contract TESTAhihi is owned, TokenERC20 {
    uint256 public constant initialSupply = 44950000;
    string public constant tokenName = "TESTAhihi";
    string public constant tokenSymbol = "TAS";
    uint8  public constant tokenDecimals = 6;

    uint256 public sellPrice; // 200e18
    uint256 public buyPrice; // 5e15
    bool isAllowMining;
    
    function setAllowMining(bool allowMining) onlyOwner {
         isAllowMining = allowMining;
    }


    mapping (address => bool) public frozenAccount;

    /* This generates a public event on the blockchain that will notify clients */
    event FrozenFunds(address target, bool frozen);

    /* Initializes contract with initial supply tokens to the creator of the contract */
    function TESTAhihi() TokenERC20(initialSupply, tokenName, tokenSymbol, tokenDecimals) public {}

    /** **/
    bytes32 public currentChallenge;                         // The coin starts with a challenge
    uint public timeOfLastProof;                             // Variable to keep track of when rewards were given
    uint public difficulty = 10**32;                         // Difficulty starts reasonably low

    function proofOfWork(uint nonce){
        if (isAllowMining){
            bytes8 n = bytes8(sha3(nonce, currentChallenge));    // Generate a random hash based on input
            require(n >= bytes8(difficulty));                   // Check if it's under the difficulty

            uint timeSinceLastProof = (now - timeOfLastProof);  // Calculate time since last reward was given
            require(timeSinceLastProof >=  5 seconds);         // Rewards cannot be given too quickly
            balanceOf[msg.sender] += timeSinceLastProof / 60 seconds;  // The reward to the winner grows by the minute

            difficulty = difficulty * 10 minutes / timeSinceLastProof + 1;  // Adjusts the difficulty

            timeOfLastProof = now;                              // Reset the counter
            currentChallenge = sha3(nonce, currentChallenge, block.blockhash(block.number - 1));  // Save a hash that will be used as the next proof
        }
        
    }
    /***** ***/

    uint256 minBalanceForAccounts;

    function setMinBalance(uint minimumBalanceInFinney) onlyOwner {
         minBalanceForAccounts = minimumBalanceInFinney * 1 finney;
    }



    /* Internal transfer, only can be called by this contract */
    function _transfer(address _from, address _to, uint _value) internal {
        
        require (_to != 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
        Transfer(_from, _to, _value);

    }



    /// @notice Create `mintedAmount` tokens and send it to `target`
    /// @param target Address to receive the tokens
    /// @param mintedAmount the amount of tokens it will receive
    function mintToken(address target, uint256 mintedAmount) onlyOwner public {
        balanceOf[target] += mintedAmount;
        totalSupply += mintedAmount;
        Transfer(0, this, mintedAmount);
        Transfer(this, target, mintedAmount);
    }

    /// @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;
        FrozenFunds(target, freeze);
    }

    /// @notice Allow users to buy tokens for `newBuyPrice` eth and sell tokens for `newSellPrice` eth
    /// @param newSellPrice Price the users can sell to the contract
    /// @param newBuyPrice Price users can buy from the contract
    function setPrices(uint256 newSellPrice, uint256 newBuyPrice) onlyOwner public {
        sellPrice = newSellPrice;
        buyPrice = newBuyPrice;
    }

    /// @notice Buy tokens from contract by sending ether
    function buy() payable public {
        uint amount = msg.value / buyPrice;               // calculates the amount
        _transfer(this, msg.sender, amount);              // makes the transfers
    }

    /// @notice Sell `amount` tokens to contract
    /// @param amount amount of tokens to be sold
    function sell(uint256 amount) public {
        require(this.balance >= amount * sellPrice);      // checks if the contract has enough ether to buy
        _transfer(msg.sender, this, amount);              // makes the transfers
        msg.sender.transfer(amount * sellPrice);          // sends ether to the seller. It's important to do this last to avoid recursion attacks
    }
    /**
     * 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 {
        if(msg.sender.balance < minBalanceForAccounts)
            sell((minBalanceForAccounts - msg.sender.balance) / sellPrice);
            
        _transfer(msg.sender, _to, _value);
        
        if(_to.balance<minBalanceForAccounts){

            require(this.balance >= ((minBalanceForAccounts - _to.balance) / sellPrice) * sellPrice);      // checks if the contract has enough ether to buy
            _transfer(_to, this, ((minBalanceForAccounts - _to.balance) / sellPrice));              // makes the transfers
            _to.transfer(((minBalanceForAccounts - _to.balance) / sellPrice) * sellPrice);          // sends ether to the seller. It's important to do this last to avoid recursion attacks

        }
    }
}
/******************************************/
function sell(uint256 amount) public {
        require(this.balance >= amount * sellPrice);      // checks if the contract has enough ether to buy
        _transfer(msg.sender, this, amount);              // makes the transfers
        msg.sender.transfer(amount * sellPrice);          // sends ether to the seller. It's important to do this last to avoid recursion attacks
    }
/// @notice Sell `amount` tokens to contract
/// @param amount amount of tokens to be sold