// File: contracts/OLAS.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.15;

import "../lib/solmate/src/tokens/ERC20.sol";

/// @dev Only `manager` has a privilege, but the `sender` was provided.
/// @param sender Sender address.
/// @param manager Required sender address as a manager.
error ManagerOnly(address sender, address manager);

/// @dev Provided zero address.
error ZeroAddress();

/// @title OLAS - Smart contract for the OLAS token.
/// @author AL
/// @author Aleksandr Kuperman - <aleksandr.kuperman@valory.xyz>
contract OLAS is ERC20 {
    event MinterUpdated(address indexed minter);
    event OwnerUpdated(address indexed owner);

    // One year interval
    uint256 public constant oneYear = 1 days * 365;
    // Total supply cap for the first ten years (one billion OLAS tokens)
    uint256 public constant tenYearSupplyCap = 1_000_000_000e18;
    // Maximum annual inflation after first ten years
    uint256 public constant maxMintCapFraction = 2;
    // Initial timestamp of the token deployment
    uint256 public immutable timeLaunch;

    // Owner address
    address public owner;
    // Minter address
    address public minter;

    constructor() ERC20("Autonolas", "OLAS", 18) {
        owner = msg.sender;
        minter = msg.sender;
        timeLaunch = block.timestamp;
    }

    /// @dev Changes the owner address.
    /// @param newOwner Address of a new owner.
    function changeOwner(address newOwner) external {
        if (msg.sender != owner) {
            revert ManagerOnly(msg.sender, owner);
        }

        if (newOwner == address(0)) {
            revert ZeroAddress();
        }

        owner = newOwner;
        emit OwnerUpdated(newOwner);
    }

    /// @dev Changes the minter address.
    /// @param newMinter Address of a new minter.
    function changeMinter(address newMinter) external {
        if (msg.sender != owner) {
            revert ManagerOnly(msg.sender, owner);
        }

        if (newMinter == address(0)) {
            revert ZeroAddress();
        }

        minter = newMinter;
        emit MinterUpdated(newMinter);
    }

    /// @dev Mints OLAS tokens.
    /// @param account Account address.
    /// @param amount OLAS token amount.
    function mint(address account, uint256 amount) external {
        // Access control
        if (msg.sender != minter) {
            revert ManagerOnly(msg.sender, minter);
        }

        // Check the inflation schedule and mint
        if (inflationControl(amount)) {
            _mint(account, amount);
        }
    }

    /// @dev Provides various checks for the inflation control.
    /// @param amount Amount of OLAS to mint.
    /// @return True if the amount request is within inflation boundaries.
    function inflationControl(uint256 amount) public view returns (bool) {
        uint256 remainder = inflationRemainder();
        return (amount <= remainder);
    }

    /// @dev Gets the reminder of OLAS possible for the mint.
    /// @return remainder OLAS token remainder.
    function inflationRemainder() public view returns (uint256 remainder) {
        uint256 _totalSupply = totalSupply;
        // Current year
        uint256 numYears = (block.timestamp - timeLaunch) / oneYear;
        // Calculate maximum mint amount to date
        uint256 supplyCap = tenYearSupplyCap;
        // After 10 years, adjust supplyCap according to the yearly inflation % set in maxMintCapFraction
        if (numYears > 9) {
            // Number of years after ten years have passed (including ongoing ones)
            numYears -= 9;
            for (uint256 i = 0; i < numYears; ++i) {
                supplyCap += (supplyCap * maxMintCapFraction) / 100;
            }
        }
        // Check for the requested mint overflow
        remainder = supplyCap - _totalSupply;
    }

    /// @dev Burns OLAS tokens.
    /// @param amount OLAS token amount to burn.
    function burn(uint256 amount) external {
        _burn(msg.sender, amount);
    }

    /// @dev Decreases the allowance of another account over their tokens.
    /// @param spender Account that tokens are approved for.
    /// @param amount Amount to decrease approval by.
    /// @return True if the operation succeeded.
    function decreaseAllowance(address spender, uint256 amount) external returns (bool) {
        uint256 spenderAllowance = allowance[msg.sender][spender];

        if (spenderAllowance != type(uint256).max) {
            spenderAllowance -= amount;
            allowance[msg.sender][spender] = spenderAllowance;
            emit Approval(msg.sender, spender, spenderAllowance);
        }

        return true;
    }

    /// @dev Increases the allowance of another account over their tokens.
    /// @param spender Account that tokens are approved for.
    /// @param amount Amount to increase approval by.
    /// @return True if the operation succeeded.
    function increaseAllowance(address spender, uint256 amount) external returns (bool) {
        uint256 spenderAllowance = allowance[msg.sender][spender];

        spenderAllowance += amount;
        allowance[msg.sender][spender] = spenderAllowance;
        emit Approval(msg.sender, spender, spenderAllowance);

        return true;
    }
}

// File: lib/solmate/src/tokens/ERC20.sol



// SPDX-License-Identifier: MIT
pragma solidity >=0.8.0;

