import frappe

def execute():
    frappe.reload_doc('payroll', 'doctype', 'employee_cost_center')
    frappe.reload_doc('payroll', 'doctype', 'salary_structure_assignment')

    employees = frappe.get_all("Employee", fields=["department", "payroll_cost_center", "name"])

    employee_cost_center = {}
    for d in employees:
        cost_center = d.payroll_cost_center
        if not cost_center and d.department:
            cost_center = frappe.get_cached_value("Department", d.department, "payroll_cost_center")

        if cost_center:
            employee_cost_center.setdefault(d.name, cost_center)
    
    salary_structure_assignments = frappe.get_all("Salary Structure Assignment",
        filters = {"docstatus": ["!=", 2]},
        fields=["name", "employee"])

    for d in salary_structure_assignments:
        cost_center = employee_cost_center.get(d.employee)
        if cost_center:
            assignment = frappe.get_doc("Salary Structure Assignment", d.name)
            if not assignment.get("payroll_cost_centers"):
                assignment.append("payroll_cost_centers", {
                    "cost_center": cost_center,
                    "percentage": 100
                })
                assignment.save()