// Contract: HomeWorkDeployer
// Target function: function deriveKeyAndDeploy(bytes32 salt, bytes calldata initializationCode)
 the home address. Bear in mind
   * that the deployed contract will interpret msg.sender as the address of THIS
   * contract, and not the address of the submitter - if the constructor of the
   * deployed contract uses msg.sender to set up ownership or other variables,
   * you must modify it to accept a constructor argument with the appropriate
   * address, or alternately to hard-code the intended address. Also, if your
   * contract DOES have constructor arguments, remember to include them as
   * ABI-encoded arguments at the end of the initialization code, just as you
   * would when performing a standard deploy. You may also want to provide the
   * key to `setReverseLookup` in order to find it again using only the home
   * address to prevent accidentally losing the key. The controller cannot be
   * designated as the address of this contract, the null address, or the home
   * address (the restriction on setting the home address as the controller is
   * due to the fact that the home address will not be able to deploy to itself,
   * as it needs to be empty before a contract can be deployed to it). Also,
   * checks on the contract at the home address being empty or not having the
   * correct controller are unnecessary, as they are performed when minting the
   * token and cannot be altered until the token is redeemed.
   */
  function redeemAndDeploy(
    uint256 tokenId,
    address controller,
    bytes calldata initializationCode
  )
    external
    payable
    onlyTokenOwnerOrApprovedSpender(tokenId)
    returns (address homeAddress, bytes32 runtimeCodeHash)
  {
    // Ensure that initialization code was supplied.
    require(initializationCode.length > 0, _NO_INIT_CODE_SUPPLIED);

    // Convert the token ID to a bytes32 key.
    bytes32 key = bytes32(tokenId);

    // Prevent the controller from being set to prohibited account values.
    _validateController(controller, key);

    // Burn the ERC721 token in question.
    _burn(tokenId);

    // Deploy the initialization storage contract and set address in storage.
    _initializationRuntimeStorageContract = _deployRuntimeStorageContract(
      initializationCode
    );

    // Set provided controller and increment contract deploy count at once.
    HomeAddress storage home = _home[key];
    home.exists = true;
    home.controller = controller;
    home.deploys += 1;

    // Emit an event with the new controller. 
    emit NewController(key, controller);

    // Use metamorphic initialization code to deploy contract to home address.
    (homeAddress, runtimeCodeHash) = _deployToHomeAddress(key);
  }

  /**
   * @notice Derive a new key by concatenating an arbitrary 32-byte salt value
   * and the address of the caller and performing a keccak256 hash. This allows
   * for the creation of keys with additional entropy where desired while also
   * preventing collisions with standard keys. The caller will be set as the
   * controller of the derived key.
   * @param salt bytes32 The desired salt value to use (along with the address
   * of the caller) when deriving the resultant key and corresponding home
   * address.
   * @return The derived key.
   * @dev Home addresses from derived keys will take longer to "mine" or locate,
   * as an additional hash must be performed when computing the corresponding
   * home address for each given salt input. Each caller will derive a different
   * key even if they are supplying the same salt value.
   */
  function deriveKey(bytes32 salt) external returns (bytes32 key) {
    // Derive the key using the supplied salt and the calling address.
    key = _deriveKey(salt, msg.sender);

    // Register key and set caller as controller if it is not yet registered.
    HomeAddress storage home = _home[key];
    if (!home.exists) {
      home.exists = true;
      home.controller = msg.sender;

      // Emit an event with the sender as the new controller. 
      emit NewController(key, msg.sender);
    }
  }

