Scenario: This scenario expects Case owner assignment depending on certain criteria. Whenever a case is created then it should check related Account Teams and according below criteria that account team member should be the owner of that Case.

• If Case Origin is Phone then owner will be the account team member having Role “Sales Rep”
• If Case Origin is Email then owner will be the account team member having Role “Channel Manager”
• If Case Origin is Web then owner will be the account team member having Role “Account Manager”

/*
Scenario: This scenario expects Case owner assignment depending on certain criteria. Whenever a case is created then it should check related Account Teams and according below criteria that account team member should be the owner of that Case.
If Case Origin is Phone then owner will be the account team member having Role "Sales Rep"
If Case Origin is Email then owner will be the account team member having Role "Channel Manager"
If Case Origin is Web then owner will be the account team member having Role "Account Manager"
 */
trigger caseTrigger on Case (Before Insert) {
    Map<Id, Id> mapCaseIdAccId = new Map<Id, Id>();
    
    Map<Id, List<AccountTeamMember>> mapAccIdTeamRole = new Map<Id, List<AccountTeamMember>>();
    List<AccountTeamMember> lstATM = new List<AccountTeamMember>();
    if(Trigger.isBefore){
        if(Trigger.isInsert){
            for(Case cs:Trigger.New){
                mapCaseIdAccId.put(cs.Id,cs.AccountId);
            }
            
            for(AccountTeamMember atm:[SELECT Id,AccountId,TeamMemberRole, UserId 
                                        FROM AccountTeamMember 
                                        WHERE AccountId IN:mapCaseIdAccId.values()]){
                                            if(mapAccIdTeamRole.get(atm.AccountId)==null){
                                                lstATM = new List<AccountTeamMember>();
                                                lstATM.add(atm);
                                                mapAccIdTeamRole.put(atm.AccountId,lstATM);
                                            }else{
                                                mapAccIdTeamRole.get(atm.AccountId).add(atm);
                                            }
            }
            
            for(Case cs:Trigger.New){
                for(AccountTeamMember atm:mapAccIdTeamRole.get(cs.AccountId)){
                    if(cs.origin=='Phone' && atm.TeamMemberRole=='Sales Rep'){
                        cs.OwnerId = atm.UserId;
                    }
                    if(cs.origin=='Email' && atm.TeamMemberRole=='Channel Manager'){
                        cs.OwnerId = atm.UserId;
                    }
                    if(cs.origin=='Web' && atm.TeamMemberRole=='Account Manager'){
                        cs.OwnerId = atm.UserId;
                    }
                }
            }
        }
    }
}