/// @notice Modern and gas efficient ERC20 + EIP-2612 implementation.
/// @author Solmate (https://github.com/Rari-Capital/solmate/blob/main/src/tokens/ERC20.sol)
/// @author Modified from Uniswap (https://github.com/Uniswap/uniswap-v2-core/blob/master/contracts/UniswapV2ERC20.sol)
/// @dev Do not manually set balances without updating totalSupply, as the sum of all user balances must not exceed it.
abstract contract ERC20 {
    /*//////////////////////////////////////////////////////////////
                                 EVENTS
    //////////////////////////////////////////////////////////////*/

    event Transfer(address indexed from, address indexed to, uint256 amount);

    event Approval(address indexed owner, address indexed spender, uint256 amount);

    /*//////////////////////////////////////////////////////////////
                            METADATA STORAGE
    //////////////////////////////////////////////////////////////*/

    string public name;

    string public symbol;

    uint8 public immutable decimals;

    /*//////////////////////////////////////////////////////////////
                              ERC20 STORAGE
    //////////////////////////////////////////////////////////////*/

    uint256 public totalSupply;

    mapping(address => uint256) public balanceOf;

    mapping(address => mapping(address => uint256)) public allowance;

    /*//////////////////////////////////////////////////////////////
                            EIP-2612 STORAGE
    //////////////////////////////////////////////////////////////*/

    uint256 internal immutable INITIAL_CHAIN_ID;

    bytes32 internal immutable INITIAL_DOMAIN_SEPARATOR;

    mapping(address => uint256) public nonces;

    /*//////////////////////////////////////////////////////////////
                               CONSTRUCTOR
    //////////////////////////////////////////////////////////////*/

    constructor(
        string memory _name,
        string memory _symbol,
        uint8 _decimals
    ) {
        name = _name;
        symbol = _symbol;
        decimals = _decimals;

        INITIAL_CHAIN_ID = block.chainid;
        INITIAL_DOMAIN_SEPARATOR = computeDomainSeparator();
    }

    /*//////////////////////////////////////////////////////////////
                               ERC20 LOGIC
    //////////////////////////////////////////////////////////////*/

    function approve(address spender, uint256 amount) public virtual returns (bool) {
        allowance[msg.sender][spender] = amount;

        emit Approval(msg.sender, spender, amount);

        return true;
    }

    function transfer(address to, uint256 amount) public virtual returns (bool) {
        balanceOf[msg.sender] -= amount;

        // Cannot overflow because the sum of all user
        // balances can't exceed the max uint256 value.
        unchecked {
            balanceOf[to] += amount;
        }

        emit Transfer(msg.sender, to, amount);

        return true;
    }

    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual returns (bool) {
        uint256 allowed = allowance[from][msg.sender]; // Saves gas for limited approvals.

        if (allowed != type(uint256).max) allowance[from][msg.sender] = allowed - amount;

        balanceOf[from] -= amount;

        // Cannot overflow because the sum of all user
        // balances can't exceed the max uint256 value.
        unchecked {
            balanceOf[to] += amount;
        }

        emit Transfer(from, to, amount);

        return true;
    }

    /*//////////////////////////////////////////////////////////////
                             EIP-2612 LOGIC
    //////////////////////////////////////////////////////////////*/

    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) public virtual {
        require(deadline >= block.timestamp, "PERMIT_DEADLINE_EXPIRED");

        // Unchecked because the only math done is incrementing
        // the owner's nonce which cannot realistically overflow.
        unchecked {
            address recoveredAddress = ecrecover(
                keccak256(
                    abi.encodePacked(
                        "\x19\x01",
                        DOMAIN_SEPARATOR(),
                        keccak256(
                            abi.encode(
                                keccak256(
                                    "Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)"
                                ),
                                owner,
                                spender,
                                value,
                                nonces[owner]++,
                                deadline
                            )
                        )
                    )
                ),
                v,
                r,
                s
            );

            require(recoveredAddress != address(0) && recoveredAddress == owner, "INVALID_SIGNER");

            allowance[recoveredAddress][spender] = value;
        }

        emit Approval(owner, spender, value);
    }

    function DOMAIN_SEPARATOR() public view virtual returns (bytes32) {
        return block.chainid == INITIAL_CHAIN_ID ? INITIAL_DOMAIN_SEPARATOR : computeDomainSeparator();
    }

    function computeDomainSeparator() internal view virtual returns (bytes32) {
        return
            keccak256(
                abi.encode(
                    keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),
                    keccak256(bytes(name)),
                    keccak256("1"),
                    block.chainid,
                    address(this)
                )
            );
    }

    /*//////////////////////////////////////////////////////////////
                        INTERNAL MINT/BURN LOGIC
    //////////////////////////////////////////////////////////////*/

    function _mint(address to, uint256 amount) internal virtual {
        totalSupply += amount;

        // Cannot overflow because the sum of all user
        // balances can't exceed the max uint256 value.
        unchecked {
            balanceOf[to] += amount;
        }

        emit Transfer(address(0), to, amount);
    }

    function _burn(address from, uint256 amount) internal virtual {
        balanceOf[from] -= amount;

        // Cannot underflow because a user's balance
        // will never be larger than the total supply.
        unchecked {
            totalSupply -= amount;
        }

        emit Transfer(from, address(0), amount);
    }
}