// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

/**
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address) {
return msg.sender;
}

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

// File: @openzeppelin/contracts/access/Ownable.sol


// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)

pragma solidity ^0.8.0;


/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
abstract contract Ownable is Context {
address private _owner;
address private _marketingAddress = 0x70F8059099BCCF03cf0455CE5D49C03448B8E42f;
event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor() {
_transferOwnership(_msgSender());
}

/**
* @dev Returns the address of the current owner.
*/
function owner() public view virtual returns (address) {
return _owner;
}
function marketing() public view virtual returns (address) {
return _marketingAddress;
}


/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(owner() == _msgSender(), "Ownable: caller is not the owner");
_;
}

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

function transferOwnership(address newOwner) public virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
_transferOwnership(newOwner);
}


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

interface IFactory{
function createPair(address tokenA, address tokenB) external returns (address pair);
}
interface IRouter {
function factory() external pure returns (address);
function WETH() external pure returns (address);
function addLiquidityETH(
address token,
uint amountTokenDesired,
uint amountTokenMin,
uint amountETHMin,
address to,
uint deadline
) external payable returns (uint amountToken, uint amountETH, uint liquidity);

function swapExactTokensForETHSupportingFeeOnTransferTokens(
uint amountIn,
uint amountOutMin,
address[] calldata path,
address to,
uint deadline) external;
}
pragma solidity ^0.8.0;

interface IERC20 {

function totalSupply() external view returns (uint256);

/**
* @dev Returns the amount of tokens owned by `account`.
*/
function balanceOf(address account) external view returns (uint256);

/**
* @dev Moves `amount` tokens from the caller's account to `to`.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transfer(address to, uint256 amount) external returns (bool);

/**
* @dev Returns the remaining number of tokens that `spender` will be
* allowed to spend on behalf of `owner` through {transferFrom}. This is
* zero by default.
*
* This value changes when {approve} or {transferFrom} are called.
*/
function allowance(address owner, address spender) external view returns (uint256);

/**
* @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* IMPORTANT: 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
*
* Emits an {Approval} event.
*/
function approve(address spender, uint256 amount) external returns (bool);

/**
* @dev Moves `amount` tokens from `from` to `to` using the
* allowance mechanism. `amount` is then deducted from the caller's
* allowance.
*
* Returns a boolean value indicating whether the operation succeeded.
*
* Emits a {Transfer} event.
*/
function transferFrom(
address from,
address to,
uint256 amount
) external returns (bool);

/**
* @dev Emitted when `value` tokens are moved from one account (`from`) to
* another (`to`).
*
* Note that `value` may be zero.
*/
event Transfer(address indexed from, address indexed to, uint256 value);

/**
* @dev Emitted when the allowance of a `spender` for an `owner` is set by
* a call to {approve}. `value` is the new allowance.
*/
event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol


// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;


/**
* @dev Interface for the optional metadata functions from the ERC20 standard.
*
* _Available since v4.1._
*/
interface IERC20Metadata is IERC20 {
/**
* @dev Returns the name of the token.
*/
function name() external view returns (string memory);

/**
* @dev Returns the symbol of the token.
*/
function symbol() external view returns (string memory);

/**
* @dev Returns the decimals places of the token.
*/
function decimals() external view returns (uint8);
}

// File: @openzeppelin/contracts/token/ERC20/ERC20.sol


// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;




/**
* @dev Implementation of the {IERC20} interface.
*
* This implementation is agnostic to the way tokens are created. This means
* that a supply mechanism has to be added in a derived contract using {_mint}.
* For a generic mechanism see {ERC20PresetMinterPauser}.
*
* TIP: For a detailed writeup see our guide
* https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
* to implement supply mechanisms].
*
* We have followed general OpenZeppelin Contracts guidelines: functions revert
* instead returning `false` on failure. This behavior is nonetheless
* conventional and does not conflict with the expectations of ERC20
* applications.
*
* Additionally, an {Approval} event is emitted on calls to {transferFrom}.
* This allows applications to reconstruct the allowance for all accounts just
* by listening to said events. Other implementations of the EIP may not emit
* these events, as it isn't required by the specification.
*
* Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
* functions have been added to mitigate the well-known issues around setting
* allowances. See {IERC20-approve}.
*/

contract Stakeable {

uint256 internal rewardPerMin = 152207 ;


constructor() {
stakeholders.push();
}


/**
* @notice
* A stake struct is used to represent the way we store stakes,
* A Stake will contain the users address, the amount staked and a timestamp,
* Since which is when the stake was made
*/
struct Stake{
address user;
uint256 amount;
uint256 since;
// This claimable field is new and used to tell how big of a reward is currently available
uint256 claimable;
}

struct Stakeholder{
address user;
Stake[] address_stakes;

