import {Contract} from 'ethers';
import {MockProvider} from '@ethereum-waffle/provider';
import {ProviderWithHistoryExpected} from './error';
import {ensure} from './utils';

export function validateContract(contract: any): asserts contract is Contract {
  const possiblyContract = contract as Contract;
  ensure(
    !!possiblyContract.address && !!possiblyContract.functions && !!possiblyContract.interface, TypeError,
    'argument must be a contract'
  );
}

export function validateMockProvider(provider: any): asserts provider is MockProvider {
  ensure(
    (!!provider.callHistory && provider.callHistory instanceof Array), ProviderWithHistoryExpected
  );
}

export function validateFnName(fnName: any, contract: Contract): asserts fnName is string {
  ensure(
    typeof fnName === 'string', TypeError,
    'function name must be a string'
  );
  function isFunction(name: string) {
    try {
      return !!contract.interface.getFunction(name);
    } catch (e) {
      return false;
    }
  }
  ensure(
    isFunction(fnName), TypeError,
    'function must exist in provided contract'
  );
}