protected function calculate()
{
$this->sip_exit_fee_rate = ParamUtils::getExitSipFreeRate($this->sip_months);
$this->sell_fee_discount_rate = ParamUtils::getSaleFeeDiscountRate($this->purchase_type);
$saleFeeRate = ParamUtils::getSaleFeeRate($this->kept_months);
$this->sell_fee_rate = ($saleFeeRate + $this->sip_exit_fee_rate) * (1 - $this->sell_fee_discount_rate / 100);
$this->sell_fee = $this->sell_fee_rate * $this->revenue / 100;
$this->profit_before_taxes = $this->revenue - $this->sell_fee;
$this->income_tax = $this->profit_before_taxes * $this->income_tax_rate / 100;
$this->profit_after_taxes = $this->profit_before_taxes - $this->income_tax;
$this->investment_result = $this->profit_after_taxes - $this->investment;
}
