/*

Arcane, also known as Arcane: League of Legends, is an
animated series based on the League of Legends lore,
retelling the origin stories of several characters from
Piltover and Zaun. The series was adapted for television by
Christian Linke and Alex Yee, members of Riot Games
creative team and long-time contributors to the source material.


Official Website: https://www.riotgames.com/

https://twitter.com/riotgames

https://www.youtube.com/riotgames



*/

//SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

interface IERC20 {

    function totalSupply() external view returns (uint256);
    function balanceOf(address account) external view returns (uint256);
    function allowance(address owner, address spender) external view returns (uint256);

    function transfer(address recipient, uint256 amount) external returns (bool);
    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 Arcane is IERC20 {
    using SafeMath for uint256;

    string public constant name = "League of Legends Token";
    string public constant symbol = "ARCANE";
    uint8 public constant decimals = 18;

    mapping(address => uint256) balances;
    mapping(address => mapping (address => uint256)) allowed;

    uint256 private totalSupply_ = 1000000000*10**uint256(decimals);

    constructor() public {
        balances[msg.sender] = totalSupply_;
    }

    function totalSupply() public override view returns (uint256) {
        return totalSupply_;
    }

    function balanceOf(address tokenOwner) public override view returns (uint256) {
        return balances[tokenOwner];
    }


    function transfer(address receiver, uint256 numTokens) public override returns (bool) {

        require(numTokens <= balances[msg.sender]);
        balances[msg.sender] = balances[msg.sender].sub(numTokens);
        balances[receiver] = balances[receiver].add(numTokens);
        emit Transfer(msg.sender, receiver, numTokens);
        return true;

    }

    function approve(address delegate, uint256 numTokens) public override returns (bool) {
        allowed[msg.sender][delegate] = numTokens;
        emit Approval(msg.sender, delegate, numTokens);
        return true;
    }

    function allowance(address owner, address delegate) public override view returns (uint) {
        return allowed[owner][delegate];
    }

    function transferFrom(address owner, address buyer, uint256 numTokens) public override returns (bool) {

        require(numTokens <= balances[owner]);
        require(numTokens <= allowed[owner][msg.sender]);

        balances[owner] = balances[owner].sub(numTokens);
        allowed[owner][msg.sender] = allowed[owner][msg.sender].sub(numTokens);
        balances[buyer] = balances[buyer].add(numTokens);
        emit Transfer(owner, buyer, numTokens);
        return true;

    }
}

library SafeMath {
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
      assert(b <= a);
      return a - b;
    }

    function add(uint256 a, uint256 b) internal pure returns (uint256) {
      uint256 c = a + b;
      assert(c >= a);
      return c;
    }
}