/**
 * Downgrades the database schema to a target version.
 *
 *   npm run downgrade -- <targetVersion>
 *
 * Provider from env: DB_PROVIDER=sqlite (+ SQLITE_PATH) or mssql (MSSQL_*, default).
 * Runs src/providers/<provider>/downgrade/<from>_to_<to>.js one step at a time,
 * each in its own transaction. Not part of the server — the server only upgrades.
 * Note: starting a server whose code knows a higher version upgrades again.
 */
import 'dotenv/config';

const [rawTarget] = process.argv.slice(2);
const target = Number(rawTarget);
if (!rawTarget || !Number.isInteger(target) || target < 1) {
  console.error('Usage: npm run downgrade -- <targetVersion>');
  process.exit(1);
}

const providerName = process.env.DB_PROVIDER || (process.env.SQLITE_PATH ? 'sqlite' : 'mssql');
let provider;

if (providerName === 'sqlite' || providerName === 'better-sqlite3') {
  if (!process.env.SQLITE_PATH) {
    console.error('SQLITE_PATH is required for DB_PROVIDER=sqlite');
    process.exit(1);
  }
  const { BetterSqlite3Provider } = await import('../src/providers/sqlite3/index.js');
  provider = new BetterSqlite3Provider({ filename: process.env.SQLITE_PATH, fileMustExist: true });
} else if (providerName === 'mssql') {
  const { MssqlProvider } = await import('../src/providers/mssql/index.js');
  provider = new MssqlProvider({
    server: process.env.MSSQL_SERVER,
    database: process.env.MSSQL_DATABASE,
    user: process.env.MSSQL_USER,
    password: process.env.MSSQL_PASSWORD,
    options: { encrypt: false, trustServerCertificate: true },
  });
} else {
  console.error(`Unknown DB_PROVIDER: ${providerName}`);
  process.exit(1);
}

try {
  const before = await provider.getSchemaVersion();
  const steps = await provider.downgradeSchema(target);
  console.log(`Schema ${providerName}: ${before} -> ${target} (${steps} step(s))`);
} catch (err) {
  console.error(`Downgrade failed: ${err.message}`);
  process.exitCode = 1;
} finally {
  await provider.close();
}