  /**
   * @notice Mint an ERC721 token to the supplied owner that can be redeemed in
   * order to gain control of a home address corresponding to a given derived
   * key. Two conditions must be met: the submitter must be designated as the
   * current controller of the home address, and there must not be a contract
   * currently deployed at the home address. These conditions can be checked by
   * calling `getHomeAddressInformation` and `isDeployable` with the key
   * determined by calling `getDerivedKey`.
   * @param salt bytes32 The salt value that is used to derive the key.
   * @param owner address The account that will be granted ownership of the
   * ERC721 token.
   * @return The derived key.
   * @dev In order to mint an ERC721 token, the assocated home address cannot be
   * in use, or else the token will not be able to deploy to the home address.
   * The controller is set to this contract until the token is redeemed, at
   * which point the redeemer designates a new controller for the home address.
   * The key of the home address and the tokenID of the ERC721 token are the
   * same value, but different types (bytes32 vs. uint256).
   */
  function deriveKeyAndLock(bytes32 salt, address owner)
    external
    returns (bytes32 key)
  {
    // Derive the key using the supplied salt and the calling address.
    key = _deriveKey(salt, msg.sender);

    // Ensure that the specified owner is a valid ERC721 receiver.
    _validateOwner(owner, key);

    // Ensure that a contract is not currently deployed to the home address.
    require(_isNotDeployed(key), _ACCOUNT_EXISTS);

    // Ensure that the caller is the controller of the derived key.
    HomeAddress storage home = _home[key];
    if (home.exists) {
      require(home.controller == msg.sender, _ONLY_CONTROLLER);
    }

    // Set the exists flag to true and the controller to this contract.
    home.exists = true;
    home.controller = address(this);

    // Mint the ERC721 token to the designated owner.
    _mint(owner, uint256(key));

    // Emit an event signifying that this contract is now the controller. 
    emit NewController(key, address(this));
  }

  /**
   * @notice Transfer control over deployment to the home address corresponding
   * to a given derived key. The caller must be designated as the current
   * controller of the home address - This condition can be checked by calling
   * `getHomeAddressInformation` with the key obtained via `getDerivedKey`.
   * @param salt bytes32 The salt value that is used to derive the key.
   * @param controller address The account that will be granted control of the
   * home address corresponding to the given derived key.
   * @return The derived key.
   * @dev The controller cannot be designated as the address of this contract,
   * the null address, or the home address (the restriction on setting the home
   * address as the controller is due to the fact that the home address will not
   * be able to deploy to itself, as it needs to be empty before a contract can
   * be deployed to it).
   */
  function deriveKeyAndAssignController(bytes32 salt, address controller)
    external
    returns (bytes32 key)
  {
    // Derive the key using the supplied salt and the calling address.
    key = _deriveKey(salt, msg.sender);

    // Prevent the controller from being set to prohibited account values.
    _validateController(controller, key);

    // Ensure that the caller is the controller of the derived key.
    HomeAddress storage home = _home[key];
    if (home.exists) {
      require(home.controller == msg.sender, _ONLY_CONTROLLER);
    }

    // Assign the new controller to the corresponding home address.
    home.exists = true;
    home.controller = controller;

    // Emit an event with the new controller. 
    emit NewController(key, controller);
  }

  /**
   * @notice Transfer control over deployment to the home address corresponding
   * to a given derived key to the null address, which will prevent it from
   * being deployed to again in the future. The caller must be designated as the
   * current controller of the home address - This condition can be checked by
   * calling `getHomeAddressInformation` with the key determined by calling
   * `getDerivedKey`.
   * @param salt bytes32 The salt value that is used to derive the key.
   * @return The derived key.
   */
  function deriveKeyAndRelinquishControl(bytes32 salt)
    external
    returns (bytes32 key)
  {
    // Derive the key using the supplied salt and the calling address.
    key = _deriveKey(salt, msg.sender);

    // Ensure that the caller is the controller of the derived key.
    HomeAddress storage home = _home[key];
    if (home.exists) {
      require(home.controller == msg.sender, _ONLY_CONTROLLER);
    }

    // Assign the null address as the controller of the given derived key.
    home.exists = true;
    home.controller = address(0);

    // Emit an event with the null address as the controller. 
    emit NewController(key, address(0));
  }

