import { db } from 'officerdb/db';
import { sql } from 'drizzle-orm';

// One-time database migration for the 2026-08-15 rename: `role_capabilities` → `role_permissions`.
//
// ── Why this is a script and not `bun db:push` ──
//
// drizzle-kit does not understand renames. It sees a table gone and a table added, and with `--force` it
// resolves that by DROPPING and CREATING — which would delete every grant on the server and silently
// reduce every member to core-only access. There is no prompt to catch it, because `--force` exists to
// answer prompts.
//
// So the database is renamed by hand, first, and `db:push` afterwards should report "No changes
// detected" — which is the proof that the two now agree.
//
// ── Safe to run twice, and safe to run on a server that never had the old names ──
//
// Every step checks first. A machine already migrated prints "already done" and touches nothing; a fresh
// install that never had `role_capabilities` is not an error either. That matters because this will be
// run by hand, on more than one machine, possibly twice on the same one.
//
// Run it BEFORE restarting the platform on the new code. The old code cannot read `role_permissions` and
// the new code cannot read `role_capabilities`, so the window between them is the outage — keep it short:
//
//     pm2 stop officer && bun run scripts/rename-capabilities-to-permissions.ts && bun db:push && pm2 restart all
//
// If it goes wrong: the OWNER is unaffected either way. `getEffectivePermissions` short-circuits on
// `role === 'Super Admin'` before it reads the table at all, so the account that can fix things can
// always sign in. Non-owners degrade to core-only until the rename completes.

const q = async (statement: ReturnType<typeof sql>): Promise<Record<string, unknown>[]> => {
  const result = (await db.execute(statement)) as unknown as { rows?: Record<string, unknown>[] };
  return result.rows ?? (result as unknown as Record<string, unknown>[]);
};

const tableExists = async (name: string): Promise<boolean> =>
  ((await q(sql`select to_regclass(${`public.${name}`}) as t`))[0]?.t ?? null) !== null;

const columnExists = async (table: string, column: string): Promise<boolean> =>
  (await q(sql`select 1 from information_schema.columns where table_name = ${table} and column_name = ${column}`))
    .length > 0;

const relationExists = async (name: string): Promise<boolean> =>
  ((await q(sql`select to_regclass(${`public.${name}`}) as t`))[0]?.t ?? null) !== null;

const constraintExists = async (table: string, name: string): Promise<boolean> =>
  (await q(sql`select 1 from pg_constraint where conname = ${name} and conrelid = to_regclass(${`public.${table}`})`))
    .length > 0;

async function main() {
  const hasOld = await tableExists('role_capabilities');
  const hasNew = await tableExists('role_permissions');

  if (!hasOld && !hasNew) {
    console.log('  Neither table exists — nothing to migrate. `bun db:push` will create role_permissions.');
    return;
  }
  if (!hasOld && hasNew) {
    console.log('  Already migrated: role_permissions exists and role_capabilities does not. Nothing to do.');
    const rows = await q(sql`select count(*)::int as n from role_permissions`);
    console.log(`  Grants on this server: ${rows[0]?.n}`);
    return;
  }
  if (hasOld && hasNew) {
    console.error('  BOTH tables exist. That is not a state this script can resolve safely — stopping.');
    console.error('  Look at both by hand and decide which holds the real grants.');
    process.exitCode = 1;
    return;
  }

  // Count before, so the transaction can be checked against something rather than trusted.
  const before = Number((await q(sql`select count(*)::int as n from role_capabilities`))[0]?.n ?? 0);
  console.log(`  Found role_capabilities with ${before} grant(s). Renaming…`);

  // EVERY existence check happens HERE, before the transaction, and against the OLD names.
  //
  // They used to be inside it, and that was a real bug caught by testing against a copy of a production
  // database rather than by reading: the helpers run on the pool, not on `tx`, so inside the transaction
  // they cannot see its uncommitted rename. `columnExists('role_permissions', 'capability')` answered
  // false — the table did not exist yet as far as that connection was concerned — so the column rename
  // was silently skipped and the migration produced a `role_permissions` table with a `capability`
  // column. Half migrated, and the failure only surfaced on the next query.
  const hasOldColumn = await columnExists('role_capabilities', 'capability');
  const hasOldUnique = await relationExists('uq_role_capabilities_role_capability');
  const hasOldPkey = await relationExists('role_capabilities_pkey');
  const oldChecks: string[] = [];
  for (const suffix of ['role', 'level', 'not_owner']) {
    if (await constraintExists('role_capabilities', `ck_role_capabilities_${suffix}`)) oldChecks.push(suffix);
  }

  // One transaction. A partial rename leaves drizzle-kit seeing a table it half-recognises, and the next
  // `push --force` would resolve that difference by dropping it.
  await db.transaction(async (tx) => {
    await tx.execute(sql`ALTER TABLE role_capabilities RENAME TO role_permissions`);
    if (hasOldColumn) await tx.execute(sql`ALTER TABLE role_permissions RENAME COLUMN capability TO permission`);
    // Index and constraint names are renamed too. drizzle-kit diffs on the NAME, so leaving them would
    // make every future push want to drop and recreate them.
    if (hasOldUnique) {
      await tx.execute(
        sql`ALTER INDEX uq_role_capabilities_role_capability RENAME TO uq_role_permissions_role_permission`,
      );
    }
    if (hasOldPkey) await tx.execute(sql`ALTER INDEX role_capabilities_pkey RENAME TO role_permissions_pkey`);
    for (const suffix of oldChecks) {
      await tx.execute(
        sql.raw(
          `ALTER TABLE role_permissions RENAME CONSTRAINT ck_role_capabilities_${suffix} TO ck_role_permissions_${suffix}`,
        ),
      );
    }
  });

  const after = Number((await q(sql`select count(*)::int as n from role_permissions`))[0]?.n ?? 0);
  console.log(`  Renamed. Grants after: ${after}${after === before ? ' — unchanged, as expected.' : ' — MISMATCH!'}`);
  if (after !== before) process.exitCode = 1;

  const rows = await q(sql`select role, permission, level from role_permissions order by role, permission`);
  for (const r of rows) console.log(`    ${r.role} → ${r.permission} (${r.level})`);

  console.log('\n  Next: `bun db:push` (expect "No changes detected"), then `pm2 restart all`.');
}

await main();
process.exit(process.exitCode ?? 0);