-- Create leave_balances table
CREATE TABLE public.leave_balances (
    id UUID DEFAULT gen_random_uuid() PRIMARY KEY,
    employee_id UUID REFERENCES public.employees(id) ON DELETE CASCADE UNIQUE NOT NULL,
    total_days DECIMAL(5,2) DEFAULT 0 NOT NULL, -- Total accrued days
    used_days DECIMAL(5,2) DEFAULT 0 NOT NULL,  -- Successfully used days
    pending_days DECIMAL(5,2) DEFAULT 0 NOT NULL, -- Days currently in pending status
    remaining_days DECIMAL(5,2) GENERATED ALWAYS AS (total_days - used_days) STORED,
    created_at TIMESTAMP WITH TIME ZONE DEFAULT timezone('utc'::text, now()) NOT NULL,
    updated_at TIMESTAMP WITH TIME ZONE DEFAULT timezone('utc'::text, now()) NOT NULL
);

-- RLS for leave_balances
ALTER TABLE public.leave_balances ENABLE ROW LEVEL SECURITY;

CREATE POLICY "Users can view their own leave balance"
ON public.leave_balances
FOR SELECT TO authenticated
USING (
    employee_id IN (
        SELECT id FROM public.employees WHERE user_id = auth.uid()
    )
);

-- Trigger to create a balance record when a new employee is added
CREATE OR REPLACE FUNCTION public.handle_new_employee_balance()
RETURNS TRIGGER AS $$
BEGIN
  INSERT INTO public.leave_balances (employee_id, total_days)
  VALUES (NEW.id, 14); -- Defaulting to 14 days per year
  RETURN NEW;
END;
$$ LANGUAGE plpgsql SECURITY DEFINER;

CREATE TRIGGER on_employee_created
  AFTER INSERT ON public.employees
  FOR EACH ROW EXECUTE PROCEDURE public.handle_new_employee_balance();

-- Trigger updated_at for leave_balances
CREATE TRIGGER update_leave_balances_modtime BEFORE UPDATE ON public.leave_balances FOR EACH ROW EXECUTE PROCEDURE update_updated_at_column();