Formulas and Definitions

IMR i = Max(1 / Max Account Leverage, Base IMR i, IMR Factor i * Abs(Position Notional i)^(4/5))
initial_margin_i = abs (position_notional_i * IMR_i)
weighted_initial_margin_ratio_i =  abs (position_notional_i / total_notional ) * IMR_i
initial_margin_ratio = sum (weighted_initial_margin_ratio_i)

MMR i = Max(Base MMR i, (Base MMR i / Base IMR i) * IMR Factor i * Abs(Position Notional i)^(4/5))
maintenance_margin_i= abs (position_notional_i * MMR_i)
weighted_maintenance_margin_ratio_i = abs (position_notional_i / total_notional ) * MMR_i
maintenance_margin_ratio = sum (weighted_maintenance_margin_ratio_i)

Qi = position_qty

liquidation_price  = max[( Mark Price + ( total_collateral_value - total_notional * MMR ) / ( |Qi| * MMRi - Qi )), 0]

/**
 * Consolidated Risk Management Logic
 * Use this to verify account health before and after placing orders.
 */

function calculateAccountHealth(accountInfo, positions, marketConfig) {
  let totalNotional = 0;
  let totalInitialMargin = 0;
  let totalMaintenanceMargin = 0;
  let totalUpnl = 0;

  for (const pos of positions) {
    const notional = Math.abs(pos.qty * pos.markPrice);
    const imr = calculateDynamicRatio(
      pos.baseImr,
      pos.imrFactor,
      notional,
      accountInfo.maxLeverage
    );
    const mmr = calculateDynamicRatio(
      pos.baseMmr,
      (pos.baseMmr / pos.baseImr) * pos.imrFactor,
      notional
    );

    totalNotional += notional;
    totalInitialMargin += notional * imr;
    totalMaintenanceMargin += notional * mmr;
    totalUpnl += pos.unrealizedPnl;
  }

  const totalCollateral = accountInfo.walletBalance + totalUpnl;
  const currentMarginRatio = totalNotional > 0 ? totalCollateral / totalNotional : Infinity;

  return {
    isLiquidatable: currentMarginRatio < totalMaintenanceMargin / totalNotional,
    canOpenNewPosition: totalCollateral > totalInitialMargin,
    withdrawable: Math.max(
      0,
      accountInfo.walletBalance - totalInitialMargin - Math.max(0, totalUpnl)
    ),
    liquidationPrice: calculateLiquidationPrice(
      totalCollateral,
      totalNotional,
      totalMaintenanceMargin
    )
  };
}

function calculateDynamicRatio(baseRatio, factor, notional, maxLeverage = null) {
  const cap = maxLeverage ? 1 / maxLeverage : 0;
  return Math.max(cap, baseRatio, factor * Math.pow(notional, 0.8));
}

newOrderSize  = (total_collateral_value - others_IM) * min(1/Base_IMR_i,maxLeverage_account) / markPrice

IMR i = Max(1 / Max Account Leverage, Base_IMR_i, IMR Factor i * Abs(Position Notional i)^(4/5))

MMR i = Max(Base MMR i, (Base MMR i / Base IMR i) * IMR Factor i * Abs(Position Notional i)^(4/5))

aftertrade_IMR.i → Max(1 / Max Account Leverage, Base_IMR_i, IMR Factor i * Abs(After Trade Position Notional i)^(4/5))

If total_collateral_value < total_initial_margin_with_orders
    if (side == buy && position_qty >=0 ) or (side == sell && position_qty < 0)
        return 0
    else
        if side == buy
            return max( abs(position_qty) - pending_long_qty, 0 )
        else
            return max( position_qty + pending_short_qty, 0 )
else
    newOrderSize = (total_collateral_value - others_IM) * min(1/Base_IMR_i,maxLeverage_account) / markPrice
    calculate afterTradeIM
    newTotalIM = othersIM + afterTradeIM
    if side = buy
        others = -holding - pendingLongQty
    else
        others = holding + pendingShortQty

    if totalCollatValue >= newTotalIM
        return max(0, newOrderSize * 99.5% + others)
    else
        newOrderSize_iter = ITERATE()
        return max(0, newOrderSize_iter * 99.5% + others)

with :
total_collateral_value = total_balance + upnl + pending_short_USDC
total_initial_margin_with_orders =  sum (position_notional_with_orders_i * IMR_i (with_orders))
position_qty_with_orders_i = max[abs(position_qty + sum_position_qty_buy_orders),abs(pos_qty + sum_position_qty_sell_orders)]
position_notional_with_orders_i = abs(mark_price_i * position_qty_with_orders_i)
others_IM = sum[i#j)(initial_margin_with_orders_i) (where j represents the pair i on which the order is being placed)

Qi = position_qty + order_qty

liquidation_price  = max( Mark Price + ( total_collateral_value - total_notional_with_order * MMR_with_order ) / ( |Qi| * MMR_with_order_i - Qi )), 0)