Add cash management schema and immediate variance alerts

supabase/migrations/0016_shift_assignments.sql

@@ -0,0 +1,78 @@
+-- =====================================================================
+-- Migration 0016: Shift Assignments
+-- Extends open_shift so managers/owners can assign a shift to any employee.
+-- =====================================================================
+
+drop function if exists app.open_shift(uuid, numeric, numeric);
+
+create or replace function app.open_shift(
+  p_till_id     uuid,
+  p_opening_usd numeric,
+  p_opening_lbp numeric,
+  p_assigned_user_id uuid default null
+) returns uuid
+language plpgsql
+security definer
+set search_path = app, public
+as $$
+declare
+  v_shop  uuid;
+  v_shift uuid;
+  v_target_user uuid;
+begin
+  if p_opening_usd is null or p_opening_lbp is null then
+    raise exception 'opening counts are required';
+  end if;
+  if p_opening_usd < 0 or p_opening_lbp < 0 then
+    raise exception 'opening counts must be non-negative';
+  end if;
+
+  select shop_id into v_shop from app.tills where id = p_till_id and is_active;
+  if v_shop is null then
+    raise exception 'till % not found or inactive', p_till_id;
+  end if;
+
+  v_target_user := coalesce(p_assigned_user_id, auth.uid());
+
+  -- Caller must have a role to open.
+  if not app.has_any_role_in_shop(v_shop, array['owner','manager','cashier']::app.business_role[]) then
+    raise exception 'not authorized to open a shift on this till';
+  end if;
+
+  -- If trying to open for someone else, must be owner or manager
+  if v_target_user <> auth.uid() then
+    if not app.has_any_role_in_shop(v_shop, array['owner','manager']::app.business_role[]) then
+      raise exception 'only managers or owners can assign shifts to other users';
+    end if;
+  end if;
+
+  -- Target user must have a role in the shop
+  if not exists (
+    select 1 from app.user_shop_assignments
+    where user_id = v_target_user and shop_id = v_shop
+  ) then
+    raise exception 'target user does not have a role in this shop';
+  end if;
+
+  -- Reject if any non-closed shift exists on this till.
+  if exists (select 1 from app.shifts where till_id = p_till_id and status <> 'closed') then
+    raise exception 'till % already has an active shift; close it first', p_till_id;
+  end if;
+
+  insert into app.shifts(till_id, shop_id, user_id, opened_by, opening_usd, opening_lbp)
+    values (p_till_id, v_shop, v_target_user, auth.uid(), p_opening_usd, p_opening_lbp)
+    returning id into v_shift;
+
+  -- Record the opening float as a cash movement for clean ledgers.
+  insert into app.cash_movements(shift_id, type, currency, amount, note)
+    values (v_shift, 'opening_float', 'USD', p_opening_usd, 'opening float'),
+           (v_shift, 'opening_float', 'LBP', p_opening_lbp, 'opening float');
+
+  perform app.log_auth_event('shift_opened', v_shop, null,
+                             jsonb_build_object('shift_id', v_shift, 'till_id', p_till_id, 'assigned_user_id', v_target_user));
+  return v_shift;
+end;
+$$;
+
+revoke all on function app.open_shift(uuid, numeric, numeric, uuid) from public;
+grant execute on function app.open_shift(uuid, numeric, numeric, uuid) to authenticated;