Salesforce Apex Trigger data copy from one field to other - triggers

Question

This is my Apex Trigger in which I am taking data from Custom Field "Picklist Multiple" named(Opportunity_Picklist__c) in Opportunity and automatically paste it to a custom field "text" in Account. Now every selected option from Custom Field "Picklist Multiple" is coming to the custom field "text". I want to copy only Custom Field "Picklist Multiple" values with API Name "Premium" and "Basic". Other selected values can be avoided. Please look into the code below and suggest me relatable changes.
Custom Field "Picklist Multiple" have these data:-
Premium
Advanced
Basic
Free
If someone selected all four values in Custom Field "Picklist Multiple" they can remain as it is but I don't want all of them to be copied in custom field "text". I want the values with API Names "Premium" and "Basic" only in the custom field "text".
trigger OppTrigger on Opportunity (After insert,After update,After delete) {
if((Trigger.isInsert|| Trigger.isupdate|| Trigger.isDelete) && Trigger.isAfter)
{
Set<Id> acctSet = new Set<Id>();
List<Account> accList = new List<Account>();
for(Opportunity opp : Trigger.new)
{
acctSet.add(opp.AccountId);
}
Map<Id, Account> mapAccounts = new Map<Id, Account>([SELECT Id, Plan__c FROM Account where Id IN :acctSet]);
for(Opportunity opp : Trigger.new)
{
Account acc = mapAccounts.get(opp.AccountId);
If(Trigger.IsDelete){
acc.Plan__c = null;
}
if(Trigger.isInsert|| Trigger.isupdate){
acc.Plan__c = opp.Opportunity_Picklist__c;
}
accList.add(acc);
}
Update accList;
}
}

Answer 1

You'll be better off cutting it up a bit. Use a helper class as trigger handler. Will let you create some reusable functions rather than just a giant block of code executing top-down. There's this for general reading, I like that one but there are lots of examples, what you'll be comfortable with.
For example imagine a method called static void rollupToAccounts(Set<Id> ids). It'd accept account ids and you could call it from different scenarios (because you'll have different entry points. Insert is easy, base it on trigger.new, cool. Delete is funnier because there's no trigger.new, you need to get Account Ids out of trigger.old And after update if I move opportunity from Account A to B - your code should recalculate both! Good luck writing straight in the trigger's body.
As for actual "meat" of the method... many ways to do it, something like this?
static void rollupToAccounts(Set<Id> ids){
final Set<String> valuesToRollup = new Set<String>{'Premium', 'Basic'};
List<Account> toUpdate = new List<Account>();
List<Account> accounts = [SELECT Id, Plan__c,
(SELECT Opportunity_Picklist__c
FROM Opportunities
WHERE Opportunity_Picklist__c INCLUDES :valuesToRollup)
FROM Account WHERE Id IN :ids];
for(Account a : accounts){
Set<String> currentValues new Set<String>();
if(String.isNotBlank(a.Plan__c)){
currentValues.addAll(a.Plan__c.split(';'));
}
Set<String> newValues = new Set<String>();
if(!a.Opportunities.isEmpty()){
for(Opportunity o : a.Opportunities){
newValues.addAll(o.Opportunity_Picklist__c.split(';')); // this will include Advanced & Free too, it's ok, we'll fix it
}
newValues.retainAll(valuesToRollup); // filter out all the ones we don't want
}
System.debug('old: ' + currentValues + '; new: ' + newValues);
if(currentValues != newValues){
// we'll need to update this account with current data
List<String> temp = new List<String>(currentValues);
temp.sort();
a.Plan__c = String.join(temp, ';');
toUpdate.add(a);
}
}
System.debug(toUpdate);
update toUpdate;
}
It's not perfect. If you have 100 opportunities for same account with "Basic" it'll take them all and possibly waste query rows. You could do it as 2 (sub)queries, WHERE Opportunity_Picklist__c INCLUDES ('Basic') LIMIT 1 and then another query for Premium if you think it'd be a problem..

Answer 2

Why not just check the value of the opportunity picklist before saving it into the account value? You could write this code a little cleaner and more efficient. However, a simple solution is just to check if the values you want exist.
if(Trigger.isInsert|| Trigger.isupdate){
String strAccountPlan;
if(opp.Opportunity__PickList__c.Contains('Premium'){
strAccountPlan = 'Premium';
}
if(opp.Opportunity__PickList__c.Containt('Basic'){
if(String.isBlank(strAccountPlan){
strAccountPlan = 'Basic');
}
else{
strAccountPlan += ';Basic';
}
acc.Plan__c = strAccountPlan;
}