  /**
   * @notice Record a key that corresponds to a given home address by supplying
   * said key and using it to derive the address. This enables reverse lookup
   * of a key using only the home address in question. This method may be called
   * by anyone - control of the key is not required.
   * @param key bytes32 The unique value used to derive the home address.
   * @dev This does not set the salt or submitter fields, as those apply only to
   * derived keys (although a derived key may also be set with this method, just
   * without the derived fields).
   */
  function setReverseLookup(bytes32 key) external {
    // Derive home address of given key and set home address and key in mapping.
    _key[_getHomeAddress(key)].key = key;
  }

  /**
   * @notice Record the derived key that corresponds to a given home address by
   * supplying the salt and submitter that were used to derive the key. This
   * facititates reverse lookup of the derivation method of a key using only the
   * home address in question. This method may be called by anyone - control of
   * the derived key is not required.
   * @param salt bytes32 The salt value that is used to derive the key.
   * @param submitter address The account that submits the salt that is used to
   * derive the key.
   */
  function setDerivedReverseLookup(bytes32 salt, address submitter) external {
    // Derive the key using the supplied salt and submitter.
    bytes32 key = _deriveKey(salt, submitter);

    // Derive home address and set it along with all other relevant information.
    _key[_getHomeAddress(key)] = KeyInformation({
      key: key,
      salt: salt,
      submitter: submitter
    });
  }

  /**
   * @notice Deploy a new storage contract with the supplied code as runtime
   * code without deploying a contract to a home address. This can be used to
   * store the contract creation code for use in future deployments of contracts
   * to home addresses.
   * @param codePayload bytes The code to set as the runtime code of the
   * deployed contract.
   * @return The address of the deployed storage contract.
   * @dev Consider placing adequate protections on the storage contract to
   * prevent unwanted callers from modifying or destroying it. Also, if you are
   * placing contract contract creation code into the runtime storage contract,
   * remember to include any constructor parameters as ABI-encoded arguments at
   * the end of the contract creation code, similar to how you would perform a
   * standard deployment.
   */
  function deployRuntimeStorageContract(bytes calldata codePayload)
    external
    returns (address runtimeStorageContract)
  {
    // Ensure that a code payload was supplied.
    require(codePayload.length > 0, "No runtime code payload supplied.");

    // Deploy payload to the runtime storage contract and return the address.
    runtimeStorageContract = _deployRuntimeStorageContract(codePayload);
  }

  /**
   * @notice Deploy a new contract with the initialization code stored in the
   * runtime code at the specified initialization runtime storage contract to
   * the home address corresponding to a given key. Two conditions must be met:
   * the submitter must be designated as the controller of the home address
   * (with the initial controller set to the address corresponding to the first
   * 20 bytes of the key), and there must not be a contract currently deployed
   * at the home address. These conditions can be checked by calling
   * `getHomeAddressInformation` and `isDeployable` with the same key.
   * @param key bytes32 The unique value used to derive the home address.
   * @param initializationRuntimeStorageContract address The storage contract
   * with runtime code equal to the contract creation code that will be used to
   * deploy the contract to the home address.
   * @return The home address and runtime code hash of the deployed contract.
   * @dev When deploying a contract to a home address via this method, the
   * metamorphic initialization code will retrieve whatever initialization code
   * currently resides at the specified address and use it to set up and deploy
   * the desired contract to the home address. Bear in mind that the deployed
   * contract will interpret msg.sender as the address of THIS contract, and not
   * the address of the submitter - if the constructor of the deployed contract
   * uses msg.sender to set up ownership or other variables, you must modify it
   * to accept a constructor argument with the appropriate address, or
   * alternately to hard-code the intended address. Also, if your contract DOES
   * have constructor arguments, remember to include them as ABI-encoded
   * arguments at the end of the initialization code, just as you would when
   * performing a standard deploy. You may also want to provide the key to
   * `setReverseLookup` in order to find it again using only the home address to
   * prevent accidentally losing the key.
   */
  function deployViaExistingRuntimeStorageContract(
    bytes32 key,
    address initializationRuntimeStorageContract
  )
    external
    payable
    onlyEmpty(key)
    onlyControllerDeployer(key)
    returns (address homeAddress, bytes32 runtimeCodeHash)
  {
    // Ensure that the supplied runtime storage contract is not empty.
    _validateRuntimeStorageIsNotEmpty(initializationRuntimeStorageContract);

