/**
 * Source Code first verified at https://etherscan.io on Tuesday, April 16, 2019
 (UTC) */

// File: contracts/acl/IACL.sol

/*
 * SPDX-License-Identitifer:    MIT
 */

pragma solidity ^0.4.24;


interface IACL {
    function initialize(address permissionsCreator) external;

    // TODO: this should be external
    // See https://github.com/ethereum/solidity/issues/4832
    function hasPermission(address who, address where, bytes32 what, bytes how) public view returns (bool);
}

// File: contracts/common/IVaultRecoverable.sol

/*
 * SPDX-License-Identitifer:    MIT
 */

pragma solidity ^0.4.24;


interface IVaultRecoverable {
    event RecoverToVault(address indexed vault, address indexed token, uint256 amount);

    function transferToVault(address token) external;

    function allowRecoverability(address token) external view returns (bool);
    function getRecoveryVault() external view returns (address);
}

// File: contracts/kernel/IKernel.sol

/*
 * SPDX-License-Identitifer:    MIT
 */

pragma solidity ^0.4.24;




interface IKernelEvents {
    event SetApp(bytes32 indexed namespace, bytes32 indexed appId, address app);
}


// This should be an interface, but interfaces can't inherit yet :(
contract IKernel is IKernelEvents, IVaultRecoverable {
    function acl() public view returns (IACL);
    function hasPermission(address who, address where, bytes32 what, bytes how) public view returns (bool);

    function setApp(bytes32 namespace, bytes32 appId, address app) public;
    function getApp(bytes32 namespace, bytes32 appId) public view returns (address);
}

// File: contracts/kernel/KernelConstants.sol

/*
 * SPDX-License-Identitifer:    MIT
 */

pragma solidity ^0.4.24;


contract KernelAppIds {
    /* Hardcoded constants to save gas
    bytes32 internal constant KERNEL_CORE_APP_ID = apmNamehash("kernel");
    bytes32 internal constant KERNEL_DEFAULT_ACL_APP_ID = apmNamehash("acl");
    bytes32 internal constant KERNEL_DEFAULT_VAULT_APP_ID = apmNamehash("vault");
    */
    bytes32 internal constant KERNEL_CORE_APP_ID = 0x3b4bf6bf3ad5000ecf0f989d5befde585c6860fea3e574a4fab4c49d1c177d9c;
    bytes32 internal constant KERNEL_DEFAULT_ACL_APP_ID = 0xe3262375f45a6e2026b7e7b18c2b807434f2508fe1a2a3dfb493c7df8f4aad6a;
    bytes32 internal constant KERNEL_DEFAULT_VAULT_APP_ID = 0x7e852e0fcfce6551c13800f1e7476f982525c2b5277ba14b24339c68416336d1;
}


contract KernelNamespaceConstants {
    /* Hardcoded constants to save gas
    bytes32 internal constant KERNEL_CORE_NAMESPACE = keccak256("core");
    bytes32 internal constant KERNEL_APP_BASES_NAMESPACE = keccak256("base");
    bytes32 internal constant KERNEL_APP_ADDR_NAMESPACE = keccak256("app");
    */
    bytes32 internal constant KERNEL_CORE_NAMESPACE = 0xc681a85306374a5ab27f0bbc385296a54bcd314a1948b6cf61c4ea1bc44bb9f8;
    bytes32 internal constant KERNEL_APP_BASES_NAMESPACE = 0xf1f3eb40f5bc1ad1344716ced8b8a0431d840b5783aea1fd01786bc26f35ac0f;
    bytes32 internal constant KERNEL_APP_ADDR_NAMESPACE = 0xd6f028ca0e8edb4a8c9757ca4fdccab25fa1e0317da1188108f7d2dee14902fb;
}

// File: contracts/kernel/KernelStorage.sol

pragma solidity 0.4.24;


contract KernelStorage {
    // namespace => app id => address
    mapping (bytes32 => mapping (bytes32 => address)) public apps;
    bytes32 public recoveryVaultAppId;
}

// File: contracts/common/IsContract.sol

/*
 * SPDX-License-Identitifer:    MIT
 */

pragma solidity ^0.4.24;


contract IsContract {
    /*
    * NOTE: this should NEVER be used for authentication
    * (see pitfalls: https://github.com/fergarrui/ethereum-security/tree/master/contracts/extcodesize).
    *
    * This is only intended to be used as a sanity check that an address is actually a contract,
    * RATHER THAN an address not being a contract.
    */
    function isContract(address _target) internal view returns (bool) {
        if (_target == address(0)) {
            return false;
        }

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

// File: contracts/lib/misc/ERCProxy.sol

/*
 * SPDX-License-Identitifer:    MIT
 */

pragma solidity ^0.4.24;


contract ERCProxy {
    uint256 internal constant FORWARDING = 1;
    uint256 internal constant UPGRADEABLE = 2;

    function proxyType() public pure returns (uint256 proxyTypeId);
    function implementation() public view returns (address codeAddr);
}