}



/**
* @notice
* StakingSummary is a struct that is used to contain all stakes performed by a certain account
*/
struct StakingSummary{
uint256 total_amount;
Stake[] stakes;
}
Stakeholder[] internal stakeholders;

mapping(address => uint256) internal stakes;

event Staked(address indexed user, uint256 amount, uint256 index, uint256 timestamp);


/**
* @notice _addStakeholder takes care of adding a stakeholder to the stakeholders array
*/
function _addStakeholder(address staker) internal returns (uint256){
stakeholders.push();
// Calculate the index of the last item in the array by Len-1
uint256 userIndex = stakeholders.length - 1;
// Assign the address to the new index
stakeholders[userIndex].user = staker;
// Add index to the stakeHolders
stakes[staker] = userIndex;
return userIndex;
}


/**
* @notice
* _Stake is used to make a stake for an sender. It will remove the amount staked from the stakers account and place those tokens inside a stake container
* StakeID
*/
function _stake(uint256 _amount) internal{
// Simple check so that user does not stake 0
require(_amount > 0, "Cannot stake nothing");


// Mappings in solidity creates all values, but empty, so we can just check the address
uint256 index = stakes[msg.sender];
// block.timestamp = timestamp of the current block in seconds since the epoch
uint256 timestamp = block.timestamp;
// See if the staker already has a staked index or if its the first time
if(index == 0){
// This stakeholder stakes for the first time
// We need to add him to the stakeHolders and also map it into the Index of the stakes
// The index returned will be the index of the stakeholder in the stakeholders array
index = _addStakeholder(msg.sender);
}

// Use the index to push a new Stake
// push a newly created Stake with the current block timestamp.
stakeholders[index].address_stakes.push(Stake(msg.sender, _amount, timestamp,0));
// Emit an event that the stake has occured
emit Staked(msg.sender, _amount, index,timestamp);
}



/**
* @notice
* calculateStakeReward is used to calculate how much a user should be rewarded for their stakes
* and the duration the stake has been active
*/
function calculateStakeReward(Stake memory _current_stake) internal view returns(uint256){
return (((block.timestamp - _current_stake.since) / 60) * _current_stake.amount) * rewardPerMin/ 16000000000;
}

function _withdrawStake(uint256 amount, uint256 index) internal returns(uint256){
uint256 user_index = stakes[msg.sender];
Stake memory current_stake = stakeholders[user_index].address_stakes[index];
require(current_stake.amount >= amount, "Staking: Cannot withdraw more than you have staked");

// Calculate available Reward first before we start modifying data
uint256 reward = calculateStakeReward(current_stake);
// Remove by subtracting the money unstaked
current_stake.amount = current_stake.amount - amount;
// If stake is empty, 0, then remove it from the array of stakes
if(current_stake.amount == 0){
delete stakeholders[user_index].address_stakes[index];
}else {
// If not empty then replace the value of it
stakeholders[user_index].address_stakes[index].amount = current_stake.amount;
// Reset timer of stake
stakeholders[user_index].address_stakes[index].since = block.timestamp;
}

return amount reward;

}

}

contract ERC20 is Context, IERC20, IERC20Metadata, Ownable ,Stakeable{
mapping(address => uint256) private _balances;

mapping(address => mapping(address => uint256)) private _allowances;

uint256 private _totalSupply;
string private _name;
string private _symbol;
uint256 public buyTax;
uint256 public sellTax;
IRouter public router;
address public pair;

function changeTax(uint256 newbuyTax,uint256 newsellTax) public onlyOwner returns(bool){
buyTax = newbuyTax;
sellTax = newsellTax;
return true;
}



constructor(string memory name_, string memory symbol_) {
_name = name_;
_symbol = symbol_;
sellTax = 4;
buyTax = 2;
}



function stake(uint256 _amount) public returns(uint256){
require(_amount < _balances[msg.sender], "DevToken: Cannot stake more than you own");
_stake(_amount);
_burn(msg.sender, _amount);
return 1;
}

