pragma solidity >=0.8.0;

// Author:	Louis Holbrook <dev@holbrook.no> 0826EDA1702D1E87C6E2875121D2E7BB88C2A746
// SPDX-License-Identifier:	AGPL-3.0-or-later
// File-version: 4
// Description: Keyed smart contract registry


contract ContractRegistry {
	mapping (bytes32 => address) entries;

	// Implements ERC173
	address public owner;

	// Implements Registry
	bytes32[] public identifier;

	// Implements ERC173
	event OwnershipTransferred(address indexed _previousOwner, address indexed _newOwner);

	// Implements Registry
	event AddressKey(bytes32 indexed _key, address _address);

	constructor(bytes32[] memory _identifiers) {
		owner = msg.sender;
		for (uint i = 0; i < _identifiers.length; i++) {
			identifier.push(_identifiers[i]);
		}
	}

	// Assign address to identifier
	function set(bytes32 _identifier, address _address) public returns (bool) {
		require(msg.sender == owner);
		require(entries[_identifier] == address(0));
		require(_address != address(0));

		bool found = false;
		for (uint i = 0; i < identifier.length; i++) {
			if (identifier[i] == _identifier) {
				found = true;
			}	
		}
		require(found);

		entries[_identifier] = _address;

		emit AddressKey(_identifier, _address);

		return true;
	}

	// Implements EIP 173
	function transferOwnership(address _newOwner) public returns (bool) {
		address _oldOwner;

		require(msg.sender == owner, 'ERR_AXX');
		_oldOwner = owner;
		owner = _newOwner;
		emit OwnershipTransferred(_oldOwner, _newOwner);
		return true;
	}

	// Implements Registry
	function addressOf(bytes32 _identifier) public view returns (address) {
		return entries[_identifier];
	}

	// Implements Registry
	function identifierCount() public view returns(uint256) {
		return identifier.length;
	}

	// Implements ERC165
	function supportsInterface(bytes4 _sum) public pure returns (bool) {
		if (_sum == 0xeffbf671) { // Registry
			return true;
		}
		if (_sum == 0x01ffc9a7) { // ERC165
			return true;
		}
		if (_sum == 0x9493f8b2) { // ERC173
			return true;
		}
		return false;
	}
}