-- Add unit_id to payment_plans
ALTER TABLE public.payment_plans ADD COLUMN IF NOT EXISTS unit_id UUID REFERENCES public.units(id);

-- Create installments table to track individual payments
CREATE TABLE public.payment_plan_installments (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  payment_plan_id UUID NOT NULL REFERENCES public.payment_plans(id) ON DELETE CASCADE,
  installment_number INT NOT NULL,
  due_date DATE NOT NULL,
  amount_due NUMERIC NOT NULL DEFAULT 0,
  amount_paid NUMERIC NOT NULL DEFAULT 0,
  paid_date DATE,
  status TEXT NOT NULL DEFAULT 'pending',
  notes TEXT,
  created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
  updated_at TIMESTAMPTZ NOT NULL DEFAULT now()
);

ALTER TABLE public.payment_plan_installments ENABLE ROW LEVEL SECURITY;

CREATE POLICY "Staff can manage installments"
ON public.payment_plan_installments
FOR ALL TO authenticated
USING (
  has_role(auth.uid(), 'admin'::app_role) OR
  has_role(auth.uid(), 'manager'::app_role) OR
  has_role(auth.uid(), 'employee'::app_role)
)
WITH CHECK (
  has_role(auth.uid(), 'admin'::app_role) OR
  has_role(auth.uid(), 'manager'::app_role) OR
  has_role(auth.uid(), 'employee'::app_role)
);