Lightning CPQ button for Submit For Approval

Lightning Component:


<aura:component controller="CpqQuoteApprovalController" implements="flexipage:availableForAllPageTypes,force:appHostable,force:lightningQuickActionWithoutHeader,force:hasRecordId">
    <aura:attribute name="requiredValuesNotAvailable" type="boolean" default="true"/>
    <aura:attribute name="displaySecondConfirmation" type="boolean" default="false"/>
    <aura:handler name="init" value="{!this}" action="{!c.doInit}" />
    <aura:attribute name="isSpinner" type="boolean" default="false"/>
    <aura:handler event="aura:waiting" action="{!c.handleShowSpinner}"/>
    <aura:handler event="aura:doneWaiting" action="{!c.handleHideSpinner}"/>
     
    <aura:html tag="style">
        .cuf-content {
        padding: 0 0rem !important;
        }
        .slds-p-around--medium {
        padding: 0rem !important;
        }       
        .slds-modal__content{
        overflow-y:hidden !important;
        height:unset !important;
        max-height:unset !important;
        }
    </aura:html>
    <div class="modal-header slds-modal__header slds-size_1-of-1">
        <h4 class="title slds-text-heading--medium" >Submit For Approval</h4>
    </div>
    
    <!-- MODAL BODY / INPUT FORM -->    
    <div class="slds-modal__content slds-p-around--x-small slds-align_absolute-center slds-size_1-of-1 slds-is-relative" aura:id="modalbody" id="modalbody">
        <aura:if isTrue="{!!v.displaySecondConfirmation}">
            <center>
                <b>Do you want to submit quote for approval?<br/>
                    Once submitted for approval Quote will be locked.</b>
            </center>
        </aura:if>
        <aura:if isTrue="{!v.displaySecondConfirmation}">
            <center>
                <b>Please provide Quote Name and Discount Justification before Submitting for Approval</b>
            </center>
        </aura:if>
    </div>
    <!-- End of Modal Content -->  
    <!-- MODAL FOOTER -->
    <div class="modal-footer slds-modal__footer slds-size_1-of-1">
        <aura:if isTrue="{!!v.displaySecondConfirmation}">
            <div class="forceChangeRecordTypeFooter">
                <ui:button class="slds-button slds-button_neutral" disabled="{!v.isSpinner}" label="Cancel" press="{!c.cancel}" /> 
                <ui:button class="slds-button slds-button--brand" disabled="{!v.isSpinner}" label="{!v.isSpinner == true ? 'Ok...' : 'Ok'}" press="{!c.proceedToSubmit}"/>
            </div>

        </aura:if>
        <aura:if isTrue="{!v.displaySecondConfirmation}">
            <ui:button class="slds-button slds-button--brand" label="Ok" press="{!c.cancel}" />
        </aura:if>
    </div>

</aura:component>


Lightning JS Controller:

({
    doInit: function(component, event, helper) {
        var action = component.get("c.checkForRequiredFields");
        action.setParams({"recordId" : component.get("v.recordId")});
        action.setCallback(this, function(response) {
            var state = response.getState();
            if (state === "SUCCESS") {
                console.log(response.getReturnValue());
                component.set("v.requiredValuesNotAvailable", response.getReturnValue());
            }
            else if (state === "ERROR") {
                var errors = response.getError();
                if (errors) {
                    if (errors[0] && errors[0].message) {
                        console.log("Error message: " +
                                    errors[0].message);
                    }
                }
            }
                else {
                    console.log("Unknown error");
                }
        });
        $A.enqueueAction(action);
    },
    cancel: function(component, event, helper) {
        $A.get("e.force:closeQuickAction").fire();
    },
    proceedToSubmit: function(component, event, helper) {
        var requiredValuesNotAvailable = component.get("v.requiredValuesNotAvailable");
   
        if(requiredValuesNotAvailable){
            component.set('v.displaySecondConfirmation', true);
        }
        else{
            var action = component.get("c.onSubmit");
            action.setParams({"quoteId" : component.get("v.recordId")});
            action.setCallback(this, function(response) {
                var state = response.getState();
                if (state === "SUCCESS") {
                    console.log(response.getReturnValue());
                    $A.get('e.force:refreshView').fire();
                    $A.get("e.force:closeQuickAction").fire();
                }
                else if (state === "ERROR") {
                    var errors = response.getError();
                    if (errors) {
                        if (errors[0] && errors[0].message) {
                            console.log("Error message: " +
                                        errors[0].message);
                        }
                    }
                }
                    else {
                        console.log("Unknown error");
                    }
            });
            $A.enqueueAction(action);
         
        }
    },

     //Call by aura:waiting event
    handleShowSpinner: function(component, event, helper) {
        component.set("v.isSpinner", true);
    },
   
    //Call by aura:doneWaiting event
    handleHideSpinner : function(component,event,helper){
        component.set("v.isSpinner", false);
    }
})

Apex Controller:

public class CpqQuoteApprovalController {
    @AuraEnabled
    public static boolean checkForRequiredFields(String recordId) {
        Boolean requiredFieldsNotAvailable = false;
        List<SBQQ__Quote__c> qt = [SELECT Id, SBQQ__Type__c, Quote_Name__c, Discount_Justification__c FROM SBQQ__Quote__c Where Id =: recordId];
        if((qt[0].SBQQ__Type__c == 'Amendment') && ((qt[0].Quote_Name__c == null) || (qt[0].Discount_Justification__c == null))){
            requiredFieldsNotAvailable = true;
        }
        return requiredFieldsNotAvailable;
    }
/*
* This method will call submit approval method
*/
    @AuraEnabled
    public static void onSubmit(String quoteId) {
        if (quoteId != null) {
            SBAA.ApprovalAPI.submit(quoteId, SBAA__Approval__c.Quote__c);
        }
    }
}