swapCallParameters static method

SwapParameters swapCallParameters(Trade trade, TradeOptions options)

Cannot be constructed. Produces the on-chain method name to call and the hex encoded parameters to pass as arguments for a given trade. @param trade to produce call parameters for @param options options for the call parameters

Implementation

// Router._() {}

/// Produces the on-chain method name to call and the hex encoded parameters to pass as arguments for a given trade.
/// @param trade to produce call parameters for
/// @param options options for the call parameters
static SwapParameters swapCallParameters(Trade trade, TradeOptions options) {
  bool etherIn = false;
  bool etherOut = false;
  if(trade.inputAmount.currency is Token){
    etherIn = trade.inputAmount.currency == Token.WETH[ChainId.MAINNET.value]!;
  }else{
    etherIn = trade.inputAmount.currency == ETHER;
  }

  if(trade.outputAmount.currency is Token){
    etherOut = trade.outputAmount.currency == Token.WETH[ChainId.MAINNET.value]!;
  }else{
    etherOut = trade.outputAmount.currency == ETHER;
  }
  // the router does not support both ether in and out
  invariant(!(etherIn && etherOut), 'ETHER_IN_OUT');
  invariant(options.ttl > 0, 'TTL');

  final dateTimeNow = DateTime.now();

  final to = validateAndParseAddress(options.recipient);
  String amountIn = toHex(trade.maximumAmountIn(options.allowedSlippage));
  String amountOut = toHex(trade.minimumAmountOut(options.allowedSlippage));
  List<String> path = trade.route.path.map((token) => token.address.toString()).toList();
  final deadline =
      '0x${BigInt.from((dateTimeNow.millisecondsSinceEpoch / 1000).floor() + options.ttl).toRadixString(16)}';
  final useFeeOnTransfer = options.feeOnTransfer ?? false;

  String methodName;
  List<dynamic> args;
  String value;
  switch (trade.tradeType) {
    case TradeType.EXACT_INPUT:
      if (etherIn) {
        methodName = useFeeOnTransfer
            ? 'swapExactETHForTokensSupportingFeeOnTransferTokens'
            : 'swapExactETHForTokens';
        // (uint amountOutMin, address[] calldata path, address to, uint deadline)
        args = [amountOut, path, to.toString(), deadline];
        value = amountIn;
      } else if (etherOut) {
        methodName = useFeeOnTransfer
            ? 'swapExactTokensForETHSupportingFeeOnTransferTokens'
            : 'swapExactTokensForETH';
        // (uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        args = [
          amountIn,
          amountOut,
          path,
          to.toString(),
          deadline
        ];
        value = ZERO_HEX;
      } else {
        methodName = useFeeOnTransfer
            ? 'swapExactTokensForTokensSupportingFeeOnTransferTokens'
            : 'swapExactTokensForTokens';
        // (uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        args = [
          amountIn,
          amountOut,
          path,
          to.toString(),
          deadline
        ];
        value = ZERO_HEX;
      }
      break;
    case TradeType.EXACT_OUTPUT:
      invariant(!useFeeOnTransfer, 'EXACT_OUT_FOT');
      if (etherIn) {
        methodName = 'swapETHForExactTokens';
        // (uint amountOut, address[] calldata path, address to, uint deadline)
        args = [amountOut, path, to.toString(), deadline];
        value = amountIn;
      } else if (etherOut) {
        methodName = 'swapTokensForExactETH';
        // (uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        args = [
          amountOut,
          amountIn,
          path,
          to.toString(),
          deadline
        ];
        value = ZERO_HEX;
      } else {
        methodName = 'swapTokensForExactTokens';
        // (uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        args = [
          amountOut,
          amountIn,
          path,
          to.toString(),
          deadline
        ];
        value = ZERO_HEX;
      }
      break;
  }
  return SwapParameters(methodName: methodName, args: args, value: value);
}