// SPDX-License-Identifier: MIT

pragma solidity 0.7.6;
pragma abicoder v2;

import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";

import "./interfaces/IInstanceRegistry.sol";
import "./interfaces/IInstanceFactory.sol";

struct InstanceAdditionData {
  address tokenAddress;
  uint40 smallDenomination;
  uint16 base10Exponent;
  uint24 uniPoolSwappingFee;
  uint16 protocolFee;
}

contract InstanceAdditionDataProvider {
  InstanceAdditionData[] public toAddData;

  constructor(InstanceAdditionData[] memory _toAdd) {
    for (uint256 i = 0; i < _toAdd.length; i++) {
      toAddData.push(_toAdd[i]);
    }
  }

  function getAllDataToAdd() external view returns (InstanceAdditionData[] memory) {
    return toAddData;
  }
}

contract InstanceAdditionProposal {
  using SafeMath for uint256;

  InstanceAdditionDataProvider public immutable provider;
  IInstanceFactory public immutable instanceFactory;
  IInstanceRegistry public immutable instanceRegistry;

  event AddInstanceForRegistry(address instance, address token, uint256 denomination);

  constructor(address _instanceFactory, address _instanceRegistry, InstanceAdditionData[] memory _toAdd) {
    provider = new InstanceAdditionDataProvider(_toAdd);
    instanceFactory = IInstanceFactory(_instanceFactory);
    instanceRegistry = IInstanceRegistry(_instanceRegistry);
  }

  function executeProposal() external {
    InstanceAdditionData[] memory _toAddData = provider.getAllDataToAdd();

    uint256 howMany = _toAddData.length;

    for (uint256 i = 0; i < howMany; i++) {
      // Read out the data for the new instance
      InstanceAdditionData memory data = _toAddData[i];

      // Safely calculate the denomination
      uint256 denomination = uint256(data.smallDenomination).mul(10 ** uint256(data.base10Exponent));

      // Create the instance
      address instance = instanceFactory.createInstanceClone(denomination, data.tokenAddress);

      // Prepare the data for the registry.
      IInstanceRegistry.Instance memory newInstanceData = IInstanceRegistry.Instance(
        data.tokenAddress != address(0),
        IERC20(data.tokenAddress),
        IInstanceRegistry.InstanceState.ENABLED,
        data.uniPoolSwappingFee,
        data.protocolFee
      );

      // Convert the data.
      IInstanceRegistry.Tornado memory tornadoForUpdate = IInstanceRegistry.Tornado(instance, newInstanceData);

      // Update the instance data in the registry.
      instanceRegistry.updateInstance(tornadoForUpdate);

      emit AddInstanceForRegistry(address(instance), data.tokenAddress, denomination);
    }
  }

  function getDataToAddByIndex(uint256 index) external view returns (InstanceAdditionData memory data) {
    // The compiler is behaving weird here. Something to do with struct type inference.
    return (provider.getAllDataToAdd())[index];
  }

  function getAllDataToAdd() external view returns (InstanceAdditionData[] memory) {
    return provider.getAllDataToAdd();
  }
}