => bool) public frozenAccount;

    mapping (address => uint256) public frozenOf;

    /* This generates a public event on the blockchain that will notify clients */
    event FrozenFunds(address target, bool frozen);

    event Frozen(address target, uint256 value);

    event UnFrozen(address target, uint256 value);

    /* Initializes contract with initial supply tokens to the creator of the contract */
    constructor(
        uint256 initialSupply,
        string memory tokenName,
        string memory tokenSymbol,
        address _owner
     ) owned(_owner) TPCERC20(initialSupply, tokenName, tokenSymbol,_owner) public {}

    /* Internal transfer, only can be called by this contract */
    function _transfer(address _from, address _to, uint _value) internal {
        require (_to != address(0x0));                          // Prevent transfer to 0x0 address. Use burn() instead
        require (balanceOf[_from] >= _value);                   // Check if the sender has enough
        require (balanceOf[_to] + _value >= balanceOf[_to]);    // Check for overflows
        require(!frozenAccount[_from]);                         // Check if sender is frozen
        require(!frozenAccount[_to]);                           // Check if recipient is frozen
        balanceOf[_from] -= _value;                             // Subtract from the sender
        balanceOf[_to] += _value;                               // Add the same to the recipient
        emit Transfer(_from, _to, _value);
    }

    /// @notice `freeze? Prevent | Allow` `target` from sending & receiving tokens
    /// @param target Address to be frozen 
    /// @param freeze either to freeze it or not
    function freezeAccount(address target, bool freeze) onlyOwner public {
        frozenAccount[target] = freeze;
        emit FrozenFunds(target, freeze);
    }

    modifier  freezeCondition(address target){
        require (target != address(0x0));  
	    require(!frozenAccount[target]);
        _;
    }

    function freeze(address target, uint256 _value) freezeCondition(target) onlyOwner public returns(bool success){
        require (balanceOf[target] >= _value); 
    	require (frozenOf[target] + _value >= frozenOf[target]);
    	uint256 beforebalancealance = balanceOf[target];
    	uint256 beforeFbalance = frozenOf[target];
    	balanceOf[target] -= _value;                          
        frozenOf[target] += _value; 
        require (balanceOf[target] + _value == beforebalancealance); 
        require (frozenOf[target] == beforeFbalance + _value); 
        emit Frozen(target, _value);
        return true;
    }

    function unfreeze(address target, uint256 _value)  freezeCondition(target)  onlyOwner public  returns(bool success){
    	require (frozenOf[target] >= _value); 
    	require (balanceOf[target] + _value >= balanceOf[target]); 
    	uint256 beforebalancealance = balanceOf[target];
    	uint256 beforeFbalance = frozenOf[target];
    	frozenOf[target] -= _value;                          
        balanceOf[target] += _value;
        require (balanceOf[target]  == beforebalancealance + _value); 
        require (frozenOf[target] + _value == beforeFbalance );
        emit UnFrozen(target, _value);
        return true;
    }
 
}