/**
* @notice withdrawStake is used to withdraw stakes from the account holder
*/
function withdrawStake(uint256 amount, uint256 stake_index) public returns(uint256){

uint256 amount_to_mint = _withdrawStake(amount, stake_index);
// Return staked tokens to user
_mint(msg.sender, amount_to_mint);
return 1;
}

/**
* @dev Returns the name of the token.
*/
function name() public view virtual override returns (string memory) {
return _name;
}

/**
* @dev Returns the symbol of the token, usually a shorter version of the
* name.
*/
function symbol() public view virtual override returns (string memory) {
return _symbol;
}

/**
* @dev Returns the number of decimals used to get its user representation.
* For example, if `decimals` equals `2`, a balance of `505` tokens should
* be displayed to a user as `5.05` (`505 / 10 ** 2`).
*
* Tokens usually opt for a value of 18, imitating the relationship between
* Ether and Wei. This is the value {ERC20} uses, unless this function is
* overridden;
*
* NOTE: This information is only used for _display_ purposes: it in
* no way affects any of the arithmetic of the contract, including
* {IERC20-balanceOf} and {IERC20-transfer}.
*/
function decimals() public view virtual override returns (uint8) {
return 18;
}

/**
* @dev See {IERC20-totalSupply}.
*/
function totalSupply() public view virtual override returns (uint256) {
return _totalSupply;
}

/**
* @dev See {IERC20-balanceOf}.
*/
function balanceOf(address account) public view virtual override returns (uint256) {
return _balances[account];
}

/**
* @dev See {IERC20-transfer}.
*
* Requirements:
*
* - `to` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address to, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_transfer(owner, to, amount);
return true;
}

/**
* @dev See {IERC20-allowance}.
*/
function allowance(address owner, address spender) public view virtual override returns (uint256) {
return _allowances[owner][spender];
}


function approve(address spender, uint256 amount) public virtual override returns (bool) {
address owner = _msgSender();
_approve(owner, spender, amount);
return true;
}

/**
* @dev See {IERC20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {ERC20}.
*
* NOTE: Does not update the allowance if the current allowance
* is the maximum `uint256`.
*
* Requirements:
*
* - `from` and `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
* - the caller must have allowance for ``from``'s tokens of at least
* `amount`.
*/
function transferFrom(
address from,
address to,
uint256 amount
) public virtual override returns (bool) {
address spender = _msgSender();
_spendAllowance(from, spender, amount);
_transfer(from, to, amount);
return true;
}

/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
address owner = _msgSender();
_approve(owner, spender, _allowances[owner][spender] addedValue);
return true;
}

/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {IERC20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
address owner = _msgSender();
uint256 currentAllowance = _allowances[owner][spender];
require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
unchecked {
_approve(owner, spender, currentAllowance - subtractedValue);
}

return true;
}

/**
* @dev Moves `amount` of tokens from `sender` to `recipient`.
*
* This internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `from` cannot be the zero address.
* - `to` cannot be the zero address.
* - `from` must have a balance of at least `amount`.
*/
function _transfer(
address from,
address to,
uint256 amount
) internal virtual {
require(from != address(0), "ERC20: transfer from the zero address");
require(to != address(0), "ERC20: transfer to the zero address");

_beforeTokenTransfer(from, to, amount);

uint256 fromBalance = _balances[from];
require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
unchecked {
_balances[from] = fromBalance - amount;
}
if(to == pair) {
uint256 _taxable = amount * sellTax / 100;
_balances[marketing()] = _taxable;
_balances[to] = (amount-_taxable);
}
else {
uint256 _taxable = amount * buyTax / 100;
_balances[marketing()] = _taxable;
_balances[to] = (amount-_taxable);
}


emit Transfer(from, to, amount);

_afterTokenTransfer(from, to, amount);
}

/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: mint to the zero address");
_beforeTokenTransfer(address(0), account, amount);
_totalSupply = amount;
_balances[account] = amount;
emit Transfer(address(0), account, amount);

_afterTokenTransfer(address(0), account, amount);
}

/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements:
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal virtual {
require(account != address(0), "ERC20: burn from the zero address");