    // Set initialization runtime storage contract address in contract storage.
    _initializationRuntimeStorageContract = initializationRuntimeStorageContract;

    // Use metamorphic initialization code to deploy contract to home address.
    (homeAddress, runtimeCodeHash) = _deployToHomeAddress(key);
  }

  /**
   * @notice Burn an ERC721 token, set a supplied controller, and deploy a new
   * contract with the initialization code stored in the runtime code at the
   * specified initialization runtime storage contract to the home address
   * corresponding to a given key. The submitter must be designated as either
   * the owner of the token or as an approved spender.
   * @param tokenId uint256 The ID of the ERC721 token to redeem.
   * @param controller address The account that will be granted control of the
   * home address corresponding to the given token.
   * @param initializationRuntimeStorageContract address The storage contract
   * with runtime code equal to the contract creation code that will be used to
   * deploy the contract to the home address.
   * @return The home address and runtime code hash of the deployed contract.
   * @dev When deploying a contract to a home address via this method, the
   * metamorphic initialization code will retrieve whatever initialization code
   * currently resides at the specified address and use it to set up and deploy
   * the desired contract to the home address. Bear in mind that the deployed
   * contract will interpret msg.sender as the address of THIS contract, and not
   * the address of the submitter - if the constructor of the deployed contract
   * uses msg.sender to set up ownership or other variables, you must modify it
   * to accept a constructor argument with the appropriate address, or
   * alternately to hard-code the intended address. Also, if your contract DOES
   * have constructor arguments, remember to include them as ABI-encoded
   * arguments at the end of the initialization code, just as you would when
   * performing a standard deploy. You may also want to provide the key to
   * `setReverseLookup` in order to find it again using only the home address to
   * prevent accidentally losing the key. The controller cannot be designated as
   * the address of this contract, the null address, or the home address (the
   * restriction on setting the home address as the controller is due to the
   * fact that the home address will not be able to deploy to itself, as it
   * needs to be empty before a contract can be deployed to it). Also, checks on
   * the contract at the home address being empty or not having the correct
   * controller are unnecessary, as they are performed when minting the token
   * and cannot be altered until the token is redeemed.
   */
  function redeemAndDeployViaExistingRuntimeStorageContract(
    uint256 tokenId,
    address controller,
    address initializationRuntimeStorageContract
  )
    external
    payable
    onlyTokenOwnerOrApprovedSpender(tokenId)
    returns (address homeAddress, bytes32 runtimeCodeHash)
  {
    // Ensure that the supplied runtime storage contract is not empty.
    _validateRuntimeStorageIsNotEmpty(initializationRuntimeStorageContract);

    // Convert the token ID to a bytes32 key.
    bytes32 key = bytes32(tokenId);

    // Prevent the controller from being set to prohibited account values.
    _validateController(controller, key);

    // Burn the ERC721 token in question.
    _burn(tokenId);

    // Set initialization runtime storage contract address in contract storage.
    _initializationRuntimeStorageContract = initializationRuntimeStorageContract;

    // Set provided controller and increment contract deploy count at once.
    HomeAddress storage home = _home[key];
    home.exists = true;
    home.controller = controller;
    home.deploys += 1;

    // Emit an event with the new controller. 
    emit NewController(key, controller);

    // Use metamorphic initialization code to deploy contract to home address.
    (homeAddress, runtimeCodeHash) = _deployToHomeAddress(key);
  }