import { BigNumberish, providers } from 'ethers';
import { isAddress } from 'ethers/lib/utils';
import { DefaultReserveInterestRateStrategy } from './typechain/DefaultReserveInterestRateStrategy';
import { DefaultReserveInterestRateStrategy__factory } from './typechain/DefaultReserveInterestRateStrategy__factory';

export interface ReserveInterestRateStrategyContext {
  reserveStrategy: string;
  provider: providers.Provider;
}

export interface CalculateInterestRatesParams {
  liquidityAdded: BigNumberish;
  liquidityTaken: BigNumberish;
  totalVariableDebt: BigNumberish;
  reserveFactor: BigNumberish;
  reserve: string;
  xToken: string;
}

export interface CalculateInterestRatesResult {
  currentLiquidityRate: string;
  currentVariableBorrowRate: string;
}

export interface DefaultReserveInterestRateStrategyInterface {
  calculateInterestRates(
    params: CalculateInterestRatesParams,
  ): Promise<CalculateInterestRatesResult>;
}

export class ReserveInterestRateStrategy
  implements DefaultReserveInterestRateStrategyInterface
{
  private readonly _contract: DefaultReserveInterestRateStrategy;

  /**
   * Constructor
   * @param context The ReserveInterestRateStrategy context
   */
  public constructor(context: ReserveInterestRateStrategyContext) {
    if (!isAddress(context.reserveStrategy)) {
      throw new Error('contract address is not valid');
    }

    this._contract = DefaultReserveInterestRateStrategy__factory.connect(
      context.reserveStrategy,
      context.provider,
    );
  }

  public async calculateInterestRates(
    params: CalculateInterestRatesParams,
  ): Promise<CalculateInterestRatesResult> {
    const rst = await this._contract.calculateInterestRates({
      liquidityAdded: params.liquidityAdded,
      liquidityTaken: params.liquidityTaken,
      totalVariableDebt: params.totalVariableDebt,
      reserveFactor: params.reserveFactor,
      reserve: params.reserve,
      xToken: params.xToken,
    });
    return {
      currentLiquidityRate: rst[0].toString(),
      currentVariableBorrowRate: rst[1].toString(),
    };
  }
}