// SPDX-License-Identifier: GPL-3.0-or-later
pragma solidity 0.6.12;

interface DSAuthority {
    function canCall(
        address src,
        address dst,
        bytes4 sig
    ) external view returns (bool);
}

contract DSAuthEvents {
    event LogSetAuthority(address indexed authority);
    event LogSetOwner(address indexed owner);
}

contract DSAuth is DSAuthEvents {
    DSAuthority public authority;
    address public owner;

    constructor() public {
        owner = msg.sender;
        emit LogSetOwner(msg.sender);
    }

    function setOwner(address owner_) external auth {
        require(owner != address(0),"ERR_ZERO_ADDRESS");
        owner = owner_;
        emit LogSetOwner(owner);
    }

    function setAuthority(DSAuthority authority_) external auth {
        authority = authority_;
        emit LogSetAuthority(address(authority));
    }

    modifier auth() {
        require(isAuthorized(msg.sender, msg.sig), "ds-auth-unauthorized");
        _;
    }

    function isAuthorized(address src, bytes4 sig) internal view returns (bool) {
        if (src == address(this)) {
            return true;
        } else if (src == owner) {
            return true;
        } else if (authority == DSAuthority(0)) {
            return false;
        } else {
            return authority.canCall(src, address(this), sig);
        }
    }
}

contract DSNote {
    event LogNote(bytes4 indexed sig, address indexed guy, bytes32 indexed foo, bytes32 indexed bar, uint wad, bytes fax) anonymous;

    modifier note() {
        bytes32 foo;
        bytes32 bar;
        uint wad;

        assembly {
            foo := calldataload(4)
            bar := calldataload(36)
            wad := callvalue()
        }

        _;

        emit LogNote(msg.sig, msg.sender, foo, bar, wad, msg.data);
    }
}

// DSProxy
// Allows code execution using a persistant identity This can be very
// useful to execute a sequence of atomic actions. Since the owner of
// the proxy can be changed, this allows for dynamic ownership models
// i.e. a multisig
contract DSProxy is DSAuth, DSNote {
    DSProxyCache public cache; // global cache for contracts

    constructor(address _cacheAddr) public {
        setCache(_cacheAddr);
    }

    fallback() external payable {}

    // use the proxy to execute calldata _data on contract _code
    function execute(
        bytes memory _code,
        bytes memory _data,
        bool bools
    ) external payable returns (address target, bytes memory response) {
        target = cache.read(_code);
        if (target == address(0)) {
            // deploy contract & store its address in cache
            target = cache.write(_code);
        }

        response = execute(target, _data);
    }

    function execute(address _target, bytes memory _data) public payable auth note returns (bytes memory response) {
        require(_target != address(0), "ds-proxy-target-address-required");

        // call contract in current context
        assembly {
            let succeeded := delegatecall(sub(gas(), 5000), _target, add(_data, 0x20), mload(_data), 0, 0)
            let size := returndatasize()

            response := mload(0x40)
            mstore(0x40, add(response, and(add(add(size, 0x20), 0x1f), not(0x1f))))
            mstore(response, size)
            returndatacopy(add(response, 0x20), 0, size)

            switch iszero(succeeded)
            case 1 {
                // throw if delegatecall failed
                revert(add(response, 0x20), size)
            }
        }
    }

    //set new cache
    function setCache(address _cacheAddr) public auth note returns (bool) {
        require(_cacheAddr != address(0), "ds-proxy-cache-address-required");
        cache = DSProxyCache(_cacheAddr); // overwrite cache
        return true;
    }
}

// DSProxyFactory
// This factory deploys new proxy instances through build()
// Deployed proxy addresses are logged
contract DSProxyFactory {
    event Created(address indexed sender, address indexed owner, address proxy, address cache);
    mapping(address => bool) public isProxy;
    DSProxyCache public cache;

    constructor() public {
        cache = new DSProxyCache();
    }

    // deploys a new proxy instance
    // sets owner of proxy to caller
    function build() external returns (address payable proxy) {
        proxy = build(msg.sender);
    }

    // deploys a new proxy instance
    // sets custom owner of proxy
    function build(address owner) public returns (address payable proxy) {
        proxy = address(new DSProxy(address(cache)));
        emit Created(msg.sender, owner, address(proxy), address(cache));
        DSProxy(proxy).setOwner(owner);
        isProxy[proxy] = true;
    }
}

// DSProxyCache
// This global cache stores addresses of contracts previously deployed
// by a proxy. This saves gas from repeat deployment of the same
// contracts and eliminates blockchain bloat.

// By default, all proxies deployed from the same factory store
// contracts in the same cache. The cache a proxy instance uses can be
// changed.  The cache uses the sha3 hash of a contract's bytecode to
// lookup the address
contract DSProxyCache {
    mapping(bytes32 => address) cache;

    function read(bytes memory _code) external view returns (address) {
        bytes32 hash = keccak256(_code);
        return cache[hash];
    }

    function write(bytes memory _code) external returns (address target) {
        assembly {
            target := create(0, add(_code, 0x20), mload(_code))
            switch iszero(extcodesize(target))
            case 1 {
                // throw if contract failed to deploy
                revert(0, 0)
            }
        }
        bytes32 hash = keccak256(_code);
        cache[hash] = target;
    }
}

// ProxyRegistry
// This Registry deploys new proxy instances through DSProxyFactory.build(address) and keeps a registry of owner => proxy
contract ProxyRegistry {
    mapping(address => DSProxy) public proxies;
    DSProxyFactory factory;

    constructor(address factory_) public {
        factory = DSProxyFactory(factory_);
    }

    // deploys a new proxy instance
    // sets owner of proxy to caller
    function build() external returns (address payable proxy) {
        proxy = build(msg.sender);
    }

    // deploys a new proxy instance
    // sets custom owner of proxy
    function build(address owner) public returns (address payable proxy) {
        require(proxies[owner] == DSProxy(0) || proxies[owner].owner() != owner); // Not allow new proxy if the user already has one and remains being the owner
        proxy = factory.build(owner);
        proxies[owner] = DSProxy(proxy);
    }
}

{
  "compilationTarget": {
    "contracts/deploy/DSProxyContract.sol": "DSProxy"
  },
  "evmVersion": "istanbul",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs",
    "useLiteralContent": true
  },
  "optimizer": {
    "enabled": true,
    "runs": 20
  },
  "remappings": []
}