-- AK-P4a · P4 Files — RLS ROLLOUT ARTIFACT (deferred, NOT in the auto-migration)
-- =============================================================================
-- Companion to R-P2b's prisma/rls/tenant-isolation.sql. The Files tables + enums
-- + indexes + the pg_trgm display-name index ship in the tracked migration
-- prisma/migrations/20260623160000_p4a_files_platform. What lives in THIS file is
-- the Row-Level-Security block, DELIBERATELY kept out of the auto-migration path
-- (same stance as R-P2b): turning RLS on before every access sets the GUC would
-- break the feature, so activation is a coordinated cutover, not a schema diff.
--
-- WHY DEFERRED: enabling RLS + FORCE makes every File query WITHOUT
-- `app.tenant_id` return ZERO rows. Per R-P2b's rule a table may only be
-- RLS-enabled once ALL its accesses set the GUC. The app-level scoping
-- (where: { tenantId }) carries isolation meanwhile.
--
-- CODE-SIDE PRECONDITIONS — DONE (AK-P4a "Teil A", 2026-06-24):
--   1. [x] File web loaders/actions run inside withTenantRLS()
--          (apps/web/app/utils/integrations/fileService.server.ts — all DB ops).
--   2. [x] Worker write-backs set the tenant GUC before file.update/updateMany
--          (jobs/file-preview.ts, jobs/file-scan-status.ts via
--          apps/worker/src/db/tenantRls.ts).
--   Proven by apps/web/app/utils/db/.server/rls-file-isolation.integration.test.ts
--   (7/7 against real Postgres: own-tenant only, 0 cross-tenant, 0 without context,
--   WITH CHECK blocks foreign insert; File + FileEntityLink).
--
-- WHAT REMAINS — "Teil B" = the org-wide P5 RLS cutover (Raffael / R-P2b):
--   a. Ship this block as its own forward-only migration.
--   b. Switch the runtime DB connection to the restricted role `hivegrid_app`
--      (NOSUPERUSER, NOBYPASSRLS); otherwise FORCE is a no-op for a superuser
--      and an empty-read trap for a non-superuser owner. The GRANTs below already
--      cover that role.
--   c. Staging cutover + live cross-tenant 404 verification.
--
-- Forward-only (DoD 28). Inverse SQL as comment per block. Order-dependent DDL is
-- DO-guarded (P3018 protection: reproducible from an empty DB). Idempotent.
-- =============================================================================

-- Row-level security on the four Files tables --------------------------------
-- Pattern: tenant_id = current_setting('app.tenant_id', true). The second
-- argument `true` returns NULL instead of erroring when the GUC is not (yet)
-- set — the policy then matches nothing (fail-closed), and server-side scoping
-- stays the hard path until the cutover.
--
-- Inverse per table:
--   REVOKE SELECT, INSERT, UPDATE, DELETE ON "<tbl>" FROM hivegrid_app;
--   DROP POLICY IF EXISTS "<tbl>_tenant_isolation" ON "<tbl>";
--   ALTER TABLE "<tbl>" NO FORCE ROW LEVEL SECURITY;
--   ALTER TABLE "<tbl>" DISABLE ROW LEVEL SECURITY;

DO $$
DECLARE
  tbl text;
BEGIN
  FOREACH tbl IN ARRAY ARRAY['File', 'FileEntityLink', 'FileUpload', 'FileUploadChunk']
  LOOP
    EXECUTE format('ALTER TABLE %I ENABLE ROW LEVEL SECURITY;', tbl);
    -- FORCE so the table owner is subject to the policies too (otherwise the
    -- owner silently bypasses RLS).
    EXECUTE format('ALTER TABLE %I FORCE ROW LEVEL SECURITY;', tbl);

    IF NOT EXISTS (
      SELECT 1 FROM pg_policies
      WHERE schemaname = current_schema()
        AND tablename = tbl
        AND policyname = tbl || '_tenant_isolation'
    ) THEN
      EXECUTE format(
        'CREATE POLICY %I ON %I USING ("tenantId" = current_setting(''app.tenant_id'', true)) WITH CHECK ("tenantId" = current_setting(''app.tenant_id'', true));',
        tbl || '_tenant_isolation', tbl
      );
    END IF;

    -- The restricted app role (R-P2b's hivegrid_app, NOBYPASSRLS) needs table
    -- privileges to reach the rows the policy then filters. Mirrors the GRANT in
    -- prisma/rls/tenant-isolation.sql for "TenantUser".
    EXECUTE format('GRANT SELECT, INSERT, UPDATE, DELETE ON %I TO hivegrid_app;', tbl);
  END LOOP;
END
$$;

-- =============================================================================
-- Verify green before the cutover migration (AGENTS.md §Prisma):
--   pnpm prisma validate
--   pnpm prisma migrate status
--   CI: `prisma migrate deploy` against an EMPTY DB (reproducible from scratch,
--       no order dependency on Raffael's P2 migration).
-- Coordination: align ordering with R-P2b — P2 ships withTenantRLS()
-- (SET LOCAL app.tenant_id); without a tenant context the policies match nothing
-- (no data leak, just empty results) until the runtime role is hivegrid_app.
-- =============================================================================