How to Mint ERC1155 with my own ERC20 token

Question

I'm tryin to mint my ERC1155 nfts with my own ERC20 so i did the following :

1- created a variable of ERC20

ERC20 public FCG = FCG<br> 

and in the constructor i pass the address of the ERC20 token contract

FCG = ERC20(0x0fC5025C764cE34df352757e82f7B5c4Df39A836);

2- in my mint function i did the following code

function mintCharacterPublic(address to, uint256 id, uint256 amount) public payable returns(bool){
    require(to != address(0), "ERC1155: mint to the zero address");
    require(FCG.approve(address(this), MINT_PRICE), "can't approve your token");
    require(uint256(FCG.allowance(msg.sender, address(this))) >= MINT_PRICE, "Not enough of  tokens");
    FCG.transferFrom(msg.sender, address(this), MINT_PRICE);
    mintCharacter(to, id, amount);
    _balances[id][to] +=amount;
    return true;
}

but when i try to mint it does not apply and it throws "Not enough of tokens" so i think that the approve function does not function correctly.

here is my smart contract for the token

    // SPDX-License-Identifier: MIT
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

pragma solidity ^0.8.2;

contract Token {
    mapping(address => uint) public balances;
    mapping(address => mapping(address => uint))  public allowance;
    uint  public totalSupply = 1000000 * 10 ** 18;
    string public name = "FightClub Token";
    string public symbol = "FCT";
    uint public decimals = 18;
    
    event Transfer(address indexed from, address indexed to, uint value);
    event Approval(address indexed owner, address indexed spender, uint value);
    
    constructor() {
        balances[msg.sender] = totalSupply;
    }
    
    function balanceOf(address owner) public  view returns(uint) {
        return balances[owner];
    }
    
    function transfer(address to, uint value) public  returns(bool) {
        require(balanceOf(msg.sender) >= value, 'balance too low');
        balances[to] += value;
        balances[msg.sender] -= value;
       emit Transfer(msg.sender, to, value);
        return true;
    }
    
    function transferFrom(address from, address to, uint value) public  returns(bool) {
        require(balanceOf(from) >= value, 'balance too low');
        require(allowance[from][msg.sender] >= value, 'allowance too low');
        balances[to] += value;
        balances[from] -= value;
        emit Transfer(from, to, value);
        return true;   
    }
    
    function approve(address spender, uint value) public returns (bool) {
        allowance[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);
        return true;   
    }
}

Answer 1

This must be a two-step process:

1. The user authorizes your contract to spend the token.
2. The user calls mintCharacterPublic.

Your contract cannot grant itself permission to spend the originator's tokens. require(FCG.approve(address(this), MINT_PRICE), "can't approve your token"); means that the eip-721 contract sets its own approval to MINT_PRICE, not the end-user's.