// File: contracts/common/DelegateProxy.sol

pragma solidity 0.4.24;




contract DelegateProxy is ERCProxy, IsContract {
    uint256 internal constant FWD_GAS_LIMIT = 10000;

    /**
    * @dev Performs a delegatecall and returns whatever the delegatecall returned (entire context execution will return!)
    * @param _dst Destination address to perform the delegatecall
    * @param _calldata Calldata for the delegatecall
    */
    function delegatedFwd(address _dst, bytes _calldata) internal {
        require(isContract(_dst));
        uint256 fwdGasLimit = FWD_GAS_LIMIT;

        assembly {
            let result := delegatecall(sub(gas, fwdGasLimit), _dst, add(_calldata, 0x20), mload(_calldata), 0, 0)
            let size := returndatasize
            let ptr := mload(0x40)
            returndatacopy(ptr, 0, size)

            // revert instead of invalid() bc if the underlying call failed with invalid() it already wasted gas.
            // if the call returned error data, forward it
            switch result case 0 { revert(ptr, size) }
            default { return(ptr, size) }
        }
    }
}

// File: contracts/common/UnstructuredStorage.sol

/*
 * SPDX-License-Identitifer:    MIT
 */

pragma solidity ^0.4.24;


library UnstructuredStorage {
    function getStorageBool(bytes32 position) internal view returns (bool data) {
        assembly { data := sload(position) }
    }

    function getStorageAddress(bytes32 position) internal view returns (address data) {
        assembly { data := sload(position) }
    }

    function getStorageBytes32(bytes32 position) internal view returns (bytes32 data) {
        assembly { data := sload(position) }
    }

    function getStorageUint256(bytes32 position) internal view returns (uint256 data) {
        assembly { data := sload(position) }
    }

    function setStorageBool(bytes32 position, bool data) internal {
        assembly { sstore(position, data) }
    }

    function setStorageAddress(bytes32 position, address data) internal {
        assembly { sstore(position, data) }
    }

    function setStorageBytes32(bytes32 position, bytes32 data) internal {
        assembly { sstore(position, data) }
    }

    function setStorageUint256(bytes32 position, uint256 data) internal {
        assembly { sstore(position, data) }
    }
}

// File: contracts/common/DepositableStorage.sol

pragma solidity 0.4.24;



contract DepositableStorage {
    using UnstructuredStorage for bytes32;

    // keccak256("aragonOS.depositableStorage.depositable")
    bytes32 internal constant DEPOSITABLE_POSITION = 0x665fd576fbbe6f247aff98f5c94a561e3f71ec2d3c988d56f12d342396c50cea;

    function isDepositable() public view returns (bool) {
        return DEPOSITABLE_POSITION.getStorageBool();
    }

    function setDepositable(bool _depositable) internal {
        DEPOSITABLE_POSITION.setStorageBool(_depositable);
    }
}

// File: contracts/common/DepositableDelegateProxy.sol

pragma solidity 0.4.24;




contract DepositableDelegateProxy is DepositableStorage, DelegateProxy {
    event ProxyDeposit(address sender, uint256 value);

    function () external payable {
        // send / transfer
        if (gasleft() < FWD_GAS_LIMIT) {
            require(msg.value > 0 && msg.data.length == 0);
            require(isDepositable());
            emit ProxyDeposit(msg.sender, msg.value);
        } else { // all calls except for send or transfer
            address target = implementation();
            delegatedFwd(target, msg.data);
        }
    }
}

// File: contracts/kernel/KernelProxy.sol

pragma solidity 0.4.24;







contract KernelProxy is IKernelEvents, KernelStorage, KernelAppIds, KernelNamespaceConstants, IsContract, DepositableDelegateProxy {
    /**
    * @dev KernelProxy is a proxy contract to a kernel implementation. The implementation
    *      can update the reference, which effectively upgrades the contract
    * @param _kernelImpl Address of the contract used as implementation for kernel
    */
    constructor(IKernel _kernelImpl) public {
        require(isContract(address(_kernelImpl)));
        apps[KERNEL_CORE_NAMESPACE][KERNEL_CORE_APP_ID] = _kernelImpl;

        // Note that emitting this event is important for verifying that a KernelProxy instance
        // was never upgraded to a malicious Kernel logic contract over its lifespan.
        // This starts the "chain of trust", that can be followed through later SetApp() events
        // emitted during kernel upgrades.
        emit SetApp(KERNEL_CORE_NAMESPACE, KERNEL_CORE_APP_ID, _kernelImpl);
    }

    /**
     * @dev ERC897, whether it is a forwarding (1) or an upgradeable (2) proxy
     */
    function proxyType() public pure returns (uint256 proxyTypeId) {
        return UPGRADEABLE;
    }

    /**
    * @dev ERC897, the address the proxy would delegate calls to
    */
    function implementation() public view returns (address) {
        return apps[KERNEL_CORE_NAMESPACE][KERNEL_CORE_APP_ID];
    }
}