SalesForce/Java Attach a File to an Email - salesforce

Question

I am trying to attach a file/attachment related to a Document__c object and am stuck. I can get the email to send without any errors but there is no file/attachment attached to the email for some reason.
Below is the code that I am using, the commented out pieces are other variations that I've tried but also haven't worked, sorry if it's a bit messy there's a lot of commented out code. Also "" represents a line break and the continued line also starts with a "\ "Thanks for the help!
global class NOAemail {
#InvocableMethod (Label='NOA Email'
Description='Sends the NOA email to the specified client')
public static void SingleMail(List<flowinput> info) {
// Create an email message object
//List<Document__c> NOAdoc = [SELECT Id FROM Document__c WHERE Id=:info[0].NOAdocId];
Messaging.SingleEmailMessage mail = new Messaging.SingleEmailMessage();
String[] sendingTo = new String[]{info[0].address};
mail.setToAddresses(sendingTo);
mail.setSubject(info[0].subject);
mail.setPlainTextBody(info[0].body);
SObject[] queryParentObject = [SELECT Id, (SELECT Id, Name FROM Attachments) FROM\
\ Document__c WHERE Id = :info[0].NOAdocId];
for (SObject parentRecord : queryParentObject){
Object ParentFieldValue1 = parentRecord.get('Id');
//Object ParentFieldValue2 = parentRecord.get('CaseNumber');
//Object ParentFieldValue3 = parentRecord.get('Status');
// Prevent a null relationship from being accessed
SObject[] childRecordsFromParent = parentRecord.getSObjects('Attachments');
if (childRecordsFromParent != null) {
for (SObject childRecord : childRecordsFromParent){
//Object childFieldId = childRecord.get('Id');
String idString = (String)childRecord.get('Id');
//List<String> childFieldId = childRecord.get('Id');
//Object ChildFieldValue2 = childRecord.get('Name');
List<String> attachId = new List<String>();
attachId.add(idString);
mail.setEntityAttachments(attachId);
}
}
}
//mail.setEntityAttachments(childFieldId);
/*
List<Document__c> docs = [SELECT Id, (SELECT Id FROM Attachments) FROM Document__c WHERE\
\ Id = :info[0].NOAdocId];
if (!docs.isEmpty()) {
//Set<Id> attachmentIds = (new Map<Id, Document__c>(docs)).keySet();
//Set<Id> attachmentIds = new Set<Id>();
//attachmentIds.add(docs[0][0]);
Set<Id> attachmentIds = (new Map<Id, SObject>(docs)).keyset();
List<Attachment> files = [SELECT Name, Body, ContentType FROM Attachment WHERE Id IN\
\ :attachmentIds];
}
List<Messaging.EmailFileAttachment> attachments = new\
\ List<Messaging.EmailFileAttachment();
for (Attachment file: files) {
Messaging.EmailFileAttachment efa = new Messaging.EmailFileAttachment();
efa.setFileName(file.Name);
efa.setBody(file.Body);
efa.setContentType(file.ContentType);
attachments.add(efa);
}
mail.setFileAttachments(attachments);
*/
/*
List<id> ContentDocumentIds = new List<id>();
for(contentDocumentLink CDLink : [SELECT LinkedEntityId, ContentDocumentId FROM\
\ ContentDocumentLink WHERE LinkedEntityId=:info[0].NOAdocId])
{
ContentDocumentIds.add(CDLink.ContentDocumentId);
}
for ( ContentVersion cversion : [SELECT Title,
PathOnClient, FileType,
versiondata
FROM contentversion
WHERE ContentDocumentId IN\
\ :ContentDocumentIds
AND Title LIKE 'WOCF%'])
{
blob WOCFbody = cversion.versiondata;
system.debug('body : '+WOCFbody+'-----------'+cversion.title);
Messaging.EmailFileAttachment efa = new Messaging.EmailFileAttachment();
efa.setFileName('NOA Doc'+'-'+cversion.title+'.'+cversion.FileType);
efa.setBody(WOCFbody);
mail.fileAttachments.add(efa);
}
*/
/*
List<String> contentVersionIds = new List<String>();
for(ContentDocumentLink thisCdl : [SELECT ContentDocument.LatestPublishedVersionId FROM\
\ ContentDocumentLink WHERE ContentDocumentId = :info[0].NOAdocId]) {
contentVersionIds.add(thisCdl.ContentDocument.LatestPublishedVersionId);
}
mail.setEntityAttachments(contentVersionIds);
*/
//SingleEmailMessage.setEntityAttachments(NOAdoc);
//message sending
Messaging.sendEmail(new Messaging.SingleEmailMessage[] {mail});
}
global class flowInput {
#InvocableVariable
global String address;
#InvocableVariable
global String subject;
#InvocableVariable
global String body;
#InvocableVariable
global String NOAdocId;
//#InvocableVariable
//global String OppAccountId;
}
}
The commented out code in the code block is all code I have tried, along with the first block of code under the mail.setPlainTextBody(info[0].body); line.