// SPDX-License-Identifier: GPL-2.0-or-later

pragma solidity >=0.8.0;

import '../interfaces/ICandidateRegistry.sol';

/// @dev Candidate registry contract
/// @author Alexandas
contract CandidateRegistry is ICandidateRegistry {

	mapping(address => Types.CandidateInfo) internal candidates;

	/// @dev return a candidate address for a specific node manifest
	mapping(string => address) public override manifestMap;

	/// @dev register a candidate with node manifest
	/// @param manifest node manifest
	function register(string memory manifest) external override {
		_register(msg.sender, manifest);
	}

	function _register(address candidate, string memory manifest) internal {
		require(candidates[candidate].grade == Types.Grade.Null, 'CandidateRegistry: candidate exists');
		require(manifestMap[manifest] == address(0), 'CandidateRegistry: manifest exists');
		manifestMap[manifest] = candidate;
		candidates[candidate].grade = Types.Grade.Secondary;
		candidates[candidate].manifest = manifest;
		emit Register(candidate);
	}

	/// @dev return a candidate
	/// @param candidate candidate address
	/// @return candidate information
	function candidateInfo(address candidate) public view override returns (Types.CandidateInfo memory) {
		return candidates[candidate];
	}

	/// @dev return whether a candidate is registered
	/// @param candidate candidate address
	/// @return whether the candidate is registered
	function isCandidateRegistered(address candidate) public view override returns (bool) {
		return candidates[candidate].grade != Types.Grade.Null;
	}

	/// @dev return grade of a candidate
	/// @param candidate candidate address
	/// @return candidate grade
	function gradeOf(address candidate) public view override returns (Types.Grade) {
		return candidates[candidate].grade;
	}

}