// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

contract Configuration {
  /// @notice Time delay between proposal vote completion and its execution
  uint256 public EXECUTION_DELAY;
  /// @notice Time before a passed proposal is considered expired
  uint256 public EXECUTION_EXPIRATION;
  /// @notice The number of votes in support of a proposal required in order for a quorum to be reached and for a vote to succeed
  uint256 public QUORUM_VOTES;
  /// @notice The number of votes required in order for a voter to become a proposer
  uint256 public PROPOSAL_THRESHOLD;
  /// @notice The delay before voting on a proposal may take place, once proposed
  /// It is needed to prevent reorg attacks that replace the proposal
  uint256 public VOTING_DELAY;
  /// @notice The duration of voting on a proposal
  uint256 public VOTING_PERIOD;
  /// @notice If the outcome of a proposal changes during CLOSING_PERIOD, the vote will be extended by VOTE_EXTEND_TIME (no more than once)
  uint256 public CLOSING_PERIOD;
  /// @notice If the outcome of a proposal changes during CLOSING_PERIOD, the vote will be extended by VOTE_EXTEND_TIME (no more than once)
  uint256 public VOTE_EXTEND_TIME;

  modifier onlySelf() {
    require(msg.sender == address(this), "Governance: unauthorized");
    _;
  }

  function _initializeConfiguration() internal {
    EXECUTION_DELAY = 2 days;
    EXECUTION_EXPIRATION = 3 days;
    QUORUM_VOTES = 25000e18; // 0.25% of TORN
    PROPOSAL_THRESHOLD = 1000e18; // 0.01% of TORN
    VOTING_DELAY = 75 seconds;
    VOTING_PERIOD = 3 days;
    CLOSING_PERIOD = 1 hours;
    VOTE_EXTEND_TIME = 6 hours;
  }

  function setExecutionDelay(uint256 executionDelay) external onlySelf {
    EXECUTION_DELAY = executionDelay;
  }

  function setExecutionExpiration(uint256 executionExpiration) external onlySelf {
    EXECUTION_EXPIRATION = executionExpiration;
  }

  function setQuorumVotes(uint256 quorumVotes) external onlySelf {
    QUORUM_VOTES = quorumVotes;
  }

  function setProposalThreshold(uint256 proposalThreshold) external onlySelf {
    PROPOSAL_THRESHOLD = proposalThreshold;
  }

  function setVotingDelay(uint256 votingDelay) external onlySelf {
    VOTING_DELAY = votingDelay;
  }

  function setVotingPeriod(uint256 votingPeriod) external onlySelf {
    VOTING_PERIOD = votingPeriod;
  }

  function setClosingPeriod(uint256 closingPeriod) external onlySelf {
    CLOSING_PERIOD = closingPeriod;
  }

  function setVoteExtendTime(uint256 voteExtendTime) external onlySelf {
    // VOTE_EXTEND_TIME should be less EXECUTION_DELAY to prevent double voting
    require(voteExtendTime < EXECUTION_DELAY, "Governance: incorrect voteExtendTime");
    VOTE_EXTEND_TIME = voteExtendTime;
  }
}