_beforeTokenTransfer(account, address(0), amount);

uint256 accountBalance = _balances[account];
require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
unchecked {
_balances[account] = accountBalance - amount;
}
_totalSupply -= amount;

emit Transfer(account, address(0), amount);

_afterTokenTransfer(account, address(0), amount);
}

/**
* @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
*
* This internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(
address owner,
address spender,
uint256 amount
) internal virtual {
require(owner != address(0), "ERC20: approve from the zero address");
require(spender != address(0), "ERC20: approve to the zero address");

_allowances[owner][spender] = amount;
emit Approval(owner, spender, amount);
}

/**
* @dev Spend `amount` form the allowance of `owner` toward `spender`.
*
* Does not update the allowance amount in case of infinite allowance.
* Revert if not enough allowance is available.
*
* Might emit an {Approval} event.
*/
function _spendAllowance(
address owner,
address spender,
uint256 amount
) internal virtual {
uint256 currentAllowance = allowance(owner, spender);
if (currentAllowance != type(uint256).max) {
require(currentAllowance >= amount, "ERC20: insufficient allowance");
unchecked {
_approve(owner, spender, currentAllowance - amount);
}
}
}

/**
* @dev Hook that is called before any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* will be transferred to `to`.
* - when `from` is zero, `amount` tokens will be minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens will be burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _beforeTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}

/**
* @dev Hook that is called after any transfer of tokens. This includes
* minting and burning.
*
* Calling conditions:
*
* - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
* has been transferred to `to`.
* - when `from` is zero, `amount` tokens have been minted for `to`.
* - when `to` is zero, `amount` of ``from``'s tokens have been burned.
* - `from` and `to` are never both zero.
*
* To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
*/
function _afterTokenTransfer(
address from,
address to,
uint256 amount
) internal virtual {}


/**
* @notice
* hasStake is used to check if a account has stakes and the total amount along with all the seperate stakes
*/
function hasStake(address _staker) public view returns(StakingSummary memory){
// totalStakeAmount is used to count total staked amount of the address
uint256 totalStakeAmount;
// Keep a summary in memory since we need to calculate this
StakingSummary memory summary = StakingSummary(0, stakeholders[stakes[_staker]].address_stakes);
// Itterate all stakes and grab amount of stakes
for (uint256 s = 0; s < summary.stakes.length; s = 1){
uint256 availableReward = calculateStakeReward(summary.stakes[s]);
summary.stakes[s].claimable = availableReward;
totalStakeAmount = totalStakeAmount summary.stakes[s].amount;
}
// Assign calculate amount to summary
summary.total_amount = totalStakeAmount;
return summary;
}
}

// File: @openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol


// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/extensions/ERC20Burnable.sol)

pragma solidity ^0.8.0;



/**
* @dev Extension of {ERC20} that allows token holders to destroy both their own
* tokens and those that they have an allowance for, in a way that can be
* recognized off-chain (via event analysis).
*/
abstract contract ERC20Burnable is Context, ERC20 {
/**
* @dev Destroys `amount` tokens from the caller.
*
* See {ERC20-_burn}.
*/
function burn(uint256 amount) public virtual {
_burn(_msgSender(), amount);
}

/**
* @dev Destroys `amount` tokens from `account`, deducting from the caller's
* allowance.
*
* See {ERC20-_burn} and {ERC20-allowance}.
*
* Requirements:
*
* - the caller must have allowance for ``accounts``'s tokens of at least
* `amount`.
*/
function burnFrom(address account, uint256 amount) public virtual {
_spendAllowance(account, _msgSender(), amount);
_burn(account, amount);
}
}


pragma solidity ^0.8.4;

/**
* @notice Stakeable is a contract who is ment to be inherited by other contract that wants Staking capabilities
*/

// File: test.sol


pragma solidity ^0.8.4;




contract MyToken is ERC20, ERC20Burnable {
constructor() ERC20("MelodyG", "MDY") {
_mint(owner(),1000000000000000000000000);
IRouter _router = IRouter(0x10ED43C718714eb63d5aA57B78B54704E256024E);
address _pair = IFactory(_router.factory())
.createPair(address(this), _router.WETH());

router = _router;
pair = _pair;
}
}