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trigger autoCreateTaskWhenStageChanged on Opportunity (before insert, before update) {
    List<Task> tasks = new List<Task>();
    
    for (Opportunity opp : Trigger.new) {
        Id managerId = [SELECT Id, ManagerId FROM User WHERE Id = :opp.OwnerId].ManagerId;
        
        if (Trigger.newMap.get(opp.Id).Stage_Seq__c == 1) {
            Task newTask1 = new Task();
            newTask1.subject = 'Automated Task 1 - Stage 1';
            newTask1.whatId = opp.Id;
            newTask1.ownerId = opp.OwnerId;
            newTask1.status = 'In Progress';
            newTask1.Priority = 'Normal';
            tasks.add(newTask1);
            
            Task newTask2 = new Task();
            newTask2.subject = 'Automated Task 2 - Stage 1';
            newTask2.whatId = opp.Id;
            newTask2.ownerId = managerId != null ? managerId : opp.OwnerId;
            newTask2.status = 'In Progress';
            newTask2.Priority = 'Normal';
            tasks.add(newTask2);
        }
        else if (Trigger.newMap.get(opp.Id).Stage_Seq__c == 2) {
            Task newTask1 = new Task();
            newTask1.subject = 'Automated Task 1 - Stage 2';
            newTask1.whatId = opp.Id;
            newTask1.ownerId = opp.OwnerId;
            newTask1.status = 'In Progress';
            newTask1.Priority = 'Normal';
            tasks.add(newTask1);
        }
        else if (Trigger.newMap.get(opp.Id).Stage_Seq__c == 2) {
            Task newTask1 = new Task();
            newTask1.subject = 'Automated Task 1 - Stage 3';
            newTask1.whatId = opp.Id;
            newTask1.ownerId = opp.OwnerId;
            newTask1.status = 'In Progress';
            newTask1.Priority = 'Normal';
            tasks.add(newTask1);
        }
        else if (Trigger.newMap.get(opp.Id).Stage_Seq__c == 10) {
            Task newTask1 = new Task();
            newTask1.subject = 'Automated Task 1 - Stage 10';
            newTask1.whatId = opp.Id;
            newTask1.ownerId = opp.OwnerId;
            newTask1.status = 'In Progress';
            newTask1.Priority = 'Normal';
            tasks.add(newTask1);
        }
    }
    
    if (tasks.size() > 0) {
        insert tasks;
    }
}