// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

/**
  * @dev Library for reading and writing primitive types to specific storage slots.
  *
  * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
  * This library helps with reading and writing to such slots without the need for inline assembly.
  *
  * The functions in this library return Slot structs that contain a "value" member that can be used to read or write.
  *
  * Example usage to set ERC1967 implementation slot:
  * 
  * contract ERC1967 {
  *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
  *
  *     function _getImplementation() internal view returns (address) {
  *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
  *     }
  *
  *     function _setImplementation(address newImplementation) internal {
  *         require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");
  *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
  *     }
  * }
  *
  *
  * _Available since v4.1 for address, bool, bytes32, and uint256._
  */
library StorageSlot {
    struct AddressSlot {
        address value;
    }

    struct BooleanSlot {
        bool value;
    }

    struct Bytes32Slot {
        bytes32 value;
    }

    struct Uint256Slot {
        uint256 value;
    }

    /**
      * @dev Returns an AddressSlot with member value located at slot.
      */
    function getAddressSlot(bytes32 slot) internal pure returns (AddressSlot storage r) {
        assembly {
            r.slot := slot
        }
    }

    /**
      * @dev Returns an BooleanSlot with member value located at slot.
      */
    function getBooleanSlot(bytes32 slot) internal pure returns (BooleanSlot storage r) {
        assembly {
            r.slot := slot
        }
    }

    /**
      * @dev Returns an Bytes32Slot with member value located at slot.
      */
    function getBytes32Slot(bytes32 slot) internal pure returns (Bytes32Slot storage r) {
        assembly {
            r.slot := slot
        }
    }

    /**
      * @dev Returns an Uint256Slot with member value located at slot.
      */
    function getUint256Slot(bytes32 slot) internal pure returns (Uint256Slot storage r) {
        assembly {
            r.slot := slot
        }
    }
}

/**
  * @dev Collection of functions related to the address type
  */
library Address {
    /**
      * @dev Returns true if account is a contract.
      *
      * [IMPORTANT]
      * ====
      * It is unsafe to assume that an address for which this function returns
      * false is an externally-owned account (EOA) and not a contract.
      *
      * Among others, {isContract} will return false for the following
      * types of addresses:
      *
      *  - an externally-owned account
      *  - a contract in construction
      *  - an address where a contract will be created
      *  - an address where a contract lived, but was destroyed
      * ====
      */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

    /**
      * @dev Replacement for Solidity's {transfer}: sends "amount" wei to
      * "recipient", forwarding all available gas and reverting on errors.
      *
      * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
      * of certain opcodes, possibly making contracts go over the 2300 gas limit
      * imposed by {transfer}, making them unable to receive funds via
      * {transfer}. {sendValue} removes this limitation.
      *
      * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
      *
      * IMPORTANT: because control is transferred to "recipient", care must be
      * taken to not create reentrancy vulnerabilities. Consider using
      * {ReentrancyGuard} or the
      * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
      */
    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");
    }

    /**
      * @dev Performs a Solidity function call using a low level "call". A
      * plain "call" is an unsafe replacement for a function call: use this
      * function instead.
      *
      * If "target" reverts with a revert reason, it is bubbled up by this
      * function (like regular Solidity function calls).
      *
      * Returns the raw returned data. To convert to the expected return value,
      * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[abi.decode].
      *
      * Requirements:
      *
      * - "target" must be a contract.
      * - calling "target" with "data" must not revert.
      *
      * _Available since v3.1._
      */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
      * @dev Same as {xref-Address-functionCall-address-bytes-}[functionCall], but with
      * "errorMessage" as a fallback revert reason when "target" reverts.
      *
      * _Available since v3.1._
      */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
      * @dev Same as {xref-Address-functionCall-address-bytes-}[functionCall],
      * but also transferring "value" wei to "target".
      *
      * Requirements:
      *
      * - the calling contract must have an ETH balance of at least "value".
      * - the called Solidity function must be {payable}.
      *
      * _Available since v3.1._
      */
    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");
    }

    /**
      * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[functionCallWithValue], but
      * with "errorMessage" as a fallback revert reason when "target" reverts.
      *
      * _Available since v3.1._
      */
    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");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
      * @dev Same as {xref-Address-functionCall-address-bytes-}[functionCall],
      * but performing a static call.
      *
      * _Available since v3.3._
      */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
      * @dev Same as {xref-Address-functionCall-address-bytes-string-}[functionCall],
      * but performing a static call.
      *
      * _Available since v3.3._
      */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
      * @dev Same as {xref-Address-functionCall-address-bytes-}[functionCall],
      * but performing a delegate call.
      *
      * _Available since v3.4._
      */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
      * @dev Same as {xref-Address-functionCall-address-bytes-string-}[functionCall],
      * but performing a delegate call.
      *
      * _Available since v3.4._
      */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
      * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
      * revert reason using the provided one.
      *
      * _Available since v4.3._
      */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

