Hi, Can some one please help me on creating lightning button and class for this below Java script button.

Thanks in advance.

{!requireScript("/soap/ajax/18.0/connection.js")} 
{!requireScript("/soap/ajax/18.0/apex.js")} 
{!requireScript("/js/functions.js")} 


Opportunity = new sforce.SObject("Opportunity"); 

// Populate the ID and the fields we're updating. 
Opportunity["Id"] = "{!Opportunity.Id}"; 

// Get the related account name 
var accId = "{!Opportunity.AccountId}"; 
var oppProducer = "{!Opportunity.Producer__c}"; 
var oppResource = "{!Opportunity.Resouce__c}"; 
var oppDept = "{!Opportunity.Department__c}"; 
var oppCat1 = "{!Opportunity.Cat1__c}"; 
var oppCat2 = "{!Opportunity.Cat2__c}"; 
var oppOppType = "{!Opportunity.Business_Unit__c}"; 
var oppOffice = "{!Opportunity.Office__c}"; 
var oppSentToSagita = "{!Opportunity.Send_To_Sagitta__c }"; 
var oppStatus = "{!Opportunity.Approval_Status__c}"; 

function validateopp() { 

var query = "Select Name, Sic, BillingStreet, BillingCity, BillingState from account where id = '" + accId + "'"; 
result = sforce.connection.query(query); 
records = result.getArray("records"); 
// alert("Account name:" + records[0]); 

var errT = "The following information must be completed before sending an account to Sagitta: "; 
var errAdditional=""; 

if ((records[0]).Name == null || (records[0]).Name == "") { 
errAdditional += "Account Name, "; 
} 
if (oppProducer == null || oppProducer == "") { 
errAdditional += "Producer, "; 
} 
if ((records[0]).BillingStreet == null || (records[0]).BillingStreet == "") { 
errAdditional += "Primary Street, "; 
} 
if ((records[0]).BillingCity == null || (records[0]).BillingCity == "") { 
errAdditional += "City, "; 
} 
if ((records[0]).BillingState == null || (records[0]).BillingState == "") { 
errAdditional += "State, "; 
} 
if ((records[0]).Sic == null || (records[0]).Sic == "") { 
errAdditional += "SIC Code, "; 
} 
if (oppResource == null || oppResource == "") { 
errAdditional += "Resource Assignment, "; 
} 
if (oppOppType == "Employee Benefits Services"){ 
if (oppCat2 == null || oppCat2 == "") { 
errAdditional += "CAT2, "; 
} 
} 
else{ 
if (oppCat1 == null || oppCat1 == "") { 
errAdditional += "CAT1, "; 
} 
} 
if (oppOffice == null || oppOffice == "") { 
errAdditional += "Office, "; 
} 
if (oppDept == null || oppDept == "") { 
errAdditional += "Department"; 
} 

if (errAdditional == "" && oppStatus=="Approved") { 
updateopp(); 
alert('Account successfully sent to Sagitta'); 
}else{ 
if (oppStatus!="Approved") { 
alert('Opportunity cannot be sent to Sagitta since it is currently not approved'); 
}else{ 
errT += errAdditional; 
alert(errT); 
} 
} 
} 

function updateopp(){ 
Opportunity["Send_To_Sagitta__c"] = "true"; 

// Try to update the object. 
saveResults = sforce.connection.update([Opportunity]); 
if(saveResults[0].errors != null) 
alert(saveResults[0].errors.message); 

// Refresh the page. 
window.top.location.href = window.top.location.href; 
} 

try{ 
if (oppSentToSagita == "true") { 
alert('Account is already in Sagitta. Thanks.'); 
}else{ 
validateopp(); 
} 
} 

catch(Exception){ 
// alert("Error: "+Exception); 
}