fix repeatable migrations

db/routines/R__004_fn_battery_cycle_audit.sql

@@ -0,0 +1,51 @@
+-- audit „ekvivalent plných cyklů“ z 1min telemetrie battery_power_w (bez LP constraintu)
+
+create or replace function ems.fn_battery_cycle_audit(
+  p_site_id int,
+  p_from timestamptz,
+  p_to timestamptz
+)
+returns jsonb
+language plpgsql
+stable
+as $fn$
+declare
+  v_usable numeric;
+  v_throughput_wh numeric;
+  v_full_cycles numeric;
+begin
+  select coalesce(sum(ab.usable_capacity_wh), 0)::numeric
+  into v_usable
+  from ems.asset_battery ab
+  where ab.site_id = p_site_id;
+
+  if v_usable is null or v_usable <= 0 then
+    return jsonb_build_object('error', 'no_battery', 'full_cycles', 0);
+  end if;
+
+  select coalesce(
+    sum(abs(ti.battery_power_w::numeric) / 60.0),
+    0
+  )
+  into v_throughput_wh
+  from ems.telemetry_inverter ti
+  where ti.site_id = p_site_id
+    and ti.measured_at >= p_from
+    and ti.measured_at < p_to
+    and ti.battery_power_w is not null;
+
+  v_full_cycles := case
+    when v_usable * 2 > 0 then v_throughput_wh / (v_usable * 2)
+    else 0
+  end;
+
+  return jsonb_build_object(
+    'full_cycles', round(v_full_cycles::numeric, 4),
+    'throughput_wh', round(v_throughput_wh, 2),
+    'throughput_vs_usable_ratio', round((v_throughput_wh / nullif(v_usable, 0))::numeric, 4),
+    'usable_capacity_wh', v_usable,
+    'window_start', p_from,
+    'window_end', p_to
+  );
+end;
+$fn$;