Accounting: back-sync bill paid status to bill_approvals on INSERT

trg_acct_bill_paid_back was AFTER UPDATE only, so bills mirrored into
accounting already-paid never triggered the back-sync that flips
public.bills + bill_approvals to 'paid'. Fire the trigger on INSERT too
and reconcile existing already-paid mirrored bills. Also backfill
invoice-track approvals that uniquely match a bill (bill_id was null).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

supabase/migrations/20260604120000_accounting_bill_paid_back_sync_on_insert.sql

@@ -0,0 +1,87 @@
+-- Fix: bill_approvals not reflecting "paid" when an accounting.bills row is
+-- created already-paid.
+--
+-- Background (see 20260601140000_accounting_sync_bills.sql):
+--   accounting.sync_accounting_bill_paid() flips public.bills + public.bill_approvals
+--   to 'paid' once the matching accounting bill is fully paid. It runs from the
+--   trigger trg_acct_bill_paid_back, which was AFTER UPDATE only.
+--
+--   When a public bill is ALREADY paid at the moment it first mirrors into
+--   accounting, the forward sync INSERTs the accounting row at status='paid'
+--   with paid_amount set. With no subsequent UPDATE to paid_amount/total, the
+--   UPDATE-only trigger never fired, so the bill's approvals were left stuck at
+--   'approved'/'pending'. This widens the back-sync to also run on INSERT.
+
+-- ---------------------------------------------------------------------------
+-- Back-sync trigger: now fires on INSERT as well as UPDATE.
+-- ---------------------------------------------------------------------------
+create or replace function accounting.tg_accounting_bill_paid_sync()
+returns trigger
+language plpgsql security definer set search_path to 'public','accounting'
+as $$
+begin
+  begin
+    if tg_op = 'INSERT' then
+      -- a bill mirrored in already-paid never produces an UPDATE; handle it here
+      perform accounting.sync_accounting_bill_paid(new.id);
+    -- on UPDATE only act when the paid position actually changed, to avoid loops
+    elsif old.paid_amount is distinct from new.paid_amount
+       or old.total is distinct from new.total then
+      perform accounting.sync_accounting_bill_paid(new.id);
+    end if;
+  exception when others then
+    raise warning 'accounting: accounting bill paid sync failed for %: %', new.id, sqlerrm;
+  end;
+  return new;
+end;
+$$;
+
+drop trigger if exists trg_acct_bill_paid_back on accounting.bills;
+create trigger trg_acct_bill_paid_back
+  after insert or update on accounting.bills
+  for each row execute function accounting.tg_accounting_bill_paid_sync();
+
+-- ---------------------------------------------------------------------------
+-- One-time reconciliation: back-sync any accounting bills that are already
+-- fully paid but whose linked public bill / approvals were never updated
+-- (the rows that fell into the INSERT gap above).
+-- ---------------------------------------------------------------------------
+do $$
+declare _id uuid;
+begin
+  for _id in
+    select id from accounting.bills
+    where external_source = 'acmacc_bill' and external_id is not null
+      and coalesce(paid_amount,0) >= coalesce(total,0) and coalesce(total,0) > 0
+  loop
+    perform accounting.sync_accounting_bill_paid(_id);
+  end loop;
+end $$;
+
+-- ---------------------------------------------------------------------------
+-- Backfill orphaned, invoice-track approvals (bill_id IS NULL) that were
+-- created via the invoice flow and never linked to a public.bills row.
+-- Only link when exactly one matching bill exists for the same association,
+-- invoice number and amount; adopt that bill's status when it is paid.
+-- ---------------------------------------------------------------------------
+update public.bill_approvals ba
+set bill_id = m.bill_id,
+    status  = case when m.bill_status = 'paid' then 'paid' else ba.status end,
+    updated_at = now()
+from (
+  select i.id as invoice_id, b.id as bill_id, b.status as bill_status
+  from public.invoices i
+  join public.bills b
+    on b.association_id = i.association_id
+   and b.amount = i.amount
+   and b.invoice_number is not distinct from i.invoice_number
+  group by i.id, b.id, b.status
+  having (
+    select count(*) from public.bills b2
+    where b2.association_id = i.association_id
+      and b2.amount = i.amount
+      and b2.invoice_number is not distinct from i.invoice_number
+  ) = 1
+) m
+where ba.bill_id is null
+  and ba.invoice_id = m.invoice_id;