Accounting: two-way bill creation + mirror pending bills

- bill_should_mirror now includes 'pending', so approval bills appear in
  Payables immediately (still excludes draft/rejected/void/cancelled/denied).
- New reverse-creation path: a bill created natively in the Accounting module
  (external_source NULL, non-auto, non-payment, non-void) now creates a matching
  public.bills row. The accounting row is pre-linked to the new public id so the
  forward sync adopts it (no duplicate mirror); vendor is mapped back to
  public.vendors and the line's GL is carried to expense_account_id.
- Backfill: mirrored existing pending public bills and reverse-created the 8
  eligible native accounting bills. Verified: 0 unlinked native, 0 duplicate
  mirrors, pending bills mirrored.

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

supabase/migrations/20260605010000_two_way_bill_creation_and_pending_mirror.sql

@@ -0,0 +1,153 @@
+-- Make bill creation truly two-way between the app (public.bills / bill_approvals)
+-- and the Accounting platform (accounting.bills), and mirror pending bills.
+--
+--   1. bill_should_mirror now includes 'pending' so approval bills appear in
+--      Payables immediately (still excludes draft/rejected/void/cancelled/denied).
+--   2. A bill created NATIVELY in the Accounting module (external_source IS NULL)
+--      now creates a matching public.bills row. The accounting row is pre-linked
+--      to the new public id so the existing forward sync adopts it (no duplicate),
+--      the vendor is mapped back to public.vendors, and the line's GL is carried.
+--   3. Backfill: mirror existing pending public bills + reverse-create eligible
+--      native accounting bills.
+
+-- ---------------------------------------------------------------------------
+-- 1) Mirror pending bills too.
+-- ---------------------------------------------------------------------------
+create or replace function accounting.bill_should_mirror(_status text)
+returns boolean language sql immutable as $$
+  select coalesce(lower(_status), '') not in
+    ('draft','rejected','void','voided','cancelled','denied');
+$$;
+
+-- ---------------------------------------------------------------------------
+-- 2) Reverse creation: native accounting bill -> public.bills (idempotent-ish;
+--    only acts on unlinked native rows).
+-- ---------------------------------------------------------------------------
+create or replace function accounting.create_public_from_accounting_bill(_acct_id uuid)
+returns uuid
+language plpgsql security definer set search_path to 'public','accounting'
+as $$
+declare
+  ab accounting.bills%rowtype;
+  _assoc uuid;
+  _pub_vendor uuid;
+  _avs text; _avext text; _avname text;
+  _exp uuid;
+  _new_id uuid;
+  _pub_status text;
+begin
+  select * into ab from accounting.bills where id=_acct_id;
+  if not found then return null; end if;
+
+  -- only native, real, non-void bills
+  if ab.external_source is not null then return null; end if;
+  if coalesce(ab.auto_created,false) then return null; end if;
+  if ab.source_payment_id is not null then return null; end if;
+  if ab.status::text = 'void' then return null; end if;
+
+  select association_id into _assoc from accounting.companies where id=ab.company_id;
+  if _assoc is null then return null; end if;
+
+  -- Map the vendor back to a single public.vendors roster (find-or-create).
+  _pub_vendor := null;
+  if ab.vendor_id is not null then
+    select external_source, external_id, name into _avs, _avext, _avname
+      from accounting.vendors where id=ab.vendor_id;
+    if _avs='acmacc_vendor' and nullif(_avext,'') is not null then
+      _pub_vendor := _avext::uuid;
+    end if;
+    if _pub_vendor is null or not exists (select 1 from public.vendors where id=_pub_vendor) then
+      select id into _pub_vendor from public.vendors
+        where (association_id=_assoc or _assoc = any(association_ids))
+          and lower(trim(name))=lower(trim(coalesce(_avname,''))) limit 1;
+      if _pub_vendor is null then
+        insert into public.vendors (name, association_id, is_active)
+        values (coalesce(nullif(_avname,''),'Vendor'), _assoc, true)
+        returning id into _pub_vendor;
+      end if;
+      update accounting.vendors
+         set external_source='acmacc_vendor', external_id=_pub_vendor::text, updated_at=now()
+       where id=ab.vendor_id and nullif(external_id,'') is null;
+    end if;
+  end if;
+
+  -- Carry the first line's GL account if it is a valid public COA id.
+  select account_id into _exp from accounting.bill_items
+    where bill_id=ab.id and account_id is not null limit 1;
+  if _exp is not null and not exists (select 1 from public.chart_of_accounts where id=_exp) then
+    _exp := null;
+  end if;
+
+  _pub_status := case ab.status::text when 'paid' then 'paid' else 'approved' end;
+  _new_id := gen_random_uuid();
+
+  -- Pre-link the accounting row so the forward sync (fired by the insert below)
+  -- updates THIS row on conflict instead of creating a duplicate mirror.
+  update accounting.bills
+     set external_source='acmacc_bill', external_id=_new_id::text, updated_at=now()
+   where id=ab.id;
+
+  insert into public.bills
+    (id, association_id, vendor_id, invoice_number, bill_date, due_date,
+     amount, amount_paid, expense_account_id, description, status, attachment_url, approved_date)
+  values
+    (_new_id, _assoc, _pub_vendor, ab.number, coalesce(ab.issue_date, current_date), ab.due_date,
+     coalesce(ab.total,0), coalesce(ab.paid_amount,0), _exp, ab.notes,
+     _pub_status, ab.attachment_url,
+     case when _pub_status in ('approved','paid') then current_date else null end);
+
+  return _new_id;
+end;
+$$;
+
+create or replace function accounting.tg_accounting_bill_reverse_create()
+returns trigger
+language plpgsql security definer set search_path to 'public','accounting'
+as $$
+begin
+  begin
+    if new.external_source is null
+       and not coalesce(new.auto_created,false)
+       and new.source_payment_id is null
+       and new.status::text <> 'void' then
+      perform accounting.create_public_from_accounting_bill(new.id);
+    end if;
+  exception when others then
+    raise warning 'accounting: reverse bill create failed for %: %', new.id, sqlerrm;
+  end;
+  return new;
+end;
+$$;
+
+drop trigger if exists trg_acct_bill_reverse_create on accounting.bills;
+create trigger trg_acct_bill_reverse_create
+  after insert on accounting.bills
+  for each row execute function accounting.tg_accounting_bill_reverse_create();
+
+-- ---------------------------------------------------------------------------
+-- 3a) Backfill: mirror existing pending public bills into Payables now.
+-- ---------------------------------------------------------------------------
+do $$
+declare r record;
+begin
+  for r in select id from public.bills where lower(coalesce(status,'')) = 'pending' loop
+    perform accounting.sync_public_bill(r.id);
+  end loop;
+end $$;
+
+-- ---------------------------------------------------------------------------
+-- 3b) Backfill: reverse-create eligible native accounting bills.
+-- ---------------------------------------------------------------------------
+do $$
+declare r record;
+begin
+  for r in
+    select id from accounting.bills
+    where external_source is null
+      and not coalesce(auto_created,false)
+      and source_payment_id is null
+      and status::text <> 'void'
+  loop
+    perform accounting.create_public_from_accounting_bill(r.id);
+  end loop;
+end $$;