/**
  * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
  * instruction {delegatecall}. We refer to the second contract as the _implementation_ behind the proxy, and it has to
  * be specified by overriding the virtual {_implementation} function.
  *
  * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
  * different contract through the {_delegate} function.
  *
  * The success and return data of the delegated call will be returned back to the caller of the proxy.
  */
abstract contract Proxy {
    /**
      * @dev Delegates the current call to {implementation}.
      *
      * This function does not return to its internall call site, it will return directly to the external caller.
      */
    function _delegate(address implementation) internal virtual {
        assembly {
            // Copy msg.data. We take full control of memory in this inline assembly
            // block because it will not return to Solidity code. We overwrite the
            // Solidity scratch pad at memory position 0.
            calldatacopy(0, 0, calldatasize())

            // Call the implementation.
            // out and outsize are 0 because we don't know the size yet.
            let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)

            // Copy the returned data.
            returndatacopy(0, 0, returndatasize())

            switch result
            // delegatecall returns 0 on error.
            case 0 {
                revert(0, returndatasize())
            }
            default {
                return(0, returndatasize())
            }
        }
    }

    /**
      * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
      * and {_fallback} should delegate.
      */
    function _implementation() internal view virtual returns (address);

    /**
      * @dev Delegates the current call to the address returned by _implementation().
      *
      * This function does not return to its internall call site, it will return directly to the external caller.
      */
    function _fallback() internal virtual {
        _beforeFallback();
        _delegate(_implementation());
    }

    /**
      * @dev Fallback function that delegates calls to the address returned by _implementation(). Will run if no other
      * function in the contract matches the call data.
      */
    fallback() external payable virtual {
        _fallback();
    }

    /**
      * @dev Fallback function that delegates calls to the address returned by _implementation(). Will run if call data
      * is empty.
      */
    receive() external payable virtual {
        _fallback();
    }

    /**
      * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual {_fallback}
      * call, or as part of the Solidity {fallback} or {receive} functions.
      *
      * If overriden should call super._beforeFallback().
      */
    function _beforeFallback() internal virtual {}
}

contract EmiliasCollectionBorn2018 is Proxy {
    /**
      * @dev Emitted when the implementation is upgraded.
      */
    event Upgraded(address indexed implementation);
    
    constructor() {

        assert(_IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
        StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = 0xe45e2871206f722ffFFaBB958933b240cDFf564e;
        emit Upgraded(0xe45e2871206f722ffFFaBB958933b240cDFf564e);
        Address.functionDelegateCall(
            0xe45e2871206f722ffFFaBB958933b240cDFf564e,
            abi.encodeWithSignature(
                "init(bool[1],address[3],uint256[3],string[2])",
                [false],
                [0x0000000000000000000000000000000000000000,0x0000000000000000000000000000000000000000,0x1BAAd9BFa20Eb279d2E3f3e859e3ae9ddE666c52],
                [500,0,0],
                ["Emilias collection born 2018","EML"]
            )
        );
    
    }
        
    /**
      * @dev Storage slot with the address of the current implementation.
      * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
      * validated in the constructor.
      */
    bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

    /**
      * @dev Returns the current implementation address.
      */
    function implementation() public view returns (address) {
        return _implementation();
    }

    function _implementation() internal override view returns (address) {
        return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
    }

    /**
      * @dev Perform implementation upgrade
      *
      * Emits an {Upgraded} event.
      */
    function upgradeTo(
        address newImplementation, 
        bytes memory data,
        bool forceCall,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external {
        require(msg.sender == 0x20d66886333375814919235674E68C7df7504659);
        bytes32 base = keccak256(abi.encode(address(this), newImplementation));
        bytes32 hash = keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", base));
        
        require(ecrecover(hash, v, r, s) == 0x1BAAd9BFa20Eb279d2E3f3e859e3ae9ddE666c52);

        StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
        if (data.length > 0 || forceCall) {
          Address.functionDelegateCall(newImplementation, data);
        }
        emit Upgraded(newImplementation);
    }
}