//SPDX-License-Identifier: UNLICENSED
pragma solidity >=0.6;

// ----------------------------------------------------------------------------
// ERC Token Standard #20 Interface
// https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20-token-standard.md
// ----------------------------------------------------------------------------

interface ERC20Interface {
    function totalSupply() external view returns (uint);
    function balanceOf(address tokenOwner) external view returns (uint balance);
    function transfer(address to, uint tokens) external returns (bool success);
    
    function allowance(address tokenOwner, address spender) external view returns (uint remaining);
    function approve(address spender, uint tokens) external returns (bool success);
    function transferFrom(address from, address to, uint tokens) external returns (bool success);
    
    event Transfer(address indexed from, address indexed to, uint tokens);
    event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}

contract ColettiMoney is ERC20Interface{
    string public name ="Coletti";
    string public symbol = "CLT";
    uint public decimals=0;
    
    uint public supply;
    address public founder;

    mapping(address => uint) balances;
    
    mapping(address => mapping(address => uint)) allowed;
    
    // example: allowed[0xdfdds][0x45555]=20
   
    constructor(uint s) {
        supply=s;
        founder=msg.sender;
        balances[founder]=supply;
    }
    
    function totalSupply() public view override returns (uint){
        return(supply);
    }
    
    
    function balanceOf(address tokenOwner) public view override returns (uint){
        return(balances[tokenOwner]);
    }
    
    function transfer(address to, uint tokens) public override returns (bool){
        require(tokens>0 && balances[msg.sender]>=tokens);
        balances[msg.sender]=balances[msg.sender]-tokens;
        balances[to]=balances[to]+tokens;
        emit Transfer(msg.sender,to,tokens);
        return(true);
    }
    
    function allowance(address tokenOwner, address spender) public view override returns (uint){
        return(allowed[tokenOwner][spender]);
    }

    function approve(address spender, uint tokens) public override returns (bool){
        require(balances[msg.sender]>=tokens);
        allowed[msg.sender][spender]=tokens;
        emit Approval(msg.sender,spender,tokens);
        return(true);
    }
    
    function transferFrom(address from, address to, uint tokens) public override returns(bool){
        require(tokens>0 && balances[from]>=tokens && allowed[from][msg.sender]>=tokens);
        balances[from]=balances[from]-tokens;
        allowed[from][msg.sender]=allowed[from][msg.sender]-tokens;
        balances[to]=balances[to]+tokens;
        emit Transfer(from, to, tokens);
        return(true);
    }

}